I have a 2.5L 1985/1 944, the oil pressure at idle is about 10 PSI, when I let off the gas in normal driving the oil light flickers, oil pressure at 2000 rpm is only about 25 psi. when oil is cold both run about 10 psi higher. Do I need a new oil pump or is this an indication I have bigger problem?

 

The oil pressure gauge will always peg high when the car is cold, and come down after about 20 minutes of driving. At idle, you should be seeing roughly 2 bar oil pressure, at about 3.5k rpms you should be seeing 4- 4.5 bar oil pressure. If you are not getting that high, it is indicative of bad rod bearings.

 

I dont know how many miles are on this engine, with oil presure this low would you guess that it is a spun bearing or that one or more of the mains are worn. Also what is a good way after I drop the engine to get it out from under the car?

 

Usually a spun #2 rod bearing is the culprit. Under hard cornering, there is lack of proper lubrication to that bearing, so it is usually the one that goes first. Main bearings are usually ok, although in high mileage engines, should be replaced while you are in there. Once you drop the motor on the ground, take the cherry picker (engine hoist) (Or get a really big freind), and hook it to the front of the car and raise it up with the picker, then slide the engine out. I usually drop the engine on a furniture dolly, that way you can just roll it out from under the car, once the front end is raised.

 

You mentioned rod bearings? do the main bearings have any vulnerability or is it mostly just he rod bearings that go? I have a 993 - are they different in this regard?

 

In the 944 it is usually the rod bearings that go out and give problems, the main bearings oiling system seems to do well in that aspect. Most guys will just drop the crossmember and pan and change out the rod bearings as the cheapest way to get by. If the motor is coming out of the car, by all means do the clutch, rod and main bearings and check the oil pickup tube which likes to crack. You end up doing a lot of "while you are in there" things if you pull the motor. It saves a lot of time in the future.

The 993's are a completely different beast from the 944 engine, so this does not apply to them.

 

Ok then…. I pulled the engine, opened it up and found a worn main bearing #4, the rod bearing for # 4 was grooved slightly like a shaving or particle got in, the center main was worn on the outside, and has lost some metal. Cut up the oil filter and did find grit, but nothing of any size. So now I have a couple more questions. What is the best way to flush the oil system out?
Also, I have a 79, 924 with a good 1984 cc XG engine. Aside from the fact that it only has 115 HP, is there any problem putting this in an 85/1 while I rebuilt or replace my M44/02? Will it bolt up and run for a while?

 

How in depth on the rebuild are you going? Are you pulling the head, etc?

 

I didn’t want to do the top, but looking around the outside of the head, #4 seems to have some kind of black sealer smeared around the outside between the block and head. So I think the heads coming off, and the balance shafts need seals, So I may as well do the whole thing.

 

Good call if you already have the motor out anyways, and if you are going to do the whole thing, then just break the entire engine down and find a place that has a steam cleaner you can put all of the parts in. That will clear out all of the passages. Virtually every engine piece we take off of a motor going through a rebuild goes through our steam cleaner before being reassembled.