Hi Carl,
My oil pump rotor shows about .010-.011" clearance. I put in a new rotor a few
years ago, but when a lifter failed, the fragments left it looking like a chunk
of stucco. That's when I found out that the new rotors are not hardened. The
original rotors are file-hard. I dug the old one out of the scrap box and put it
back in the engine. It's been running fine ever since. The car has 180,000 miles
and the original oil pump delivers 60 psi hot. I'd say if you have .007-.009"
clearance on an original rotor, leave it alone. TR4 oil pumps are fairly easy to
change with the engine in the car if you ever have to. I would dress the rotor
scuff marks off of the bottom cover plate. Where do you measure .020 with the
rotors removed?
If the bearings are showing copper, they're toast. Which may also mean that the
crank will need attention. BTDT :-/
Cheers
Pete Fullam
'63 TR4 since '63
CarlSereda@aol.com wrote:
> Anyone have the experience of measuring their oil pump rotor clearances? My
> manuals say wear between inner and outer rotor should not to be above .010.
> Mine measures from .007 to .009 on four points if I measure with the rotors
> in place but if I take rotors out of the case I get more like .020.
> My low oil pressure I'm sure is due to worn bearings (down to copper) but am
> thinking of replacing rotor innards on the pump while I have it out - don't
> want to spend the $40 if it's not neccessary though - any thoughts out there?
> Carl
> '64 TR4 since '74 (approx. 150,000 miles on the oil pump and I still had
> pretty good oil pressure to the rockers)
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