Hi there!

I just joined in here today, and I have a question regarding a 231 I'm going to have to re-rebuild for my 1980 Olds Starfire. It will replace the 231 that's in there, that one has some seriously low compression (60 PSI) on one cylinder and no cylinder's above 90 PSI. When I removed the back plugs on each side, the side electrodes were bent up to nearly touching the center electrode, the other four were OK. It ran well until about four weeks ago, just before I was sent to Guam on active duty. Upon returning I found out about the plugs and compression, so it's time to transplant the other 231 into this car, which had only about two years of use before the car was hit in an accident.

When I used to start this engine up (the one I rebuilt, but the current 231 did this too) the oil pressure looked good, over 60 PSI at around 3000 RPM. Once the car warmed up the oil pressure dropped like a rock. At regular operating temperature (20 miles on the highway to work) the oil pressure light would come on if you kept the car in gear at idle, registering under 5 PSI -- oil pressure reading taken at the block where the warning light connected. On the highway it wasn't uncommon to be running around 3000 RPM and have less than 20 PSI oil pressure -- that scared me, my experience being with Brand C 350's and Oldsmobile engines that always had over 10 PSI for every 1000 RPM of engine speed.

Other than the oil pressure this rebuilt 231 ran like a top, and got decent mileage. Before I install it in the good Starfire I want to check it over (been sitting for about 8 years) and address this oil pressure problem. A local Buick Skyhawk owner told me the issue lies in the front cam bearing, is there a heavy duty replacement available? I have used a new front cover, wear plate and high-capacity oil pump kit with the stiffest spring available but the problem never changed.

If anyone has tips on upgrades I can do inexpensively while I'm cleaning up this low-mileage rebuilt engine (gaskets, rings and bearings are already ordered just in case) it would be greatly appreciated.

Take Care,
SrA Ken Snyder
Kansas City, Kansas

Before you spend money on cam brgs. you said you replaced the front timing cover .. you may need to r&r the front cover and look at the cover
gasket at the oil passage .. new covers & old design gaskets DONOT match
and can cause this problem and with the cover off then look at cam brgs.
( you could pressurise the oil sys. to look for leakage at front cam brg.)
HTH guyopel

Before you spend money on cam brgs. you said you replaced the front timing cover .. you may need to r&r the front cover and look at the cover
gasket at the oil passage .. new covers & old design gaskets DONOT match
and can cause this problem and with the cover off then look at cam brgs.
( you could pressurise the oil sys. to look for leakage at front cam brg.)
HTH guyopel
Thanks! I will double-check this when I get the engine out.

It's just odd that both of these engines did roughly the same thing, and I've never had more than the intake off of the current engine. I was going to install the high-volume kit and wear plate, but found out this engine already had them installed. The 231 I rebuilt needed the front cover replaced due to some fairly serious gouges in the oil pump gear recesses. I kept the old cover, so once I get the engine out and disassembled I'll compare them.

I straightened the side electrodes on the #5 and #6 cylinders and reinstalled them. When I started the car back up, it ran reasonably OK but still had more vibration than usual. With the oil pressure being what it's been I'm still committed to removing and replacing the engine -- I need this to be reliable and get the best mileage it can for my National Guard responsibilities.

Thanks again, and Take Care!
SrA Ken Snyder
Kansas City, Kansas

Ken , I would like to edit my post so we are on the same page .The gasket
I was talking about is the side gasket at the engine & timing cover assy.
The oil is pumped from filter to oil gallery passage at front of eng. block
this is where the gaskets donot match and cause internal pressure leak
and low oil pressure . The oil pump cover at base of timing gear housing is not what I was talking about. Just wanted to be clear and save you a lot
of extra trouble . HTH :beers:
Guyopel

Guyopel,

I understand completely, and I remember seeing the holes you mention in the block and cover.

I remembered the e-mail address of my friend with the Buick 350-powered Skyhawk and sent him an e-mail asking about the notorious oil pressure -- here's what he sent me back:

Re: the bearings. Yes. Poston Enterprises, 1-800-635-9781 have a cam bearing that has a full circle groove on the back side and is much harder than stock. The factory front cam bearing has a tendency to get hot and actually melts over part or all of the oil feed hole. This melting covers the oil hole that feeds the 1-3-5-etc side lifters. All this is due to the load the oil pump and the distributor places on the front bearing. But, low oil pressure is most likely to be caused by wear in the the oil pump housing itself. I would seriously look into replacing the front cover assy. JC Whitney sells it for about $130. I bought mine on eBay for about $80.

While you have the engine apart, and prior to having the block tanked, you might want to do this mod.
After removing the front cam bearing, you grind a small groove about 1/8" X 1/8" from the oil feed hole to the hole that feeds the 1-3-5 bank. It is a simple redundant measure that really doesn't need to be done if you use the Poston bearing. But it is not a replacement for the hard cam bearing.

If I had to do one over the other, I'd invest in a new front cover and do the 1/8" groove in the block. A little oil pressure is lost past a soft front bearing, if or when is melts. But it's not a big deal if the driver's side lifters are getting oil and not rattling. Buick says 5-7 psi oil pressure at idle is OK. Can you believe that? ! Well, my 350 idles at somewhere around 15-20 psi. Also,it is suggested to not use a high pressure spring kit or a high volume oil pump kit. All this extra load is very hard on the front cover.....especially in the winter. The steel wear plate on the bottom side of the pump is OK and probably a good idea. Also, Fram is now carrying a new line of oil filters that have a special check valve that keeps oil wher it was when the engine last shut down........a great idea for Buick engines! They have a tendency to bleed down.

So these are on my list of things to do once the engine's out and disassembled. Once I'm actually in progress on this rebuild I'll post more of what I find.

Take Care,
KS

Listmembers and Guests,

Since I last posted I'v torn down both 231's here, and found pretty much the same thing:

The front cam bearings showed excessive wear -- the one I rebuilt in 1996 had noticeable grooves worn into it and the one from the 231 I had been driving (until early September) was really worn. Both had the wear on the bottom side, and I'm sure this contributed to the lack of oil pressure.

I intend to order the improved cam bearings from Poston, replace the front cover with a new unit and use the wear plate only (no high-volume pump conversion) when I rebuild. When we're back on the road here I'll post some more about this.

Take Care,
SrA Ken Snyder