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Re: oil pump and compression ratio info needed

To: SpiwakD@aol.com
Subject: Re: oil pump and compression ratio info needed
From: "Joe Boruch" <jaboruch@netzero.net>
Date: Fri, 22 Jul 2005 12:28:48 GMT
Stay away from the pumps from the big 3 suppliers.  The slot at the top of the 
rotor shaft is cut very sharp and will break.  I siezed a motor years ago as a 
result of one failing.  I have found others with one tab broken off.  Another 
part of the problem is the shafts are dead soft, whereas the original ones were 
hardened somewhat (Rc 50-55).  I never fully investigated this to see if they 
were just case hardened or if they were thru hardened.

I made my own shafts with generous radiuses and had them heat treated.  I am 
not set up for any kind of production.  Making each is very time consuming 
(which I seem to have less and less of).  I also replace the pin that the rotor 
attaches to the shaft with, with set screws that are locktighted in.

As for compression ratio I have been running 13.6 last year and this year.  So 
far so good, but last year I did crack a Moldex crank due to a mixture problem 
and injested steel imbedded in a piston causing detonation in that cylinder.  
With lower compression it may have tolerated the conditions better?  Joe B

-- SpiwakD@aol.com wrote:
I need a new oil pump and need to know if an improved or high-quality unit is 
available. Also need to know a recommended compression ratio in a TR3 engine 
for a combination of good power and reliability.
                                                                 Dave


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