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I have a 67 327/300 that was rebuilt about 8 yrs ago. a melling high volume oil pump was installed at that time. Does anyone know what type of oil pressure i should be getting at idle, 2000 RPM?
running Valvoline VR1 20w50 oil.
I have put 3 different 80lb oil pressure gauges in and the are all well over 80lbs when the car is first started and them right around 80 crusing at 2500 RPM.
Is this normal? for some reason all gauges read 0 when installed but now ready 40 when car is off, they never return to 0.
One was the original guage one was a reproduction and one was an original that was recalibrated.
Last edited by johngandersonjr; 05-20-2016 at 04:03 PM.
Remove the unneeded high volumn pump and install the correct standard pump and your stock 60psi gauge will work fine. Some told me on here that a high volume does more harm then good on a stock street engine
I think the rebuilder put a hi-vol pump in my '61s 283ci....the 60lb gauge will peg on startup and stay pegged at anything over about 2500 RPM. Idle is around 35lb. It clearly hasn't hurt anything after a decade of me flogging it, but the hi-vol pumps are unnecessary....
I think what you're seeing is normal so you'll just have to adjust to it or install a different pump...
Last edited by Frankie the Fink; 05-20-2016 at 05:12 PM.
I have a 67 327/300 that was rebuilt about 8 yrs ago. a melling high volume oil pump was installed at that time. Does anyone know what type of oil pressure i should be getting at idle, 2000 RPM?
running Valvoline VR1 20w50 oil.
I have put 3 different 80lb oil pressure gauges in and the are all well over 80lbs when the car is first started and them right around 80 crusing at 2500 RPM.
Is this normal? for some reason all gauges read 0 when installed but now ready 40 when car is off, they never return to 0.
One was the original guage one was a reproduction and one was an original that was recalibrated.
It sounds more like you have a high pressure pump or the relief spring was shimmed in a regular pump. High volume pumps have taller gears and are easily distinguished from a regular volume pump. You'd have to pull the pan to able to tell but I would be doing that anyway and changing the pump to a standard volume/pressure one if I had that much oil pressure.
It sounds more like you have a high pressure pump or the relief spring was shimmed in a regular pump. High volume pumps have taller gears and are easily distinguished from a regular volume pump. You'd have to pull the pan to able to tell but I would be doing that anyway and changing the pump to a standard volume/pressure one if I had that much oil pressure.
I know for a fact it was a high volume pump. The individual that helped me rebuild the engine was a drag racer and recommended it.
Other than lowering the oil pan is changing the pump relatively easy?
I know for a fact it was a high volume pump. The individual that helped me rebuild the engine was a drag racer and recommended it.
Other than lowering the oil pan is changing the pump relatively easy?
Its been 10 years since I had it open.
It's a simple task to change the pump. Only one bolt. Were the main and rod bearing clearances increased more than stock requiring the use of a high volume pump? High oil pressure doesn't mean you have a high volume pump. It only means the relief spring is heavier than stock. You can have a high volume pump with normal pressures. The stock Chevy oiling system is more than adequate for all street applications. High pressure/volume pumps only add stress to the pump, pump driveshaft, distributor gear and cam gear with zero benefit.
The ’67 GM oil pump specs for a small block were 30-45 PSI @ 1500 RPM, with a capacity of 4.3 GPM @ 2000 RPM.
I don’t have any personal experience with Melling high volume pumps but your figures are probably typical.
When I bought my ’67 300HP/327, it had a Melling M55 oil pump and the Melling #55058 (yellow) bypass spring. My oil pressure gauge read 30 psi at a hot 600 RPM idle, and 60+ at 2000 RPM.
I bought and installed a GM #3814903 spring and my hot idle (600 RPM) pressure is now 30 psi, and 45 psi at 2000 RPM - measured running Shell Rotella T 15W-40 oil.
If you’re going to change the oil pump, all of the work is in pulling and replacing the oil pan – the pump is a piece of cake. Here is a Melling M55:
It's a simple task to change the pump. Only one bolt. Were the main and rod bearing clearances increased more than stock requiring the use of a high volume pump? High oil pressure doesn't mean you have a high volume pump. It only means the relief spring is heavier than stock. You can have a high volume pump with normal pressures. The stock Chevy oiling system is more than adequate for all street applications. High pressure/volume pumps only add stress to the pump, pump driveshaft, distributor gear and cam gear with zero benefit.
The motor is the original to the car so we wanted it rebuilt as it sat for 30 yrs. the block needed a lot of machine work. it needed to be align bored and stamped as the caps were loose. it only has 54000 miles on it but was driven pretty hard in its early years.
The ’67 GM oil pump specs for a small block were 30-45 PSI @ 1500 RPM, with a capacity of 4.3 GPM @ 2000 RPM.
I don’t have any personal experience with Melling high volume pumps but your figures are probably typical.
When I bought my ’67 300HP/327, it had a Melling M55 oil pump and the Melling #55058 (yellow) bypass spring. My oil pressure gauge read 30 psi at a hot 600 RPM idle, and 60+ at 2000 RPM.
I bought and installed a GM #3814903 spring and my hot idle (600 RPM) pressure is now 30 psi, and 45 psi at 2000 RPM - measured running Shell Rotella T 15W-40 oil.
If you’re going to change the oil pump, all of the work is in pulling and replacing the oil pan – the pump is a piece of cake. Here is a Melling M55:
Will the drive shaft stay in the motor when I pull the pump or does it come out like what you show in the picture?
Yep, that's the high volume version of the pump in the above picture.
And with the pressures the OP has, it's obvious the builder didn't increase the bearing clearances like he should have. I'd change out the pump for a standard M-55.
Should I get a new pickup as well or transfer the old one?
I don't remember if the HV and standard pumps use the same dia. pick-up but being a racer, he most likely brazed the pick-up to the pump. A new one is only a few bucks.
I don't remember if the HV and standard pumps use the same dia. pick-up but being a racer, he most likely brazed the pick-up to the pump. A new one is only a few bucks.
Sounds good.
I will get an m55 ordered as well as a new pickup. Wondering if the same bolt can be used or if they are torqued/stretched when installed.
05-20-2016, 04:02 PM
67 327/300 Oil pressure at idle/2000 rpm, etc....
And with the pressures the OP has, it's obvious the builder didn't increase the bearing clearances like he should have. I'd change out the pump for a standard M-55. 