Gintani exposes BMW S65 Motor Bearings/Blown Motor (Video Inside)

[akh23456]

nice info guys thanks.

[BMRLVR]

It is not uncommon for any engine to have increased wear on the main/rod bearings that are furthest away from the oil pump since oil pressure and flow is lowest furthest away from the pump. No doubt their have been a few cases of rod/main bearing issues, however, by increasing the horsepower/torque output of an engine, you are drastically accelerating any engine wear that would have been present in a stock engine.

Increased power/torque results in (or are a result of) increased BMEP's and IMEP's (brake mean effective pressures and indicated mean effective pressures). BMEP's are the peak mean effective pressures calculated from displacement and brake torque. IMEP's are indicated mean effective pressures and are the average of cylinder pressures averaged out over one complete engine cycle.

Thinking that an engine originally designed with an output of 414 BHP and 295 Ft/Lb will last just as long and with no added wear with 50+% more horsepower and torque is not sensible. I work on engines for a living (mostly heavy duty diesels, but piston engines none the less) and one thing I can tell you is that as engine output is increased, the internals are strengthened along with it. A lot of the engines I work on come in multiple horsepower ratings in the same engine family.

As the horsepower ratings are increased via larger turbos and added fuel, pistons, rods, crankshafts, bearings, oil pumps, heads, and compression ratios are changed along with it. I know what you are all thinking, of course pistons, rods, cranks and compression ratios are changed because you are increasing displacement. The fact of the matter is displacement is rarely changed. The internal engine parts used are dependant upon the rating of the engine. Higher horsepower ratings use stronger rods, pistons, cranks, etc. The reason for this is in a heavy duty application, and engine has to make the same number of hours no matter what the horsepower rating. To get equal hours out of an engine that has additional power, changes are required to get equal longevity.

What you have uncovered is no doubt very relevant and valuable to everyone in the M3 community however, two seasons of racing at the added horsepower levels are probably equal to 200,000+miles of street use at stock or near stock horsepower levels. I honestly don't think this engine would have had any issues if it were stock power levels and driven on the street. It just wasn't built to deal with the service and output levels it was operating at. If anything, I think that this shows how strong the engine actually is, to be able to add so much power and stay together is a testament to the over engineering and quality parts that were put into an OEM engine.

I think what this should tell you guys (and what you already realize I am sure) is that if you are going to boost the S65 to the levels that these two engines were boosted, the engine will have to be built with stronger parts, and all tolerances on the rotating assembly must be checked and must be absolutely spot on.

Thanks for taking the time to analyze the failure and to show the internals of Paul's engine.

P.S. Rod stretch is usually due to overspeeding or too much stress on the rod from too much power. Since forces acting on a rod increase with the square of engine speed, operating an engine like this even at the factory redline would mean forces acting on the rod that were multiplied by many times over the factory design spec. Please show us that the bearings are tight in all the other rods as well or the loose bearing shells in those rods are irrelevant.

[erm324]

^ You sir know exactly what you are talking about

[Mbauer]

Originally Posted by Sales@Gintani.com

Yes it doesn't matter if the vehicle is stock or supercharged. We have seen this happen on completely stock M3s. Some even with very little mileage. These motors pictured here were both 2008 models.

There was in fact updates to a few components on the newer s65 M3 models. However, The problem has not been completely solved. We have also seen some 2010 models do this and we know of two 2011 models that are at the dealer right now for similar issues. They are both completely stock M3s, one of them is here in California. The other is a customer of ours who had just finished getting his first break in service done and was barely gonna take delivery of his fully paid exhaust system. He called to tell us to hold off on shipping his exhaust system because his motor let go @ 2,xxx miles.

These are just a few cases, there are many more S65 M3 motors that have let go like this around the world.

I think there are a few things that need to be addressed......

Using realoem.com (not as good as ETK) however is shows the same p/n's for both oil pumps, and connecting rod bearings for 2008MY and 2009MY.

Now there are different part numbers for the crankshaft bearing between 2008 and 2009MY's and this makes some sense to what I have seen.

I have seen and heard a 2008MY S65 make this ticking noise. Now I'm going to describe it as best as I can. It sounds like a lifter type tick, but its not in the top end of the motor. Those who have heard the N52 lifter tick, very similar noise. It is mainly heard on cold starts but eventually happens when its warm also. Its very audible from the below the car, but the tick dances around forward and back and doesn't stay in the same spot. The car was fixed with a new crank and bearings. This was the ONLY M3 I have seen with this noise.

A "birdy" told me BMW thought it was an issue with the tightening order of the bed plate. They took one apart, found nothing, put it back together, drove it 10k and the noise cam back. They did this like twice, never found anything. Eventually, they put a crank and bearings in it, problem stayed away for good. This makes sense as to why there is different number for crank bearings.

I agree Drews motor had lubrication issues and so did Pauls..... You def got lucky with Paul's motor!!! However after watching the video you have abnormal wear on the crank and rod bearings, so this is not an OEM engine issue. It appears forced induction on the S65 requires some internal changes wit higher boost right? Correct me if I'm wrong here, Drew was at like 10 psi? I'm not sure where Paul's motor is???

The first question is: What is the boost limitation to the S65 with out making any internal changes?
I'm no engineer but Id like to think near 6psi?

What changes must be made to sustain these cylinder pressures?
Rods? Probly forged, maybe with a more bearing surface area (ie slightly wider if possible)
Lubrication..... As I stated before I'm no engineer, the oil supply system for this engine is pretty complicated. Literally I have got 5 pages on it.
Low compression... already being done
Sleeves... I guess if you want to get crazy...

Im really interested in the changes to the lubrication system? It seams people have got the AFR's handled pretty well.

[Mbauer]

Originally Posted by BMRLVR

It is not uncommon for any engine to have increased wear on the main/rod bearings that are furthest away from the oil pump since oil pressure and flow is lowest furthest away from the pump. No doubt their have been a few cases of rod/main bearing issues, however, by increasing the horsepower/torque output of an engine, you are drastically accelerating any engine wear that would have been present in a stock engine.

Increased power/torque results in (or are a result of) increased BMEP's and IMEP's (brake mean effective pressures and indicated mean effective pressures). BMEP's are the peak mean effective pressures calculated from displacement and brake torque. IMEP's are indicated mean effective pressures and are the average of cylinder pressures averaged out over one complete engine cycle.

Thinking that an engine originally designed with an output of 414 BHP and 295 Ft/Lb will last just as long and with no added wear with 50+% more horsepower and torque is not sensible. I work on engines for a living (mostly heavy duty diesels, but piston engines none the less) and one thing I can tell you is that as engine output is increased, the internals are strengthened along with it. A lot of the engines I work on come in multiple horsepower ratings in the same engine family.

As the horsepower ratings are increased via larger turbos and added fuel, pistons, rods, crankshafts, bearings, oil pumps, heads, and compression ratios are changed along with it. I know what you are all thinking, of course pistons, rods, cranks and compression ratios are changed because you are increasing displacement. The fact of the matter is displacement is rarely changed. The internal engine parts used are dependant upon the rating of the engine. Higher horsepower ratings use stronger rods, pistons, cranks, etc. The reason for this is in a heavy duty application, and engine has to make the same number of hours no matter what the horsepower rating. To get equal hours out of an engine that has additional power, changes are required to get equal longevity.

What you have uncovered is no doubt very relevant and valuable to everyone in the M3 community however, two seasons of racing at the added horsepower levels are probably equal to 200,000+miles of street use at stock or near stock horsepower levels. I honestly don't think this engine would have had any issues if it were stock power levels and driven on the street. It just wasn't built to deal with the service and output levels it was operating at. If anything, I think that this shows how strong the engine actually is, to be able to add so much power and stay together is a testament to the over engineering and quality parts that were put into an OEM engine.

I think what this should tell you guys (and what you already realize I am sure) is that if you are going to boost the S65 to the levels that these two engines were boosted, the engine will have to be built with stronger parts, and all tolerances on the rotating assembly must be checked and must be absolutely spot on.

Thanks for taking the time to analyze the failure and to show the internals of Paul's engine.

P.S. Rod stretch is usually due to overspeeding or too much stress on the rod from too much power. Since forces acting on a rod increase with the square of engine speed, operating an engine like this even at the factory redline would mean forces acting on the rod that were multiplied by many times over the factory design spec. Please show us that the bearings are tight in all the other rods as well or the loose bearing shells in those rods are irrelevant.

We posted almost the exact same thing at the exact same time haha. Well stated, I agree 100% They have found the weakest link in the chain, and shared it with everyone.

[radiantm3]

I had this issue on my 2011.5 E92 before it even hit a year old. Only did one HPDE and one autocross before it happened. Oil changed every 6k miles. A few people have had this issue right out of the break in period so I wouldn't just write it off to "abuse".

[AlteredBe4st]

good info. thanks

[MSPORTWORLD]

Good info video...I'll keep my fingers crossed and just keep on driving it the way it was meant to be driven.

[E90///M3`]

Originally Posted by BMRLVR

It is not uncommon for any engine to have increased wear on the main/rod bearings that are furthest away from the oil pump since oil pressure and flow is lowest furthest away from the pump. No doubt their have been a few cases of rod/main bearing issues, however, by increasing the horsepower/torque output of an engine, you are drastically accelerating any engine wear that would have been present in a stock engine.

Increased power/torque results in (or are a result of) increased BMEP's and IMEP's (brake mean effective pressures and indicated mean effective pressures). BMEP's are the peak mean effective pressures calculated from displacement and brake torque. IMEP's are indicated mean effective pressures and are the average of cylinder pressures averaged out over one complete engine cycle.

Thinking that an engine originally designed with an output of 414 BHP and 295 Ft/Lb will last just as long and with no added wear with 50+% more horsepower and torque is not sensible. I work on engines for a living (mostly heavy duty diesels, but piston engines none the less) and one thing I can tell you is that as engine output is increased, the internals are strengthened along with it. A lot of the engines I work on come in multiple horsepower ratings in the same engine family.

As the horsepower ratings are increased via larger turbos and added fuel, pistons, rods, crankshafts, bearings, oil pumps, heads, and compression ratios are changed along with it. I know what you are all thinking, of course pistons, rods, cranks and compression ratios are changed because you are increasing displacement. The fact of the matter is displacement is rarely changed. The internal engine parts used are dependant upon the rating of the engine. Higher horsepower ratings use stronger rods, pistons, cranks, etc. The reason for this is in a heavy duty application, and engine has to make the same number of hours no matter what the horsepower rating. To get equal hours out of an engine that has additional power, changes are required to get equal longevity.

What you have uncovered is no doubt very relevant and valuable to everyone in the M3 community however, two seasons of racing at the added horsepower levels are probably equal to 200,000+miles of street use at stock or near stock horsepower levels. I honestly don't think this engine would have had any issues if it were stock power levels and driven on the street. It just wasn't built to deal with the service and output levels it was operating at. If anything, I think that this shows how strong the engine actually is, to be able to add so much power and stay together is a testament to the over engineering and quality parts that were put into an OEM engine.

I think what this should tell you guys (and what you already realize I am sure) is that if you are going to boost the S65 to the levels that these two engines were boosted, the engine will have to be built with stronger parts, and all tolerances on the rotating assembly must be checked and must be absolutely spot on.

Thanks for taking the time to analyze the failure and to show the internals of Paul's engine.

P.S. Rod stretch is usually due to overspeeding or too much stress on the rod from too much power. Since forces acting on a rod increase with the square of engine speed, operating an engine like this even at the factory redline would mean forces acting on the rod that were multiplied by many times over the factory design spec. Please show us that the bearings are tight in all the other rods as well or the loose bearing shells in those rods are irrelevant.

Originally Posted by Mbauer

I think there are a few things that need to be addressed......

Using realoem.com (not as good as ETK) however is shows the same p/n's for both oil pumps, and connecting rod bearings for 2008MY and 2009MY.

Now there are different part numbers for the crankshaft bearing between 2008 and 2009MY's and this makes some sense to what I have seen.

I have seen and heard a 2008MY S65 make this ticking noise. Now I'm going to describe it as best as I can. It sounds like a lifter type tick, but its not in the top end of the motor. Those who have heard the N52 lifter tick, very similar noise. It is mainly heard on cold starts but eventually happens when its warm also. Its very audible from the below the car, but the tick dances around forward and back and doesn't stay in the same spot. The car was fixed with a new crank and bearings. This was the ONLY M3 I have seen with this noise.

A "birdy" told me BMW thought it was an issue with the tightening order of the bed plate. They took one apart, found nothing, put it back together, drove it 10k and the noise cam back. They did this like twice, never found anything. Eventually, they put a crank and bearings in it, problem stayed away for good. This makes sense as to why there is different number for crank bearings.

I agree Drews motor had lubrication issues and so did Pauls..... You def got lucky with Paul's motor!!! However after watching the video you have abnormal wear on the crank and rod bearings, so this is not an OEM engine issue. It appears forced induction on the S65 requires some internal changes wit higher boost right? Correct me if I'm wrong here, Drew was at like 10 psi? I'm not sure where Paul's motor is???

The first question is: What is the boost limitation to the S65 with out making any internal changes?
I'm no engineer but Id like to think near 6psi?

What changes must be made to sustain these cylinder pressures?
Rods? Probly forged, maybe with a more bearing surface area (ie slightly wider if possible)
Lubrication..... As I stated before I'm no engineer, the oil supply system for this engine is pretty complicated. Literally I have got 5 pages on it.
Low compression... already being done
Sleeves... I guess if you want to get crazy...

Im really interested in the changes to the lubrication system? It seams people have got the AFR's handled pretty well.

great video... nice to see a company come forward with these issues to help the community as a whole.

as for the two i quoted.

[BMRLVR]

To add to my post above:

IMO it is not strictly a lubrication issue that caused these engine issues, it is an issue of too much power for the stock oil pump and/or stock oil clearance of the main and rod bearings to handle. If there were severe lubrication issues the engines wouldn't have lasted as long as they did.

In an application like this, higher volume oil pumps (if necessary, I don't know the flow rate of the stock oil pumps) should be part of the package along with slightly increased bearing oil clearance to allow for the 10W60 to take best advantage of the hydrodynamic lubrication that is created in journal bearings from the spinning shaft. With a nice high viscosity oil like the 10W60 used in the S65 a fairly thick oil film is possible. No matter what viscosity of oil and what oil clearance you use, remember, that there is always a point where the force exerted on the connecting rod and crank is going to exceed the strength of the oil fluid film. At and beyond this point the pressure will literally push the oil out the sides of the bearing and you will have metal to metal contact, just like happened with these motors.

If I were to assemble an S65 myself I would go with 0.0010" oil clearance per inch of journal diameter + another 0.0005" for good measure. I would also ensure that there were no more than a 0.0001 variance between any of the main bores/rod big end bores. This coupled with higher volume oil pumps (again if required) and stronger rods and I would assume no more problems would be present.

It would really be interesting to take apart a brand new S65 and measure the oil clearance that BMW is using from the factory. If I ever decide to do a Dinan stroker some of the main questions I will be asking are: 1) What do they set their bearing oil clearances to? 2) What type of rods are used? 3) Do they feel the stock oil pump has enough flow to supply adequate oil to the bearings under full power and full load?

One final thing, I know you mentioned that there were no signs of detonation. But what you actually showed that there were no signs of prolonged detonation. The pitting type of marking that detonation puts on a piston are caused over a period of time. Isolated events of detonation will not cause damage that is visible on the piston crown, It is possible that in Drew's engine an isolated detonation event caused the rod failure. There is just not enough information for me in that video to draw a definitive conclusion of the exact cause of the failure.

Again, thanks for sharing this though!

[Beedub]

gintani.... really impressed with that video...... im absolutly convinced that if i was to have an e92 m3 id be considering your kit..... i love the approach this video takes and this is the way to air out any past concernsw, very well done, this stands your company in very good light imo.....

gintani.... very impressed!

[OM VT3]

so your saying its just a matter of time b4 all our motors let go? lol

[paradocs98]

Originally Posted by BMRLVR

If I ever decide to do a Dinan stroker some of the main questions I will be asking are: 1) What do they set their bearing oil clearances to? 2) What type of rods are used?

I'm fairly sure that the Dinan stroker motor for the E60 M5 V10 uses Carrillo rods--I would assume Carrillos are also used for the M3 V8 Dinan stroker. Thanks for the very interesting and informative posts above.

[alpine335i]

Originally Posted by BMRLVR

To add to my post above:

IMO it is not strictly a lubrication issue that caused these engine issues, it is an issue of too much power for the stock oil pump and/or stock oil clearance of the main and rod bearings to handle. If there were severe lubrication issues the engines wouldn't have lasted as long as they did.

In an application like this, higher volume oil pumps (if necessary, I don't know the flow rate of the stock oil pumps) should be part of the package along with slightly increased bearing oil clearance to allow for the 10W60 to take best advantage of the hydrodynamic lubrication that is created in journal bearings from the spinning shaft. With a nice high viscosity oil like the 10W60 used in the S65 a fairly thick oil film is possible. No matter what viscosity of oil and what oil clearance you use, remember, that there is always a point where the force exerted on the connecting rod and crank is going to exceed the strength of the oil fluid film. At and beyond this point the pressure will literally push the oil out the sides of the bearing and you will have metal to metal contact, just like happened with these motors.

If I were to assemble an S65 myself I would go with 0.0010" oil clearance per inch of journal diameter + another 0.0005" for good measure. I would also ensure that there were no more than a 0.0001 variance between any of the main bores/rod big end bores. This coupled with higher volume oil pumps (again if required) and stronger rods and I would assume no more problems would be present.

It would really be interesting to take apart a brand new S65 and measure the oil clearance that BMW is using from the factory. If I ever decide to do a Dinan stroker some of the main questions I will be asking are: 1) What do they set their bearing oil clearances to? 2) What type of rods are used? 3) Do they feel the stock oil pump has enough flow to supply adequate oil to the bearings under full power and full load?

One final thing, I know you mentioned that there were no signs of detonation. But what you actually showed that there were no signs of prolonged detonation. The pitting type of marking that detonation puts on a piston are caused over a period of time. Isolated events of detonation will not cause damage that is visible on the piston crown, It is possible that in Drew's engine an isolated detonation event caused the rod failure. There is just not enough information for me in that video to draw a definitive conclusion of the exact cause of the failure.

Again, thanks for sharing this though!

If its too much power for the stock oil pump, why have we seen stock low mileage engines fail?

[BMRLVR]

Originally Posted by alpine335i

If its too much power for the stock oil pump, why have we seen stock low mileage engines fail?

I didn't say that it was the oil pump for sure, if you notice I said: "it is an issue of too much power for the stock oil pump and/or stock oil clearance of the main and rod bearings to handle"

To definitively say that the stock oil pumps (the S65 uses two, I corrected my self in the next paragraph down) is the lone culprit, one would need to know the flow rate of the stock pumps. I am not aware if anyone has that information nor have I seen the information published. The stock oil pumps may indeed flow more than enough oil for applications with additional power.

Another contributing factor that I mentioned could be that the oil clearance that BMW has specced for the bearings of this engine is insufficient. This is very plausible and would explain why there have been some issues of failures and abnormal bearing wear on stock engines.

If an engine has been assembled and the spec for oil clearance is tight or right on the borderline, a thousandth or a few ten thousandths of an inch variance between crank journals, rod journals, rod big end bores , or main journal bores on either taper, roundness, or alignment (which is actually quite common, no mass produced engine is perfect in all specs and tolerances) may cause the oil film separating the parts to be too thin or be unable to take the loads placed on the fluid film and allow metal to metal contact.

One of the main things that decides the amount of force a bearing can take is the bearing area. Bearing area is combination of the diameter of the journal and the width of the bearing. Since there is no room to alter either of these dimensions in the S65, there is a maximum amount of power this engine can take and is very little we can do to change this. The S65 does have a nicely designed Forged Crankshaft, relatively large (for the displacement) crank and rod journals, a nice large sump with dual oil pumps, and a generously sized oil cooler. The design features make for a very robust engine, more robust than many other designs on the market.

The thing that people have to realize is that as power and engine speed increases in engines longevity decreases. The engine has proven to be plenty strong to handle 50% increases in power with no internal upgrades and last for extended periods of time. If people are looking for the engine to last forever even with uprated power, that is silly. When someone modifies an engine to the extent that they are being modified they have to realize failures are quite possible and probable.

So alpine 335i to answer your question above in short: I think the main cause for the engine failures on stock engines is not the oil pumps but rather tolerances on the main and rod bearings that are too tight for this high revving high performance application.

[alpine335i]

You sir are a very intelligent person! Great info! It would be great if BMW would acknowledge this problem. I drive an early model M3 (04/08) and would love to do a supercharger but have held off for just this reason.

[m33]

Good input/info

[Mbauer]

Originally Posted by BMRLVR

One of the main things that decides the amount of force a bearing can take is the bearing area. Bearing area is combination of the diameter of the journal and the width of the bearing. Since there is no room to alter either of these dimensions in the S65, there is a maximum amount of power this engine can take and is very little we can do to change this. The S65 does have a nicely designed Forged Crankshaft, relatively large (for the displacement) crank and rod journals, a nice large sump with dual oil pumps, and a generously sized oil cooler. The design features make for a very robust engine, more robust than many other designs on the market.

Exactly!!!!!!

Gintani, have you torn apart any engines with a stage 1 or 2 kit and inspected the bearings for signs of wear?

[Mbauer]

Originally Posted by BMRLVR

One of the main things that decides the amount of force a bearing can take is the bearing area. Bearing area is combination of the diameter of the journal and the width of the bearing. Since there is no room to alter either of these dimensions in the S65, there is a maximum amount of power this engine can take and is very little we can do to change this. The S65 does have a nicely designed Forged Crankshaft, relatively large (for the displacement) crank and rod journals, a nice large sump with dual oil pumps, and a generously sized oil cooler. The design features make for a very robust engine, more robust than many other designs on the market.

Exactly!!!!!!

Gintani, have you torn apart any engines with a stage 1 or 2 kit and inspected the bearings for signs of wear?

[turbo8765]

Originally Posted by BMRLVR

P.S. Rod stretch is usually due to overspeeding or too much stress on the rod from too much power. Since forces acting on a rod increase with the square of engine speed, operating an engine like this even at the factory redline would mean forces acting on the rod that were multiplied by many times over the factory design spec. Please show us that the bearings are tight in all the other rods as well or the loose bearing shells in those rods are irrelevant.

Exactly

[Eugene-TAIWAN]

Originally Posted by Mbauer

Exactly!!!!!!

Gintani, have you torn apart any engines with a stage 1 or 2 kit and inspected the bearings for signs of wear?

I thought Paul's car was a stage 2 and they found the ''wear''

[ImolaMpower]

Very useful information provided by your knowledge, Thank You!

Originally Posted by BMRLVR

It is not uncommon for any engine to have increased wear on the main/rod bearings that are furthest away from the oil pump since oil pressure and flow is lowest furthest away from the pump. No doubt their have been a few cases of rod/main bearing issues, however, by increasing the horsepower/torque output of an engine, you are drastically accelerating any engine wear that would have been present in a stock engine.

It's also important to note that just by driving your vehicle hard (tracking, racing or whatever the case may be) can drastically increase engine wear too, stock motor or not.

Originally Posted by BMRLVR

Increased power/torque results in (or are a result of) increased BMEP's and IMEP's (brake mean effective pressures and indicated mean effective pressures). BMEP's are the peak mean effective pressures calculated from displacement and brake torque. IMEP's are indicated mean effective pressures and are the average of cylinder pressures averaged out over one complete engine cycle.

Thinking that an engine originally designed with an output of 414 BHP and 295 Ft/Lb will last just as long and with no added wear with 50+% more horsepower and torque is not sensible. I work on engines for a living (mostly heavy duty diesels, but piston engines none the less) and one thing I can tell you is that as engine output is increased, the internals are strengthened along with it. A lot of the engines I work on come in multiple horsepower ratings in the same engine family.

It seems like this is where the major confusion begins. What most people don't realize is that adding boost has its pros and cons. Yes, you will make more power. However you will decrease the life span of your engine. This is the case with any F/I on any vehicle which was not designed to be Forced Inducted. Even with engines that were designed for boost, when adding even more boost you are again decreasing the life span.

As the saying goes, "you gotta pay to play". Unfortunately there is no 100% fail safe way to boost these engines and expect them to last as long as the manufactures intended them to, especially with some of the faults/issues the S65 is known to have. There are however ways to help address these issues, and that's what Gintani is saying based on the research they've done.

Originally Posted by BMRLVR

As the horsepower ratings are increased via larger turbos and added fuel, pistons, rods, crankshafts, bearings, oil pumps, heads, and compression ratios are changed along with it. I know what you are all thinking, of course pistons, rods, cranks and compression ratios are changed because you are increasing displacement. The fact of the matter is displacement is rarely changed. The internal engine parts used are dependant upon the rating of the engine. Higher horsepower ratings use stronger rods, pistons, cranks, etc. The reason for this is in a heavy duty application, and engine has to make the same number of hours no matter what the horsepower rating. To get equal hours out of an engine that has additional power, changes are required to get equal longevity.

Exactly! And this is what people truly have to understand. Building your motor is a great idea as you can better suit it for a F/I application.

Originally Posted by BMRLVR

What you have uncovered is no doubt very relevant and valuable to everyone in the M3 community however, two seasons of racing at the added horsepower levels are probably equal to 200,000+miles of street use at stock or near stock horsepower levels. I honestly don't think this engine would have had any issues if it were stock power levels and driven on the street. It just wasn't built to deal with the service and output levels it was operating at. If anything, I think that this shows how strong the engine actually is, to be able to add so much power and stay together is a testament to the over engineering and quality parts that were put into an OEM engine.

Again, this it's just too difficult to confirm being that a good number of bone stock and unmolested S65's have failed.

Originally Posted by BMRLVR

I think what this should tell you guys (and what you already realize I am sure) is that if you are going to boost the S65 to the levels that these two engines were boosted, the engine will have to be built with stronger parts, and all tolerances on the rotating assembly must be checked and must be absolutely spot on.

Thanks for taking the time to analyze the failure and to show the internals of Paul's engine.

P.S. Rod stretch is usually due to overspeeding or too much stress on the rod from too much power. Since forces acting on a rod increase with the square of engine speed, operating an engine like this even at the factory redline would mean forces acting on the rod that were multiplied by many times over the factory design spec. Please show us that the bearings are tight in all the other rods as well or the loose bearing shells in those rods are irrelevant.

Yes, rod stretch can be caused by overspeeding or stress from too much power, however it is not limited to just that. Overheating from a lack of lubrication is just as likely to stretch the rods. And being that lubrication is an issue with these motors, it is likely the culprit for an engine failure.