[bigdog7373]

Originally Posted by carolinacustoms

That is a possiblity, not sure break in would have caused enough to clog it, but something may have. And for the record I wasn't saying you built the engine wrong just giving ideas of what may be the cause. After I read my post it did not read the way I intended. Sorry if I came across wrong.

Kelly

I didn't take it offensively at all. The problem is probably my fault anyway! Lol

Originally Posted by lg1969

There are two areas you should chck. A defective oil pump or the distributor itself. The housing itself may not be sealed causing the oil passage to leak back in the oil pan. I had to replace my distributor twice. Once on a 307 and most resent my 406. Hope this helps ya.

How could I check for the dist sealing correctly?

[lg1969]

The only way you can tell is to grab another distributor from someone.

[shane.,herold]

I had a fresh 350 with very tight tolerances idle with low pressure but above idle it was fine. It had a standard oil pump. I used to run HD 30w in it in the summer. just make sure its up to temp before you run it hard. I DO think that you should have more than 20 cruising, but it shouldnt fail...

[bigdog7373]

It cruises at like 1300-1500 rpm so I don't think 20 is bad at all.
I don't know anyone who would have a distributor that I could use. Id have to get a new one, but that's a lot of money just to do a test.

[bigdog7373]

I'm gonna grab some 10w40, a quart of w60 and a fresh filter today. I'll see how the 40 works and if needed I'll mix in some 60 to bring it up a little more.

[ap72]

when you rebuilt the engine you did use a new oil pump right? I wouldn't dream of reusing one since they're so cheap. I also almost always use a high volume unit which would probably have fixed this problem before it started.

20psi at 1500 RPM is fine, BUT you also have the problem of lower than normal oil pressure along with far too low of cruise speed- together these can wear bearings pretty quickly.

[snakebit68]

Just my opinion...but I think adding thicker oil to boost pressure would only be masking a more serious issue. Low oil pressure is an indication of an underlying issue. First, make sure your sending unit is functioning properly and then verify your gauge is reading correctly. If so, its time to open it up and check oil returns, pump pickup, oil pump...and then on to clearances. But don't ignore it. My buddy tried the thicker oil trick to boost pressure...it worked...until he made a pass at the track and it seems the thicker oil was unable to return to the pan fast enough at 7000 RPMs and "BANG". There are alot of details and steps involved to diagnosing your issue...but don't put a bandaid on it, please.
Just my opinion...no better then anyone else's

[ap72]

20psi at 1500 RPM is NOT that low. its below average for a new crate engine but many people have built engines with this pressure or less. I'm tempted to think he reused the oil pump and a worn oil pump will have such a poor seal that it will have little pressure at low speeds- the other option is that he is just running larger clearances, and at one time that was a VERY common thing to do.

I wouldn't go too much thicker and I'd give serious thought to buying a better pump (m155hv from melling is about $40 without the pickup, which is about another $10). You may have other issues (leaky pick up, clogged pick up, leaking oil main, etc.) but it is possible for everything to be fine and just have low oil pressure if you have large rod, and main, or lifter, or cam clearances.

[snakebit68]

I agree with ap72. Dead on with his thoughts, as I was thinking the same. Besides, I've had alot of small block Chevys and they have always seemed to run a bit low on pressure at idle. As long as the pressure comes up upon acceleration to a reasonable level he should have no problems. But if the problem persists, dont ignore it

[vinniekq2]

If you bother to change the oil pump,then add a bigger pan.

[snakebit68]

I was a little struck by the fact that you stated your engine was bored .080 over. I was under the impression that a 383 is a 350 block that is .030 over with a 400 crank and flywheel...bringing the cubic inches to 383. If your block is .080 over you may never get good oil pressure. I believe the limitations on boring a 350 block border around .060 and that is pushing the cylinder wall dangerously close to being to thin. Those cylinder walls are surrounded by water jackets, ports in the block that allow coolant to dissapate the heat of the cylinders. Are you certain of the bore?

[bigdog7373]

Originally Posted by ap72

20psi at 1500 RPM is NOT that low. its below average for a new crate engine but many people have built engines with this pressure or less. I'm tempted to think he reused the oil pump and a worn oil pump will have such a poor seal that it will have little pressure at low speeds- the other option is that he is just running larger clearances, and at one time that was a VERY common thing to do.

I wouldn't go too much thicker and I'd give serious thought to buying a better pump (m155hv from melling is about $40 without the pickup, which is about another $10). You may have other issues (leaky pick up, clogged pick up, leaking oil main, etc.) but it is possible for everything to be fine and just have low oil pressure if you have large rod, and main, or lifter, or cam clearances.

I'll see how it does with the new filter and oil but I may end up changin the pump. I have a change the pan gasket anyway cause its leaking a little. I can't remeber what pump I used or if I even changed it. Its was a while ago. I had a thought that maybe I left out the gasket that seals the pump to the block? Seems like it could cause this problem. I don't know how I could get the pan off with it in the car though.. For the pump I would think I could pull the old one out and let the drive shaft drop out with it, then just put the shaft on the new pump and slide it up in. This way I wont have to do anything from above.

Originally Posted by snakebit68

Just my opinion...but I think adding thicker oil to boost pressure would only be masking a more serious issue. Low oil pressure is an indication of an underlying issue. First, make sure your sending unit is functioning properly and then verify your gauge is reading correctly. If so, its time to open it up and check oil returns, pump pickup, oil pump...and then on to clearances. But don't ignore it. My buddy tried the thicker oil trick to boost pressure...it worked...until he made a pass at the track and it seems the thicker oil was unable to return to the pan fast enough at 7000 RPMs and "BANG". There are alot of details and steps involved to diagnosing your issue...but don't put a bandaid on it, please.
Just my opinion...no better then anyone else's

I'm not looking to mask the problem. But if going from 30 to 40 weight oil will fix it I don't think that's really considered masking it.

Originally Posted by snakebit68

I was a little struck by the fact that you stated your engine was bored .080 over. I was under the impression that a 383 is a 350 block that is .030 over with a 400 crank and flywheel...bringing the cubic inches to 383. If your block is .080 over you may never get good oil pressure. I believe the limitations on boring a 350 block border around .060 and that is pushing the cylinder wall dangerously close to being to thin. Those cylinder walls are surrounded by water jackets, ports in the block that allow coolant to dissapate the heat of the cylinders. Are you certain of the bore?

Wrong thread lol

[bigdog7373]

Originally Posted by vinniekq2

If you bother to change the oil pump,then add a bigger pan.

Vinnie, is that a 2nd gen fbody in your pic? If so have you even changed the pan with the engine in the car? Like I said before I can't pull the engine cause of my pita hoa people.

[vinniekq2]

Originally Posted by bigdog7373

Vinnie, is that a 2nd gen fbody in your pic? If so have you even changed the pan with the engine in the car? Like I said before I can't pull the engine cause of my pita hoa people.

Its a C-3 with a 434 stroker,7 qt pan. The center link is quite close,other than that I could probably change the pan in the car. I would not do that. I would take the engine out and put it on the stand.If I have to do something else like a crank seal or timing chain,its easy with the engine on a stand.
I use a roller cam so I would inspect the gear and back of the manifold. Maybe do a quick wash and detail before it goes back in. Thats just me though,,

[bigdog7373]

Going out now to change the oil. I'll post results in a few.