how to shim oil pump
05-13-2005, 03:53 AM
#4
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Shimming is used to bump PSI not flow. As in how to shim one i have no idea but from what i have read it just bumps psi you will not get any more flow.
05-13-2005, 10:39 AM
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Well, I just went through this. I put a number of posts up asking about it, but only got 1 or 2 responses and they were educated guesses. I did a h/c in Oct and changed to a Katech ported pump. I found out afterwards that Katech doesn't shim the pump. I had 35 psi at idle to around 70 psi at 6500 rpms before. After I put it all back together I had lost 5lbs. across the board. So I had 29-30 psi at hot idle (oil temp 195+) and 65psi at 6500 rpm's. I just did a cam redegree and pulled the heads to have them milled some more. When I had the front cover off to change the timing gears I pulled the oil pump and shimmed it. I removed the bypass seal and put a washer in that was just shy of .060" thick. When I put it all back together I had 33psi hot and 70psi at 6500rpms. If I were to interpolate from my experience I should have put in about .100" of shim to get back my 5psi. But I do feel better about my pressure now.
05-13-2005, 11:15 AM
#6
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From GM there is no shim under the bypass spring. I read that TSP adds a .110 shim, that should be good for about a 10-15 PSI increase. I recently added a .145 to my race motor, that brought it up from 45 to 60. I just turned a small piece of aluminum on the lathe. It's about .41 in diameter, it fits inside the allen head threaded plug on the bypass spring.
05-13-2005, 11:28 AM
#7
So all that I do is lets say that the pump is on the motor, On the right side there is a little allen head bult I take that out and put a washer in that spot and then put the allen head bolt back in. I just made another post about what is going on with my oil pump if you guys can look at that. I really apreciate the help I wish I would have know this back in Februrary.....
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05-13-2005, 12:04 PM
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yea .110 sounds good. thats what i'll be shimming my oil pump when i take it apart to port it myself.
and i read your other post, it sounds like the o-ring went bad.
and i read your other post, it sounds like the o-ring went bad.
