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Progress, engine out
- Thread starter jlaird
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OP
jlaird
Great Pumpkin
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Pulled engine etc etc.
Oil pressure was 60 or so cold then down to 20 running warm and 10 idle.
Have a new pump, no prob. now that I have one that was cut down.
Question concerns old pump.
Has a lot of wear that I can see on the outside of the outer pump part where it rubs against the housing, both sides and circumference.
For my education, what is acceptaple for tolarances?
I expect between the circular part of the pump and the case is over .010 can get that one in but would need a wire guage to really tell.
Yep going with the new one of course but refuse to take it apart therefor the question.
Thanks all
Oil pressure was 60 or so cold then down to 20 running warm and 10 idle.
Have a new pump, no prob. now that I have one that was cut down.
Question concerns old pump.
Has a lot of wear that I can see on the outside of the outer pump part where it rubs against the housing, both sides and circumference.
For my education, what is acceptaple for tolarances?
I expect between the circular part of the pump and the case is over .010 can get that one in but would need a wire guage to really tell.
Yep going with the new one of course but refuse to take it apart therefor the question.
Thanks all
OP
jlaird
Great Pumpkin
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I saw none in the manual Doc. Oh wait let me look again. Noop, don't see anything. But this one is toast. Walls and back and front internaly is like a mtn range. It is really eaten up. I bet it is an orginal from the factory.
Haveing a heck of a time getting the backing plate on, just will not fit. going to a bit of grinding at one edge of the plate where the crank shaft comes through, think the plate might be just a bit off center for this new pump. The small amount I seem to need should not effect bolting it on.
Haveing a heck of a time getting the backing plate on, just will not fit. going to a bit of grinding at one edge of the plate where the crank shaft comes through, think the plate might be just a bit off center for this new pump. The small amount I seem to need should not effect bolting it on.
R
RonMacPherson
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What is the material, i.e. are we dealing with: aluminum rotors and body, aluminum rotors, steel body, steel backing plate, etc.
There may be no mention of specific freeplay/sizing in the manual, but engineering rule of thumbs can apply to general sizing on pumps, rotor to body, body to back plate, etc. Just wanna find out the materials before I give you what I know; as aluminum is more "spacious" than steel or iron for thermal expansion..
Years ago, Melling used to have available a general sizing chart recommendation for rotor depth(gallons per hour flow) and freeplay sizing(for pressures built). But I doubt it's available anymore. Smokey Yunick, Grumpy Jenkins did a bit of research on oil pressure and flow. You might find interesting the info via a little web searching on their info.
hth. but let us know what materials the pump is made of.
There may be no mention of specific freeplay/sizing in the manual, but engineering rule of thumbs can apply to general sizing on pumps, rotor to body, body to back plate, etc. Just wanna find out the materials before I give you what I know; as aluminum is more "spacious" than steel or iron for thermal expansion..
Years ago, Melling used to have available a general sizing chart recommendation for rotor depth(gallons per hour flow) and freeplay sizing(for pressures built). But I doubt it's available anymore. Smokey Yunick, Grumpy Jenkins did a bit of research on oil pressure and flow. You might find interesting the info via a little web searching on their info.
hth. but let us know what materials the pump is made of.
OP
jlaird
Great Pumpkin
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Got that sucker now, had to take another 1/16 inch or so off of each or the oil pump ears. I would guess that the factory that made the backing plates did not get the can exactly centered.
So much for quality control, however it did fit with the orginal oil pump so guess I best shut up.
I have two, one unmodified and one where the edges of the case where the bolts
go through are cut down. Both are same brand both are new.
There is no way that pump will fit under the backing plate I have. The pump is
just too large for the cut out where the tin can is soddered on.
What the heck, am I stupid or something in my old age. This is not rocket
science.
Anyone else put a new 948 pump in lately and where did you get it. OR OR OR do
I have a backing plate from something else????? the tranny bolts up to it ok.
So much for quality control, however it did fit with the orginal oil pump so guess I best shut up.
I have two, one unmodified and one where the edges of the case where the bolts
go through are cut down. Both are same brand both are new.
There is no way that pump will fit under the backing plate I have. The pump is
just too large for the cut out where the tin can is soddered on.
What the heck, am I stupid or something in my old age. This is not rocket
science.
Anyone else put a new 948 pump in lately and where did you get it. OR OR OR do
I have a backing plate from something else????? the tranny bolts up to it ok.
OP
jlaird
Great Pumpkin
Offline
Pump body is alum, roter and the outside circular part that the roter drives is steel.
Alum lookid like mountains, very scored, might have been run dry at one time even. Or maybe just old.
No question in my mind that the old pump is toast and clearances are too large, quite worn except for steel to steel.
New pump in now so hopefully all is well now that I know how to modify a new pump to fit.
Alum lookid like mountains, very scored, might have been run dry at one time even. Or maybe just old.
No question in my mind that the old pump is toast and clearances are too large, quite worn except for steel to steel.
New pump in now so hopefully all is well now that I know how to modify a new pump to fit.
racingenglishcars
Darth Vader
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Typically the clearances are measured in 1/10000" while micrometers generally measure by 1/1000"
You really should plastigauge them. But it can be done once the motor is back in if you still have low oil pressure.
Sorry if I seem like a drip.
You really should plastigauge them. But it can be done once the motor is back in if you still have low oil pressure.
Sorry if I seem like a drip.