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Good race oils:<br>
economical - Valvoline VR-1 and VR-1 synthetic (I run non-synthetic for
break-in and synthetic afterwards)<br>
Known good quantities:<br>
Brad Penn<br>
Redline<br><br>
All of those have enough ZDDP to keep our cams / lifters intact.<br><br>
Regards, Tony Drews<br><br>
At 07:12 AM 7/13/2016, Brian Schirano wrote:<br>
<blockquote type=cite class=cite cite="">Marty, I think Peter is right.
The GT motor I am about to rebuild had similar symptoms. Great pressure
cold, 75-80, then dropping to 20-25 hot at idle, sometimes less and I had
to keep RPMs up to ensure lubrication. Uppon teardown, I had a a couple
of big end rod bearings showing some copper, and others indicating wear
also, all on the compression stroke side (opposite side of oil journal).
Mains were all OK. I run street Mobil One 15-50, but think I will change
after rebuild.<br><br>
Would welcome a few race oil opinions from FOT<br><br>
Best<br>
Brian<br><br>
26A GT6+, 28 TR6<br>
Brian Schirano<br>
585-305-0349 Cell <br>
BSchirano@yahoo.com<br><br>
<br>
<br>
<font size=2><b>From:</b> Peter Vucinic
<pvucinic@netspace.net.au><br>
<b>To:</b> 'marty' <trmarty@hotmail.com>; 'FOT'
<fot@autox.team.net> <br>
<b>Sent:</b> Tuesday, July 12, 2016 9:54 AM<br>
<b>Subject:</b> Re: [Fot] Oil Pressure Conundrum<br>
</font><br>
Marty,<br>
Sounds like some of the bearings clearances are larger than they should
be and you are losing oil pressure as the oil warms up and starts leaking
through the journal(s) faster once you are at operating temps. <br>
If you are running an aggressive cam profile and/or high valve spring
rates? This will adversely affect cam bearing wear for sure.<br>
<br>
<br>
<b>"You can Make a Small Fortune From Motor Racing. As long as You
Started With A Lage Fortune!"<br>
</b>Kind Regards<br>
Peter Vucinic<br>
TR4 - TR7 V8 - Spitfire MkII<br>
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<b>From:</b> Fot
[<a href="mailto:fot-bounces@autox.team.net" eudora="autourl">
mailto:fot-bounces@autox.team.net</a>] <b>On Behalf Of </b>marty<br>
<b>Sent:</b> Tuesday, 12 July 2016 4:09 AM<br>
<b>To:</b> FOT<br>
<b>Subject:</b> [Fot] Oil Pressure Conundrum<br>
<br>
<br>
I could use some opinions. Some history. Spitfire small journal 1296
engine, rebuilt 6 race weekends ago included all new bearings. I tore it
down this spring to check it over prior to last weekend PVGP event. Cam
and crank end floats were to spec. Rod and main bearings checked between
.002 and .003 clearance. I do not have the actual numbers in front of me
at the present. Cam bearings appeared to have some slight visual wear at
the bottoms but I did not actually measure them. I run Brad Pen 20W50.
Oil temps run 210 and water temps run 190. EGT are 1200/1250 range on
track. I was fighting low oil pressure at running temps all weekend. Once
my oil temps come up on track the pressure drops down to 35psi. If I add
enough springs to the pressure relief valve I see over 125 psi cold so I
am thinking my pump is putting out enough pressure. I tried shimming to
get 50/60 cold at idle and it drops to 35 at operating temps at 7000 rpm.
I tried a new pressure gage over the weekend and the numbers did not
change. I am currently running an auxiliary oil line to the head, I
removed it at one point over the weekend and it had no effect. I tried a
new pressure relief valve assy and it had no effect. I believe this
situation actually started a season ago because I added a washer to the
pressure relief valve last season. I’m thinking it most likely is
cam bearing wear even though all the bearings were fresh 6 events ago.
Any guidance? One thing I did learn this weekend is my accusump pressure
gage is incorrect. It was reading about 30 psi higher that my dash
gage. I was thinking it was probably correct and my dash gage was wrong
until I replaced my electric dash gage with a mechanical gage and its
reading matched the gage I just disconnected. Oil pressure readings are
taken at the port below the distributer. <br>
<br>
Side note. Car ran awesome. I ran a 2.22 at PittRace Sunday and that was
6 seconds faster than my previous best lap there. <br>
<br>
Thanks,<br>
Marty <br><br>
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