Can this M96 crankshaft be saved?
07-14-2014, 10:08 PM
#16
Former Vendor
Would be nice if it actually worked as it's designed. The heat exchanger does a great job of warming the oil when cold, but a marginal job of cooling it when its hot. My data logs of this are staggering in high ambient temps and on the track the arrangement isn't effective after around 83*F generally.
The crankshaft oil pasages are also poorly positioned for high speed oil delivery to the rod journals, which is the major defect that leads to spun bearings with these engines. Bet you never heard that one before.
The crankshaft oil pasages are also poorly positioned for high speed oil delivery to the rod journals, which is the major defect that leads to spun bearings with these engines. Bet you never heard that one before.
07-14-2014, 10:55 PM
#17
Drifting
Thread Starter
The Laminova heat exchangers on Ford/Jaguar Duratech engines have the same problem and are removed to fit real oil coolers .
Not surprisingly LN sell a a heat exchanger delete for the M96.
Not surprisingly LN sell a a heat exchanger delete for the M96.
07-16-2014, 06:22 PM
#18
Drifting
Thread Starter
Back to Crankshafts !And the cause of the bearing damage.
Mine has a spun bearing in #5 and rear main bearing damage. But why?
Interesting on the rear main bearing damage - it was slight and it did not 'spin'. The Machinist who has done many M96 engines said he guessed the DMF was 'bad'. Indeed it was.I posted about this a month ago. But it was not very far outside spec(according to the PO who had done an IMS job) .
The Machinist loves old DMFs - brings him new customers ! My DMF was original,now at 90k miles.
He advises balancing the new DMF with pressure plate attached and mark it to avoid reassembly errors. He commented adversely about out of balance/worn DMF+clutch assy and the damage it causes to bearings/cranks and even the c/s carrier.
So be careful to measure the 'play' on the DMF correctly. The spec is easy to misread as an allowable movement clockwise or ccw.It isn't.The spec is for total movement -the sum of both cw & ccw. I posted a photo of this highlighted in white marker paint previously.Yes a DMF is expensive -$350 but an engine rebuild is......I was tempted to fit a regular flywheel+sprung clutch but deterred by advice of the experts here. It just seems technically risky to have so much poorly balanced weight hanging past the end of such a small main bearing....
He'll get a used,good rod for #5 and repair the mess. Presumably the oil supply to #5 was plugged by debris from the main ? The LN filter did not catch everything unfortunately?
And I still don't know why 22 of the 24 hydraulic tappets in the lifters had jammed solid. Still no confirmation if the revised lifter part number 996.105.041.72 is modified to address this issue or not.For reference the old lifter # is 996.105.041.50
Confusingly the OEM supplier(INA in Germany) does not have a revised part number - it is unchanged from 1997 to date : INA420 0049 10
Hopefully I'll start rebuilding the engine in a week or so.
Mine has a spun bearing in #5 and rear main bearing damage. But why?
Interesting on the rear main bearing damage - it was slight and it did not 'spin'. The Machinist who has done many M96 engines said he guessed the DMF was 'bad'. Indeed it was.I posted about this a month ago. But it was not very far outside spec(according to the PO who had done an IMS job) .
The Machinist loves old DMFs - brings him new customers ! My DMF was original,now at 90k miles.
He advises balancing the new DMF with pressure plate attached and mark it to avoid reassembly errors. He commented adversely about out of balance/worn DMF+clutch assy and the damage it causes to bearings/cranks and even the c/s carrier.
So be careful to measure the 'play' on the DMF correctly. The spec is easy to misread as an allowable movement clockwise or ccw.It isn't.The spec is for total movement -the sum of both cw & ccw. I posted a photo of this highlighted in white marker paint previously.Yes a DMF is expensive -$350 but an engine rebuild is......I was tempted to fit a regular flywheel+sprung clutch but deterred by advice of the experts here. It just seems technically risky to have so much poorly balanced weight hanging past the end of such a small main bearing....
He'll get a used,good rod for #5 and repair the mess. Presumably the oil supply to #5 was plugged by debris from the main ? The LN filter did not catch everything unfortunately?
And I still don't know why 22 of the 24 hydraulic tappets in the lifters had jammed solid. Still no confirmation if the revised lifter part number 996.105.041.72 is modified to address this issue or not.For reference the old lifter # is 996.105.041.50
Confusingly the OEM supplier(INA in Germany) does not have a revised part number - it is unchanged from 1997 to date : INA420 0049 10
Hopefully I'll start rebuilding the engine in a week or so.
07-16-2014, 06:40 PM
#19
Former Vendor
So why do the failures occur in the exact same manner when a single mass flywheel is fitted?
What leads to the connecting rod bearing failure isn't rooted with the DMF. Give me a couple of days and I';ll be on a plane heading to instruct one of my classes in San Fran and I'll take the time to explain the dynamic of this failure. We have caught many of these during failure and of course we've seen hundreds post failure and as a researcher I document all of those things. Its very easy to see what actually occurs.
Thats how we keep it from recurring with our engines.
What leads to the connecting rod bearing failure isn't rooted with the DMF. Give me a couple of days and I';ll be on a plane heading to instruct one of my classes in San Fran and I'll take the time to explain the dynamic of this failure. We have caught many of these during failure and of course we've seen hundreds post failure and as a researcher I document all of those things. Its very easy to see what actually occurs.
Thats how we keep it from recurring with our engines.
07-16-2014, 06:54 PM
#20
Drifting
Thread Starter
"So why do the failures occur in the exact same manner when a single mass flywheel is fitted"
I am unqualified to respond.
And I doubt I am even qualified to attend the seminar even though I live nearby, so just a guess :
1.perhaps the bearing is too small even for an unbalanced lighter mass flywheel ?
2. A helpful fellow on this Forum also said that a regular/lightweight flywheel fails to absorb harmonic imbalance from elsewhere in the drive-train - that the DMF does absorb .
So the solution may indeed be to balance ..but what ? just the DMF plus pressure plate ?
I am unqualified to respond.
And I doubt I am even qualified to attend the seminar even though I live nearby, so just a guess :
1.perhaps the bearing is too small even for an unbalanced lighter mass flywheel ?
2. A helpful fellow on this Forum also said that a regular/lightweight flywheel fails to absorb harmonic imbalance from elsewhere in the drive-train - that the DMF does absorb .
So the solution may indeed be to balance ..but what ? just the DMF plus pressure plate ?
07-16-2014, 07:01 PM
#22
Drifting
Thread Starter
Jake you are a busy guy - building an R&D extension ,flying around like a rock star - it is impressive but instead of all this sturm und drang ,couldn't you just offer a video conference so we could all pay/sign up and share the knowledge ? After all, some of us have contributed a little to your meticulous research :-).
And please, please publish your book! My engine is in pieces and I have no reliable resource to put it back together intelligently -I am waiting for your book!
And please, please publish your book! My engine is in pieces and I have no reliable resource to put it back together intelligently -I am waiting for your book!
07-16-2014, 10:41 PM
#24
Race Director
Back to Crankshafts !And the cause of the bearing damage.
Mine has a spun bearing in #5 and rear main bearing damage. But why?
Interesting on the rear main bearing damage - it was slight and it did not 'spin'. The Machinist who has done many M96 engines said he guessed the DMF was 'bad'. Indeed it was.I posted about this a month ago. But it was not very far outside spec(according to the PO who had done an IMS job) .
The Machinist loves old DMFs - brings him new customers ! My DMF was original,now at 90k miles.
He advises balancing the new DMF with pressure plate attached and mark it to avoid reassembly errors. He commented adversely about out of balance/worn DMF+clutch assy and the damage it causes to bearings/cranks and even the c/s carrier.
So be careful to measure the 'play' on the DMF correctly. The spec is easy to misread as an allowable movement clockwise or ccw.It isn't.The spec is for total movement -the sum of both cw & ccw. I posted a photo of this highlighted in white marker paint previously.Yes a DMF is expensive -$350 but an engine rebuild is......I was tempted to fit a regular flywheel+sprung clutch but deterred by advice of the experts here. It just seems technically risky to have so much poorly balanced weight hanging past the end of such a small main bearing....
He'll get a used,good rod for #5 and repair the mess. Presumably the oil supply to #5 was plugged by debris from the main ? The LN filter did not catch everything unfortunately?
And I still don't know why 22 of the 24 hydraulic tappets in the lifters had jammed solid. Still no confirmation if the revised lifter part number 996.105.041.72 is modified to address this issue or not.For reference the old lifter # is 996.105.041.50
Confusingly the OEM supplier(INA in Germany) does not have a revised part number - it is unchanged from 1997 to date : INA420 0049 10
Hopefully I'll start rebuilding the engine in a week or so.
Mine has a spun bearing in #5 and rear main bearing damage. But why?
Interesting on the rear main bearing damage - it was slight and it did not 'spin'. The Machinist who has done many M96 engines said he guessed the DMF was 'bad'. Indeed it was.I posted about this a month ago. But it was not very far outside spec(according to the PO who had done an IMS job) .
The Machinist loves old DMFs - brings him new customers ! My DMF was original,now at 90k miles.
He advises balancing the new DMF with pressure plate attached and mark it to avoid reassembly errors. He commented adversely about out of balance/worn DMF+clutch assy and the damage it causes to bearings/cranks and even the c/s carrier.
So be careful to measure the 'play' on the DMF correctly. The spec is easy to misread as an allowable movement clockwise or ccw.It isn't.The spec is for total movement -the sum of both cw & ccw. I posted a photo of this highlighted in white marker paint previously.Yes a DMF is expensive -$350 but an engine rebuild is......I was tempted to fit a regular flywheel+sprung clutch but deterred by advice of the experts here. It just seems technically risky to have so much poorly balanced weight hanging past the end of such a small main bearing....
He'll get a used,good rod for #5 and repair the mess. Presumably the oil supply to #5 was plugged by debris from the main ? The LN filter did not catch everything unfortunately?
And I still don't know why 22 of the 24 hydraulic tappets in the lifters had jammed solid. Still no confirmation if the revised lifter part number 996.105.041.72 is modified to address this issue or not.For reference the old lifter # is 996.105.041.50
Confusingly the OEM supplier(INA in Germany) does not have a revised part number - it is unchanged from 1997 to date : INA420 0049 10
Hopefully I'll start rebuilding the engine in a week or so.
Collapsed they could offer less resistance to oil flowing from the oil holes that are intended to lube the lifter bucket in its bore and feed high pressure oil to the zero lash aduster. Thus the top end develops an oil leak that robs the bottom end of oil.
It doesn't take a rod or main bearing long at all to manifest all sorts of problems from inadequate oiling.
(Oh, and I know when a lifter collapses it does not cause the lifter to get smaller in diameter but it does allow the lifter bucket to pull away from the cam and sit lower or make that further down into the lifter bore. Even if this doesn't uncover the oil hole in the lifter bore it does offer less resistance to the oil from the oil and this constitutes an internal oil leak.)
07-17-2014, 12:36 AM
#25
Drifting
Thread Starter
The lifter theory is interesting but there was no indication of reduced oil pressure-even when the rod bearing started banging. I am beginning to think a 'real' oil pressure gauge is required -&/or a Scangauge/Ultragauge
07-17-2014, 01:37 PM
#26
Former Vendor
The oil pressure to the rod bearings is partly generated by the centrifugal force of the crankshaft.
Think about this and then I'll let you piece the puzzle together.
Think about this and then I'll let you piece the puzzle together.
07-17-2014, 02:07 PM
#27
Drifting
Thread Starter
I think I shall ask the Mod. to rename you "Riddler Raby" :-). I feel bifrucated -if you follow Batman.
By the time I save up for your Costa Mesa class and complete my rebuild, I shall have some riddles for you too!
I worked in Prod Dvpt for truck diesel engines so have a rusty, basic understanding the role of the crankshaft creating oil pressure through the wedge/rotation effect between the bearing shells. When the clearance between the shells increases too much &/or the oil supply to the bearings is obstructed ,the crankshaft can no longer pump pressurized oil. Only the oil pump remains for that duty and it is inadequate alone because it creates flow, not pressure. The pump collects unfiltered oil so distributes debris.Then the cascade of oil pressure-related failures starts -including 22 of my lifters.
Am I even close?
By the time I save up for your Costa Mesa class and complete my rebuild, I shall have some riddles for you too!
I worked in Prod Dvpt for truck diesel engines so have a rusty, basic understanding the role of the crankshaft creating oil pressure through the wedge/rotation effect between the bearing shells. When the clearance between the shells increases too much &/or the oil supply to the bearings is obstructed ,the crankshaft can no longer pump pressurized oil. Only the oil pump remains for that duty and it is inadequate alone because it creates flow, not pressure. The pump collects unfiltered oil so distributes debris.Then the cascade of oil pressure-related failures starts -including 22 of my lifters.
Am I even close?
07-17-2014, 02:12 PM
#28
Former Vendor
You are thinking too hard…
So, what if the engine oil loses film strength and due to this and inadequate factory running clearance this created main bearing wear that damaged the rear main bearing?? Would that debris laden oil not be centrifugally delivered to the rod bearing journals for cylinders 3 and 6?
If that happened, what would happen?
So, what if the engine oil loses film strength and due to this and inadequate factory running clearance this created main bearing wear that damaged the rear main bearing?? Would that debris laden oil not be centrifugally delivered to the rod bearing journals for cylinders 3 and 6?
If that happened, what would happen?
07-17-2014, 02:31 PM
#30
Drifting
Thread Starter
Part of the answer may be here:
http://lnengineering.com/resources/2...m96m97-engine/
and in this oil flow diagram:
http://tunersmotorsports.com/wp-cont...IAGRAM-001.jpg
Come on Rennlisters -help me keep up with the Riddler here!
http://lnengineering.com/resources/2...m96m97-engine/
and in this oil flow diagram:
http://tunersmotorsports.com/wp-cont...IAGRAM-001.jpg
Come on Rennlisters -help me keep up with the Riddler here!