Olds oil pressure advice wanted

[DRIVEN]

There's an ad that pops up on CL every few weeks that has me tempted. Seller has a 403 that's complete minus carb and fresh heads (who cares, right?) that he claims "Runs well but oil pressure drops when it warms up. This was a common problem and neeeds main brgs to fix." <-from the ad
He also has a complete-minus-carb '84-'86 307 that runs with a rod knock. The asking price for the pair is $200. I don't want the 307 at all and am hoping I might be able to get the 403 for $100. I haven't even called yet because I want to get some experienced advise about the low pressure issue. I've never been very deep into a 403 and I'm not afraid to but just don't want to buy junk that can't be fixed.

Should I or not?
Whats the fix?
Any reason to get the 307 too?

 

[CHRIS.O]

Well he sounds like hes trying to skirt around the fact the motor needs a total rebuild, or atleast the bottom end. If you can get the shortblock for a 100 and want a 403 then go for it. Your in for a crank grind probably, new bearings for sure of course, possibly an align hone for the main bores, RX the rods possibly, new pistons and a bore. All depends on what kind of shape it is in. Oil pressure dropping A LOT when warmed is your first sign that something is starting to go in the rotating assembly. Could be wear, could be a bearing starting to take a dump.

 

[pontiacgp]

the good thing is you can hear the engine run so at least you know the engine is good for a rebuild...

 

[rustyroger]

What do you want for $200?, thats just about the scrap value of the motors.
Treat it as getting a core motor for a rebuild, check them out for cracks and put the $$$ into getting them built how you want.

Roger.

 

[DRIVEN]

Well he sounds like hes trying to skirt around the fact the motor needs a total rebuild, or atleast the bottom end.

Yeah, that pretty much goes without saying. Not being an Olds guy (yet), I was just looking for some guidance in the "worst case scenario" department. Things like fractured block issues, etc, that might make this a boat anchor. The seller makes the problem sound simple and common but I was just looking for some other input based on his description. At $100-200 it's a pretty safe buy and I really don't expect much -- I'm just not in the scrap buying business :lol: .

 

[CHRIS.O]

You won't know until you get it on the stand and torn down. Just a chance ya gotta take.

 

[Mathematic]

Well he sounds like hes trying to skirt around the fact the motor needs a total rebuild, or atleast the bottom end. If you can get the shortblock for a 100 and want a 403 then go for it. Your in for a crank grind probably, new bearings for sure of course, possibly an align hone for the main bores, RX the rods possibly, new pistons and a bore. All depends on what kind of shape it is in. Oil pressure dropping A LOT when warmed is your first sign that something is starting to go in the rotating assembly. Could be wear, could be a bearing starting to take a dump.

even for a rebuit engine? im having the same issue. I just got my engine rebuilt about 2/3 weeks ago. The first day i drove the car home...i drove about 25-30 miles and when i stopped at a red light the engine idled down and cut off. I got it back home. Initially i thought it was a carb issue but wasnt sure. I called the guy who rebuilt it and he said thats probably what it was. Fast forward to last weekend, I installed some gauges oil/temp and i noticed that at cold start up my oil pressure is around 40-45 but after about 15-20 minutes the pressure drops to 30-20-10- and 0 when i come to a complete stop. I have to hold the brake and gas to keep the car from shutting off. I talked to the guy again and he said everything is brand new so it shouldnt be bad bearings...im gonna take the car to him this thurs.

Could what you described, be my problem??? Even on a rebuilt motor?

 

[DoubleV]

Could what you described, be my problem??? Even on a rebuilt motor?

Yes because most people who 'rebuild' motors don't do it right. Even the top level rebuilders can miss something now and again, but the low level rebuilders just don't take the time to measure everything properly, don't do quality machine work, and use inferior parts. A recipie for disaster!

 

[CHRIS.O]

Mathematic,

I would definitely take the engine back to the builder. It could be something like loose bearing clearances or possibly an oil pick up issue. I would think with low oil pressure on a new motor that it would be loose bearing clearances. Simply a guess though. Did you assemble this motor yourself or did the engine builder?

 

[Mathematic]

Mathematic,

I would definitely take the engine back to the builder. It could be something like loose bearing clearances or possibly an oil pick up issue. I would think with low oil pressure on a new motor that it would be loose bearing clearances. Simply a guess though. Did you assemble this motor yourself or did the engine builder?

engine builder....im taking it back to him this thurs. ill keep you guys updated.