Changing an oil pump on a SBC

[pontiacfan18]

It's a g-body (85' Grand Prix) with a Chevy 350. Possible to change the oil pump with the engine still in the car (will I be able to jack it up enough to get the pan off?). Looks like yes, just wanted to double check before I jump into it though.

Thanks!
-Mike

 

[SLICK79WGN]

yes just take off your dist cap for some extra clearance... on second thought you might want to pull the dist so you dont have any problems aligning up the oil pump drive shaft. also if you pull the motor mount bolts and put a floor jack with a block of wood under the dampner for some extra room

 

[pontiacfan18]

Sounds good The reply is much appriciated. I put in an engine I bought off ebay which fired right up and runs excellent. Only problem is it's getting too much oil pressure (~70-80 at hot idle). It was rebuilt and I think whoever did it messed up with something with the oil pump. Just going to toss a stock spec'd one in and call it a day. Nice relief knowing I don't have to pull the whole damn engine out again.

Thanks!
-Mike

 

[SLICK79WGN]

is there a reason you dont want the high oil pressure???? If you are set on changing it I would use a melling high volume low press. but if it was me and getting good oil press i'd leave it alone

 

[pontiacfan18]

I was told that is too much pressure to be getting, was I told wrong? At the moment the issue is oil is very very slowly spraying out of the oil filter gasket (it's just a regular old basic fram filter). So my two questions are:

I'm getting 70-80 at cold idle (wrote that wrong above) and 50-60 at hot idle. In gear and at high RPMs it'll go pretty high (80-90-100+). Is this too high?

If not, what filter can I use that'll hold up to that pressue and not leak out the gasket?

I was told this high of an oil pressue can cause long-term bearing issues and maybe damage the oil pump shaft.

PS - This is 10w-30 oil. I could always switch to 5 or 0w and see what things look like then.

 

[SLICK79WGN]

That is a little high and you run the risk of blowing seals other than the oil filter gskt. on a side note I was told by my engine builder to never run fram filters as they are to restrictive. I run WIX filter on everything I own and gain about 5 psi of oil press by switching filters. I have never heard anything bad about long term effect on high oil pressure on the bearings. I am sure some of the others will chime in on this in a little bit

 

[pontiacfan18]

I never run Fram either, I actually put it on in hopes it would cut the oil pressure (but for the record, it didn't really change much from the Purolator filter that was on it before). So you would agree that the pump needs to be changed out?

-Mike

 

[SLICK79WGN]

I think the main problem with high pressure pumps is it is pumping the oil out faster than it is picking it up. I say change it to a high volume low press pump and dont worry about it

 

[Doober]

The reason the pressure is so high is likely they put something in the pressure release spring inside the pump. You'll be fine with a std. volume pump, high volume pumps move more oil, you'd be better off going with a higher volume pan then. 100lbs. is a bit high, probably the max you would want to see in a street SBC. Mine runs 60+ cold/40-50 hot idle, and cruising it's 60+ (not sure exactly because I'm using a stock electric gauge). No issues/leaks.

http://www.summitracing.com/parts/SLP-224-4146A/

Good pump to use, the casting is thicker.

How my pump arrived from Summit

 

[patmckinneyracing]

I know this is a really old thread, but Doober do you know anything about that Z28 style pump (M55A) having any quality issues? Everyone has been freaking out now that melling has been cutting corners and it's hard to find anyone that doesn't have their oil pumps built by them. I think Milodon is the only one looking good right now as far as having a strong casting.