Oil pump gear tolerances

[Brad S.]

Couldn't find this in my 7.3 book last night.
Couldn't find it on a search of the OB.
Measuring mine last night the .0015 feeler gauge seemed ok, gonna take it with me to the machine shop when I pick up the balanced engine parts.(thats the smallest measurement on my feeler gauge)
Thought I'd ask the experts here, thanks guys.

 

[icanfixall]

So your asking for the fit between the gears. I recall it being a 3 or 6 thousands feeler gauge fit. That means you fit that in the teeth and try to spin the pump. If it wont spin its good. Or could you be asking about the fit between the gears and the cover. I think thats also a 6 thousands fit. Russ aka typ4 knows this fit very well. He made a post about the poor quality control of the Melling replacement pumps. If the pump cover or body needs lapping use a piece of mirror for this. Glass plate is flat but a mirror is much flatter. If it wasn't your reflection would be messed up looking. Use some wet and dry paper of about 600 or 800 grit and keep it oiled up.

 

[Brad S.]

I was thinking of the gear-wall of pump measurement.
Mostly unknowing I did the "rolling gauge" through the gears, with the .0015 it was fine, I'll try the other sizes.
Thanks Gary, for the advice on the mirror/ fine grit paper.

 

[ifrythings]

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[riotwarrior]

First thanks, I thought of scanning my book and then laughed as it's burried in the shop while doing renovations.

You should put that post as a single post submission in the Tech thread section, nice to have info like that easy to get on the site!

JM2CW

Al

 

[typ4]

I know with that info springs can be made for the relief.
We used to have a small run coil spring co. here in portland, ill look into it.

 

[icanfixall]

Russ if we can make up new springs will that cause the bypass spring to open more often. Or should we make a new spring for that too. No sense in boosting the line pressure if the bypass is going to open all the time. I have been wondering about the 80 thousands shims I placed under the spring in the new rear header. I know dirty oil is much better than no oil idea too. Just some thoughts I have with no criticism...