Jim Clark

I've been told that the #2 rod bearing on the 944 needs to be upgraded.

Can anyone tell me the correct and needed items to be done to the crank.

My understanding is that a secondary oil passage needs to be added to #2 as well as the new bearings.

Can this be done to a hardened crank without loss of durability.?

Would it be as effective to enlarge the existing passages in the crank, new bearings, and girdle?

Thanks in advance for the help.

DAR951

This is a topic of major discussion/opinion... there is no single/right answer. Try a search in this and the 944 turbo/NA forums for a ton of info on rod bearing failure prevention.

JJG

http://www.nasaforums.com/viewtopic.php?t=2010

SeaCay

One of the best, comprehensive writings I've seen on this subject yet. Thanks for posting the link!

M758

I put some recommendations in this thread.

https://rennlist.com/forums/showthre...hreadid=119681

There are other as well.

There are no simple "one fix" cures. There ARE things you can do to reduce the risks however.

adrial

Agreed!

Anybody know what sort of modifications to the oil pickup Milledge is talking about? Is it just a ring around the pickup tube?

Or how you could improve baffling? I've seen the Lindsey weld-in baffle but I'm not clear as to where exactly it gets mounted.

thanks

--adrial

Jim Clark

Thanks for all the input.......I'm so confused as to the need for oversizing the oil ports, to cross drilling crank, to perpendicular drilling the crank, to baffles in the pan, to just replace bearings every 40 hours, to extra oil, to just running the engine to the max but not over it.

From all this I have come to a few conclusions.
No one knows exactly why the bearing fail.
No one has a specific fix.
Everyone understands the need to keep an eye on the bearings.
And everyone has an opinion, good or bad.

From this I suggest to anyone else that has this same question, that they prepare to change oil often, use Mobil 1 synthetic, utilize an accusump, check oil continuously, change bearings every 30-40 hours, keep revs below 6700, and just run it and have fun. The total cost of trying to fix the problem is more than just maintaining the engine. And if the bearing spins, the cost of a used engine and putting all your goodies on it, is much cheaper in the long run.

Again, thanks for the insight and suggestions from all.

JPII

smokey

Adrail, the oil pick-up modification is the welding of a collar round it to reduce the possibility of air entrainment. It minimizes the gap between the pickup and the bottom of the sump. The "trap-door" modification can be done a number of ways, but its purpose is to keep the oil from running "up hill" on the right hand side of the sump on left turns. Powerhaus uses a hinged flap, while I have a welded-in divider with a trap door that is normally open but closes on a hard left turn due to the g-force. I think Lindsey Racing sells the parts, and a local shop could weld in the divider. I'll post some pictures when I track down my Rennlist membership number. Is it the cure? No, but it probably helps.

Jim Clark

If you find the picture that would be great.

The oil pick up collar? Any thoughts on length? Would it be adventages to extend the tube and allow screened pick-up surface area to stay the same but just lower into the pan?

APKhaos

This is a scary issue! Does anyone know for certain what mods the factory made to the later [88/89] 951 models to deal with this?

M758

There were none.
We are all on our own to address this issue.

APKhaos

Is that right? Oil pan baffles were stock on the later turbos, right?
Was that all the factory did?

M758

Tony... No!

The factory oil pans do have plastic baffles, but nothing like what is being discussed. The factory never resolved the problem and ALL 944 series engines including the 968 Turbo S and 928's have rod bearing issues.

smokey

Some pictures, if I did it right.

smokey

And the modified pickup.