Ops Ck - PV test - Oil Pressures

[Loren L.]

For those who cringe in fear druing PV or Ops when the oil pressure gauge is showing something other than a "drip" method, you might to consult Page 6 of the July 1965 Chevrolet Service News:

"High Engine Oil Pressure !

CORVETTE 327 CU. IN.-365-375 HP.

The above 327 cu. in high performance

Corvette engine oil pressures in the area of

80-95 psi (at 2,000 RPM) can be expected and

are perfectly normal. However, damage may

occur to this engine if the 283 cu. in. engine oil

pump is used which delivers oil pressure of

65 psi at 2,000 RPM."

Contrary to how NCRS has been judging this item, it would seem the last statement indicates that you should FAIL PV if it is NOT HIGH.

[Mike M.]

Re: Ops Ck - PV test - Oil Pressures

i wouldn't have a problem with 80-95 psi on a cold 327 solid lifter sbc engine at 2000 rpm but that's way too high for a cold solid lifter 327 AT IDLE.most sbc chevy engines that fail pv due to high oilpress do so because they are pegging the oil press guage AT IDLE. 2000 rpm not idle. regards, mikie

[Larry L.]

Re: Ops Ck - PV test - Oil Pressures

There is another problem with the peged oil pressure gauge on some rebuilt clusters. Since the 0 80 psi gauge is hard to come by some rebuilders just silkscreen the gauge and you have an 80 lb guuge. Wrong.
Before you accept your cluster and put it in the car - check the gauge with a known good or new commercial gauge. Then you know. If the restorer did not get it right make them fix it.

I have checked several oil pressure gauges both NOS and from Rebuilt Clusters and there was a lot of discrepency's between them. I use a calibrated AshCroft gauge and it is about 2%.

Always check you oil pump by pass and make sure it reads 55 lb at 1000 RPM - 30 weight at 70 deg. F.

If you have a solid lifter SB and a 5 Quart pan and have replaced your oil pump with a high volume pump. The clearance between the oil pump exit and pan may not be adequate. This needs to be 3/16 or more to allow the bypass regulator to function properly. I checked my clearance and found that it didn't have any and this would have peged the gauge when cold.
The prcedure is simple - put modeling clay on the oil pump exit and do a trial fit of pan. Remove the pan and pull it away from oil pump and you will know.
I had to remove 3/16 from the casting and on engine test it was dead on.
Attention to these details saves you a lot of time and $ unscrewing it.

[Loren L.]

I don't have any problem with what you

offer, Mike. But I do WONDER about how it has been done on the field. There IS a connection in 1963 between the "2nd Version" oil pump and the change from a 60 lb oil gauge to an 80 lb in the cars. My 10XXX FI coupe had a 60 - my 15XXX CV had an 80.
As I said in the initial post, I am possibly more intrigued by the last statement in Chevrolet Service News - that the 283 pump at 65 lb might not be enough to escape damage to the engine.