Do you need to Balance your engine??? Will it survive if you don’t???
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- เผยแพร่เมื่อ 3 ก.ค. 2024
- Will Casey’s budget build 350 SBC
Do you need to balance your engine?
Watch and find out. For anyone watching that is building a small block Chevy, I strongly recommend buying @DavidVizard ‘a book Max- Performance Small Block Chevy’s on a Budget. - ยานยนต์และพาหนะ
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Machinist for 40 years 12 years Automotive the rest Aerospace prototype but built lots of race motors I truly believe in balancing and Blueprinting in the block especially in a Chevrolet just for example typically the old 350 327 Etc were about anywhere from 5 to 1700 thousands of an inch in duct kites different from left to right just for starters balancing extends the life of a motor greatly harmonics due to vibration are the most destructive power on Earth also helps motor rev higher RPMs and create better horsepower and Blueprinting brings it all together
I built my first engine when i was 17 back in the mid 80s .i only had the "how to rebuild a sbc " book to learn from. The motor lasted 13 years over 100k miles , in 4 different vehicles and made thousands of passes down the track. It was not balanced it was a.30 over 355 stock crank trw forged flat tops and resized rods
Thanks for the confirmation Biden. AG
In 71 I built nearly the same engine except it was a steel crank 327 with the 11.25 pop ups, Dontov 30-30 solid cam, Edelbrock 2 x 4 Carter afb, and Mallory double life Dist., Ran really good with that clacking when starting from rocker arms In a 55 Chevy with a (lucky me) m-22 rock crusher. First time I drove it was smooth as glass. Just loved that whining Transmission. Got it to idle around 1100 RPM. First time I really got down on it I was surprised when my head hit the roof. Worst wheel hop I have ever felt. Traction bars fixed that. Tore up three 55-57 Chevy rear ends and 3 clutch center hubs. Better Clutch and rear from 69 GTO 10 bolt Posi. Fit right in with little cutting and welding , emergency brakes and hydraulic lines hooked right up. Car would then tote the front wheel about three car lengths. Don't ever ruin a 55 two door hardtop in Coral and Gray doing this to it. Had to cut rear fender to accommodate some really wide Micky Thompson tires and Anson Wheels. But life went on and it's gone many years go. OH Yea I changed gears at 7000 rpm and this engine was not Balanced. And withstood 100's of over rpm shifts. Engine was still running great when it was sold.
Thank you for the video
David Vizard is a genious ,
always learning
Keep 'em coming !!!
Thanks, will do!
Thanks for sharing. I will be refreshing a LQ4 6.0 soon. I have been watching many videos to see what I’m about to get myself into. compared to 30 years ago, the parts are amazing.
Good luck with your LQ4. They are very different but the critical things like clearances are still the same. AG
Excellent video, thanks!
Glad you liked it! AG
Great video! thanks!
Glad you liked it! AG
Love the “straight edge..” you used at 3:48 in the video! I knew you’d put it to good use 😉 I also “eye spy” something that I’m very interested in, glowing like a pumpkin in the background! Great job answering people’s questions/comments and referencing back to David’s book on said subjects. Will has his 350 in good hands and will love what you’re doing to it!
Thanks Roland, I will demonstrate the slide rule in a future video, cool gift, thanks. AG
Great info thanks for sharing
Thanks for watching! AG
I like this guy's take on things and his style
Nice compliment, thanks Paul. AG
People have been told they must balance as well as many other things so much that they believe it as Gospel.
Car guys in the early decades of hot rodding knew not everything had to be done & proved it in real life. Not everything one has read or been told for decades holds water in every situation. Mr Gold brings a lifetime of real world experience to his viewers & it’s a breath of fresh air compared to the “must do without question” mentality people have come to believe. Thank You Mr Gold!
Wow, what a nice compliment and endorsement. Thanks Hotrod! AG
Great job Mr. Gold!!!!
Thank you kindly Eric AG
Stumbled across your channel, been building engines for over 50 years watching you I’ve already learned a few things. That’s great and what all of us that do this type of work are looking for, knowledge. You got me boss, I’m a subscriber and I love your channel. You were talking about Mr Vizard, I find he is extremely knowledgeable but boring, you Sir are actually a joy to listen to.
What a nice compliment, thank you Charger for watching, subscribing and commenting. More to come. AG
Great video AG
Thanks Larry. AG
Excellent approach to this rebuild. The owner should be super happy when the car is back together. It will definitely run better than when new.
That's the plan! Thanks. AG
@4speed3pedals - you are correct! I am VERY happy with the progress! 🙂
I have that book, along with the one about how to build horsepower, his cylinder head book, and his intake and carburetor book, plus a few others. They are worth every penny.
For sure, glad I had an opportunity to feature it.AG
Balancing is money well spent even on a budget build. I light clean up skim of the deck of the block is a very good idea. Machinists can stop short of the engine serial number when decking blocks. All the best with the build 👍🇦🇺
Thanks for the tips! AG
great info ..like the channel had to sub ...... I agree with what you are saying about semi-stock (budget) engines using parts that are within a few grams ... of the original setup... from what I see for the intended use where you are not seeing crazy high rpms for extended times this should last for years and be fun to drive ....
Thanks for subscribing Maldo and for you comments. AG
Allan, concerning decking the block. If you find the right machine shop you should be able to get then to stop the cut just short of the serial number pad. Finding or ordering the required piston CD is the best option provided the deck is flat, square and no scratches or rust pits.
You are correct on the balance issue, depends on application. Gas pressure differences in the cylinder can cause vibrations for the really anally retentive. Cylinder head volumes and differnces in air flow can contribute to this.
Thanks Dale. AG
In regards to balancing, so long as the replacement components are within a few grams (calculating bobweights are a bit more complicated that weighing the entire assembly, but in this case the rod small end and big ends will be very close to stock considering they are both I beam rods) the crank has no knowledge of what's imparting the force on it. (assuming it was reasonably balanced to begin with, and the Chev small blocks are quite good from the factory)
What will show up for the end user if it's too far out of spec, is an annoying shake typically between 2000 and 3000 RPM, right where a street vehicle spends 90% of it's life.
As a side not, I just rebalanced a Gen III Hemi stroker crank to work with 70 gram lighter pistons, it required a correction of under 20 grams per end in the crankshaft counterweights.
Thanks Yaarda. AG
I saw a 50s Jag. awesome car, with a replacement engine in it. The original was pulled years ago. My friend found a rod that weighed 60 grams more than the others. It now wears its original smooth running engine.
Thx for bringing us along for another superb engine build.....Don't think Circlip & SpiroLock Retainers are mutually Substitutable as Circlips are intended for Rounded cross section piston Groove shape compared to SpiroLocks designed for straight Rectangular cut piston retainer Groove......Builders have probably mixed Matched them in Actual build Applications with no problems but I wouldn't do it......
Thanks Tom, we will use the clips that Sealed Power provides. AG
If you're going to change pistons and they don't weigh the same you might want to rebalance?
It can be as easy as removing a little weight from the new pistons if they're a bit heavier. If they're lighter it will need to be spin balanced. At this point you might as well spend the time polishing the beams, shot peening and weight matching the rods. Might as well replace the bolts with ARP and recon the rods as well.
This way if he has a weak moment and lets someone borrow the car, when they tach it up to 6,500 RPM, the thing will stay together. An ounce of prevention is worth more than a ton of cure.😎👍
Thanks for your comments Itseither. AG
I have all od David's books.👍👍👍
I have built both balanced and un-balanced engines.
At 6000rpm or above, I can hear the difference, as the engine for some reason sounds smoother, and like it likes the high rpm?
When trying to run an un-balanced engine up to or past 6000rpm, the engine sounds like it is struggling to get there a little.
Balancing is cheap.
Last engine I build was a SBC Dart 434ci, with an Eagle rotating assy. Think they are balanced to 2gr. I get my rotating assy. balanced to .5gr.
I cant argue with anyone on this, but know that an un-balanced engine vibrates, from building industrial engines with counter balancers. You get the balancers out of time, or remove them, and it really rocks the boat.
Thanks for sharing your knowledge and experience GFugate. AG
I forget about the numbers at the front of the block on the chevys. I'm used to working with ford FE & 385 series engines. They don't have such numbers on the deck surface. I agree .050 quench is ok. I run a .045 quench on my 390. But somthing I wasn't thinking of at first though, if u are using Cometic head gaskets, they require a 50 RA finish. U might want to skim it for the finish surface? On my 390 I balanced the pistons & rods myself & I took a piston & rod from what used to run on the crank I was using & figured the bobweight so I knew what it had run with, then tried to match my new pistons & rods to the same bobweight, but I did not spin balance the crank. It runs great!!!
Thanks Jesse. AG
As an engineer in piston machines, compressors to be precise, I can simplify the matter a little; there is no such thing as a balanced piston engine. Actually... that doesn't simplify anything now that I think about it, does it? 😁
So what do I mean by this? Well let's look at the rule of thumb for balancing engines (and it really is a rule of thumb, because with offset cylinders and detailed calculations of the dynamic forces you can do a little bit better, but I digress), is to take half of the translating/reciprocating mass (piston and top half of the connecting rod) and the full rotating mass together to come up with the bobweight mass. The bobweight are affixed to each of the crankpins to simulate the assembled engine on a balancer. Some mass is added or removed on each end of the crank and now the thing is balanced, right? Wrong. It's only balanced at 4 points during the crankshaft rotation; roughly (not exactly due to conrod angularity) 45, 135, 225 and 315 degrees.
Why is this? Because in reality the balance varies as the pistons go up and down. When the conrod is at maximum sideways deflection, the piston (almost) halfway down the bore, the mass of the translating components is felt 100% by the crankshaft as if it were rotating mass, because it acts on exactly the crank radius (half the stroke). When the rod is centered (TDC, BDC) the reciprocating mass isn't felt by the crankshaft at all, at least not in terms of balance. This is why the rule of thumb is 1/2 of the reciprocating mass. It's merely the average of the varying imbalance. The best you can do (before getting into complex dynamic analysis of the differences between the 4 strokes) is to just split the difference and follow the rule of thumb.
Now that in and of itself doesn't mean you shouldn't "balance" your engine, but the automotive industry and engine building aftermarket tend to "balance" crankshafts to a much greater degree than necessary. There are various standards to which rotating assemblies can and should be balanced. The standards often used by high performance engine builders are the level of 20-50K RPM turbine engine assemblies, which is about an order of magnitude stricter than necessary for car engines, which turn 5-8K RPM, for the most part. The standards of production tolerances of modern engine components is such that the "balancing" is already done in the design of the parts, and the rest-imbalance as a result of production tolerances is small enough that rebalancing is not necessary unless you use parts that weren't designed to go together as such. So if you're building your 383 stroker from a quality kit, you're good.
Having said that, if you need to balance your parts anyway, given the fact that engine builders are already set up to balance to an order of magnitude (or two) more precision than necessary, there's no real reason not to take advantage of it. While under full load the combustion forces throw the balance off anyway (hence you can do better with offset cylinders and slightly different mass bobweights with careful analysis), you will get a nice smooth idle. Considering the fact the engine in a car tends not to be at full load all the time, this is a somewhat nice thing to have, but it won't increase the service life of the engine by anywhere near that same order of magnitude (let alone two).
A much better thing to do is to use polymer composite bearings. No, not the polymer coated ones. Use the actual composite ones, where a sintered metal (usually bronze) is impregnated with a polymer (usually teflon, although PFAS restrictions may see that change to PEEK or other alternatives over the coming years). This structurally binds the self-lubrication polymer to the steel backing of the bearing shell. These bearings ARE an order of magnitude better than ANY metal top-layer bearing. They are incredible at handling momentary lack of lubrication (i.e. starting, stopping, and high-G-oil-starved-cornering). We've done a test on one of our compressor where we started loading pistons with compressed nitrogen (imagine peak cylinder pressure, but CONTINUOUS during the ENTIRE rotation, so WILDLY worse load than normal). In this machine we had several metal bearings and some of the polymer ones. We ran at 1500 RPM (our compressors resemble large diesel engines in size and proportions) and increased the continuous cylinder pressure as we went. The first tri-metal bearings started failing at 25 atmospheres, after about 15 minutes. Did I mention we closed off the lubrication system entirely? Since this effectively "destroyed" the machine, we disassembled it. The cheap aftermarket bearings were entirely destroyed, worn bearing-wide grooves into the "crank" (it didn't have crank pins, it was entirely concentric since we got the load from outside pressure), the white metal layer melted and in general it was a mess. Our own high quality OE tri-metal bearings fared better... but not much. Now, to be honest, I was very impressed with a 25 bar load for 15 minutes without any lubrication short of oiling the parts during assembly, but the metal-polymer composite bearings were in a leage of their own. You could barely see they ran at all. Brand new. In fact, the polymer running layer looked somwhat smoother than before.
If you build an engine, always always always always use metal-polymer composite bearings. For the cam too. Always. Also use the thinnest PVD-coated piston rings you can fit for similar reasons, by the way. And have the cylinder bores plateau honed professionally. The combination will last forever. Don't fuck around with ball hones.
Also, I can't confirm this last bit from experience but apparently conical valve springs are the bees knees too. The science behind them is sound, at the very least, and I know enough about harmonics to tell you that your entire valvetrain will thank you for any way in which you can reduce them. Definitely consider them over twin springs and even beehives. And this is a great segue to talk about Mr. Vizard, who was a wizard back in his day. But I feel, from reading his material, that he hasn't gone with the times much. He;s a great source of information for anything old school. But if you want the best modern technology can offer, I think it's best to listen to the Billy Godbolds and Ben Straders of the world. They might as well be Vizard's spiritual successors.
Thanks Shiel, lots of great information from your experience. Thanks for taking the time. AG
Easy to tell you are an engineer! AG
I’ve always wondered how the position of the piston in the bore affected things. The mass of the crankshaft counterweight never changes but the acceleration of the piston and connecting rod changes significantly. This is further complicated when you have two sets on one bearing journal. I haven’t sat down and really tried to work out the math of it with my limited physics skills but I was always like: this doesn’t sound right. Your comment put into words what I had already been thinking. And thanks for the heads up on the polymerized bearings.
@@michaeloboyle8798 Happy to help
Your part right.
The dowls are a good idea, you can only put them on one side to line up the intake to the head and also lay the gasket on the head first and line up to the ports and make a mark on each end of the gasket to make sure it stays in place when you install the intake and if it slips you van move the gasket back to where you have it marked...
Thanks Leonard. AG
I was always under the impression that all vette 350s had 4-bolt mains and forged cranks...then I looked up the specs of the 1981 L81s. What on oinker!
Thanks for the info. AG
Looks like you've got another Quality high Performance Smooth running engine build going there !! ....Something you didn't mention (Or I missed it) is All new Lifters should be Checked & Verified for Correct lifter face Convex crown geometry & Camshaft lobe Taper as Either of these can cause Inconsistent lifter Rotation & early cam/lifter..... Failure.....
thanks Tom
Balancing an engine and considering all the internal forces in an engine has a lot of mystery to it, all we can do is what we believe is right. Last 383 I did we bought a scat kit pre-balanced and we used the rod bearings that came with the kit for mockup and after spinning the crank a million times, grinding and clearancing, the bearings didn't look as good as they did when we put them in so I had another set of chamfered bearings I was gonna put in and I thought "I might should weigh these" and if my memory is correct one half shell was 4 grams different by weight, just one shell, that's 8 grams per rod. How many guys have cranks turned that don't balance? Just think of the weight difference between the steel or iron being turned off the crank vs the lighter bearing and babbitt material. Then you have all these folks mixing gen 3 and 4 rotating assemblies that claim no vibration at all, there's a lot of weight bias there. I feel a little different about it than I use to, I'm not as picky. But still if I'm building an all out race engine, whether it needs it or not whether it's right or not, I strive for it to be the best it can be and until advanced technology or better knowledge in the future has a better understanding or a better way I'm gonna stick with old tried and maybe true method we're using today because atm it's believed to be the correct way.
Thanks Steve. AG
When you are playing with a stroker engine, this is not Factory, it should always be balanced. Most of these Strokers come from China and some are way out of balance.
@@mylanmiller9656 oh yea I agree and I feel that goes without saying, aftermarket rotating assemblies that are pieced together are most definitely in left field. My comment was aimed more to the oem or balanced kits that have cranks turned later down the road, or just refreshed with different style bearings or ring packs or even rebuilder claimer pistons with no re-balance. There's a big weight difference in bi-metal vs tri-metal bearings, much less a crank that has been turned 020 or 030 vs a 020 or 030 bearing shell. I'm still blown away folks throwing gen 4 rods on gen 3 cranks, gen 4 rods are like 50grams heavier. I always thought if that weight wasn't countered you would feel it.
I really enjoyed Smokies book many years ago!
These guys were pioneers! Thanks Pro. AG
One more note I learned a lot from Smoky eunuch who is one bad dude Top Line engine builder and much research development and prototypes were built in his shop and tested he's one of the best in the world still in my opinion
What you call 'Circlips' are really 'Spirolox'. A 'Circlip' is just an internal 'E-clip'. Totally different. A Circlip has 2 holes for a pair or expansion pliers. Spirolox do not. The old method of wrist pin clips was either single or double Circlips with the flat faces towards each other for double installations. Whatever clips you use is dependent upon the piston clip groove machining. The clips need to be close enough to the pin to prevent hammering of the clips which will eventually cause failure. Yes, balance is critical, more so at higher revs, but as long as the balance factor favors Overbalance by a small margin it's 'OK'.
Should use snaprings.
Circlips installation. I would understand your comment about the flat sides to be the sides with the almost sharp 90° edges rather than the rounded edges on the other side. If you install the clip with the rounded edge facing out, any wear can form a "ramp" which will eventually allow that clip to come out. I have installed them with the sharp edge out.
On turbos with floating bearings, the inner clips must be installed with the sharp edge to the housing center and the rounded side to the bearing. After oiling and installing the bearings, the outer clips have to be installed with the rounded side again toward the bearing. If the sharp side is installed toward the bearing, that sharp edge will act like a drill bit on the soft aluminium and peel the bearing off.
Circlips installation. I would understand your comment about the flat sides to be the sides with the almost sharp 90° edges rather than the rounded edges on the other side. If you install the clip with the rounded edge facing out, any wear can form a "ramp" which will eventually allow that clip to come out. I have installed them with the sharp edge out.
On turbos with floating bearings, the inner clips must be installed with the sharp edge to the housing center and the rounded side to the bearing. After oiling and installing the bearings, the outer clips have to be installed with the rounded side again toward the bearing. If the sharp side is installed toward the bearing, that sharp edge will act like a drill bit on the soft aluminium and peel the bearing off.
@@daledavies2334 You're right. I didn't say that very well. What I meant was that you want the squared 'flat' side of the ring against the outside machined 'flat' groove of the piston. If you use 2 the 'rounded sides of the lock rings face each other, on the inside of the pair. Otherwise, yes, they could eventually hammer out.
There is circle clips don't have any holes just a circle and are round... snap rings have the two holes in them for the pliers to install them. I have used them and you put the flat side out like one of you comments by a guy...
I just bought a mustang with a bad engine shake. It was definitely worse the higher the rpm’s got. Felt like it was gonna shake the dash off. Took it apart and took it to the machine shop for balancing. It was out 139 grams on the flywheel side and 89 grams on the balancer side. So yes it is necessary in some cases.
Thanks Shane, in your case it sure was. AG
That'd be me in regards to the wire wrist pin clips. Just for fun you should put a proper .927" spirolox in that pin groove, you'll find the lock is a loose fit.
It is, i did try it. Thanks. AG
Agreed on a wet sump motor you don't know how many grams of oil are behind the pistons when it's slinging around....
Good point, thanks Power. AG
I don't mean to be rude, but you are Giving away alot of power with those pistons being that far down the bore and by using that cam profile..
Balancing is a must in a performance application, however so long as the calculated Bob Weight matches within 2 percent of target as you said it is, it will be fine.
for some applications the SpeedPro pistons are great but,
And Ive used those without problems and there are also Silvolite brand pistons that are fine for stock or mild builds. but if you want floating pins and alot more choices, and a very strong piston
I've found
The Keith Black Claimer or their 390 series to be the best budget build cast hypereutectic pistons to use. But they may need expensive machining of the bottom of the skirts for the 350 crank combo.
As far as cost goes, you could have had a Scat 383 crank and stock rods and 2 valve relief cast pistons combo for the money you will spend buying gaskets and all the other parts individually and buying new rods and the name brand camshaft etc..
But that can be tricky if you don't know what combination of parts works.
And
I get it though if the Original Rods need re-sizing and weight matching and you don't have the tools and experience or the time to find another set or money to pay someone to bring the originals back too spec.
Thanks for taking the time to provide your input Brent. AG
After market postins can be lighter or heavyier than stock. Ot depends if they are cast or forged...
These are slightly lighter Leonard. AG
depends on how high you want to turn the engine . stock balance - stock RPM =5000. For every 1000RPM above ,the force is squared ,generally. If you"re going to run 6000 RPM and above on the street or track , I would balance the complete rotating assy. We all want a happy engine ! Mr. gold is correct . Thank you for the knowledge sir.
Thanks for the nice compliment Doug! AG
If you do domed pistons, it's a must, and it's not that expensive. Built a Cleveland with TRW 11.25 domed pistons, and you could balance a dime on the dash at 6k rpms.
Thanks for the comment. AG
Wow! Shocked you were able to order something from Howards. I tried for a week and couldn't even get them to call me when they said they would. Anyways,,, good info, thanks for sharing..
Thanks 83, i think Mike sourced it from Ebay for me. AG
Yes
Thanks for your vote PMD. AG
I love your content! I too have a 1979 Corvette L-82 that I need to rebuild. Knowing your views on balancing and increasing the compression ratio is invaluable. What is your opinion on align boring for the crankshaft and camshaft?
Thanks Andy, you do not need to align bore for the camshaft or crankshaft ever, unless your block has had some major trauma. AG
The last years GM used flat tappet cams they used the Delphi lifters with a flat cut on the side of the lifter, to allow extra oil to flow to the cam lobes. I will buy Delphi lifters and set them up in my mill and grind a flat on the side of the lifter.
its a lot easier to groove the lifter bores using the tool sold by Comp Cams.
Thanks for the tip Racer. AG
Hell yes you do
It helps it have longevity
Remember the washing machine I would shut off when it's out of balance what do you think the engine does 😅
Thanks for your input Scott. AG
I couldn't find that part number for the pistons can you give it again im looking at 0 deck or .008 out of hole for better quench
70"s and 80"s never balanced street engines and never had any issues . Average teenagers could not afford to have a special speed shop balance cranks. we were lucky to afford cams ,intakes and headers on top of normal rebuild. lapping valves by hand was normal back then.
Thanks Col, that is how i remember it too! AG
Out of balance will show up at different rpms...
I had my 28 oz imbalance rotating assembly balanced by the machine shop who performed the machine work
Thanks Piercer. AG
Thanks for the video. Just what I needed. I'm in the process of doing a mild SBC build and was wondering if l had to balance it. Also what is the best head gasket for aluminum heads?
Thanks GasCar. Felpro and Cometic are both good. The only one that I think you should avoid on an aluminum head is the .015" Stainless steel gasket. AG
Thanks, much appreciated 👍
I pretty sure the factory didn't balance every engine the job was figured out + or - a few grams, I always figured if rod and piston weight was lighter it never caused a problem, I only balance if crank , rods and pistons are changed, if you think about it using 5/20 compared to 20/50 would change the balance a fair bit, using a crank scraper or not, overfilling the crank case by a litre, we can go on and on, that's my opinion.
Thanks for your input Bill. AG
That block is a late 70's into the 80's block. Where the ID pad is small and square'ish, that's a later block. What kind of car does he have that he needs it numbers-matching?
I got a lq4 gen 3 short block and bored it .030 over and put ls2 flat top pistons in with beefier gen 4 rods ……didnt balance it either…heck i didnt even check the gap on the rings….plus i added an LSA supercharger …..motor runs great and even better at 12psi boost…..now im building it into a 408 stroker…but the rotating assembly came balanced from the factory….i also took a gen 3 LS 5.3 with the dished pistons and swapped them out for 4.8 flat tops for more compression….didnt balance that motor either….and its a screamer…ive got roughly 15k mi on the supercharged 6.0 and around 20k on the 5.3…all trouble free miles with zero issues…..unless your building a stroker i dont think balancing is very nessicarry…..
Thanks Trent. AG
The part number for the pistons do t come up anywhere - can you verify that? You stated 361CP and those don’t bring any search results.
Also - what part number for the Vortec Summit intake manifold?
What compression are u going run with combination of your parts on this 350?
Also I'm doing a budget 454 build. Swapping the low compression factory cast flattops pistons out for some 22 CC dome hyperutectic pistons and new rings and hone job. Should it be balanced or leave it alone? Stock compression was 7.9 I'm guessing, binging it up to 9.4/9.5 to 1. Going be a low rpm torque pulling engine with peanut port heads and a small single pattern RV camshaft with headers.
Thanks for the question Jesse. Can you weigh the new vs. old pistons? AG
I' Balance all of my builds now yes there is a difference from the factory balance imho
Thanks Dave. Ag
Doesn't matter what the usage of the engine is, every engine that leaves my shop gets balanced and so should everyone else.
Thanks' for your comment Jay. AG
Agree, increasing longevity an decreases bearing wear dramatically
Factory balance by weighing old parts and stay with factory balance is poor mans way. You can balance rods and pistons are usually very close but check everything. Balance of power is another area to get a smoother engine. Cc chambers, presise porting and if power balance is off balanced masses are being forced unequally so it all gotta be close. Thanks for video. I follow David Vizard.
All good info, thanks Jacqueline. AG
Balancing gets more complex with externally balanced engines.
That is correct GM. Thanks for the comment. AG
Hello, What rods are in this build ? maybe I missed it
Thanks Stormin, they were Summit I beam rods with full floating pin set up. AG
Is there a difference in balancing procedures for American V8 vs a 60° import v6?
Thanks Az. I am not an expert on balancing but I think the logic is the same. Get all the reciprocating parts like pistons and rods equal weight, determine the bob weight, then add or subtract weight from the crankshaft counterweights to balance.
If anyone out there has more to add, please weigh in. AG
I use to balance everyone i built. I built a 355 dirt track motor 2 years on a last minute build. No balancing with after market pistons and turned it 7500 for 2 seasons before rebuilding it and it looked great inside. I just wonder if all pistons weights are equal and rods are equal and crank is a neutral balance- do any of them really need balancing? I understand on super light cranks and aftermarket combos. But i have my doubts on alot of the balancing now
Thanks for sharing Jeremy. Your experience validates my theory about balancing. AG
Longevity and parasitic losses/damaging harmonics depends on how far OUT of Balance the engine is.... and the intended application.
"Stock' Balancing tolerances were deemed adequate for the application.
Just say'in.... when re-tasking the Engine or it's intended application and power output... better "Balancing" as an investment is a consideration to aforementioned longevity as it relates to rpm/damaging harmonics/parastic stresses/power losses.
Thanks for your comment Dirt Lump. AG
I’m wondering why the quench area can to too much? I would think that the more quench area, it would just lower the compression is the only issue I can see. I’m not an expert so I’m wondering what’s the issue with the quench? Can you explain this so I can understand this?
Great question Rocking. Proper quench compresses the combustible mixture and distributes it more homogeneously in the combustion chamber for complete and faster combustion. This reduces the opportunity for "ignition knock or pinging". The tighter the better, except you don't want the piston to hit the head. About .045" or so is a good compromise, although some go tighter than this. Hope this helps. AG
@@goldsgarage8236 thanks for the reply. I think I have a bit of an understanding now!
I disagree on your view on balancing, but I might use the same engine differently then the owner will. Afterall, it won't be a monster of an engine, with only 1hp/ci, which is close to factory specification and they did not balance each engine when producing them. I guess it's a middle ground or even closer to your take on balancing this engine Mr Gold. Great video :)!
Thanks D for your input. AG
Or rather, how far out of balance can it be?
Very encouraging "balancing" revelation in this video.
(Finally gets to the subject at 15:21)
Thanks for your comment N. AG
@@goldsgarage8236 I'm in a situation where I have to balance my crankshaft myself. The local shops all claim to be too busy. I have to make my own balancer. I have the Software and the Computer, but don't know what sensors to use or even how to apply them. So I'm using a Laser method. There is no way I will be able to get to +/- 2 grams etc. The knowledge you've shared is comfort for me.
Probably my Old School build technique but I absolutely despise the so called hardened "Spiro Lock" wrist pin Retainers as both Removal & Insertion scars up & Damages the relatively Softer piston lock Groove area......These things were obviously Design intended for 1 time use and Throw away Piston applications......Properly Sized & correct Thickness "Tru-Arc" wrist pin clips used with Low End clearance piston Pin Fitting assure trouble free operation without scarring up & Damaging the soft piston Lock grooves
& are Simple to use.......
Thanks Tom, i don't think anyone likes installing Spirolox, I will let you know haw the Sealed power Clips work. AG
Bearings seem to last longer in balanced engines above 6500rpm
Good point, I also balance for sustained high RPM engines. The 302 and the 406 race engine are balanced. AG
What's your likes and dislikes on a sbc 383 stroker engine?
a 383 Stroker is a great engine. I am surprised GM never built one. AG
The quench thing is why I always disliked the 4 valve relief pistons, those two dents in the quench surface have to cause problems.
What if they benefit by tumbling the mixture?
I'm with you, but just tossing my thoughts out there.
@@randywl8925 It would hard to verify I think, the main point of good quench is detonation resistance. Be interesting to see if the dyno showed anything.
The valve 4 notches generally account for a 7cc (average) difference. So if you reduced the CD by say in the area of .028-.030 it would be roughly the same (in a flat top piston). If you didn't need the notches for cam lift or duration it would depend on the particular build and quench clearances. As far as the notches producing more eddy currents for the mixture swirl and homogenization, that is probably true, if you needed them.
@@vincemajestyk9497 instead of valve relief semicircles, maybe 7ccs of angled or swirl shaped reliefs actually designed to induce swirl?
Don't start overthinking your build that's one thing starts growing up, I don't understand what you're doing
Balancing an engine is not a bad thing but, when the engine left the Factory, it was Balanced good enough to lasting 200,000 miles. For a street engine that should be good enough! If you want to spin the engine to 7000 it should be balanced! When I had my 400 ford engine balanced, they remover 4 grams off between three bob weights.
My thoughts exactly, thanks Mylan. AG
Can you bake the nastyness off the pan?
thanks William, I think Mike scrubbed it off. AG
Are you saying quench?
It's not complicated to understand, yes you can actually put an engine together without balancing it... well it be OK though? That depends on how far off your combo is, it might just happen to be close enough to not matter it also could be off enough to not feel but wear stuff out faster and it just might be off enough that you feel it vibrating...
Thanks for your comments David. All good points. AG
If your crank wasnt in need of machining, and you weigh your pistons and rings, then weigh the small end of the rod and get them all equal....... what's left to balance?
............asks the guy who has only built two engines in his life, both barely over stock.
...... but had both rotating assemblies balanced 😂
Hey, it made me all warm and fuzzy inside. 😉
Warm and fuzzy is good Randy. AG
You can still deck the block without removing the original number's used to do it all the time just stop the mill before they hit the original number's on the block have done this for hundreds of original engine blocks you machinist should be able to do this easily.
Thanks for the info @jims. AG
Answer starts at the 16 minute mark.
Well, the simple answer is, "how do the automobile manufacturers handle the warantee claims that would come from poorly built engines?" GM knows how their Corvettes will get used, and the truck versions of Ford and Dodge as well can get past 100K on the odometer.
Thanks Albert. AG
For a stock build you can get away without balancing, if it’s a high rpm race motor it will help it last longer! Most people don’t realize Chevrolet never balanced anything!
I agree Operating. With all the external forces acting on a rotating assembly, it is really never in balance. AG
I thought this video was about balancing why is a quarter of the video about oil pans?
David Vizard has done enough testing to give a very educated opinion.
Agreed, thanks Diana. AG
If you don't balance your engine or something wrong with you
I am pretty sure that I remember David Vizard having a tech column in Car Craft magazine back in the 70's. I still have all my old magazines, one day I should dig through them to see!
One topic I think that needs addressing is the supposed "high nickel" SBC blocks. Is it real, or BS??
It's BS. GM had the softest iron alloy blocks.
@@vincemajestyk9497 Many years ago I did a deep dive into that topic searching for any info out there. I found a couple guys saying they sent in some samples to a lab, it found nothing to support any difference in block content. But I did find hundreds of guys saying they own high nickel blocks(even one guy claiming he has a hi nic 454, lol), but nothing to support their claims..🤔
Thanks Alleyoop. There are also videos of David in the younger days. AG
Will a balanced engine handle 40PSI of boost better ? Or is unbalanced going to send those pistons to meet Jesus ?
Good question @bee. The force on the piston during the power stroke with 40PSI boost is about 10 tons. I don't think a couple of grams imbalance will make that much difference. AG
Progessional racers balancer their engines at 52% and prostock are usual at 55%...
Thanks for your input Leonard. AG
My V6 engine had a 30gr spread on the piston/rod assemblies. So it doesnt seem to me that these engines are very balanced to begin with. I assume they had a standard bob weight to wich the cranks were balanced but with a high tolerance on parts.
So now when I have weight matched all and taken off around 30gr on each assembly it should only have gotten better even though its still not ”balanced”.
My machinist/engine builder is of the opinion that weight matching is far more important than balancing. On a street engine that revs 5500-6000 revs that is. A street engine sees those high rpms maybe 10% or less of its life anyways so why would it be so important?
But balancing sure isnt bad. So if one want to spend the money go ahead.
But between balancing and a pair of headers I know where my money would go 🙃
Even those "balanced" Scat and Eagle ,are+/- 2/3 ,grams. And if your not going over 5500 rpm. Kinda ok. But myself, K1 Technologies, or Callies is worth the extra money
@@ronniecox109 I ground and polished the oem rods. When done right theyre good for 7000rpm (might need to shot peen for that).
Got every rod/piston within 1gr of each other. Compared to the stock weights and difference Id say its an improvement even without balancing the crank.
The money saved from balancing I used for boring and honing, decking and resizing/honing the big ends on the rods (”critical” on oem sbc rods).
@@magnusdanielsson2749 thats the way do do at home balance. Same with the pistons ,weigh em all, lightest one is your target weight for other 7.Rods the same. Can refine a little by making a stand ,to weigh big and little end of rod. Or just weigh em ,match em .and run em. My 527 Small block stroker has balanced forged bottom end. But its a track car. Sees rpm regularly. Keep wrenching , and racing. Just do it safely.
427 stroker , big aszz fingers . Tiny keys.
Thanks Magnus. AG
Balancing is cheap!
Thanks for your comment David. AG
I only seen the thumbnail. I don't know how or why anyone would say balancing an engine is controversial??
That is the dumbest thing I've ever heard!
If you care and want your mill to last and make good power Balancing is an absolute must.
Pretty simple.
Thanks for your opinion Joe. AG
I always balance the engine at 52%...
Its not a necessity, but i still disagree. You have the engine stripped , its disassembled. You say , you prefer things done well.
Yess its a budget build , but a balance job nowdays is not that expensive . And I think , a better balance is never bad. May not benefit this build , but I see no reason why NOT to do it , the most expensive thing is ripping the enginr out and tearing it down then reassembly and stuffing it back in the car.
So , while its apart anyways , its a no brainer to get it done.
The price of the job vs the price of say.. 8 pistons is next to nothing.
Now , will it impact performance or longetivity ? Highly likely not. But , as you mentioned , it will be a hotrod. It will be idling a lot more Than a race engine. And at idle , and at peak tourqe rpm , it will shake / rattle less. But will the difference be big ? Hell no. It will be as insignificant as the extra price and work.
However , thats the way its done when you do not want to make a compromise Just to save an insignificant amount of money.
And from that stand point , yess it should be done.
Thanks Nagy! AG
You build ENGINES right? Why does this generation say motors? Huge difference. People like Richard holdner says he calls it a motor because general motors made it😂😂😂...
Technically it is an ENGINE. Only engines use combustion. A motor converts electrical energy into mechanical energy. A motor could also be an air motor or a hydraulic motor. AG
@@goldsgarage8236 yes sir. My dad built Detroit diesel engines for 50 years. I understand. Some people don't
I'm glad this guy isn't building my engine
Every engine I build gets balanced. An engine that is balenced is smoother, revs quicker, lasts longer, and makes more power. I consider anyone who doesnt take the time or spend the money to balence an engine a hack, aka someone who does things half ass.
Thanks for your opinion Bdd. Maybe you should ask Uncle Tony or David Vizard what they think? AG