I have a polished aluminum "high volume" street rod style water pump on the sbc in my 55. The engine is way more of a 7500 rpm bracket race engine than a street cruiser, and I pretty much don't fail to bang it through the gears wide open pretty much at least once every time out. When I first finished the car, I experienced a radiator hose blowing loose during a shake down run. Since then I have driven 5 years or so with no problems. So tonight... I buzz it up to 7500, bang second gear, and instantly fog the car down with antifreeze. It looks like the Felpro intake manifold gasket blew out at the top front side along the head. With the cross ram it is hard to tighten the bolts, so it may just be my fault for letting them get loose, or never having them tight enough to begin with (combined with the gasket getting older and maybe shrinking a little). Does that make sense, or am I way off base trying to use a "high volume" pump on a higher rpm engine? I am a little concerned that maybe I have been on the edge of a problem for some time. Watering down the tires at speed would be a bad idea for sure... Any idea what sort of pressure an engine develops in the cooling system at high rpm?? Has anyone tried a gauge in the system to see? Thoughts?
Extremely unlikely that a centrifugal pump could build enough pressure to blow out a intake gasket. The pump is working within a sealed system, so the pressure it builds is only the slight pressure differential between inlet and outlet. Perhaps you've got a head gasket that's leaking combustion gases into the water jacket? Bob
Have you run the engine after the spray down. Perhaps a little detonation and a blown head gasket is the problem.
It has a 15 pound cap and a puke tank, both functioning well, but I am thinking it is building up extreme pressure, or maybe just volume on a very short term basis right on the outlet side of the water pump (in the intake and engine itself). Just talking about a few seconds or less at higher rpm in each gear. It may be fine once the car settles back down and the pressure equalizes, which may be why the cap and puke tank are not coming into the equation? I don't know... Maybe I am over thinking this... Edit: Regarding the head gasket potential, I guess that might be... I have a kit to check for combustion in the radiator, but I suppose I need to fix the intake gasket prior to finding out if I need to pull it again and replace head gaskets.
I recently bought a book that goes WAY in depth on automtive cooling systems, it's got formulas for friction loss, air flow requirements, alternative coolants, etc etc. Anyway, seems to me it did have a paragraph about hi-volume water pumps unseating pressure caps in some instances - I'll dig it out and see what it says.
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