| Re: [GMCnet] High volume oil pumps [message #246154 is a reply to message #246120] |
Wed, 02 April 2014 10:26   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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| Jeff Marten wrote on Tue, 01 April 2014 23:18 |
Where does the oil spray originate? Are you inferring filling the pan with an excess volume of oil, and thereby using the crank to splash oil around??? (terrible idea if so) Or installing spray nozzles so the extra volume of oil pumped is utilized?
A high volume oil pump does nothing but bypass more oil than a standard pump if the bearing clearances aren't set to utilize the extra volume of oil. Clearances at X" will only flow X volume of oil, nothing more; the additional pump volume will just be bypassed.
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Jeff,
I have a leg up on most people. This a direct result of being a refugee from engine test laboratories.
The lube oil to cool the piston crowns is thrown up there by the connecting rods as they come around. Actually, this is a little bit of a misrepresentation. What really happens is the lower end flings oil up ward, but it will never reach the piston at top dead center, but that is OK because the piston will come right down to get it. It really is kind of fun to watch at 1800fps.
If you look at the article Rob referenced, it shows a rod drilled for a "piston cooler", but what is also interesting is that they used a rod with oil grooves. That is the job those two grooves each side of the rob beam are supposed to do. Sometimes rods even have notches in the bearing shell to line up with said grooves. The oil hole as pictured will do more to lubricate the trust face of the cylinder wall.
Dick Paterson very much understands the higher volume would be little value on a standard clearance engine, so he uses the high volume pump, but then also sets the engine up "looser" than minimum clearance to take advantage of the extra cooling that is then possible.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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