clearances where oil escapes the route through the passages (lowers overall
pressure)
are the lower rod bearing of course, but like the Spit 1500 that is worst of
all, the cam shaft journals.
Without cam bearings and the cam riding right in the cast iron block the
expansion ratios of the metal open up the clearances and allow oil to escape
as the car warms up
100 psi is a bit high. The relief should be closer to 80 psi.
Have you purged all the air out of your oil pressure gauge line (or is it an
electric gauge?)
What oil grade/brand are you using? ..can make a BIG difference...
synthetics usually run lower pressures when warm, but a fresh build should
not be using non-dino oil yet anyway.
My own GT6 6 cyl scared me once or twice on long trip/events when at highway
speeds I was only getting 30 psi. A filter change (right on the show field)
brought the pressure right back up to the usual 50-55 hot at speed, 20-25 at
idle.
Pop one of the oil gallery set screw plugs out the side of the block and
screw a mechanical gauge directly into the block as a secondary test reading
apparatus to validate your gauge is not an issue.
.
Paul Tegler
ptegler@verizon.net
www.teglerizer.com
----- Original Message -----
From: "Peter Arakelian" <peterara@msn.com>
To: "Listers" <triumphs@autox.team.net>
Sent: Monday, January 13, 2014 10:01 PM
Subject: [TR] oil pressure
>I will try to keep this brief, but there is a LONG story here that I will
> share some other time.
> For reasons I now question, I had XK's Unlimited in San Luis Obispo, CA,
> rebuild my engine. Jason, the owner said he would give me a good deal and
> allow me to supply parts. When I picked up the car after 2 months, it
> started
> up with 100 psi! Great! By the time I got home - 60 miles of freeway, and
> yes
> I did vary speed, the pressure was down to 50 psi and was idling at 10
> psi. I
> called, and after some testy conversations and insulting e-mails, I took
> the
> car back up for evaluation. I talked with the mechanic who worked on the
> engine for about an hour and we discussed the old parts and the old pump
> and
> the oil pressure. He felt it was my oil filter, a K&N, he said he had
> heard
> that there were occasional problems with the internal relief valve. We
> changed to a Fram and yes the pressure did pick up about 10 psi! He then
> told
> me my rocker shaft was worn and should be replaced and I might be losing
> pressure there, too. Why it wasn't done during the rebuild instead of
> polishing the old, is part of the longer story. By the time I got home,
> same
> story with the pressure. I did then change out the rocker shaft with a
> new
> one with bushed rockers honed to fit the shaft. The old one was
> noticeably
> worn and grooved where the rockers had been. When I drove into work this
> AM,
> temp in low 30's to low 40's, about 35 mile on the freeway, the pressure
> was
> about 5 psi higher. When I drove home, temps in mid 60's, just over 50
> psi @
> 3200 rpm, When I stopped at the off ramp 10 psi. After I drove the mile
> home, 12 psi. Yes, we did change the relief valve plunger and spring.
> Always
> starts cold at 100 psi. The new oil pump was a NOS AE pump.
> Thoughts?
> Peter Arakelian - '71 TR6, Daily Driver
>
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