Back in the 1970s got involved with clubman style car powered by a 1310 cooper s motor. Held lap record around most circuits in Australia for about 5yrs after it was retired. Had head gasket issues which no one could cure & put down to very high compression. I did few experiments & finally fixed it by countersinking the head stud holes in the block. Have noticed some manufacturers stop the threads about 5 to 8 mm down from the block face, which I'm guessing achieves the same thing. For the past 55yrs I have countersunk all threaded holes in everything & deleted gaskets in favour of loctite. Solved many oil leaks. Some of us old farts have learnt a thing or two. 😂
Loving your signature "There y'are now!" opening. Feels all friendly, like going to hang out with a mate and tinker in his garage on a Saturday arvo. :-D
As an Engineer, I was taught by an old timer (I'm now an old timer) that if you take a copper penny and scrape it gently across the machined surface, the copper should 'just' pick up on the machined surface (for either a gasket surface or a cylinder bore)... I've been building my own race and rally engines for decades and not had any problems with this principle. Great channel BTW 😁
Hi Paul you nailed the pronatation of my name. Thanks for answering the question. It's your detail that makes your videos stand out from the rest. Kind regards Bernard
Just found this one and started it. Now im going to have to go and find the first in the series. Wish you didn't make such good content (the last bits a lie btw, keep it up).
Hi. This is great content to show the average Joe what it actually takes to build and machine a competitive, reliable race A-Series engine. I have a friend that used to work for Leyland here in South Africa and he raced competitively in the '70s and mid '80s and he said quite plainly a out and out race engine will take some 200 to 300 hours of machining and blue printing to build, this includes the gearbox, flywheel and induction systems etc. Great job and keep it up with the excellent content.
What a fabulous video. I'm a novice so sometimes the engineering is a bit beyond me. Learning fast though thanks to your videos and the people commenting. Can't wait to try and build my own now
Extremely interesting, as I've previously mentioned I'm really impressed with the degree of accuracy you wok to, it's far greater than we ever did, we just used a steel rule and feeler gauges. No idea either where the myth about cast cranks came from surly they'd be too brittle. As you rightly said different metals were used over the production period, the best S cranks were the early ones, definitely 1071's and 950's and they were nitrided, later ones only tuftrided, not certain what the early 1275's were, can't remember. Was suprised that you only ran your racer to 8000rpm I would have expected it to be much higher with modern machined crankshafts. Back in 1961 I was using 8k in my racing mini. Keeping my fingers crossed for your next race.
If these are fully floating, would you not have been inclined to rebush the small end to eliminate any machining angle inaccuracies? I’d also like to have attempted to measure if the big end is honed square in the rod.
Ra is spec not unit but is typically measured in microns. There's a lot for surface finishes/roughness (Rpm, RMS,Rp...) Ra is the average roughness across a surface. These specs would be measured on a surface profileometer
Late to the party, but 40 micron Ra would be really rough - like a rough machined surface. I suspect it could be referring to 40 micro-inch Ra which would be a very fine machined surface as Paul described (~1µm average maximum deviation from true over 0.8mm - the definition of Ra is that it is the average of the maximum deviation on (I think) 4 test lengths - it's all laid down in the various standards.).
I have just bought a reconditioned "A" series head from the great old guy, that used to be one of the top guys in the development division of the old MG Abingdon works and Cowley.. he also runs a MG midget race team ... he said that they always use a smear Wellseal when they used to build MGs and also on the race car.. what's your opinion
The problem was we had a race 7 days after this video so a solution that we could do in house had to be found if time was on our side that exactly what we would have done :)
Another fascinating video. Aren't the pistons now out of square with the cylinders even a little? What's the impact of that? Let's say the angle was worse than you have, wouldn't the piston potentially be wedged in the cylinder and/or the pin bore have uneven wear or cause damage? Or, is there enough tolerance to take up the discrepancy?
I've had to resize Eagle rods before. I'd of bored and rebushed the little end as technically the ring won't be square in the bore. Problem is its probably cheaper to buy new rods by the time you do all that
Paul, surely if the rod has not been machined true the pistons are not sitting square in the bores this could lead to premature wear in the piston skirts and could lead to excess scoring of the bores, maybe even causing problems in a freshly built engine with "close" tolerances. Or am I talking out of my big end.....
You are on the right track all right Dave, however the engine came back apart after the next race. We only did this modification to get us through a race and now a new motor is in the pipe line for the car 👍
Another great video. Do you think that the tilt in the pistons would cause any other issues? You mentioned that you might need to redo the CR calculations. Surely taking material off the top of the piston will still reduce the CR, even though the piston dish is effectively smaller?
Hi Paul great video and detective work to trace it back to the pin and bore I was just wondering is there any danger going forwards to the pin wearing unevenly and thus over time allowing the piston to rise higher into the head, just curious.
Loving the content!! Just a quick oversight but I think your getting a maximum deflection of 0.4mm on one side of the piston an not the other side. Possibly the small end of the rods is cone shaped. Maybe worth taking a measurement from side to side of the small end.
Yeah, poor quality machining from the Chinese Factorage, quality at it's lowest to liberate your money, then a local shop passing these on ruins their reputation of quality to make an extra few bucks. These rods taken to a good rebuild shop will have the pin bores sleeved and resized. I'd also be checking the big-end to the centre line of the rod first. You may have a factorage Z rod as that's some extra dollars in factorage saving.
Nice work and investigation👍🏻 rather than modding the piston, could you have rebushed the rods to correct? Would be forever fix then??? K Series heads on the shelf too……
Hi Paul, Fascinating as always. I’m worried that you now have addressed a problem with rods by machining the pistons. Now the pistons will always have to be fitted to the same rod, and replacing either the rods or the pistons for any cylinder will reintroduce the problem. Is that an issue, or is part of your race management process to record all these changes and always make sure that pistons and rods are always matched? I would have thought that you would have preferred to address a problem with a rod by machining the rod, perhaps by fitting an ‘undersized’ bush and reaming it out at the correct angle: I’m sure you could do that with your lovely milling machine and your obvious machining skills. Love to hear your thoughts on this. And still wondering why you’d turn across the full with of the piston top: why not just turn a 0.6 x 0.6mm chamfer al the way around the edge of the piston top, thus minimising any change in compression ratio. Not complaining, just wondering! Cheers, Will
You are right Will these pistons will have to always remain in the same rod and bore. You are 100% correct the right way to fix this is to re-machine the little end with a new bush and at the correct angle. Unfortunately with a race next weekend and this motor needing to be in the car and at the rolling road by Wednesday we need to come up with a solution that would be quick to implement and allow the motor to run safe. In the off season we will change pistons and rods in this motor to properly rectify this problem
Sorry I missed the last part of you message. The reason I went across the piston was to allow a little more space in the combustion chamber as with the head being skimmed and the block being skimmed we where very tight on the CR so this just helped a little
Depends David. If you are not replacing piston rings/honing the bore. Then yes the rods and pistons should be replaced in the same order but if you are replacing piston rings and honing no problem as long as all are in balance 👍👍
@@HREIRL Hi Dave, I agree, but the point I was really thinking about - but not explaining very well - is that you can’t renew the pistons now without either changing all the rods as well, or machining the new pistons. But Paul has explained the reasoning behind this, so I now fully understand his approach.
Don't understand why there is so much 'rock' on the pistons? All the pistons I have had experience of are a really good fit on the little ends with no appreciable movement?
Awesome.. you helped confirmed my belief in that the typical mini con rods were/are forged. Everything you mention makes wonderful sense, but for a standard street engine (not race engine), should the difference from .6 to .1 on the piston head be concerning? Thanks to you and your camera person for capturing and sharing..
Your most welcome Friend, the in deference would be less critical in a road motor but still something that would need to be rectified for proper running
You could enlarge the bore on the small end and add a bronze sleeve, we used to do this to diesel rods then put them in a cross flow as they were forged steel rods but the pin holes were too large for the cross-flow pistons so we sleeved the small end. Also which is the pin meant to float in the piston or the rod?
not sure about your method or theory you measure no 3 cyl time stamp on video 14:31 it looks to me that the piston rocks axially, that is the gudgeon pin is acting as a see saw - did you check the gudgeon pin fit in the little end of the rod ? did you check the pin fit in the bore on the piston ? Was the rod torqued up to the crank? At the beginning of the video you say you check the rod length to 6.040 ins original was 5.750 from memory Was the piston machined previously to accommodate the extra rod length ? if it was is the pin bore parallel to the piston face as checked against a known flat face (surface plate) it cant see your method being accurate esp if your using floating pins esp without checking the amount of clearance on the pin in the piston and the pin in the rod Why not put the piston on a surface plate and measure the face to pin boss height on both sides also why not put the rods on the face plate and put the pin in the little end sticking up then check the pin is square (with set square or dial gauge) - the cranks do flex in extreme applications but you would see contact marks of the pistons on the head (unlikely) looking at the 10:00 min mark look at the squish ring on the top of the piston its not concentric all the pistons ive seen have concentric squish rings to me it looks like the pistons were not machined square to either originally or to deal with the extra rod length.
Do you think this issue would occure in this manufactures pistons alone, or would a higher quality be more precise ? Still must be chaffed you solved this problem. I am truly enjoying these vids on our race engine .
The pistons where all balanced after machining so no problem with imbalance. You are right tho the piston is not sitting 100% square in the bore which will effect top power but thems the brakes
Your are spot on Joao 100% a temporary solution but when your racing in 7 days and the car needs to go back together you have to work with what you got. New rods for this motor would be 2 weeks out in the island 👍
Rods is rubbish and having pins not parallel to big end your forces in engine will be bit odd and wrecking. Is painfull to see that and I hope it is not bogineer ignorance just engine is test bitch and is to be destroyed or how fare we can go with this.
Please stop the tinging subscribe noises in your videos, they scare the hell out my dog to the point I'm going I'm going to ban my other half from watching your videos. Very random Sorry!!
@@HREIRL OMG thank you so much, he's such a fan of your channel I have to tell him off and put it on silent and I feel bad. My dog had a random noise phobia develop after being in the vets for her teeth done earlier in the year. Sorry to be a nuisance 😂💙💚
Back in the 1970s got involved with clubman style car powered by a 1310 cooper s motor. Held lap record around most circuits in Australia for about 5yrs after it was retired. Had head gasket issues which no one could cure & put down to very high compression. I did few experiments & finally fixed it by countersinking the head stud holes in the block. Have noticed some manufacturers stop the threads about 5 to 8 mm down from the block face, which I'm guessing achieves the same thing. For the past 55yrs I have countersunk all threaded holes in everything & deleted gaskets in favour of loctite. Solved many oil leaks. Some of us old farts have learnt a thing or two. 😂
Loving your signature "There y'are now!" opening. Feels all friendly, like going to hang out with a mate and tinker in his garage on a Saturday arvo. :-D
thats a lovely comment Dude and its exactly how I feel as well I love hanging out in the shop with you all
As an Engineer, I was taught by an old timer (I'm now an old timer) that if you take a copper penny and scrape it gently across the machined surface, the copper should 'just' pick up on the machined surface (for either a gasket surface or a cylinder bore)... I've been building my own race and rally engines for decades and not had any problems with this principle. Great channel BTW 😁
Hi Paul you nailed the pronatation of my name. Thanks for answering the question. It's your detail that makes your videos stand out from the rest. Kind regards Bernard
Im delighted and thanks for the lovely comment 👍👍
Just found this one and started it. Now im going to have to go and find the first in the series. Wish you didn't make such good content (the last bits a lie btw, keep it up).
And there you have it, a perfect example of "To be sure, to be sure" 😂
Thanks JJ
Hi. This is great content to show the average Joe what it actually takes to build and machine a competitive, reliable race A-Series engine. I have a friend that used to work for Leyland here in South Africa and he raced competitively in the '70s and mid '80s and he said quite plainly a out and out race engine will take some 200 to 300 hours of machining and blue printing to build, this includes the gearbox, flywheel and induction systems etc. Great job and keep it up with the excellent content.
thanks Philip
What a fabulous video. I'm a novice so sometimes the engineering is a bit beyond me. Learning fast though thanks to your videos and the people commenting. Can't wait to try and build my own now
you will do great Toby 👍👍
Nice bit of measuring, investigating and machining. 👍
Thanks bro all part of the service hahah
Extremely interesting, as I've previously mentioned I'm really impressed with the degree of accuracy you wok to, it's far greater than we ever did, we just used a steel rule and feeler gauges. No idea either where the myth about cast cranks came from surly they'd be too brittle. As you rightly said different metals were used over the production period, the best S cranks were the early ones, definitely 1071's and 950's and they were nitrided, later ones only tuftrided, not certain what the early 1275's were, can't remember. Was suprised that you only ran your racer to 8000rpm I would have expected it to be much higher with modern machined crankshafts. Back in 1961 I was using 8k in my racing mini. Keeping my fingers crossed for your next race.
We could rev these motors higher but with modren cam profiles and head porting all the power is down lower
@@HREIRL Another example of how everything has changed.
I spy BMW Bike heads on the high shelf behind the lathe !! Will you be doing a twin-cam build on the channel ??
you sure do If we get enough interest I can make that happen
It’s fantastic to watch a Pro do the job👍🏻 and learn something new😊
Thanks Peter
Great content don’t change anything.
Thanks man 👍
If these are fully floating, would you not have been inclined to rebush the small end to eliminate any machining angle inaccuracies? I’d also like to have attempted to measure if the big end is honed square in the rod.
Ra is spec not unit but is typically measured in microns. There's a lot for surface finishes/roughness (Rpm, RMS,Rp...) Ra is the average roughness across a surface. These specs would be measured on a surface profileometer
Thanks Callum I always wondered
@@HREIRL looking forward to the next Gretal installment!
Late to the party, but 40 micron Ra would be really rough - like a rough machined surface. I suspect it could be referring to 40 micro-inch Ra which would be a very fine machined surface as Paul described (~1µm average maximum deviation from true over 0.8mm - the definition of Ra is that it is the average of the maximum deviation on (I think) 4 test lengths - it's all laid down in the various standards.).
I have just bought a reconditioned "A" series head from the great old guy, that used to be one of the top guys in the development division of the old MG Abingdon works and Cowley.. he also runs a MG midget race team ... he said that they always use a smear Wellseal when they used to build MGs and also on the race car.. what's your opinion
I know this would have been a a cost in time and money, but could you not return the faulty ones and replace with new?
The problem was we had a race 7 days after this video so a solution that we could do in house had to be found if time was on our side that exactly what we would have done :)
Really interesting video Paul 👍 keep u the good work!
Thanks Andrew
the most fascinating video to date,,top job..
thanks bro 👍
DID THE OFFSETS LINE UP WITH EXHAUST PORT OPENINGS ,, MAYBE BY DESIGN .
no unfortunately Carl just bad engineering
Paul, will you have to recreate the dish in the top of piston to retain the same CC?
we got away with just slightly opening up the combustion chambers 👍
Another fascinating video. Aren't the pistons now out of square with the cylinders even a little? What's the impact of that? Let's say the angle was worse than you have, wouldn't the piston potentially be wedged in the cylinder and/or the pin bore have uneven wear or cause damage? Or, is there enough tolerance to take up the discrepancy?
I've had to resize Eagle rods before. I'd of bored and rebushed the little end as technically the ring won't be square in the bore.
Problem is its probably cheaper to buy new rods by the time you do all that
Fascinating as ever, thank you. I'm interested to know if you "run-in" your race engines at all? Keep up the great, thoughtful and interesting videos!
We sure do Paul typically 20 mins in the car and then 10-15 laps on the track 👍👍
What do you think is the the highest 1098cc MPG A-Series (Morris Minor). possible?
would the movement in the piston be a collection of the tolerances for oiling. that would explain the accuracy
its defiantly a factor
Paul, surely if the rod has not been machined true the pistons are not sitting square in the bores this could lead to premature wear in the piston skirts and could lead to excess scoring of the bores, maybe even causing problems in a freshly built engine with "close" tolerances. Or am I talking out of my big end.....
You are on the right track all right Dave, however the engine came back apart after the next race. We only did this modification to get us through a race and now a new motor is in the pipe line for the car 👍
Would if not be better to re-bush the conrod little end and then have it bored and honed straight?
IT deffinatly would have been but time didn't allow
Another great video.
Do you think that the tilt in the pistons would cause any other issues?
You mentioned that you might need to redo the CR calculations. Surely taking material off the top of the piston will still reduce the CR, even though the piston dish is effectively smaller?
it would but we also skimend the head and block so everything basically came back to where we wanted it
Hi Paul great video and detective work to trace it back to the pin and bore I was just wondering is there any danger going forwards to the pin wearing unevenly and thus over time allowing the piston to rise higher into the head, just curious.
Your spot on Jer and there most deffinatly is we have already decided to solve that problem
Loving the content!! Just a quick oversight but I think your getting a maximum deflection of 0.4mm on one side of the piston an not the other side. Possibly the small end of the rods is cone shaped. Maybe worth taking a measurement from side to side of the small end.
Thanks for that Lee your spot on
Yeah, poor quality machining from the Chinese Factorage, quality at it's lowest to liberate your money, then a local shop passing these on ruins their reputation of quality to make an extra few bucks. These rods taken to a good rebuild shop will have the pin bores sleeved and resized. I'd also be checking the big-end to the centre line of the rod first. You may have a factorage Z rod as that's some extra dollars in factorage saving.
Nice work and investigation👍🏻 rather than modding the piston, could you have rebushed the rods to correct? Would be forever fix then??? K Series heads on the shelf too……
defiantly the right job would be to fix the rod but unfortunately time did-not allow
Hi Paul,
Fascinating as always. I’m worried that you now have addressed a problem with rods by machining the pistons. Now the pistons will always have to be fitted to the same rod, and replacing either the rods or the pistons for any cylinder will reintroduce the problem. Is that an issue, or is part of your race management process to record all these changes and always make sure that pistons and rods are always matched? I would have thought that you would have preferred to address a problem with a rod by machining the rod, perhaps by fitting an ‘undersized’ bush and reaming it out at the correct angle: I’m sure you could do that with your lovely milling machine and your obvious machining skills. Love to hear your thoughts on this. And still wondering why you’d turn across the full with of the piston top: why not just turn a 0.6 x 0.6mm chamfer al the way around the edge of the piston top, thus minimising any change in compression ratio. Not complaining, just wondering!
Cheers, Will
You are right Will these pistons will have to always remain in the same rod and bore. You are 100% correct the right way to fix this is to re-machine the little end with a new bush and at the correct angle. Unfortunately with a race next weekend and this motor needing to be in the car and at the rolling road by Wednesday we need to come up with a solution that would be quick to implement and allow the motor to run safe. In the off season we will change pistons and rods in this motor to properly rectify this problem
Sorry I missed the last part of you message. The reason I went across the piston was to allow a little more space in the combustion chamber as with the head being skimmed and the block being skimmed we where very tight on the CR so this just helped a little
Surely it doesn't mater what engine is being rebuilt the rods and pistons should always be replaced to the same position they came from.....
Depends David. If you are not replacing piston rings/honing the bore. Then yes the rods and pistons should be replaced in the same order but if you are replacing piston rings and honing no problem as long as all are in balance 👍👍
@@HREIRL Hi Dave, I agree, but the point I was really thinking about - but not explaining very well - is that you can’t renew the pistons now without either changing all the rods as well, or machining the new pistons. But Paul has explained the reasoning behind this, so I now fully understand his approach.
Don't understand why there is so much 'rock' on the pistons? All the pistons I have had experience of are a really good fit on the little ends with no appreciable movement?
Awesome.. you helped confirmed my belief in that the typical mini con rods were/are forged. Everything you mention makes wonderful sense, but for a standard street engine (not race engine), should the difference from .6 to .1 on the piston head be concerning? Thanks to you and your camera person for capturing and sharing..
Your most welcome Friend, the in deference would be less critical in a road motor but still something that would need to be rectified for proper running
@@HREIRL email sent…
I would've been inclined to fit other conrods not made of Chineseum, but your solution was ingenious
Thanks Allan, Plans are already a foot to do just that
You could enlarge the bore on the small end and add a bronze sleeve, we used to do this to diesel rods then put them in a cross flow as they were forged steel rods but the pin holes were too large for the cross-flow pistons so we sleeved the small end. Also which is the pin meant to float in the piston or the rod?
These actully have a bronze bush in them so I think I will replace it in the off season and machine it correctly 👍
not sure about your method or theory you measure no 3 cyl time stamp on video 14:31 it looks to me that the piston rocks axially, that is the gudgeon pin is acting as a see saw - did you check the gudgeon pin fit in the little end of the rod ? did you check the pin fit in the bore on the piston ? Was the rod torqued up to the crank? At the beginning of the video you say you check the rod length to 6.040 ins original was 5.750 from memory Was the piston machined previously to accommodate the extra rod length ? if it was is the pin bore parallel to the piston face as checked against a known flat face (surface plate) it cant see your method being accurate esp if your using floating pins esp without checking the amount of clearance on the pin in the piston and the pin in the rod Why not put the piston on a surface plate and measure the face to pin boss height on both sides also why not put the rods on the face plate and put the pin in the little end sticking up then check the pin is square (with set square or dial gauge) - the cranks do flex in extreme applications but you would see contact marks of the pistons on the head (unlikely) looking at the 10:00 min mark look at the squish ring on the top of the piston its not concentric all the pistons ive seen have concentric squish rings to me it looks like the pistons were not machined square to either originally or to deal with the extra rod length.
Could there be an inconsistency in the machining of the little ends on the rods, not entirely parallel to the crank/block surface?
Ignore that, just watched the rest of the video!
haha thats alound 👍
What is the difference in price of rods from China, and ones from MED?
Is there a big saving given the machining looks to be questionable?
the saving would be in the realms of 3-400 euros all said and done
Do you think this issue would occure in this manufactures pistons alone, or would a higher quality be more precise ? Still must be chaffed you solved this problem. I am truly enjoying these vids on our race engine .
The issue was in the rods little End Guy as apposed to the Pistons, the pistons where 100% on point all pins where level and true
@@HREIRL I was listening honest , got distracted by the machining of said pistons lol 🤔😃
Will it make a difference to the combustion as the dish in the piston is no central?
It’s specifically of set Nicolas. It helps introduce Swirl into the combustion proses to get better burn
Isn't the little end being slighty on the skew cause imbalance and vibration even after the piston top has now been squared up?
The pistons where all balanced after machining so no problem with imbalance. You are right tho the piston is not sitting 100% square in the bore which will effect top power but thems the brakes
@@HREIRL Half time catch up lol?
Doing this will always have piston off square but I know you’ll know this 😵💫
you are spot on
I think you are applying a temporary solution and not applying the correct solution, which would be to put good connecting rods of the correct size.
Your are spot on Joao 100% a temporary solution but when your racing in 7 days and the car needs to go back together you have to work with what you got. New rods for this motor would be 2 weeks out in the island 👍
😳
😅
wouldnt doing this cause an imbalance in the piston weight? clearly doesnt seem to make much of a difference if no one else asked this question.
Offset con rods.
1st
👍
Rods is rubbish and having pins not parallel to big end your forces in engine will be bit odd and wrecking. Is painfull to see that and I hope it is not bogineer ignorance just engine is test bitch and is to be destroyed or how fare we can go with this.
you are right and it is a test mule, plans are a foot to get new rods
Please stop the tinging subscribe noises in your videos, they scare the hell out my dog to the point I'm going I'm going to ban my other half from watching your videos. Very random Sorry!!
Im very sorry to hear this, I will reduce the volume hopefully that will help stay safe and I hope your dogo is not scared in future 👍
@@HREIRL OMG thank you so much, he's such a fan of your channel I have to tell him off and put it on silent and I feel bad. My dog had a random noise phobia develop after being in the vets for her teeth done earlier in the year. Sorry to be a nuisance 😂💙💚