Thread: blow by and swirly port heads.

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I have experienced stock mechanical replacement pumps that push more than 10psi. I have experienced stock mechanical replacement pumps pushing fuel past the needle seats in my Edelbrock carbs. I have a pressure gauge and a regulator on all of my carburetors, Edlebrock's are set at 4-5psi, Holley's are set at 4-5psi. SMELL YOUR OIL for fuel.

YES, both my Edelbrock and Holley carbs are set at the same pressure. Carburetors fuel supplies DO NOT operate by high fuel pressure, rather by gravity, atmospheric pressure (differentials of) and fuel VOLUME.

IMHO, no carburetor needs more than 5psi. If you need more than 5psi, you have a supply volume problem (fuel line and/or pump rating is too small), not a pressure problem. The carburetor only needs enough fuel pressure to overcome gravity and atmospheric pressures, SUPPLY volume (Gallons Per Hour) is what keeps the fuel bowls full.

And, JMHO, if you think the rings are not seated, TRY what JERRY said, use BonAmmi and see if it seats the rings. BonAmmi is a mild abrasive that will break the cylinder glaze and allow the rings to seat (in most cases).

However, if you have a ring gap or misalignment problem, BonAmmi will be no help at all..

Originally Posted by 36 sedan

I have experienced stock mechanical replacement pumps that push more than 10psi. I have experienced stock mechanical replacement pumps pushing fuel past the needle seats in my Edelbrock carbs. I have a pressure gauge and a regulator on all of my carburetors, Edlebrock's are set at 4-5psi, Holley's are set at 4-5psi. SMELL YOUR OIL for fuel.

i am taking your advice 36 sedan.fuel pressure seems too important to overlook.