Oil Pump Relief Valve Shimming

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.
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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.
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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.
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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.
 
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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.
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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.
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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.
 
Lets discuss my 401 oil pressure issues. The engine has less than 2000 miles and my oil pressure drops to about 18 psi at 60 mph. When I slow down the psi picks up tp 30+ psi when traveling around town. Installed a shim plus quart of lucas which raised my pressure to 18psi. Prior to the quick fixed the top end would start rattling at freeway speeds and would disappear when I slowed. Installed new pump gears and double checked the front cover housing and all is in spec. Starting to see spending big money in the future!
 
dave clifton said:
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
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Hey guys! Thanks for the very informative thread. I've been curious about shimming oil pumps as well and I have always felt very comfortable that the information I get on this forum is accurate, so thank you. I do have a couple questions regarding this test. If someone can clarify, that would be great.

1. The only real change I see is in cold start up. All of the readings when warmed up are pretty much the same. The only minor change is at very high rpms. I'm @ over 70mph at 3000rpm so I see no advantage to doing this? Can someone explain why it's more important to increase your cold start pressure readings?

2. I noticed the final results with the 15/40 oil gave a reading of 5 psi hot @ 700. This be roughly the reading with the car idling in park/neutral. It would be lower in gear as the idle would be around 500-550rpm. Isn't that a pretty big problem? That seems really low compared to what I've read on this forum regarding minimum pressure at idle especially considering we're talking about a freshly rebuilt engine that has a shimmed oil pump.

My 39 year old 304a engine and un-shimmed oil pump w/ 110k produces 12 psi @ 550, 20 psi @1000 rpm. (15/40 or 20/50)

I know this isn't completely on topic but I found it odd that no one mentioned that reading being low. If someone doens't mind explaining, that would be great.

Thanks a lot,

jason
 
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Hello all,

as a follow-up, I swapped my oil filter to a napa gold (wix) from a fram (the fram was nearly new) and my oil pressure went up about 6psi when I started her (caveat...not a nist traceable gauge). Although I was delighted to see the higher pressure, I'm still getting near zero when I stop coming off the highway and she's fully warmed up. Next step will be to pull the pan and pump and see what's up.

May you all have better oil pressure than me, jack
 
cearly said:
lets discuss my 401 oil pressure issues. The engine has less than 2000 miles and my oil pressure drops to about 18 psi at 60 mph. When I slow down the psi picks up tp 30+ psi when traveling around town. Installed a shim plus quart of lucas which raised my pressure to 18psi. Prior to the quick fixed the top end would start rattling at freeway speeds and would disappear when I slowed. Installed new pump gears and double checked the front cover housing and all is in spec. Starting to see spending big money in the future!
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Gee dave, those symptoms sound perzactly like what is commonly experienced with an sv engine that has major cam bearing issues. Such low miles too. Are ramblermotors as susceptible to top end oiling issues as the sv engines?
 
Jack, when you pull the pan you will know if your cam bearings are trashed, they'll be in the bottom. My 345 has an untold amount of miles, the guy I got it from said it had 88k on it when pulled, I pulled the pan and it was clean, no metal what so ever.
I began the process of removing bearing caps to check, all good for 88k, put her back together.
I did follow the pump shim procedure outlined in this thread as you will see by the previous post.
After running this engine with nothing but shims and a complete regasket, hot oil pressure at idle is 10 psi, with 15/40. With a rapid increase to 55lbs as I accelerate. And it never moves..as I came off the interstate this morning after a 45 mile trip at 60+ it dropped to 10 psi and came right back up.
These motors are hi volume low pressure, not like a Chevy or Ford, if you dont hear the lifters rattlin at idle hot your ok.
Hope this eases your mind a little
and as for daves 401, I agree with Scout boy. If he's added the shims and topped her up with lucas which is about 200 weight and 18 lbs is all she'll muster, cam bearings are gone for sure!!!
 
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