[TR] oil pressure

[Alex&Janet Thomson]

Pete - 100 psi sounds quite high for a cold start. I wonder if the relief
valve is operating correctly including sticking at either end of its travel.
Did you verify these pressures with a good quality master gauge? If not, try
to find a gauge with a 270 degree scale that tops out at about 125 psi.

 A 10 psi difference based on a filter change seems odd. I don't know where
the oil pressure gauge picks up its reading - is it before or after the
filter?

 I think I saw in a previous listing that some other NOS pumps had an
excessive clearance between the sides of the gears and the cover plate. The
pump that I bought from TRF made a tremendous difference in an otherwise
average condition engine. Hot idle pressure went from 10 psi to better than
20 psi. I think it was an import, but not from the UK.

Alex Thomson

-----Original Message-----
From: triumphs-bounces at autox.team.net
[mailto:triumphs-bounces at autox.team.net] On Behalf Of Peter Arakelian
Sent: Monday, January 13, 2014 10:01 PM
To: Listers
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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