DanG

Reason I asked about findig the crack is the shop I had pull my motor before I knew how bad things were had the whole assembled block resting on it! Pan off, nothing but the pickup and a corner of the block supporting everything. A-holes!

Ahmet

The car has been at my shop since I spotted this problem a few days ago. I had noticed louder lifters, but I doubt I let low or 0 oil pressure go on for too long, I THINK I'm ok. The idea of replacing rod bearings seems appealing, but while doing that do I stop there or continue to pull the head to be rebuilt (after all compression is only around 115), and while there why not throw rings at it? I really don't like this process... Thanks a bunch for all the replies.
Ahmet

Ahmet

Update, pulled the pan today and the pick up tube looks fine with no cracks, and certainly not loose. The seal at the very top of the pick up doesn't look so happy however, but I didn't remove the pick up off the block so I don't know for sure.

I also looked at the #2 rod bearing, and that appears fine as well. It's got normal wear, but it doesn't need replacement at all. Anyway, ideas as to what maybe the problem?
Ahmet

DanR 1201

Check the backs of the bearing shells if there are any spots that appear polished. Also were they tight in the rods or did they slip out easily? Either can indicate they are starting to walk and could eventually spin. The bearing surfaces meanwhile could look ok. Suggest you check all four and replace them and the rod nuts while you can.

Ahmet

The back of the bearing shell looked OK for #2. It fit on the crank snugly, but when I pulled it off from the crank, it would not really fit into the bearing cap (too loose, the semi circle was too tight). It fit back on the crank fine however.

Though I appreciate the input on this, my primary concern is fixing the oil pressure issue...
Ahmet

Ahmet

I should clarify, when i say it fit fine onto the crank, I mean that it seemed too tight to fit on the crank as well, but snapped into place fine... It appeared to be fine on the bearing cap once it was sitting on the crank.
Ahmet

Ahmet

Any ideas guys? I'd like to throw this thing together soon!
Ahmet

Dal Heger

Bearings are one use items. If you've taken it off, replace it. Remember to replace the rod nuts too, they are one use only.

Dal.

Ahmet

Dal, I don't mean to sound disrespectful with the following but I have no problem going against the recommended procedure on a whole lot of things on a car, especially one that's not a customers, or on a race car.

Factory manuals wouldn't approve of running more than 12lbs of boost on a 944 turbo, let alone a larger turbo or different exhaust. I've been around 944 turbos pushing 2x their original power, again none of which is "approved"... What about 15lbs worth of wastegate mounts? People go with aftermarket wastegates that are often heavier, and seldom supported...

Do you have any data on why I should not re-install the same bearing (other than what's printed in a manual)? Again, I'm not saying you're wrong or that your philosophy is flawed. All I'm saying is in my honest opinion, and from my experience it's quite allright to go against what maybe printed in a manual.
Ahmet

Dal Heger

With the Rod nuts, they are one time use, the serrations get "dull" and won't grip the second time you use them. The bearing shells get deformed when you put them in and torque the caps down, evidenced by the fact that you had trouble removing them from the crank. When you put them in the first time they are tight on the rods, when you torque them down they deform a little bit. When you run an engine they deform slightly more. Besides rod bearings are cheap.

No disrespect noted. I had these questions also when I started out, heck I still have questions.

Good luck.

Jaak Lepson

Got this off the 951 e-mail digest ... it may help.

Jaak

******************************************************

Let me first thank all the people who responded with potential solutions
to my problem, which was zero oil pressure for about 10 seconds when
starting cold, combined with a Brake Fluid warning light and noisy valves.
After that time, when I blipped the throttle a few times, the oil
pressure shot up to 5 bar, the Brake Fluid light went out, and the valves
quieted instantly. I especially want to thank the folks who sent e-mails
to me directly – when you operate in digest mode, it’s a very happy
feeling to get an e-mail from someone who takes the time to try to help.
This List is great!!

The problem was the oil pressure relief valve! The prize winners for
getting it right are Michael Louie, Dave Cooley, and Markus Blaszak (I
appologize if I left anyone one out), with extra credit on this test as
follows:

1. Markus gets extra credit for predicting that my car would have the
older, three piece OPRV, which it did, and giving the best explanation as
to why the OPRV was the likely culprit.

2. Michael gets extra credit for telling me “Porsche recommends
replacement with the new OPRV which is a single piece, and has an outer
body manufactured from a rust resistant metal. The cost of a new one is
about $300-$400 depending on where you get it from.” He was exactly right
– there is a technical bulletin that says to get rid of the three piece
OPRV and replace it with a one piece unit that has a S/S sleeve, for which
I was charged $297.

3. Dave gets extra credit for concluding that the Brake Fluid warning
light was just a red herring and had nothing to do with the problem. I
have had this car for 6-1/2 years during which time I maintained an
adequate brake fluid level, so I never had the Brake Fluid warning light
come on, except when I turn the key to the On position before starting
it…..so, I just assumed that it worked correctly. As it turns out, the
Brake Fluid warning light is apparently cross-connected to the Low Oil
Pressure sensor. Tonight, I removed the cap on the top of the brake fluid
reservoir on my 1987 – the Brake Fluid warning light came on. When I did
the same to my 1986 (the one with the oil pressure problem), I got no
indicator light at all. Dave also gets extra credit for explaining that
the OPRV gets contaminated with debris, as debris was found in the OPRV
after it was removed.

The problem was solved by Nino Performance in Bethany, CT, where I have
taken my 944’s since 1988. I happened to have an appointment for an air
conditioning problem, so I said, “Gee Joe, while the car is here anyway,
how about looking into a situation where I have no oil pressure at
startup. A few guys on the List seem to think it might be the OPRV.” Joe
immediately recalled seeing some technical bulletins on exactly that
problem – apparently, there have been several. It’s a great feeling to
speak with a mechanic with at least a little knowledge about your problem
– I went there with a pretty good idea as to the problem, and a pretty
good idea as to the solution with its cost. THANKS GUYS!!
Now, if someone could only tell me why my interior lights (overhead and
rear hatch) turned themselves on after I was driving for about 15 minutes
on Friday, I would be even happier. When I manually open and close either
door switch, the intensity of the light changes, which indicates to me
that both door switches are working properly and it’s probably picking up
a stray ground from somewhere which is completing the light circuit.
Anyone interested in going for some additional extra credit?

Ahmet

Thanks for the reply, but my car being an 87 should already have the single piece valve.

The more I think about the oil pressure problem, and speaking to my friend who was with me when I noticed the light, it may have come on while turning right very very slightly, and thus I'm probably looking at an intermittent low oil pressure problem that may not have much to do with turning at all. My oil pressure sometimes does seem slow to build when first starting the car, but not to the order of 10 seconds (not even 5, maybe more like 3, if that). I have a feeling it's not the relief valve.

Dal, I have a problem imagining that the rod nuts getting appreciably more dull when taken off as they did when being put on...
Ahmet

special tool

For any racers concerned with this - I am developing a dry-sump system for the 951.
It uses a Peterson tank in the back for weight dist., and retains the stock pump only for scavanging.
The stock pickup get tossed in the can.
You will be able to use the stock filter, or a remote filter if you like.

I have delivered the pan and pickup assembly for my modifications for a very good price. This is a company that ONLY does dry sump systems.

Ahmet

Hello all,

Thanks a bunch for the replies. I have replaced the oil pick up tube to block seal. The car now has oil pressure quickly when starting, and does NOT loose oil pressure at any time. Engine is much quieter as well. Bearings looked slightly worn but not in need of replacement, so I did not replace them.
Thanks again.
Ahmet