Any 944 Rod bearing failures WITH drilled crank?
11-03-2003, 02:09 AM
#31
Which Mobil 1 is been used? There is different versions of this that I know of. The oil sold in stores is not for racing. There is a racing Mobil 1 oil in different weights. I think the typical race oil is in fact a 0-60 weight.
11-03-2003, 11:10 AM
#32
Race Director
Thread Starter
Derrick,
Thanks for the input on the cranks.
Unfortunalty that is what I was afraid of. As I dig deeper there seems to be a couple reoccuring issues on these bearings
1) Oil supply levels in general
2) Oil Quality - Ability to Mantain Viscosity & prevent foaming
3) Oil Foaming.
You stated using a race oil.
Presuably this would help #2
Would the knife edge crank help reduce oil foaming?
The more I look the more it looks like oil foaming is also an issue in these motors. That is why a dry sump is so desired.
My conclusion is that you have done 4 things to make your customer's motor last
1) Perp Drill
2) Knife edge crank
3) Oil Cooler
4) Quality Race oil
So it is not quite right to assume that the perp drill by itself would produce the good results your customer's have had. I can easly see us adopting 1, 3, 4 in our cars, but a knifge edge crank is probably not for us to the cost and performance advantages.
Thanks for input.
M42
I believe all the 944 guys are using standard commonly avalaible Mobil 1. I was not aware of a special race blend of Mobil 1.
Thanks for the input on the cranks.
Unfortunalty that is what I was afraid of. As I dig deeper there seems to be a couple reoccuring issues on these bearings
1) Oil supply levels in general
2) Oil Quality - Ability to Mantain Viscosity & prevent foaming
3) Oil Foaming.
You stated using a race oil.
Presuably this would help #2
Would the knife edge crank help reduce oil foaming?
The more I look the more it looks like oil foaming is also an issue in these motors. That is why a dry sump is so desired.
My conclusion is that you have done 4 things to make your customer's motor last
1) Perp Drill
2) Knife edge crank
3) Oil Cooler
4) Quality Race oil
So it is not quite right to assume that the perp drill by itself would produce the good results your customer's have had. I can easly see us adopting 1, 3, 4 in our cars, but a knifge edge crank is probably not for us to the cost and performance advantages.
Thanks for input.
M42
I believe all the 944 guys are using standard commonly avalaible Mobil 1. I was not aware of a special race blend of Mobil 1.
11-03-2003, 11:32 AM
#33
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I'd also like to note that when i used amsoil in my previous 944, not only did i not loose any oil pressure during my weekly 8mile up hill race with a vette. But after changing it at 5k miles, it looked much cleaner and probably had more life to it then when i change mobil at 3k. I think i'm going to test out amsoil in my 911 when i finish putting it together.
11-03-2003, 04:57 PM
#34
Rennlist Member
Derrek,
why do you not look at Accusumps? IM curious. I dont have one and never had. hadnt had the #2-6 bearing issue that many of the 928 guys have had. I also run Amsoil, never shift at past redline, keeping Rs below 6200 generally. many of the listers have been banging off rev limiters and using Mobil 1. any take on that??? again, in our old 79 trackcar, I saw a 2 bar change in oil pressure with mobil 1. also, my S4 and my old part euro 84 5 liter had 4 bar at 1500rpm hot or cold, and were always at 5 bar plus in a race condition.
MK
why do you not look at Accusumps? IM curious. I dont have one and never had. hadnt had the #2-6 bearing issue that many of the 928 guys have had. I also run Amsoil, never shift at past redline, keeping Rs below 6200 generally. many of the listers have been banging off rev limiters and using Mobil 1. any take on that??? again, in our old 79 trackcar, I saw a 2 bar change in oil pressure with mobil 1. also, my S4 and my old part euro 84 5 liter had 4 bar at 1500rpm hot or cold, and were always at 5 bar plus in a race condition.
MK
Originally posted by Derrek Khajavi
Regarding the breakdown of cranks sold that were also knife edged, without taking lots of time to look them all up I would say 80%-90% are also Knife edged, lightened, and upgraded to thread in plugs vs. press in plugs as well as very extreme balancing. Most the customers that I have sold cranks to are racers either dedicated or part time. Also most dont run Accusumps or baffled pans but a few have one or the other. Many of the cranks are in our 8V 2.8 and 3.1 ltr motors and 16V 3.2-3.4 ltr varients including several engines that are turning 8000+ RPM with solid lifters. I truly believe that if we were going to have problems we would have seen them years ago. I absolutly agree that the more you do to improve the oiling the better. That being said I dont prescribe to Accusumps, baffled pans (I have never had a pickup uncover), or overfilling the oil. Perp drilled, knife edged, screw-in plugs, good oil (we use TORCO Race oils with MTZ), running good oil coolers if you are getting up there in temps, or Dry sump if done right.
As far as my customers chiming in here, thats up to them. I know several that come to Rennlist ocationally so we will see if they post.
Regarding the breakdown of cranks sold that were also knife edged, without taking lots of time to look them all up I would say 80%-90% are also Knife edged, lightened, and upgraded to thread in plugs vs. press in plugs as well as very extreme balancing. Most the customers that I have sold cranks to are racers either dedicated or part time. Also most dont run Accusumps or baffled pans but a few have one or the other. Many of the cranks are in our 8V 2.8 and 3.1 ltr motors and 16V 3.2-3.4 ltr varients including several engines that are turning 8000+ RPM with solid lifters. I truly believe that if we were going to have problems we would have seen them years ago. I absolutly agree that the more you do to improve the oiling the better. That being said I dont prescribe to Accusumps, baffled pans (I have never had a pickup uncover), or overfilling the oil. Perp drilled, knife edged, screw-in plugs, good oil (we use TORCO Race oils with MTZ), running good oil coolers if you are getting up there in temps, or Dry sump if done right.
As far as my customers chiming in here, thats up to them. I know several that come to Rennlist ocationally so we will see if they post.
11-03-2003, 05:41 PM
#35
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He's selling www.huntleyracing.com services. I'm surprised that you didn't recognize the "zebra" car which is his avatar.
Just a thought, is it maybe possible that the 944 motor was originally designed with the notion of running regular thick weight oils? I mean just about any regular oil is thicker looking than the thickest synthetic. That might also have an affect on the oil pressure at extreme conditions.
Just a thought, is it maybe possible that the 944 motor was originally designed with the notion of running regular thick weight oils? I mean just about any regular oil is thicker looking than the thickest synthetic. That might also have an affect on the oil pressure at extreme conditions.
11-03-2003, 06:07 PM
#36
Rennlist Member
Ive seen the car, its not on the track that much though (from what i Have seen, but then again, im up north.
I would agree,with you , but the amzoil 20-50 and redline for that matter have not shown the reduction in pressure that mobil 1 has
just an observation, but we will soon find out by some of the reduced oil pressure guys trying new synthetics this coming weekend. (and the 79 track car that I found this oil problem with!)
MK
I would agree,with you , but the amzoil 20-50 and redline for that matter have not shown the reduction in pressure that mobil 1 has
just an observation, but we will soon find out by some of the reduced oil pressure guys trying new synthetics this coming weekend. (and the 79 track car that I found this oil problem with!)
MK
Originally posted by 1FastRedSC
He's selling www.huntleyracing.com services. I'm surprised that you didn't recognize the "zebra" car which is his avatar.
Just a thought, is it maybe possible that the 944 motor was originally designed with the notion of running regular thick weight oils? I mean just about any regular oil is thicker looking than the thickest synthetic. That might also have an affect on the oil pressure at extreme conditions.
He's selling www.huntleyracing.com services. I'm surprised that you didn't recognize the "zebra" car which is his avatar.
Just a thought, is it maybe possible that the 944 motor was originally designed with the notion of running regular thick weight oils? I mean just about any regular oil is thicker looking than the thickest synthetic. That might also have an affect on the oil pressure at extreme conditions.
11-04-2003, 11:19 PM
#37
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"My conclusion is that you have done 4 things to make your customer's motor last
1) Perp Drill
2) Knife edge crank
3) Oil Cooler
4) Quality Race oil"
There was an SAE paper by GM that concluded that cross-drilling 302 and 348 cranks killed the bearings. OK, this may not be a porsche, but the theory is the same. Each rod journal relies on the main journal for half-oiling its journal. This oil is fed through that hole on the rod journal when the crank is unloaded(sometime before TDC) and when the pressure hits it uses that film toabsorb the impact.
Now when you cross drill the crank, you have two holes now, the original and the the one 180 degrees one the other side. The theory is that instead of half oiling the crank, you continuosly oil it. This may be true at idle, but at high RPM air is accumulated in the journal. If full circle oiling is needed, use full groove upper and lower bearing and get a higher volume oil pump to conpensate for more oil getting spit off.
1) Perp Drill
2) Knife edge crank
3) Oil Cooler
4) Quality Race oil"
There was an SAE paper by GM that concluded that cross-drilling 302 and 348 cranks killed the bearings. OK, this may not be a porsche, but the theory is the same. Each rod journal relies on the main journal for half-oiling its journal. This oil is fed through that hole on the rod journal when the crank is unloaded(sometime before TDC) and when the pressure hits it uses that film toabsorb the impact.
Now when you cross drill the crank, you have two holes now, the original and the the one 180 degrees one the other side. The theory is that instead of half oiling the crank, you continuosly oil it. This may be true at idle, but at high RPM air is accumulated in the journal. If full circle oiling is needed, use full groove upper and lower bearing and get a higher volume oil pump to conpensate for more oil getting spit off.
11-05-2003, 12:28 AM
#38
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could someone explain the difference between cross-drllling and perp drilling.. The Huntley site is not very informative except to mention that it is vastly superior...
11-05-2003, 10:33 AM
#39
Race Director
Thread Starter
It is my understanding that the drilling of cranks we speak of is only in the rod journal. The main bearing journal oil feeds are untouched.
The stock crank has one hole to supply oil to the rod journal. This hole is 90 deg to the length of the crank. This mean if the crank offset for the rod were considered down then hole exits sideways.
A standard cross drill adds another hole 180 to the stock oil hole.
The Huntly perp drill adds the second hole 90 deg to stock hole. This in the same direction down as is the crank offset.
Lets see if this picture I annotated from Huntley's site helps.
The stock crank has one hole to supply oil to the rod journal. This hole is 90 deg to the length of the crank. This mean if the crank offset for the rod were considered down then hole exits sideways.
A standard cross drill adds another hole 180 to the stock oil hole.
The Huntly perp drill adds the second hole 90 deg to stock hole. This in the same direction down as is the crank offset.
Lets see if this picture I annotated from Huntley's site helps.
Last edited by M758; 11-06-2003 at 10:52 AM.
11-05-2003, 09:52 PM
#40
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11-06-2003, 12:00 AM
#42
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Thank you M758, that explains it.
Derrek, IMVHO, someone should consider updating the "complete info" link to explain what is meant by the only reference :
"Huntley Racing however took the cross-drilling to the next level and developed the Perp drilled crank. We perpendicularly bore a new feed into the rod journal"
to what perp drilling is....
to explain the context ... which I am sure is very clear to many, but perfectly opaque, if, for example, one assumed from the beginning that "cross drilling" would naturally be at 90 degrees to the original hole..
i mean , why else would they call it "cross" drilling ... if it *wasn't* at 90 degrees
Apologies for being a pedantic and ignorant ***
Will likely send you a crank to be perp drilled...
Best,
Derrek, IMVHO, someone should consider updating the "complete info" link to explain what is meant by the only reference :
"Huntley Racing however took the cross-drilling to the next level and developed the Perp drilled crank. We perpendicularly bore a new feed into the rod journal"
to what perp drilling is....
to explain the context ... which I am sure is very clear to many, but perfectly opaque, if, for example, one assumed from the beginning that "cross drilling" would naturally be at 90 degrees to the original hole..
i mean , why else would they call it "cross" drilling ... if it *wasn't* at 90 degrees
Apologies for being a pedantic and ignorant ***
Will likely send you a crank to be perp drilled...
Best,
11-06-2003, 03:59 AM
#43
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To M and Paul,
I am going with the AMSOIL to see how things go. Don Jackson's has it at $7.xx. Also adding an oil temp gauge to keep an eye on that issue.
While I won't be running the enduro, (don't want to risk spinning another bearing that quickly, twice in one month would not be pleasant to explain to the wife), I should have the car back and plan on doing the Sat 40 min race.
Kevin
I am going with the AMSOIL to see how things go. Don Jackson's has it at $7.xx. Also adding an oil temp gauge to keep an eye on that issue.
While I won't be running the enduro, (don't want to risk spinning another bearing that quickly, twice in one month would not be pleasant to explain to the wife), I should have the car back and plan on doing the Sat 40 min race.
Kevin
11-06-2003, 10:50 AM
#44
Race Director
Thread Starter
Kevin,
Good to hear that you will be back on the track. If you have been following these threads you know that I have been working to understand the issues with then intent of providing the info to the rest to the racrers to give us the best chance of making our motors last.
Unfortuantly there seems to be no clear answers.
Derrick,
Based on a response in 951 forum on this I have question. Where is source for oil for the main beaing journals? I know that galleys in the crank feed at the mains the passages that supply oil to the rod journals. What is supply for the mains? Is oil pumped directly in to the crank from the oil pump or is the oil for the mains pumped in from the bearing carrier and then flows into the crank after flowing through the main journals?
Good to hear that you will be back on the track. If you have been following these threads you know that I have been working to understand the issues with then intent of providing the info to the rest to the racrers to give us the best chance of making our motors last.
Unfortuantly there seems to be no clear answers.
Derrick,
Based on a response in 951 forum on this I have question. Where is source for oil for the main beaing journals? I know that galleys in the crank feed at the mains the passages that supply oil to the rod journals. What is supply for the mains? Is oil pumped directly in to the crank from the oil pump or is the oil for the mains pumped in from the bearing carrier and then flows into the crank after flowing through the main journals?
