427 CBB oil pressure

[70RS/SS396]

Have done that, and it looks great. And it has new head gaskets ect. The motor is in perfect condition.

But maybe I need to change the oilpump go get more oil pressure.

Originally Posted by james schaechter

If this hasn't seen daylight since the 80's it sure would be a good idea to pull the pan and look it over if you can. Much cheaper to do that than to wait for trouble.

[Mike Taylor 3601]

If you dont know what bearing clearances you have I would check them most likely they are a loose, you can test oil pump by taking old main cap and tap it to accept gauge where oil come from pump,stick in bucket oil spin it w/drill and can see what pressure pump is bypassing at,have someone help hold it or mount to bucket it's hard to hold by yourself.
Mike Taylor 3601

[70RS/SS396]

If I going buy a new oilpump, what should I buy?

Melling has one Anti-cavatation design pump.
"Approximately 25 percent over stock volume. Anti-cavatation design. Reduces cavitation effects in high RPM applications. Using this oil pump will reduce pressure at idle. Chromoly steel drive shaft included. Standard pressure spring is included."

http://www.summitracing.com/parts/MEL-10778C/

Is this a good choice? Or can you recommend something else?

Or maybe a GM pump?

http://www.summitracing.com/parts/NAL-3969870/

Or a standard Melling?

http://www.summitracing.com/parts/MEL-M77HV/

Going to rew this engine about 7-7200 RPM

[Alan Roehrich]

The Schumann pump is probably the best off the shelf pump for under $200.

[Mike Taylor 3601]

70SS/RS396
Evidently this is less oil pressure than this engine had when ran before or you probaly would'nt be concerned about it? I ran and seen lots of engines live long lifes with that pressure.
If this is lower than engine had before,does it have main studs or have you changed to a stud set? The reason I'm asking this is because BBC main studs alot of them have a 12 point nut that goes next to oil pump,because the hex nut alot of times won't clear the oil pump and will hold pump off main cap.
If nothing else is wrong and you have HV pump w/hi press.spring that comes in them you probaly have about .004-.0045 bearing clearance
std. vol std.press pump you probaly have about .003-.0035 bearing clearance,that is if you don't have leak somewhere.
I would test pump before I bought another one installed it and had same results,if pump puts out around 60 lbs then you know it's not the problem.
Mike Taylor 3601

[70RS/SS396]

Originally Posted by Mike Taylor 3601

70SS/RS396
Evidently this is less oil pressure than this engine had when ran before or you probaly would'nt be concerned about it? I ran and seen lots of engines live long lifes with that pressure.
If this is lower than engine had before,does it have main studs or have you changed to a stud set? The reason I'm asking this is because BBC main studs alot of them have a 12 point nut that goes next to oil pump,because the hex nut alot of times won't clear the oil pump and will hold pump off main cap.
If nothing else is wrong and you have HV pump w/hi press.spring that comes in them you probaly have about .004-.0045 bearing clearance
std. vol std.press pump you probaly have about .003-.0035 bearing clearance,that is if you don't have leak somewhere.
I would test pump before I bought another one installed it and had same results,if pump puts out around 60 lbs then you know it's not the problem.
Mike Taylor 3601

Hi

No the engine has the same oil pressure as before (in the 80s, when it was raced in stock eliminator).
I know the engine has ALOT of 1/4mile runs with this oil pump and pressure. So it sould be fine. Talked to the builder of the engine and he modified the pump to have this low oil pressure. He drove QS w40 oil, he tried thinner oil, but he had some problem with the puchrods went thrue rockers when he rew 7400+ rpm. But with the w40 oil it was OK.

But when I talk to people now all say, change the pump....you need more pressure....7-10 psi / 1000rpm.

So I dont know what to do

[Alan Roehrich]

Originally Posted by 70RS/SS396

Hi

No the engine has the same oil pressure as before (in the 80s, when it was raced in stock eliminator).
I know the engine has ALOT of 1/4mile runs with this oil pump and pressure. So it sould be fine. Talked to the builder of the engine and he modified the pump to have this low oil pressure. He drove QS w40 oil, he tried thinner oil, but he had some problem with the puchrods went thrue rockers when he rew 7400+ rpm. But with the w40 oil it was OK.

But when I talk to people now all say, change the pump....you need more pressure....7-10 psi / 1000rpm.

So I dont know what to do

Unless the rockers are turning blue, the pushrods did not go through the rockers due to oil weight. If they did turn blue, there are probably a pair of oil flow restrictors in the back of the block, take them out and throw them in the garbage, put a pair of pipe plugs in the block in their place. Then put a good oil pump in the engine with a 70 psi relief spring. I'd put a high volume pump in it with anti-cavitation slots, but that's just me. Then you could probably run a decent 10W30 racing oil and be just fine.

Why didn't you say the oil pump was intentionally modified in the first post? It would have saved a ton of time and effort.

[70RS/SS396]

Originally Posted by Alan Roehrich

Unless the rockers are turning blue, the pushrods did not go through the rockers due to oil weight. If they did turn blue, there are probably a pair of oil flow restrictors in the back of the block, take them out and throw them in the garbage, put a pair of pipe plugs in the block in their place. Then put a good oil pump in the engine with a 70 psi relief spring. I'd put a high volume pump in it with anti-cavitation slots, but that's just me. Then you could probably run a decent 10W30 racing oil and be just fine.

Why didn't you say the oil pump was intentionally modified in the first post? It would have saved a ton of time and effort.

Please read the first post again Sorry, didnt mention that it was modified to have less oil pressure.

"The motor have a stock GM modified oil pump (anti-cavitation grooves)"

The rockers isnt blue, they looks just great

I have looked at this pump, what do you think about this pump?
http://www.summitracing.com/parts/MEL-10778C/

Its a Anti-cavatation design pump, but it says "Using this oil pump will reduce pressure at idle"
Is it any problem to drive this pump on the street with the reduced idle oil pressure?

[Alan Roehrich]

Originally Posted by 70RS/SS396

Please read the first post again Sorry, didnt mention that it was modified to have less oil pressure.

"The motor have a stock GM modified oil pump (anti-cavitation grooves)"

The rockers isnt blue, they looks just great

I have looked at this pump, what do you think about this pump?
http://www.summitracing.com/parts/MEL-10778C/

Its a Anti-cavatation design pump, but it says "Using this oil pump will reduce pressure at idle"
Is it any problem to drive this pump on the street with the reduced idle oil pressure?

Anti-cavitation grooves did not reduce your idle oil pressure too much in your current pump, did they?

I would not be surprised to find that the relief spring in your current pump has been clipped to reduce the oil pressure.

You could probably just call Melling and ask them to send you the high pressure relief spring for an M-77HV, and just put that in the pump you have now.

The weight of the oil had nothing to do with the pushrods going through the rockers if the rockers did not turn blue.

You can run whatever oil you want, but as a customer once said, "I wouldn't pour Quaker State on a rusty plow".

[Mike Taylor 3601]

When pushrods went through that was valve float that caused that,if engine has ran this way parts look good I would leave it alone.
Oil has changed since it was last run get something made for racing that has zinc,Brad Penn,Lucas are what I use most of
Mike Taylor 3601