Oil Pump Relief Valve Shimming

Well duh!

See I told you the she/it knocked me off-kilter too early this am.

"the shim/pressure values are added shim to the existing oil pump spring, poppet and,washer stack-up."

my original skewed thinking would have resulted in only a 5psi increase. And I would have finished the pan re-seal! Glad I asked and didn't get flamed for a non-thinking question. Can you imagine if I only wanted a 1 psi increase? I'd have tried to surface grind the oem washer down to .009"

I'm ok now. Whew! Is it the weekend yet?
 
01-01-2010 update:

happy new year!

Dropped the pan and shimmed the relief valve yesterday. Upon close examination I found that my relief spring had collapsed over time. It's fsm was 2.180" a departure from the 2.25" spec of -0.07". Funny that when I removed the cotter-pin I was prepared for a spring-loaded event. But nothing. It all just sat there. So basically I don't believe the relief valve was doing anything. Always letting some oil bypass. So my oil pressures were totally driven by cam bearing clearances and pump output pressure.

After a quick consult with prof mayben, I decided to augment the shim decision with added thickness. So I added 0.070" + 0.038" for a total of 0.108". No special science here. I had both thicknesses in existing washers without any grinding. With a spec fsm spring that total should provide around 12 psi increase per Robert's numbers. But with the collapsed spring I'm still hoping to hit around 10 psi.

The other interesting thing I found was that the oem spacer or spring stop is a larger diameter (mine was 0.682") than the spring or spool valve. So it doesn't actually depress any further into the housing than just enough to clear the cotter-pin. My spacers were smaller, around 0.625". They do compress the spring into the housing. Moral of the story: the oem washer must remain on the outside end of the "stack". The shims must be on the inside of the oem washer (between it and the spring). Vice-versa and I couldn't insert the cotter-pin. This time when I installed the cotter-pin I did have to depress "slightly" against spring pressure to provide clearance. So now I know there will be some relief valve performance.

The radiator is removed, getting a pin-hole repaired under warranty at griffin so I can't fire the engine just yet for a pressure test. (yeah I could run it briefly without a rad but I'd still slop what coolant is still in the block all over my garage floor.)

I'll test run and post the pressure results in a couple weeks. This also gives me a chance to paint and install a new dip-stick tube (just purchased from IH only) when it gets here next week and allows the new paint on the oil pan and mounting nuts to fully cure.

Dave
 
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Hey, happy new year to you too!!! Looks like we made it through another one.

When I look at your posted hot oil pressure readings I can see when your relief valve was just starting to crack or uncover the return port.
Hot (195°f thermostat open after 20 min drive)
700 rpm = 10 1000 rpm = 15 2000 rpm = 30 3000 rpm = 43 4000 rpm = 45
if you plot the rpm vs pressure you quickly see the curve is linear like it should be. The pressure curve should be basically linear right until the relief valve cracks then it becomes a diminishing ratio.

From 700 to 1000 the pressure rose 5 psi or 1.6 psi/ 100 rpm
from 1000-2000 the pressure rose 15 psi or 1.5 psi/100 rpm
from 2000-3000 the pressure rose 13 psi or 1.3 psi/100 rpm
(roughly 200 rpm before 3000 at 2800 the relief valve cracked and the curve began to diminish.)
From 3000-4000 the pressure rose 2 psi or 0.2 psi/100 rpm
well there she is.

You will see the biggest change in the cracking pressure which should increase in 12 psi from 41 to 52.

Post the same telemetry during your next test and we can plot it.
 
That all makes clear sense. But there had to be very little spring pressure on the valve. Just the mass of the spool valve + mass of the spring, friction of the stack in the chamber and what little pressure the spring was providing.

Too bad new springs aren't available....hehe.

The first test run will be with the replaced 20w50 oil. Second test run will be the new swepco 15w40 oil sitting on my shelf and new wix filter.

Dave
 
This thread only reminds me how much I want id & od dial calipers, an assortment of dial bore gauges & micrometers, maybe a good dial indicator built into a heavy straightedge, a motor mount, etc...

Hundreds of dollars worth of dreams right there! I'll be taking off my oil pan just about as soon as I can get around to it, and this May be one of the things I'm interested in doing. As of right now, though, my oil pressure basically remains at the halfway point in the oem gauge. It maybe dips 1/8 of its travel below the midpoint at idle, and reflects across the midpoint by the time I'm traveling 65 in a 55. :icon_rotate:

translation? This thread got me excited about my IH equipment all over again.

I've been looking into a custom dash, too, so that I could get both oil temp and pressure gauges, but with my current figuring, autometer would set me back $400-450 and then just buying a custom-cut dash panel would be about the same price. Then again, I do have two dash panels, and I do know how to plasma cut and weld (somewhat)...

Conclusion? If it wasn't for this forum, I might not be poor! But kudos to all the factual info that we can gather at this hub from these real situations with real rigs.
 
dave clifton said:
that all makes clear sense. But there had to be very little spring pressure on the valve. Just the mass of the spool valve + mass of the spring, friction of the stack in the chamber and what little pressure the spring was providing.dave
Click to expand...

The installed length isn't really what determines the pressure, it is the test length and force that equates to when the relief valve is compressing the spring and the poppet is uncovering the return port.

But hey the proof in it the pudding. We'll see for sure when you test.

Thanks for posting your info.
 
Yes, the autometer path is kinda costly. But I slowly incremented my set over a couple of years. Started with mech oil and mech water when the v392 went in exactly because of the fuzziness in the oem gauge readings/movements. I really wanted numbers to know what was going on. I disconnected the oem amp gauge when I went to a 140 amp alternator. So I was only using the oem fuel and speedometer. I built my own wood form and fiberglass/carbon fiber panel last year. I now run a total of 9 gauges. Two sit where a clock should be but my Scout didn't come with one.

For the curious,
left to right in my main cluster:
engine temp, radiator temp, rpm, fuel, speed, volts, oil pressure.

Down where the IH clock would be:
clock (autometer), tranny temp, outside ambient air temp (non-autometer, digital)

dave
 
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When dave and I talked this morning, told him I didn't think there was any way to get a new regulator spring. But later I thought that maybe I'll contact melling directly and see if they would sell some in a small quantity.

I haven't torn down all that many pumps to determine if a loss of spring free length is any kind of an issue, and the ones I have gutted I didn't bother to record data at the time.

So maybe Robert can use his reference library and find a suitable replacement spring...something like he worked out regarding the replacement poppet spring for the 1904 economizer valve??

Kyle...I have done many comparisons between the oem oil pressure gauge and a mechanical aftermarket gauge tee'd into the same port simultaneously (I run one that way on my dd rig also). If...the oem gauge cluster circuit board contacts are nice and clean, and the connector male/female terminals equally as clean...and the bulkhead connectors are clean and resistance-free...then the nominal oil pressure with the needle dead in the center of the long horizontal tick Mark is 45>50psi when using either a new or recently-replaced oem oil pressure sender.
 
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then the nominal oil pressure with the needle dead in the center of the long horizontal tick Mark is 45>50psi when using either a new or recently-replaced oem oil pressure sender.
Click to expand...
I'll x2 that.
A couple of weeks ago I checked the 1210's engine oil pressure, I too have noticed it varied from the middle of the gauge at about 2000 rpm to just below the middle in the left part of the bar when idling. Hot idle pressure was around 20 psi, it topped out around 45 to 48 psi around 2,500. There was distinct shift in pressure around 52 psi to where it dropped to 48 psi at about 2,800/3,000 rpm.

All in all I'd say being in the bar(the gauges' range bar), is a good thing.
 
michael mayben said:
so maybe Robert can use his reference library and find a suitable replacement spring...something like he worked out regarding the replacement poppet spring for the 1904 economizer valve??
Click to expand...

Sure, all I need I already have posted in this thread.

But I would not get to concerned with free length, simply shim to comp like you have recommended unless rebuilding the pump and then you get one in the kit. The spring rate will not change with loss in free length.
 
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:
 
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