Oil Pump Q's

[capriceowns]

For my 1981 350 for my 87 caprice, Do I need a high volume High pressure pump? Can I use one with a stock oil pan?

are all oil pumps switchable with Gen I SBC?

[silicon212]

You can use an HV/HP pump, and there's no modification aside from switching it out, but it'll waste power. You can still run a high volume pump if you wish, but replace the relief spring with the lower pressure one (included with the pump but not installed). The HV/HP pump will also put more stress on the cam/distributor gears. Get a chrome moly pump driveshaft with a steel collar for the pump in any case - cheap, dependable insurance against shaft failure.

[capriceowns]

Originally Posted by silicon212

You can use an HV/HP pump, and there's no modification aside from switching it out, but it'll waste power. You can still run a high volume pump if you wish, but replace the relief spring with the lower pressure one (included with the pump but not installed). The HV/HP pump will also put more stress on the cam/distributor gears. Get a chrome moly pump driveshaft with a steel collar for the pump in any case - cheap, dependable insurance against shaft failure.

Will a HV/standard pressure pump cause more stress?

Do i need a driveshaft for it, doesnt my Dist run it? Is changine the dist gear a better insurance to? like using a bronze one?

[silicon212]

Originally Posted by capriceowns

Will a HV/standard pressure pump cause more stress?

Do i need a driveshaft for it, doesnt my Dist run it? Is changine the dist gear a better insurance to? like using a bronze one?

The driveshaft connects the oil pump with the distributor gear, and it's about 4" or so long. One end has a tang - this interfaces with the distributor shaft. The other side has a notch that indexes with the tang on the oil pump drive gear. The oil pump side of the shaft, on an OEM install, has a nylon collar that prevents the shaft from "walking" off of the oil pump drive gear, which always has catastrophic results for the engine. The shaft fits up inside the distributor gear, which prevents the top of the shaft from moving around. The problem with the OEM collar is that being made out of nylon, they tend to crack and wind up in the oil pan. The chromemoly aftermarket piece is harder than the softer steel of the OEM shaft, and it has a steel collar which will never crack, fall off and wind up in the oil pan.

A high volume pump with a 35psi spring will not cause excessive wear on the drive system. Also, a bronze distributor gear is actually softer than the steel gear, so it would wear faster. Bronze gears exist for use with billet steel cams, which are softer than the nodular cast iron cams. A steel gear would wear the gear right off of a billet steel cam, hence the need for a bronze gear.

[J-Mech]

Originally Posted by capriceowns

Will a HV/standard pressure pump cause more stress?

Do i need a driveshaft for it, doesnt my Dist run it? Is changine the dist gear a better insurance to? like using a bronze one?

there is no need for putting a high volume oil pump in a stock engine. a high volume pump will tend to overlube the system because it pushes oil up the system so fast it will bypass the crankshaft and go to the top of the engine. this will result in too much oil getting stuck in the top of the engine resulting in less oil in the pan for cooling. High volume pumps are intended for high rpm engines. when running one you need to put a restrictor in the oil passage so that the pressure will stay at the crank.

[silicon212]

Originally Posted by J-Mech

there is no need for putting a high volume oil pump in a stock engine. a high volume pump will tend to overlube the system because it pushes oil up the system so fast it will bypass the crankshaft and go to the top of the engine. this will result in too much oil getting stuck in the top of the engine resulting in less oil in the pan for cooling. High volume pumps are intended for high rpm engines. when running one you need to put a restrictor in the oil passage so that the pressure will stay at the crank.

Once again, this depends on the selective spring used in the pressure relief valve. If you use the 35psi spring that comes with the pump in place of the installed 65psi spring, you won't encounter this problem. This is a good setup for a mild performance build street engine that sees the occasional trip to 6k RPM. Also, the condition you are remarking on depends on the selection of valve lifters as well. This was common with the old Rhoads flat tappet hydraulic lifters with excessive bleed-down but not so much with standard flat tappet hydraulic lifters.

I've been running the high-volume TRW pump with a 35 psi spring for the last 270,000 miles on the 350 in my 9C1 with no ill effects - in fact, if anything, there's not quite enough oil to the top end as the roller tip COMP rockers I have make the thing sound like a diesel when it's cold. Then again, I am running Sealed Power (Federal Mogul) flat tappet hydraulic lifters.

[capriceowns]

Originally Posted by silicon212

Once again, this depends on the selective spring used in the pressure relief valve. If you use the 35psi spring that comes with the pump in place of the installed 65psi spring, you won't encounter this problem. This is a good setup for a mild performance build street engine that sees the occasional trip to 6k RPM. Also, the condition you are remarking on depends on the selection of valve lifters as well. This was common with the old Rhoads flat tappet hydraulic lifters with excessive bleed-down but not so much with standard flat tappet hydraulic lifters.

I've been running the high-volume TRW pump with a 35 psi spring for the last 270,000 miles on the 350 in my 9C1 with no ill effects - in fact, if anything, there's not quite enough oil to the top end as the roller tip COMP rockers I have make the thing sound like a diesel when it's cold. Then again, I am running Sealed Power (Federal Mogul) flat tappet hydraulic lifters.

mine is a mild performance build. If I just buy a High volmue and standard pressure pump do i switch the springs?

like this one http://store.summitracing.com/partde...5&autoview=sku

[silicon212]

That pump would be fine, and it even already has the correct spring in it.

Melling makes a good pump. I have the same one in my engine.

[Blue Bowtie]

The old Melling (M55) pumps were good. The jury is still out on the "new" M55 pumps. They have changed, and on the surface there are some questions surrounding them. The pump body castings are thinner, and thinner in some critical areas.

There is evidence of a few failures directly attributable to the new Melling pumps, even though there is a lot of evidence that they are just fine.

You can avoid the issue entirely if you use the Melling "Select Series" pump, like the 10553 instead of the cheaper M55.

[silicon212]

Wow, good to know! I haven't used one of these 'newer' Melling pumps yet, so I was oblivious to the change. Noted for future reference.

[capriceowns]

Originally Posted by Blue Bowtie

The old Melling (M55) pumps were good. The jury is still out on the "new" M55 pumps. They have changed, and on the surface there are some questions surrounding them. The pump body castings are thinner, and thinner in some critical areas.

There is evidence of a few failures directly attributable to the new Melling pumps, even though there is a lot of evidence that they are just fine.

You can avoid the issue entirely if you use the Melling "Select Series" pump, like the 10553 instead of the cheaper M55.

Thats a lot of good info BB. Good thing I havent placed my order yet.

the 10553 looks good, even has the pickup bolted on, I looked at the 10555 to and it was the same as the 10553 just its high volume.

is there really much to gain from using a high volume pump?

does anyone here know if the sealed power pumps from federal mogul are any good?

[silicon212]

Originally Posted by capriceowns

does anyone here know if the sealed power pumps from federal mogul are any good?

They're OEM quality if that means anything - in other words, yes they are good.