[6pack] Bearing clearances and Plastiguage

[Robert M. Lang]

Hi,

I haven't had a chance to flush this thread out completely, but if you 
haven't tried this yet, it will PROBABLY solve your low o.p.:

blueprint your oil pump.

The Bentley manual lists all the clearances in the oil pump. That's all 
really kool and everything, but unless your motor has a gazillion miles on 
it, the rotor clearances are _probably) okay and close to spec.

However, there is a fix that I've done a bunch of times that is easy and 
pretty much automatically raises o.p pressure 10 psi everywhere. Drop the 
pan and pull the oil pump. the bottom cover of the oil pump will likely 
have scoring. On a flat surface with some emery cloth of very find wet or 
dry (400 or 600 grit) and some OIL, polish the cover 'till all evidence of 
scoring is gone. Clean the part three times with brake cleaner (make sure 
there is no grit left on the surface (hopefully, for obvious reasons)). 
Reassemble.

I did this a couple of years ago when my oil pressure idiot light kept 
coming on at idle (motor hot). Oil pressure went from under 10 psi to 
about 25 psi. If your oil pump rotors are knackered, you can buy new guts 
for something like $30 from the various sources. You do not need a new 
pump body unless the outer rotor clearance is way off - the inner rotor 
tips to the rotating body clearances are most important, then the pump to 
body clearance and the only one (in my experience) that matters is the 
rotor to bottom clearance. Also note that if the rotor is too deep in the 
pump body (scoring on the upper end of the body) you can reduce the 
"height" of the pump body be polishing as described above, BUT you must 
make sure the pump body is square as well as flat or you'll dish the 
bottom cover and you'll be back to crappy oil pressure in due time.

Cost: $5, $10 if you screw up the oil pan gasket (or (shame of shames) you 
glued it to the pan and block).

Time: 1 2 hours MAX. Most of that time will be trying to figure out how to 
put the three pan bolts that are just above the  frame rail. Leave 20 
minutes to wash your hair of all the oil that drips on you while you 
remove the pump. Hint: use cardboard to keep the drips off the floor and 
let the motor drip for an hour or two before you pull the pump.

Seriously, this is an easy fix. If it doesn't work, then check your 
bearing clearances. I'm amazed at how many motors have low oil pressure 
and the only prob is the oil pump clearances.

regards,
rml
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Bob Lang              Triumph TR6!!            |  This space for rent
2010 NER Solo Chair                            |
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