hobiecat

I'm in the process of building up a replacement engine for my track/DE 944S.

I bought a used engine with 55,000 on the odometer. Upon inspection, it shows no signs
of significant wear anywhere....totally consistent with an engine with low mileage. So...because
I figured it wouldn't be a bad thing to do, I put the engine on a stand, took off the oil pan (to install
a pan baffle) replaced the rod bearings and was in the process of installing a crank scraper when
I noticed something very interesting.

The crank moves.... laterally....front to back. More than I would expect. So far, in fact, that if I push as far
as it will go to the rear, the #4 piston rod rubs against the back of the block. When I push it forward,
everything is lined up perfectly....even the crank scraper. Move it back....no go.

So...given the low (documented) mileage on this motor....do I have an issue here, or is this normal?

Considering there are not any (ZERO) marks inside the block that would lead me to believe that #4 is
rubbing on the back of the block, nor were there shavings or scratches anywhere else, is there
some explanation for this? Clearly if this was a problem before I got the motor, it would've
manifested itself in some way....I'd see some damage somewhere....right?

Has anyone else seen a similar issue? The engine is in really great shape....I just don't want to button
it up if I'm going to have to replace something deeper in the block. Make sense?

Leonel_944

maybe the thrust bearing? did ya take off the oil pump gear? If you do look to see if the gear has been rubbing on the front of the pump. When i started the build on my 944 spec car I noticed this also but not as bad and I could see that the oil pump gear was rubbing on the oil pump because of the back and forth play.

I took it apart and found a lot of wear on my main bearings and thrust bearing was real bad crankshaft was also. had some bad scoring ended up replacing the crankshaft, rod bearings, and main bearings.

KuHL 951

The thrust bearing I removed from a 91K block was pretty bad and end play was past spec. The 150K motor I broke down was well within spec. The difference was the 91K motor was from San Francisco with lots of hills and was used for a DD in the city. The higher mileage motor was used for 150 mile daily commutes on freeways. It all comes down to how hard and often the clutch was used or abused. I would do main bearings for sure from your description.

JohnKoaWood

+951....

and here is why

hobiecat

So...I've never done main bearings before. Other than a standard bearing set, what else do I need?

JohnKoaWood

Rod bearings, main bearings, patience... oil pickup seal ring, loctite 574 (IIRC)... seals, rod nuts, pan gasket set, more patience.. and a soft non fiberous roller for the locktite...

I may be missing something, but left my engine FSM in the garage, I can double check for you tomorrow...

whalebird

Before you go to all the trouble. Take a dial gauge and measure the amount of axial play in the crank. Your description is curious, but confirm your suspicion.

StoogeMoe

The previous owner of that engine must have been a clutch rider.

You'll have to replace the mains and maybe the crank too. See factory manual for limits on end play.

JohnKoaWood

I digress, If it is moving far enough to allow #4 to scuff the cylinder wall, it doesn't need to be checked, but the crank WILL need to be looked at after it is apart!

John_AZ

Post #2 & post #3. Just to complete the information...

http://forums.pelicanparts.com/porsc...ml#post5839420

John

hobiecat

All bad news. Well, I'll do some additional checking.....then do the deed.

Will report back if I find anything unusual.

Thanks for all the help.

xsboost90

prob. easiest to find a good crank. I'd bet the thrust is worn out where it rides on the bearing as ive had to replace a couple cranks because of this. Take it to the machine shop w/ the factory specs and have it properly measured- i think its the same crank as a normal 2.5 right?Pretty easy to come by.

hobiecat

Well.....

Thrust bearing AND crank are both shot. Will definitely have to find a new crank. The thrust bearing wore pretty
deep into the crank journal and that's what was causing the excess play. Not sure what or how it happened.
Will post pics when I get a chance. It's not pretty........

Anybody out there have a good crank they're looking to sell?

JohnKoaWood

There is a recycler in the Richmond area that posts up 944 parts on craigslist quite often.. I run down to Richmond at least once a week, often more than once, and if they have a crank I could pick it up for you and bring it back up here!

I'm in Stafford VA, but could deliver it as I enjoy just driving!

heres a link..
http://richmond.craigslist.org/pts/2169610105.html

Tom M'Guinn

I have a crank or two if you need one, though shipping from CA probably would cost more than it's worth...