Small Block oil Pump Question
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Joined: Oct 2004
Posts: 65
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From: Long Valley NJ
Small Block oil Pump Question
I have a 69 small block 350-350. I bought a high pressure oil pump for the rebuild. Will the High pressure pump give me problems? Will there there be to much oil in the upper part of the block? The pump was puchased from Corvette America.
Racer
Joined: Jan 2007
Posts: 314
Likes: 0
From: Pittsfield, Ohio
I find they require a little more hp to turn. Just as good flow / pressure can be had with a std pump with the proper porting / polishing with a die grinder at the Rear main caps / oil pump union. They tend to be the largest contributor to this oil flow restriction due to oil paths being tight and rough.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
High pressure or high volume? The high-pressure pump is fine - the stock Z-28 pump is high pressure. High volume I'm not a big fan of if the clearances are factory - you end up with a bunch of bypass going back into the pan and as noted it takes more HP to drive.
Le Mans Master
Joined: Apr 2000
Posts: 5,202
Likes: 10
From: cincinnati ohio
St. Jude Donor '09
High pressure pumps require no more effort to turn, it's the longer gears in the high volume pumps that are harder to turn.
No problems with too much oil upstairs running a hp pump.
No problems with too much oil upstairs running a hp pump.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
This comes up all the time, and I am amazed at the take so many have on it. Besides wasting power, excessive oil pressure puts additional heat in the oil and increases oil pump drive component wear (that wasted power doesn't just magically disappear), not to mention causing oil to bypass the filter more often. According to Smokey Yunick (who among us is qualified to question his wisdom?) anything very much more than 10psi/1000rpm (hot) is excessive (racing, or no). So, insurance it's not. 
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
No pushback on the high pressure overall, but we need to differentiate just a bit. High VOLUME is a structurally different pump. High PRESSURE is controlled by a spring in bypass. Almost all of the high pressure pumps come with a second spring for lower pressure if needed.
It's worthy of note that although no one would ever question The Great One (Smokey), times change and for example the LT1/LT4 pump is a high-pressure pump.
I think the nut here is that HV is not required, and you should run a pressure that's appropriate to the use of the engine.
It's worthy of note that although no one would ever question The Great One (Smokey), times change and for example the LT1/LT4 pump is a high-pressure pump.
I think the nut here is that HV is not required, and you should run a pressure that's appropriate to the use of the engine.
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Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
RUN THE DAM PUMP!!! You have it use it. The 3 or 4 horse power you lost, will never be noticed. Pumping all the oil to your heads? Only if you drive a 4500 rpms for 1/2 hour and your drain backs are clogged. The Only precaution I would take, is buy a oil pump drive with a steel collar (SUMMITRACING $10.00) and warm the engine up before REVVVVING AND ENJOY!!!
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
Pressure
I don't think that a higher oil pressure than stock will come for free !!!!
More power is needed to produce more pressure, be shure!
Tha main concern for higher pressure is the scattering of the igniction.... as you know the oil pump is driven via the distributor shaft and a bigger load will produce more timing oscillation.
The small-block pump have 7 teeth gears wich are quite big, producing a sensible pulsation of load to the shaft.
The Big-block pump have 11 teeth gears and a more smooth rotation.
Specially if you have rebuilt your engine with stock timing set (nylon camshaft gear) I really don't think the HP pump is a good move............. unless you have too much clearance in main and rod bearings..... in wich case you will need an high volume pump!
Just my two cents...
More power is needed to produce more pressure, be shure!
Tha main concern for higher pressure is the scattering of the igniction.... as you know the oil pump is driven via the distributor shaft and a bigger load will produce more timing oscillation.
The small-block pump have 7 teeth gears wich are quite big, producing a sensible pulsation of load to the shaft.
The Big-block pump have 11 teeth gears and a more smooth rotation.
Specially if you have rebuilt your engine with stock timing set (nylon camshaft gear) I really don't think the HP pump is a good move............. unless you have too much clearance in main and rod bearings..... in wich case you will need an high volume pump!
Just my two cents...
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
I don't think that a higher oil pressure than stock will come for free !!!!
More power is needed to produce more pressure, be shure!
Tha main concern for higher pressure is the scattering of the igniction.... as you know the oil pump is driven via the distributor shaft and a bigger load will produce more timing oscillation.
The small-block pump have 7 teeth gears wich are quite big, producing a sensible pulsation of load to the shaft.
The Big-block pump have 11 teeth gears and a more smooth rotation.
Specially if you have rebuilt your engine with stock timing set (nylon camshaft gear) I really don't think the HP pump is a good move............. unless you have too much clearance in main and rod bearings..... in wich case you will need an high volume pump!
Just my two cents...
More power is needed to produce more pressure, be shure!
Tha main concern for higher pressure is the scattering of the igniction.... as you know the oil pump is driven via the distributor shaft and a bigger load will produce more timing oscillation.
The small-block pump have 7 teeth gears wich are quite big, producing a sensible pulsation of load to the shaft.
The Big-block pump have 11 teeth gears and a more smooth rotation.
Specially if you have rebuilt your engine with stock timing set (nylon camshaft gear) I really don't think the HP pump is a good move............. unless you have too much clearance in main and rod bearings..... in wich case you will need an high volume pump!
Just my two cents...
Racer
Joined: Jan 2007
Posts: 314
Likes: 0
From: Pittsfield, Ohio
J, did you learn anything or open up a can-o-worms?
Lots of good point of views, I guess I'll depend on what your working with in the big picture. Oh yeah, run a good / long oil filters too, little less oil by-pass on cold starts..
Lots of good point of views, I guess I'll depend on what your working with in the big picture. Oh yeah, run a good / long oil filters too, little less oil by-pass on cold starts..