<VV> Re: Was Hi Vol Oil pump/now lifter oil loss

kenpepke at juno.com kenpepke at juno.com
Fri Dec 21 14:37:48 EST 2007

Chuck S said (in Part):

>Question. In a racing Corvair engine , running stock pump, remote cooler, 10 
>psi per thousand rpm ~ 70 psi or so, hydraulic lifters, turning up to 7500 
>rpm, why do lifters lose their adjustment, meaning clacking like the oil 
>within the lifter is low, after a half hour on track? Are they improperly 
>adjusted (nominal 5/8 turn)? 

I have not had a Corvair engine that did not run out of breath around 6000 RPM ... 
To sustain 6000 RPM for any length of time I would back the rockers off until the
lifters would pump all the way up then set them cold with .001 clearance on the 
intakes and .002 clearance on the exhaust (hydraulic lifter cams do not have an 
acceleration ramp so the lash is small) then they will function much as a solid lifter.  

Above 6000 RPM Corvair engine pieces move around quite a bit and soon will show
evidence of wear on the block under the cylinder barrels and on the head above.
I am not sure how effective a windage tray would be on the flat engine design but
if one could be worked out to scrape away the loose oil it would reduce the amount 
of aeration and foaming in the oil.  Fitting up a dry sump with an air separator could
also help.

Ken Pepke 
Lose up to 20 lbs in one month with a new diet. Click here.

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