Low oil pressure

[fireguywtc]

I need some help and advice from you all who know how to work on these old engines. My 352 has been kinda cursed with low oil pressure since I have owned it. When I first bought it the truck started burning, blowing, and leaking oil as well as it had low oil pressure. In late 99 I had the motor rebuilt, and all was well for a while. I have since put 33k miles on it and recently the oil pressure has gone way down.

After the rebuild at idle it would have about 50 psi when cold, once warm about 30 psi. As I would cruise down the road around 55 mph it would have 40 psi. Now I am down to 10 psi cold idle, 2-3 psi warm, and no more then 25 psi when going down the road. My oil changes have been consistent and is always maintained @ full level. I don't have any problems with perfomance, buring or leaking oil either.

Please help because I am lost and want to know how to fix it. Thank you in advance for your replies.

[DuckRyder]

I am going to assume that you have put a manual gauge on it, and that if you have a permanent manual gauge you have tried a different one. (in other words that the pressure is actually low and the gauge is not bad.)

High mileage / neglected FE's generally chew up the cam bearings and thats where you lose the pressure at. Since yours has been rebuilt and assuming the cam bearings were replaced, I would check to see if perhaps the drain back holes in the heads are stopped up holding oil in the head, I would probably even drop a couple of #90 Holley jets in the oil feeds to the rocker arms.

After all of that checks out put a pump and pickup in it and see if there is anything strange in the pan... (like bearing material).

I sure would not run it much until fixed because 2-3 warm isn't enough, FE's are pretty tolerant, but not that tolerant.

[sideoilerfe]

Also, try using 20W50 oil. I used it in my engines with low oil pressure and it helped a little. It's not a permanent fix but It might help for a while.

[fireguywtc]

Yup I have a manual oil gauge and I have not got a new one yet to double check the pressure. I will soon. However I know it has to be close since the pressure has diminished in the last year or so, as well as some valve clacking when the motor is lugging.

I am going to start tearing into it soon to see if I can track down the culprit. I was just hoping it wasn't the bearings. And yes everything was replaced when it was rebuilt, the original problem was fixed until now.

I try not to let my truck sit too much, but while I was stationed in Germany for 2 yrs. 2000-2002 I left it at a buddys house back home in OR. Those 2 yrs he had put only 90 miles on it. I have drove it ever since I got back though Including the trip for OR to MS when I got back from Germany. So I am kind of afraid that sitting hurt it. That was the problem when I first bought it is it had sit for a few years. After I bought it the motor started developing problems, leaks, blowby, burning oil, low oil pressure and so on.

I also want to put a bigger oil pan on it since it only holds 4 quarts total. I will keep you all posted on how it goes and if I have any more questions of course. Thanx for all the replies

[DuckRyder]

A 352 only holds 4 QTS ?

[BobbyFord]

Melling high volume oil pump is what you need.

[Jake11]

They usually hold 5/6qt's. Mine takes 6. Could be a oil pan thing.
Add a extra quart and see if that helps. Jake

[fireguywtc]

They usually hold 5/6qt's. Mine takes 6. Could be a oil pan thing.
Add a extra quart and see if that helps. Jake

I promise it is only 4 quarts total, counting the oilfilter and it sits right at full. I have changed the oil in it for as long as I have owned it (11 years). It does have a small oil pan that I would like to trade out. I don't know if a lot of 352s came with the same oil capacity since I have not talked to a lot of people with the 352s. I run synthetic oil to help make up for this shortfall even if it only helps a little.

[BobbyFord]

Depends on the pan.

[fireguywtc]

Well I confirmed the low oil pressure with a brand new manual gauge. Pressure is so low that at idle when warmed up, the oil drains from the guage tube back to the motor. I am going to take some pics right now before I start cracking into it and then pull the motor.

BTW how much are cam bearings and how difficult they are to put in? Also, how much is a high volume oil pump and where can I get one? I am going to do a lot of touching up to the motor while I have it out as well as front end work

I may scrap putting this motor back into it in favor for a newer 460 or something. IDK but i'm quite frustrated with this oil pressure problem.

[OldRedFord]

I think around $30. I have never installed them myself tho. Depends on how comfortable you feel with the job. I had a machine shop do mine.

[fireguywtc]

I have torn down the engine and found several problems with it aside from what might be causing low oil pressure Cam bearings looked good though, and there is no telling about the oil pump because I am redoing the whole motor with the rest of the frame up.
Anyways, I did find some brass looking peices at the bottom of the oil pan and some that where sucked up to the screen on the bottom of the oil pump. I don't know what they could be from since everything else looks pretty normal. I should have put something there to help size it, but the larges piece is about 1 1/2 - 2 inch long. If you can tell me what these might be and I will be very thankful.

Bill

[DuckRyder]

The picture is pretty small, but it looks like bearing material to me, perhaos the thrust surfaces of the main thrust bearing?

[fireguywtc]

Thanks for the reply and sorry about the picture. I don't know why but when I put it on this thread it shrank. BTW where is the main thrust bearing? I have not been able to find anything on the motor that looks out of the norm and I have the motor torn all the way down with only the pistons and cranks, ect. still left in the block.
Here is the link to my gallery and the picture is much larger there. http://www.fordification.com/galleries/ ... 0602&pos=0

[DuckRyder]

Yep, looks like bearing material.

The thrust bearing is a main bearing with "sides", I don't recall immediatley whuch one it is but it is pretty obvious.