951 Block vs. 944 Block

Gerry Dz · 01-29-2002, 06:36 AM

I threw a rod in my '88 951 last fall and am in the process of looking for a new short block. Does anyone know if there is a difference between '86 , '87 or '88 engines. How about short blocks for 944's(non-Turbo) vs. 951's (Turbo).

Scott R · Scott R's Garage

86 Did not have the auto cam belt tensioner. So if you can I would get an 87 or better block. The short block will have a difference with the oil cooler setup, but where the oil cooler line goes there is a plug that can be removed. Or you can just get old parts off of your block and bolt them on. Long blocks are of course different as the 951 head has ceramic port inserts.

wolfrpi · 01-29-2002, 05:29 PM

86 had forged rods

marksportcts · marksportcts's Garage

If the '86 are forged, what are the others? What is sintered rods?
How different do they look?

Gerry Dz · 01-30-2002, 04:10 AM

Why is it that every 944 with bottom end problems is with the #2 rod bearing. My motor thru the #2 rod thru the block and every motor with bottom end isses has had a bad #2 rod bearing issue. My plan is to find a new short block, rebuild it with good heavy duty forged rods and possibly cross drill the crank. I don't want to go crazy, just build it strong. Before my incident @ road america, I just had the top end done ie rebuilt head, wide fire gasket and raceware studs. New rod bearings and an oilpan mod were made the prior year.

Does anyone know if there is a dry sump kit available for these motors?

JR944 · 01-30-2002, 07:03 AM

The explanation I find most plausible is the angle the oil passage is drilled in the crank to feed the #2 bearing. Also In sustained high G turns (the Carousel at Road America), the oil pickup can be "starved" causing a poor flow to the bearings. Since #2 gets the worst flow to begin with, it is the most likely to be damaged.

If you haven't heard this before.... you MUST run the oil in 944's ABOVE the full mark for track use.

For a car that is used regularly on the track, I think treating rod bearings as a wear item and just replacing them regularly is a good idea.

Joe

JR944 · 01-30-2002, 07:05 AM

The explanation I find most plausible is the agle the oil passage is drilled in the crank to feed the #2 bearing. Also In sustained high G turns (the Carousel at Road America), the oil pickup can be "starved" causing a poor flow to the bearings. Since #2 gets the worst flow to begin with, it is the most likely to be damaged.

If you haven't heard this before.... you MUST run the oil in 944's ABOVE the full mark for track use.

For a car that is used regularly on the track, I think treating rod bearings as a wear item and just replacing them regularly is a good idea.

Joe

Mike B · 01-30-2002, 09:45 AM

This recently was discussed in a thread on rennlist about Engine Failure and Why

Derrek H. Khajavi of Huntley Racing had an intersting theory ...it's near the end of the post (if you haven't read it)

Scott R · Scott R's Garage

So does the "Accusump" actually help cure this problem? Or is there no real cure?

garrity928 · 02-03-2002, 09:50 AM

I read Derrek's comments and he is summarizing what has been found out so far. They are fine.

I do strongly disagree about no further baffling need in the oil pan.

During long sweepers, the pickup can become uncovered and starve the engine.

Also there are better fixes. It however is expensive. We have some racing crankshafts made from billet material that are stronger, lighter and better engineered than the factory cranks. They have much different oiling passages and the use of the center main in oiling does in fact help as the 928 people discovered with much thanks to Red McClintoch of the old DEVEK.

Marc Thomas has proved that the use of an accusump also helps.

A dry sump with good oil pan baffling, modified main bearings, high quality motor oil like Redline and Motul with a designed crank for racing can solve the problems. But realize this can easily cost $8k, but for a racing engine, it is worth it.

Garrity

Gerry Dz · 07-10-2002, 09:44 AM

I am in the process of shopping for a new block and find many 944 blocks at good prices. I was told by some people that they can be easily converted to a Turbo with Turbo balance shaft covers, pistons and crank. However, I also heard that the turbo block is cast thicker. Does anyone know if this is true?

slevy951 · 07-15-2002, 11:20 AM

Quote:

Originally posted by Gerry Dz
I am in the process of shopping for a new block and find many 944 blocks at good prices. I was told by some people that they can be easily converted to a Turbo with Turbo balance shaft covers, pistons and crank. However, I also heard that the turbo block is cast thicker. Does anyone know if this is true?

The blocks are the same. Except for a hole in the upper balance shaft cover for oil supply for the turbo. The balance shaft covers are NOT internchangable between blocks. They MUST go with the block they came from along with the main bearing cage. But, a hole can be drilled in a N/A cover and tapped to accept the oil line.

HTH.