Oil Pump Relief Valve Shimming

Well, finally got my griffin re-welded and now no leaks. Yeah!

First test run with the shimmed oil pump results are in!!

Original test run:
oil pressure (psi):

cold start-up:
1000 rpm = 40 2000 rpm = 45 3000 rpm = 50 4000 rpm = 50

hot (195°f thermostat open after 20 min drive)
700 rpm = 10 1000 rpm = 15 2000 rpm = 30 3000 rpm = 43 4000 rpm = 45

Today's test run with shimmed pump and previous oil and filter:
oil pressure (psi):

cold start-up:
1000 rpm = 53 2000 rpm = 57 3000 rpm = 60 4000 rpm = 60

hot (195°f thermostat open after 20 min drive)
700 rpm = 10 1000 rpm = 15 2000 rpm = 30 3000 rpm = 50 4000 rpm = 53

Results are exactly as predicted. Fantastic when everything works that way. I'm pleased with the results. Looks like when warm I'm getting 7~8 more psi. I think this provides a nice safety buffer when highway cruising. And I believe due to the thicker, cold oil I get get higher psi at cold start and warm up which should be a very good thing. I wanted to remain conservative with my alteration since my pressures were ok to begin with. I think if I had been able to start with a new spec spring (or maybe if I had tried to stretch mine back to spec) I might have achieved 10~12 psi.

In a week or two I'll change out the oil for the swepco 15w40, add a new napa gold 1452 filter and retest again.

Dave
 
Great results and with real world data to back it up. This type of follow through makes it all worth while!!

Thank you dave.:thumbsup:
 
Ok I'm not plumb dumb just sum dumb!!!! But all this shit has confusious'd the hell outta me.
If I'm gonna shim the spring, I need to leave the factory retainer spring and add washers to it. Correct?
So in order to increase pressure by 10psi, I would add .090 in shims plus put the factory retainer back in?
Just wanna be sure. Have seen guys shim pumps and blow oil filters apart. Doing this process 1 time is enuff.
And the bad part is ,I shouldnt be confused. Guess the bourbon is wearin off. But I can fix that lol
 
Yes, that is correct, add a 0.090" for ~10psi. Be sure the new shim is a little smaller in diameter than the oem washer (spring retainer) so that it fits in the bore. And put the new one inside of the oem washer next to the spring. Not vice-versa.

Dave
 
Dave and Robert get the gold stars for developing exact data to support this IH oil pump urban myth crap!!!

Great work boyz!!!!
 
Ok fellas, today I drained the 20w50 and added the swepco 15w40 and a new napa 1452 filter.

First observation was the surprise when the swepco poured out of the bottle purple! Startled me for a moment. I did recheck the labels to make sure it was motor oil and not anything else!!

Original test run:
oil pressure (psi):

cold start-up:
1000 rpm = 40 2000 rpm = 45 3000 rpm = 50 4000 rpm = 50

hot (195°f thermostat open after 20 min drive)
700 rpm = 10 1000 rpm = 15 2000 rpm = 30 3000 rpm = 43 4000 rpm = 45

Test run with shimmed pump and previous oil and filter:
oil pressure (psi):

cold start-up:
1000 rpm = 53 2000 rpm = 57 3000 rpm = 60 4000 rpm = 60

hot (195°f thermostat open after 20 min drive)
700 rpm = 10 1000 rpm = 15 2000 rpm = 30 3000 rpm = 50 4000 rpm = 53

Today's and final test run with swepco 15w40 and new napa 1452:
oil pressure (psi):

cold start-up:
1000 rpm = 52 2000 rpm = 56 3000 rpm = 63 4000 rpm = 63

hot (195°f thermostat open after 20 min drive)
700 rpm = 5 1000 rpm = 15 2000 rpm = 28 3000 rpm = 44 4000 rpm = 52

I expected a drop due to the thinner oil. But it doesn't appear to have been much. Probably within the error of the gauge, my reading the gauge while driving, etc.

I also think the engine was warmer today when I finished the test run so that I believe answers for the 5~8 psi I sorta guessed the gauge was reading at hot idle. Really hard to read that low and near the stop peg.

Anyway to sum up, I'm glad I shimmed the pump. I believe I'll be happy with the swepco and the probable superior properties it brings as a friction fighter to the new-old iron.

Happy IH'ing everyone! Thanks to Robert and michael for the "high fives". And also thanks to all the other contributors.

Dave
 
Ok, needing a pertinent opinion here. After pulling the relief spring in the 345 I picked up from matthew, I checked the free length and it comes up 2.200 which is .050 short. Should I try to stretch it back to 2.250 or just add another .050 shim to take up for the loss in free length.
I dont have the oil pressures this engine was operating on , being it's a new to me motor but im figuring wth can it hurt.
Knowing that the free length is short lets me know it does have some flow by on the valve. And like the one mentionned in the thread, no spring action when the pin was removed. Actually had to pull the washer and spring out. And it wasnt gummed up or stuck.
 
Don't attempt to "stretch" the regulator spring!!!!

Simply add additional shim(s) to compensate.
 
Ok after adding .158 worth of shims, the extra .050 was to make up for the loss in free length, I finally got around to oiling up and spinning the pump.
The oil is just cheap 10w40 from advance ,as im gonna swap it out for rotella after its fired off, but I got 65 psi with 550 rpms
[drill rating] At the middle oil port on the left side. While rolling the engine with a ratchet , ive got oil freely flowing from the rocker shafts on both sides. Cant wait to get this thing in and get some real numbers especially at idle and hot.
It'll be a while on the install duue to funding and time ,but I'll keep up the post. :icon_rotate:
 
You win this time dude!

That's better than a xmas bonus and two ex-wives!!!! And ya pay no dam taxes on this chunka luv!
 
In the midst of my 304 rebuild and about to install the oil pump that my engine builder redid with the melling oil pump repair kit part number: k71e

this kit came with a new spring and washer. I am assuming this pump is good to go as is now without shimming the spring. Has anyone found the need to try to improve the performance of a pump using the k71e kit?

Fyi this is for a 1975 IH 150 4x4 pickup.
 
rusty Scout said:
in the midst of my 304 rebuild and about to install the oil pump that my engine builder redid with the melling oil pump repair kit part number: k71e

this kit came with a new spring and washer. I am assuming this pump is good to go as is now without shimming the spring. Has anyone found the need to try to improve the performance of a pump using the k71e kit?

Fyi this is for a 1975 IH 150 4x4 pickup.
Click to expand...

Does the free length of the melling-supplied replacement spring match the free-length spec that has been posted? The washer that is included simply serves as a "stop" for the spring to keep it from bearing directly on the cotter pin.

If the spring length is the same, then adding an additional shim won't hurt anything and "should" boost final oil pressure by numbers real close to what has been described. I'd not go any additional pre-load than what has been discussed.
 
IH oil pump # 448663-c1 old spring length was 2.210.

The melling k71e kit spring is 2.223 long and the shim was .041 thick x .663 od.

I found some .063 thick x .631 od washers.

I think I am going to add 2 of the .063 washers to the .041 existing shim for a total shim thickness of .167 to match Jeff's shim thickness of .170 as reported early on in this thread by mr. Mayben.
 
rusty Scout said:
I think I am going to add 2 of the .063 washers to the .041 existing shim for a total shim thickness of .167 to match Jeff's shim thickness of .170 as reported early on in this thread by mr. Mayben.
Click to expand...

I do not recommend running 65 psi on a stock engine. It is simply not necessary.

Rule is 10 psi per 1000 rpm. 4500 = 45 psi. 50-55 is what I consider a good peak oil pressure to shoot for. That is what I set up every sv/ IH 4 cylinder at.

Add 1 .063 washer. The existing washer that is between the spring and cotter pin is not considered an increase but stock.
Cotter pin , washer, spring, and plunger in that order is stock.
 
Robert kenney said:
I do not recommend running 65 psi on a stock engine. It is simply not necessary.

Rule is 10 psi per 1000 rpm. 4500 = 45 psi. 50-55 is what I consider a good peak oil pressure to shoot for. That is what I set up every sv/ IH 4 cylinder at.

Add 1 .063 washer. The existing washer that is between the spring and cotter pin is not considered an increase but stock.
Cotter pin , washer, spring, and plunger in that order is stock.
Click to expand...

I concur...these are medium pressure high volume lube systems designed into these motors. I know we say this over and over,...but they are not chryfordrolets and we can't treat 'em like one!
 
Just to be crystal clear Robert is saying to add one .063 washer to the stock .041 washer for a slight increase in this case. Sorry I am a little slow due to high levels of rust inhalation.
 
Last edited:
rusty Scout said:
just to be crystal clear Robert is saying to add one .063 washer to the stock .041 washer for a slight increase in this case. Sorry I am a little slow due to high levels of rust inhalation.
Click to expand...

Yes!

Don't mix carb cleaner vapor with rustdust, that makes the rust look like the offspring of breedin' lava lamps.
 
michael mayben said:
yes!

Don't mix carb cleaner vapor with rustdust, that makes the rust look like the offspring of breedin' lava lamps.
Click to expand...

Cuda yoozd this warning last night. Daggum. I had monster-sized chickens wanderin arount in the shop at one point. I wuz defnlee in the spirit world a-hole!
 
Hey trevor!!
I believe you wazz in the a-hole but waz it sailor jerry's a-hole rather than a rust and carby cleaner a-hole?:icon_xd:
 
Hello mr. Mayben,

thank you for this excellent thread. I'm curious of your comment regarding oil filters in post #3:

"without knowing what oil filter ya typically run, as compared to any of the common fram part numbers,...a wix, hastings, baldwin, or purolator (pure one version only) will give a nominal 10psi+ increase in hot pressure also at say 2200rpm and higher.

All those numbers are found with 15w-40, straight 40, or 20w-50 oil and a fresh oil filter and observed continuously on my beater 392 for the last ten years. And when the hot oil pressure "drops" ten psi aver about 3500 miles, I know that is a signal to change the filter!"

2 questions:
- why does oil pressure drop with an aging filter (I would have guessed the reverse but don't pretend to know much)?
- why does filter type affect oil pressure?

Thank you for the oil pressure gospel!

-jack
 
I know you asked m/m this question, but look at the oil system I n question. The filter is before any type of pressure sensing device. As the carbon and dirt build up in the media of the filter pressure and flow decrease. Once it reaches critical blockage the bypass valve in the filter is supposed to take over and let it go, but going that far on an oil filter would be terrible. Might as well get bearins when you get a new filter!!
Question 2, this is my unejemekated answer. The construction and type of media along with the tyoe and quality of the bypass system means everything, cheap is cheap, wix is good!!! Baldwin and purolator also make good filters.
Actually it all comes down to oil flow and filtration,good filters flow and filter. Cheap filters either flow or filter not both. Such as with a fram. Cut one open compared to a wix and you'll see whats goin on.

Hope this helps! Im sure m/m will get anything I left out
 
Towpainter is correct in his analysis of the oil filter situation.

The main differences in all the variations of filter elements lies with the design of the filtration media and it's conformed shape and actual surface dimension (in square inches).

Many filters simply use a very minimal amount of media that has a relatively large flow rate. The best filters use much more actual media and the flow-through characteristics are much smaller.
 
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