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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