How Come Timing Marks Don't Always Line Up Perfect?
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- เผยแพร่เมื่อ 3 ต.ค. 2024
- Ever do a timing belt or chain and you go to line up the timing marks and find that they’re just a little bit off? This video has the answer to that question.
Also, if you ever wondered how many camshaft rotations it takes for the same tooth on a belt to come into contact with the same cam gear on a Honda D series engine, this is your video.
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ETCG1
I timed my car 4 times with all the marks lined up, once i rotated the engine back it never lined back up, i was going insane. Thank you so much for this video. I can breathe a sigh of relief now. My family left me alone in the garage because i was yelling so loud to myself😂😂😂😂
This was me rite now until i seen this lol
It’s happening to me now 😂😂😂😂
Same.. LMFAO
I did the same removed belt 7 times so far 🤬🤬🤬
Hahaaa thats why i come here.
OUTSTANDING video, Eric! You are the only guy on YT who has addressed this issue, as far as I know!
It explains my OCD worries and still having an engine that beat ass after a head gasket, water pump, and radiator; at different times in one month, and still breathing like a beast. It made me sketchy, about the work I had done, but after lifting the cylinder head, slapping it down twice, and revving harder than when I bought the car, I felt satisfied enough. All my worries on my first timing/head gasket job, over less than a tooth. Of course they won't say that in manuals, or most people online, liability reasons. Though, all the mechanics around me always told me not to sweat the small things like that here, it's nice hearing the logic behind it. Thanks again Eric! I would rather have a teacher like you than most others any day, keep at your approach and realism, I believe there are many that appreciate it.
Thanks dude, you've been here for me for the last 5 years. Learning how to fix my cars and helping troubleshoot problems. I couldn't have done most of the work without you and this channel. Thank you Eric.
Glad I could help. Thanks for the comment.
Thanks Eric. I’m doing the belt now and was not sure why the marks weren’t lining up after rotating the crankshaft. You answered the issue perfectly.
Reason number 14,973 why I love the internet.
I'm putting a new timing chain on a 3.7 L Ford duratec, I couldn't figure out why the timing marks would point in the right direction every 4 Revolutions of the crank, but the timing marks on the Chain we're always way out of whack. I suspected it was something similar to hunting but now you have confirmed it. And you just saved me 5 hours of misery. I owe you a beer. Thank you!
It's always great to know when my work helps people. Thanks for the comment.
super crazy it’s actually my birthday that felt personal thanks etcg1!!!
Excellent video Eric, I don't think I've seen any auto repair channel even discuss this topic. Thumbs up!
Thank you! I never usually mark the belt, just line up marks at TDC. On this 1.8t i did both and after rotating marks were off and I could not understand why. You have reasurred me!
You bring up a good point, Eric. I remember doing the timing job on a 2001 Camry V6, and customer had bought the timing belt kit himself. I recommended buying the Dayco or Gates timing kit, but he went with the dirt-cheapest option he could find (which always surprised me when he did that, because he was certainly well-off, but never understood the value of buying quality parts). Anyway, the marks on the timing belt would not line up with the cams and crank marks no matter what orientation I tried; so, frustrated and concerned, I had him go buy another new timing belt because I wasn't comfortable not knowing if the belt was spaced properly between the pulleys. Sure enough, with a Gates timing belt, it lined up perfectly. It could very well have been fine, as evidenced by your video, and knowing that now, I could have probably gotten away with it, but since I had never done one of those engines before, I wasn't going to take any chances and have to do it all over again!
sometimes those people are well off BECAUSE they are miserly. If you are always spending extra on everything, you tend to have a lot less overall especially if you are making modest income; but if that same person penny pinches everywhere, it can have a huge effect on savings and therefore you appear more well off (ofc your guy could be a millionaire, but to some extent it still applies ... but you did say a 01 camry, so probably not 'rich').
And to be clear, sometimes those cheap things ARE the same. Go to Wal-Mart. Look at Melitta coffee filters and then Great Value coffee filters. The only literal difference is the bag they are in and how much melitta cares about how centered that stack of filters are in the bag (they care very much, and the display cases, they need to be lined up straight too). I worked for a company that made them, the difference between runs was a bag switch and if the machine was slightly off, how finicky you had to be straightening them in the bag and keeping up with the machines. This company also made wet wipes, Clorox had their own line and product (they owned it) but the other lines for store and other brands were pretty much the same outside changes for 'natural' or brand specific scents (rare); and the hospital only line.
The quality was all good, the company wasn't bad; just know that many products are a label or sometimes a container change, but can be the exact same product inside. If you ever wondered why something looked very similar or smelled pretty much the same, that is why. The products are basically contracted through other companies that focus on that industry.
I worked for dayco at one point, they shipped hoses to a lot of places including actual manufacturers, not just your local parts store. If someone has that knowledge, they may just buy the cheap generic thing because they truly do believe it to be the same; and I guess he trusted your judgement and realized they could be different as well. That would be my attitude towards it except I usually do tons of research first, and hopefully if I found a mechanic that respected my efforts and willing to have a short conversation about the parts I want to get to put on the car, we wouldn't have one of Eric's other video's problems, the customer that buy bad/wrong parts and makes their life harder; that would never be my point, I just want to know what I put on and would like to purchase it. Like if I wanted Idemitsu oil in my car instead of generic 0w20 they get in bulk because it is proven to work in rotaries as it is what Mazda used at LeMans and in their race series to this day, it was developed specifically for the rotary and its use in being used in the combustion chamber to lubricate the seals and burn cleanly. (that is the type of research and detail I consider respectful to a mechanic that respects me, but what the hell do I know, I'm just passionate about the cars I own and want as much involvement as I can get, but I'm clumsy when I work on cars and usually hurt myself and sometimes the car, so I try not to do major stuff any longer so I don't break something (car or self!)).
@@kuromurasaki5273 You scratched the surface with this mindset, having capital allows you to be opportunistic with your investing. But this is a situation where you have to calculate if the upfront cost savings offsets the amount of time until the next belt change and the increased odds of the belt snapping and seizing up the engine. I would argue with the risk to reward ratio of purchasing a compentnet as important as a timing belt, you're much better off spending 100 dollars more to leave you that cushion for what if it does snap and costs you 4-5k towards an engine swap.
Wow... very interesting, never heard about "hunting" before. Never told us that in tech school. Learn so much from Eric, thanks 🙏
I believe final drives are usually the same, and for the same reason. it spreads out any unevenness in wear - rather like rotating your tyres. :-)
@@aussiebloke609.
@@aussiebloke609 ....
@@aussiebloke609 mc..... El problema. M. ...mc
Eric, hats off to you for having the time to do this workout. Over 50 times? I would give up after 5 times. I was so pissed off when I changed my first timing belt in one of my civics. I marked the old timing belt, moved the marks to the new belt to make sure everything was done correctly, and after rotating the engine, I never managed to get the marks aligned again. Guess what, I tool everything off, did it again, and the same thing happened. I just thought, possibly this is the way it is, god knows. Next day, me and my mate did it all over again, yes, 3 times in total, I just wanted to make sure I wasn't doing anything wrong before starting the engine for the first time after changing the timing belt. After the third time I just thought, screw it, I will start it, and it was ok. Now, before I attempted to change this timing belt, I watched some videos and so on, and I never came across about this so called " Chain or timing belt hunting" just after one year or so I came across another of your videos when you mentioned chain hunting, and I thought, bloody hell, this information is a bit late for me. It would avoid some phenomenal bad language used on the precess of changing this timing belt.
I feel your pain...took it 4 times on my panda
@@giogio4833 join the club 😀
This was legitimately fascinating. Not even being sarcastic.
Only you could take something trivial, and make a fun and informative educational video about it.
*BRAVO!*
Great video and information! Was going crazy trying to line the timing marks up only to repeat this over and over again.
I thought about that for a couple of minutes the first time I noticed, then I slapped my forehead for not understanding right away. Of course there is no specific limit of the belt length, it is as long as it needs to be to get around all the pulleys. The key to timing is that there are twice as many teeth on any camshaft pulley as on the crank pulley. The belt itself is only a passive participant, much like the road in a Nascar race. Even a small uniform stretch will affect the cam and crank pulleys equally, and timing stays in line! Manufacturers like to choose common lengths just so their parts dept can supply the same part to many engines. The mark will move around the perimeter of the belt path by exactly twice the number of crankshaft teeth every cycle, so the mark on the belt naturally creeps even without somebody planning it out. They aren't confined by the notion of keeping the belt length to pulley length to a specific ratio. The mark doesn't even have to return to home after a specific limit, though with the carefully designed notch spacing it will seem to do that because the length needs to be an exact multiple of one notch length (so that there are no gaps where the belt is joined end to end in the factory). As long as the pulley timing marks are aligned properly, the universe is in sync.
I've read a lot of fun comments about this video. This is fun too, but it's also the best explanation I've seen. Great comment. Good to see you Spelunkered.
it would be one very odd "short engine" to make it line up on the cam every other rotation even (belt would be exactly 2x diameter of the cam, lol)
the longer the belt, the more rotations it takes to line back up at the cam and 2x that at the crank since cam runs half the rotational speed. rocket surgery =p
271 rotations to get the marks to line up again on a Subaru EJ25 (2.5L motor used in WRX/Sti and other Subaru models)! Eric should consider himself lucky that he didn't try this experiment on that motor!
P.s. thanks for the explanation!
yeap, exactly. when we make some custom engines, theres actually a few different belts that will work on something like...
lets say, a RB25/30 (rb30 SOHC block, with a RB25 DOHC head on it) , depending on where the new tensioner and idler pulley locations are,
anything from a 250 to 255 tooth belt, usually we'll use a 253 tooth belt,
just to have an easier time installing the belt, without too much slack
Your comment fully explained it best! Thanks! 😁👍
So glad i came across this video. I was so scared I jumped a tooth or two.. Turned it a few times and couldnt get my marks to line up again and just gave up.. This gave me a bit of hope back.
Thank you for making this video. I just about had a heart attack when I did my timing. I did the exact same thing other people did. I aligned everything spun the crank around numerous times to make sure that the belt marks came back around. I literally thought that I had bent all of my valves, lol. No more paying attention to the belt marks for me.
I'm happy to help. Thanks for the comment.
OMG I've gone through the timing on this Nissan Sentra 5 x now trying to get it to line back up, bout to lose it. Thank you so much for this
Just finished a timing job on a 2005 ford f150 needed to hear this was scratching my head over this thanks Eric your awesome
Thanks for that. I'm having that same problem right now but I took the belt off like 3 times and recounted the teeth over and over!!! Thanks! Now I can relax.
Thanks so much! I'm rebuilding a Chevy 350 5.7L V8 and the timing marks are slightly off for the timing chain. Not too much. I'm glad I found your video. Now I can move on to the rest of my project because I would be here struggling forever to get it perfectly aligned.
My rebuild book says it has to be exact but there's no way to get it right on each other.
Hunting I think further confuses most , but I’m glad you explained and illustrated how long it takes before our marks will line up again. Excellent
Why would anyone thumbs down this vid? EXCELLENT INFO!
The first time you realize this, you think something is drastically wrong with the work you did. I remember my first time. Good video.
Yeah I remember way back when when I first did my Xterra 3.3 L timing belt same thing happened with me I couldn't figure out why the marks would not lined back up again turns out of course they are install marks only so the little white pen marks would never line backup but of course everything else did so little dimples drives you crazy sometimes thanks Eric
This really threw me for a loop the first time I changed a OHC chain. I rotated the crank a couple of times to verify alignment, only to find the links WAY off. But the TDC marks showed that the crank and cams were still in sync, and that's all that matters.
YOU SAVED ME ON A LATE NIGHT AT THE SHOP. THANKS MAN. ETCG1 ALL DAY.
excellent video. this is why initial cam to crank timing is important. do that right an all is good. reusing old belt/chain? mark it to each gear, replace it to the exact marked locations. all is good. no worries
Awesome information Eric! I just timed my F-150 and was crapping my pants when i saw that the marks weren’t lining up!! Whew!
Lol i did this once too for absolutely no reason. Can't remember it being that many revolutions though 😮 but pretty cool that you actually filmed it 😆 thanks Eric
The perfectionist in me doesn't like it, but, it makes sense. Thanks, Eric!
Hello I'm from England just got 1liter turbo honda civic with wet belt I've got to change it thanks for info Honda dealer recalled them back but don't won't nothing to do with calr saying don't worry I'm going to leave it and sort it out and look at you videos thanks and keep the good work up god bless have a good new year never give up we are all with you😊
Eric, thank you so much. 🙏 I'm an experienced home mechanic but almost had a nervous breakdown when glancing over at my phasers.
I have wondered about this for years but never really researched it, thanks.
In theory, since the crank has exactly 1/2 the teeth as the cam, you should be able to line everything up with your painted timing marks 12 o'clock on the cam and 6 o'clock on the crank, spin the crank around 2 times your crank mark should be lined up with the cam mark? Ive found that sometimes you have to literally put the belt on one tooth off to take up slack or whatnot and when you spin it around like you did here all is kosher.
Wow that was a crap ton of work for this one video. That explains when i was paranoid about the marks not lining up when i had to move the crank after taking the timing belt off. Internal combustion engines where never supposed to run perfectly. It is a miracle that they do considering all the varibles that go into them.
It actually is my birthday thats weird that i just happened to watch your video. I love your. Videos i find them most informative
Happy Birthday!
@@ETCG1 thank you😄👍
Wooooow! I never knew that and definitely didn’t think it would have taken so many! Cool. Learned something new today. Thanks!😮
Wow, All these years ,Never new. Thanks!
this saved my life just about to strip the motor down as I thought I had jumped the teeth , now makes sense why the mark on the chain disappeared but my sprockets remained in line
How many licks to get to the center? Has now been answered!!!!!
Eric very cool stuff man I was panicked about the links on the chain and timing dots not lining back up after timing the vehicle but the 2 cams and frank line up every second revolution
thanks man, this saved me some grey hair, I changed my belt on my Lexus and after the first rotation it didn't line up any more...now I know why!
I knew they HUNTED, but never would have guess how many revolutions to get back home... enjoyed that .. Thank YOU
Wouww. Everybody just shows how to rotate the pulleys but you are explaining what we should expect and why we should not surprise if we cannot align at the first place. Now it makes sense. The question is when should we align the timing belt?)I mean I want to change only tensioner. I am planning to use old timing belt. Do I have to still align it?
Okay, what is going on here is there are three different marked items that need to eventually come back into sync. It's not just the crank pulley and the cam pulley correlation, better described more like a crank and cam pulley correlation to specific timing belt tooth. It just so happened to take 52 revolutions to get the mark that he made on the belt to line back up on that same cam sprocket tooth and land on both sprocket timing marks. Though it never went out of correlation / time. One last way to think of it is for example 60 teeth on cam pulley 30 teeth on crank pulley is a 2:1 ratio. But let's say the belt has 300 teeth.. the belt would throw in an additional ratio in the equation. I hope that makes sense, cuz I got no time for math. 👏👍😀
Thanks for this...just changed belt on my old panda and on flywheel marks seemed a couple of degrees out..tried to reseat belt 4 times.now I know why👍👍👍👍
Thank you ETCG1. Good info. It help me to understand a lot more how does the system works. I appreciate.
Holy crap Eric, bet that was a workout...
Heck yeah! He should show off his guns afterwards. Kidding. Lol
he had the plugs out i think
@@360fanboy360 smarter not harder, right? Lol
Wow, an automotive video that actually has some useful info in it. I didn’t think people made those anymore lol. This reminds me of a timing belt I did on a 2004 Chrysler 300m. I must have had the belt on and off 10 times because every time the one camshaft would be a tooth off. I actually ended up having to backseat the one camshaft to get the marks to all line up after turning the engine over. I’m starting to like belts more and more after having a recent stretch of timing chain problems on multiple vehicles. Both need repairs/replacement at some point, and timing belts always come out cheaper and easier to replace in my experience.
Timing chains are supposed to NEVER need replacing.
Timing chains tend to only go out due to neglect. They're a bit more difficult to swap out as they usually outlive the engine, unlike belts which are a wear item and you have to go through this every X miles.
@@TheEgg185 Tell that to nissan and their vq35 engines.
amak1131 well the chains stretch and wear just as much of not more than belts do. Ok, let me guess the tensioner should account for that wear? The tensioners are usually what fail on timing chains. Ask bmw, Nissan, gm ecotec owners, Mini Cooper 1.6 owners, early dodge and Chrysler hemi owners, I could keep going. Especially with cars staying on the road a considerable amount of time longer than they did 10 years ago. Hate to tell you, but if timing chains didn’t ever need to be replaced they wouldn’t make them replaceable. If you consider 100k-150k the lifespan of a car then I guess timing chains are a lifetime part, but any more than that they become a wear item.
This is awesome, thank you Eric, this addresses this question that was always in the back of my head. If machining is so fine nowadays that they can target tiny fractions of a mm precision, why are the marks off??? Now I know why
I've noticed if the heads been milled twice and or the block decked it can cause this. Half tooth off..great video
Thanks you I was so close to pulling the belt off again. I noticed my crank and cam gears we're in the right spot but the belt was way off. Short story thank you
I’ve waited years to catch this on my actual birthday!!!
Im glad I saw this first lol, I was about to start rotating mine to make sure is align and was gonna take me a while to figure-out is miss-align
Your a damn wizard you reading my thoughts I just changed a timing chain and was thinking about that I'll try on mine to thanks perfect timing 😉
Eric!!! Where was Count Dracula??? One rotation...Ha, Ha, Ha, Ha.....Be Safe Stay Dirty
Ive always wondered about this. I always thought it was a quality assurance issue. Now I know. Always best to hear it from Eric lol
Btw, my profile picture are a set of k20a3 cam shafts and gears lol
Thanks for all the videos will definitely be watching the timing belt videos when I replace my timing belt on my civic
Always hated that and was scared that I was gonna mess something up thanks for the info ur the man!!!!
Cool topic! Ah Honda, anti-clockwise rotation..
My thoughts too .i never rotate my engs in the opposite direction from normal rotation .not sure if it matters just something i dont do
Yep. Can't use the time-tested starter trick to break that crank bolt loose. Honda should have made them left-hand thread.
@@derekholdt747 question. Is a normal bolt, left or right hand threaded?
Only older honda rotate this side
@DE Nichols // Standard conventional threads are right-handed
Beautiful video. It seemed everything was fine despite the chain seeming a bit loose (changing it anyways, engine rebuild bc of overheating 70K mile car from ‘99). This vid shows that it’s probably fine that it’s slightly not perfectly lined up.
Finally! It IS my birthday! Thanks Eric
Happy Birthday!
On DOHC Honda engines with 2 cam gears, there are timing marks on each cam sprocket that directly align with each other when at TDC. After I replaced my head gasket and had the head resurfaced, the timing marks were just every so slightly off from one another, 1-2 mm or so. I just went with it, and the engine has run just fine in the 35,000 miles since I did the work.
EricTheCarGuy just broke the Internet... The first mamal on Earth to break in his engine by hand!
Years ago, my shop "mentor" explained this to me, but I had neither the apptitude nor capacity to understand. 22 years later, Eric explains it, and it's like: oh yeah, duh. That makes sense.
THANK YOU!!!. sorry to shout but, that really helps me. I thought i would be ok but you splained that real good.
Want to hear the most annoying sound in the world?? haha. This information is great, thanks Eric!
thanks for that , almost finished working on a bike , with that very same puzzle
Ive been watching you for years and just realized I hadnt subscribed to your channel...I remedied that problem today...sorry about that
Super patient to do!
I once had to remove the Bosch fuel pump on a Jungheinrich forklift with a Perkins diesel engine,took me about 35min to align all 5 marks on the gears(no belt,no chain,5 sprockets)
My Ford Courier 2.0 did this and I didn't know why, Now I do! I counted 53 turns to get it back to "installation links to dots" and strangely it had 106 links...double the rotations..? It was a 19/36 gear set.
Eric, I think you're a bit confused on why the belt or chain hunts. The sprockets teeth are not offset, they are symmetrical. Having them asymmetrical would be diffcult to time and correctly align and require a keyed belt or chain and cause problems especially Piston to valve or valve to valve contact on interference engines.
The belt or chain itself will always hunt because the difference in sprocket sizes and number of teeth on belt or chain. *large cam sprockets, small crank sprocket*
The difference in these sizes make it appear the belt or chain has shifted or is hunting but not really, it's due to turn ratios in cam to crank, I beleive it's 1 complete revolution of crank for every quarter turn of the cam on the 4 bangers. The belt in your case took 52 revolutions of the cam due to the number of teeth on the belt, if that is a d16 engine, it will use 104 tooth timing belt (go find the old belt and count, I bet I'm right), divide that by 2 and you get 52. That's how many times that belt has to go around the cam before it lines up again. Even though every 4 revolutions of the crank makes one complete revolution of the cam itself.
The TDC marks on cam and crank will always line up when cylinder 1 is TDC, always! That's why shop manuals tell you to rotate engine several times by hand and verify the forged alignment marks and ensure that nothing odd is happening with the tensioners or slack guides causing it to go out of time.
Which is why it's recommended to bring the engine to TDC before you do a belt or chain replacement.
Absolutely correct. I would add that the reason timing Mark's dont always line up is due to a combination of initial manufacturing tolerance, cylinder head gasket compression (which affects the distance between pulleys, cylinder head re surfacing (which reduces the distance between pulleys and belt stretch. Additionally there is a measurable change in distance between pulleys when tbe engine is hot. Thermal expansion is a notable effect.
Wooow.. I never knew that, it's nice to learn something new after so many years.. love your videos btw.. :)
ONE DAY after my timing belt change on my 92 Acura integra GS! I was wondering the same thing 😁
Thanks, I did not know about that. I wanted to check my timing belt on my Mitsubishi Lancer but i was so unsure about getting the timing correct that i took it to a mechanic shop to have it checked. Turns out it would have cost a lot less if i just did it myself. Thanks for making the video. If you can can you make a video on the timing belt replacement on a double cam engine japan made vehicle.?
This is the design that’s not given in repair manuals in order to prevent because they might be afraid that it would cause people to set timing a tooth apart. Every time I did a stupid timing belt on my Honda’s I though it was my fault because the stupid pictures on the manuals would show it lining up perfectly, it was a major learning curve that I eventually got over. This video would have been so useful back then lol well I hope it helps people. I learned the stressful way.
Wow, doing dodge/chrysler 2.7 lined it up perfectly, rotated to watch them realign any one that's done anything with timing knows the feeling that over took me instantly when it never did line back up but I only rotated it 20 times maybe.
That's what I've been telling people all the time, when it comes to setting the timing on Honda engines. Just as long as the crank pulley is set to TDC, make the cam gear at closest as possible to factory specs. It will start every time. People have a tendency of setting the cam gear first and then the crank pulley, which leads to jumping a tooth or two and not starting.
Thanks for the heads up.
Now it all makes sense. I always kind of wondered why they were a little bit off. It made my brain hurt when it wasn't perfect. Engineering at its finest.
I just did a timing belt on a 3.0 accord, I noticed they didn't line up perfectly. I was hoping it was normal.
Makes sense for wear. Good topic. Thanks!
That reminds me of the first time I did a cambelt, a twin cam at that, I added my own marks on the belt and pulleys, I wondered why they didn't all line up again soon when manually turning the crank.
BS! The "hunting" of the belt is a function of the ratio of teeth on the belt to teeth on the sprockets. This has NOTHING to do with the alignment of the timing marks on the sprockets and block/head. Which depends on the ratio of teeth between the crank and the cam sprockets (1 to 2 for 4-stroke engines), belt tension/stretch/wear, the precision of the belt manufacturing, AND the actual distance between the block and head. How many times has the head been surfaced? Is the head gasket thinner or thicker than stock?
I was going to say the same thing, albeit a little nicer.
I got this information from an engineer. It's done to minimize wear on the system according to what he told me.
@@ETCG1 I think there might be confusion on what you mean when you say "timing marks". The timing marks on the crank pulley and cam pulley (if it's got marks) should line up within a fraction of a tooth with every rotation, while any pre-printed mark on the belt itself (or one you make) absolutely should shift as the crank is repeatedly rotated to minimize wear on the belt.
@@petermescher332 exactly. The belt processes around by some number of teeth per rotation, while the pulleys stay in sync.
Say the crank pulley has 30 teeth (the cams have 60), if the belt has 301, every 10 crank rotations a mark on the belt would move back by 10 teeth behind the timing marks on the pulley and block/head...and every 300 crank rotations the belt mark would be back aligned? But none of this has anything to do with the timing marks on the crank and cam being off by some fraction of a tooth.
@@ETCG1 no matter the position, the belt length and pulleys stay the same. Yes the belt position on the pulleys drift by tooth but the actual true crank/Cam alignment stays true. This has no impact to the true position of cam timing. When installing a new belt with the marks in place, any variation under a single tooth can be attributed to variation in machining or tension. Often the marks will align more true after rotation and slack is redistribute. Often in high performance applications we use a degree wheel and degree the cam to account for such variances as they can accumulate into multiple degrees when head gasket sizes and machining variances are taken into account.
The manual for my B5 Passat had you make sure the crank and one cam sprocket (I think it was the exhaust) were both really close to the marks on the block/head, and then they should be completely "on the money" when you pulled the pin on the tensioner. I'm not even sure the belt itself came with timing marks, since they become useless as soon as you rotate the crank to check for proper operation.
Shade Tree Mechanic Pro Tip: If doing a timing belt with a mechanical (or spring with a jamb nut) tensioner, and the timing marks seems slightly off, check if the belt tension is set correctly. I was doing a timing belt job on my Nissan 300ZX and I noticed that the timing marks didn't exactly line up. I started turning the engine over by hand and the belt got sloppy either between the crank and a cam gear, or between both cam gears. Retensioning the belt fixed that.
Lovely, that explained my not understanding the issue :-)
I've always wanted to do this, but never had the patience! Thanks! 😅
I'd imagine every car would have a different number of rotations, when the marks meet again ...
very interesting, I never thought about it...I guess it's made to hunt over and over to distribute equally the wear and tear of the belt or chain evenly. That's efficient engineering.
Thank you for letting me know this I have an 06 Chrysler 300 and it was just a half a teeth off I was worry about it would mess up
Very interesting. I hope this explains the problem I have on my 97 Ford Ranger. When I line up all the marks, then put the belt on, the mark on the camshaft goes off a little, like a 1/4". No matter what I've done, I can't get them to line up perfectly once the belt is on. With the tension released, and the belt loose, a belt tooth and a camshaft gear tooth rest on top of one another. The only way to get the belt and teeth to mesh, is to throw the camshaft gear off slightly one way or the other.
Mind BLOWN!!!!!
Learned something new today, thanks
I changed the vvt sprocket on my Camry a month ago and The marking on the chain n the exhaust gear were off by a tooth or 2 , I was just driving myself crazy thinking about it and wanted to wake up early tomorrow and adjust it , even though the car works perfectly fine I guess I’m just a perfectionist. So I guessing this is normal and me trying to “adjust” it is foolish if the car runs great
That makes sense though because what’s the chances of the chain and gear or belt will always lining up perfectly , I guess as long as the marks are somewhere in the realm of where there supposed to be its fine
Hey Eric............awesome info AS EVER , man you are the BOSS !.........
The easiest way to change a timing belt is to mark the upper and lower sprockets, and put corresponding marks on the block or head. If you're rebuilding the engine then that's a different story. But if its just a belt replacement you just need those sprockets in the same place when putting the new belt on.
TargaWheels it does work but it’s not always the simplest or best way. Sometimes a valve spring will be under tension and when you take the belt off, the cam shaft will spin round a bit. Then you end up trying to put the belt with one hand while holding the camshaft in position with a spanner. Then you’re left wondering if a valve hit the piston crown and got damaged until you start the engine. The other issue is that if your old belt had a bit of stretch, you’re putting the new belt back on the wrong position which could be a tooth out. Sure, it’ll run but it’s not good practice. The best way is just to use the timing marks or better still, locking tools if you have them. If not, some engines can be locked with bolts in strategic places.
On my car there are colored markings on the head and block and sight holes on the pulleys that you line up with those markings.
Just sharing what I've been doing. Honda/Acura, Toyota, I've done it this way without a hitch. If it does move slightly I'll rotate it back when putting the belt on. After I set the tensioner I go back around and make sure all my marks line up.
Barry McNicholl Yes.! you nailed it,I I used camshaft locking tools on my GM 3.6 and I feel so mucho confident that I did right after every 2 turns the timing marks on camshafts are aligned with locking tools,those $18 that I pay for them makes me sleep well 🙋🏻♂️
@@TargaWheels what if I rotated the crank after I put the belt on, and when I looked after rotating a few the marks on the belt did not line up...
Yes the physical positions of the two pulleys are the only concern NOT the fact that the paint mark keeps moving as the teeth ratio is diff. It threw me first time when doing a belt as i always did double chains and the everything seemed to be all out of place. Car started and ran smoothly and the amount of valve timing i checked alone against the top dead centre on the crankshaft and was perfect
Always rotate a few times to check for binding, looseness and to do final check on actual physical timing.
Same with adjustable bearing. Turn turn turn when adjusting and keep turning!! .
I assume that this may also be because you want the impulse from combustion events to hit all portions of the belt, such that certain spots take all that stress at once and wear out faster?
I love the race car noises in the background