mein51

My complete engine rebuild has about a year and a half on it (rings, gaskets, bearings, oil pan baffles, etc...) and recently I've been keeping my car from track duty due to some weird oil pressure. This condition was slight at first, but has slowly become more of a problem. Here are the symptoms:
1) On startup, the oil pressure needs to be brought up by revving the engine. Once the pressure reads close to 5, it remains there...
2) As the engine warms up, the lifters begin to tick worse and worse only at idle. Lifters only though, I've listened all around my block (especially the #2 cylinder) and can't hear anything else.
3) Also as the engine warms up, when I come to a stop the pressure drops low enough for the bottom of the gauge to go red (along with my favorite ! light). As soon as I bring up the revs, the pressure climbs, but will fall back to a low reading.
4) While driving in 5th and a cruising speed, I have pressure of at least 3. When I get brave and give the engine load, it still raises to at least 4.5 bar.

I'm confused! Part of me wants to get a new pump and rod bearings, but for some reason I think there is something else causing this because I have good oil pressure while driving around. Anyone have any ideas/input? Thanks in advance...

jimbo1111

If you are removing the oil pan. Check the pickup tube seal and inspect the rod bearings.

Ski

easy things to do are a new oil pressure sender and inspect the OPRV - since this is an 86, did you stick with your original three pc or opt for the new two pc one?

since jimbo brought it up, what seal did you put in the oil pick up tube?

Tom M'Guinn

Also check to make sure your front pulley bolt is torqued to spec (150-155 ft. lbs. ish).

Also make sure you have enough oil (drain and add 6.5 quarts) -- there are a couple dip stick types out there that can cause confusion is mixed up.

tedesco

Hi, my guess: Oil pick up seal not mounted or not sealing. The oil pump sucks air from the crank case though this leak. When at idle the pumps capacity is not sufficient to suck oil from the pan due to this leak. If you rev a bit higher oil is fed through the pump due to its higher available flow capacity. Still there would be a mix of oil and air fed trough the engine. The behaviour of the engine you described changes due to the change of oil viscosity. Don´t know how to ckeck if it is realy that seal (or the oil girdle) without removing the oil pan.

tedesco

AHH, sorry, just saw now, Jimbo had the same idea...

DDP

I would say check the cank bolt before anything. Good luck.

mein51

I already have the updated 1pc orpv and I replaced my sending unit after it crashed. I used the seal for the pickup that came in my gasket kit that resembled the one that I took out. I think I'm going to go try the torque on my crank pulley (since that is my easiest and cheapest option for right now). Thanks! I'll keep y'all updated.

DDP

My crank bolt, just today, was a LITTLE loose and I wasn't getting ANY oil pressure. I torqued it back to 155 ft lbs and boom, 5 bar.

mein51

I got started on tightening my crank bolt, but then I realized that my friend with the flywheel lock tool moved to Colorado so I have to wait on the one I ordered to get here to try that.
Did you have any oil pressure before? The only time my pressure goes low is when its warm and at idle.

Zero10

Don't need the flywheel lock tool, do it the ghetto way.
Put it in gear, and have a friend hold the brake pedal firmly.
I've done it before

mein51

I just got back in from my test drive after the crank bolt re-torqueing. All the same problems still exist. Anyone care to input?

Dal Heger

Cracked oil pick up tube (initial slow pressure buildup) and worn out main and/or rod bearings (drop in oil pressure when warm).

If the OPRV is correct, and working properly then that's the only other conclusion. You are using the Mann, or Mahle oil filters, right? If not, then the slow oil pressure buildup might be due to the lack of a anti-drainback valve on the oil filter (the oil pump has to re-fill the oil filter before it can produce pressure). Either way, the drop in oil pressure is wear on the main/rod bearings.

Dal.

mein51

If its my bearings I'm going to just blow up this stinkin car I just did a rebuild a year ago.

Dal Heger

As oil gets hot it thins out. If the clearances are out of spec then it'll flow through those areas too quickly, and at a much lower pressure. The oil pump is a high volume oil pump, it keeps the oil flowing very well. Did the shop that replaced your bearings measure the clearances? Did they polish the crank to get a good surface? Did they use enough assembly lube? What oil are you using? 20w50 is recommended for these cars. Some people here like mobil1 15w50, but I find that it thins out WAY too much after the car gets warm. What is your oil filter?

I need more information.

Right now, to me it sounds like it was a sub-par rebuild. Especially if it started happening right after the job.

What oil filter are you using? (yes, it's important).

Good luck.

Dal.