Oil Pump Relief Valve Shimming

[Robert Kenney]

Funny, the felpro gasket kit I have for a 392 I am going through is missing the same 2 gaskets. We need to find a source for them. I will make them for this engine too.

 

[Michael Mayben]

funny, the felpro gasket kit I have for a 392 I am going through is missing the same 2 gaskets. We need to find a source for them. I will make them for this engine too.

Oh well, I've never found the gaskets to be missing out of either the full sets or the conversions sets (fel-pro only).

Did ya rip that small manila envelope completely open and make sure they are not stuck to the adhesive??? They should have been packed in that envelope with the "o" rings, the oil pump cover gasket, cam plate gaskets, etc.

I have a new pair on the desk now, I can scan 'em and post as a .pdf for a template. But in the past when I've done the same for other small gaskets, the scan somehow is "reduced" slightly in scale so the templates are not exact, but they would be close enuff for working out a slight enlargement!

 

[Dave Clifton]

I have some gasket material, plenty in fact. I would have thought of that first but sight-unseen I didn't know if they were special in some way. Embossed or o-ringed, etc. Not sure of the thickness but I'll make my own. A pdf would be cool.

I'm anxious to see the shimming procedure and photos. Should be illuminating!

 

[Michael Mayben]

Ok, here's a .pdf'd scan of the two gaskets.

Using the lexmark all-in-one printer setup, if you set the scaling to "none", it appears that it will print the templates actual size. I've verified that on my end...so now I've learnt shit too! The problems I had in the past making template scans were involving various older hp printer/scanners.

But since you are a pooter dude, ya prolly know all about that schnizz!

To review...ya need to always use both gaskets, even though one goes under the secondary mounting leg to shim the pump off the block and carries no liquid. Otherwise, there is a very real danger of either cracking the pump housing (since it's cast iron) or distorting the housing when torqued so that the pump gears could potentially bind.

I'd dare say that the majority of these engines in service that ever had a oil pump r&r'd, most likely do not have the gaskets in place! Or even worse...sum dumscruu used rtv!

I'll do a work-up on the oil pump shim stuff and get that posted later today.

 

[Dave Clifton]

Ok michael, to check my printer's accuracy I make it 1.25" center to center on the outlet gasket mounting bolt holes. And I gather that since I measure the same holes to be .323" in diameter the mounting bolts must be 5/16 (.323 is a close fit clearance hole spec for that size machine screw).

Getting close to dropping the pan. This weekend I'm tackling a stubborn coolant drip from my radiator's tranny cooler input adapter, adding 1/4" spacers to my front wheels, replacing the chewed up tie-rod boots (refer to previous wheel spacer item), and dropping my front drive shaft for redo (too short in compressibility for a reverse shackle. Big oops that! Glad I caught it before wrecking something!!).

 

[Michael Mayben]

I'm still trying to get out in the shop and do that erl pump shim deal!

Yes...the mounting holes are for 5/16" bolts, both sides! The gasket punch sets that harbor freight sells are all "standard" uss/sae bolt/screw diameter sizes and work as well for metrics!

The actual c-to-c of the gasket and the pump casting measures 1-5/16".

 

[Michael Mayben]

Here's the "shimming" detail for an ihc-produced oil pump pressure regulator for either a I-4 version, a fullsize version, or a Scout II version. While the details in the oil pump castings differ, the actual gears and shaft included in an oil pump service kit are identical for all versions. The actual "shim gaskets" included in a pump kit differ also in shape since the bodies differ, but the various thicknesses of the gaskets are consistent, those are used in a selective fit mode to set the end clearance of the pump gears when re-assembling the pump.

Simply remove and discard the cotter pin that retains the pressure regulator spring shim, spring, and spool valve. Clean these parts carefully, and also clean the oil pump pressure regulator valve bore before moving on!

The cotter pin is nothing special...just a standard cotter pin! Don't be surprised to find a finish nail, or a chunk of bobwire stuck in that hole, after all this is IH schnizz and typical tightazz IH folks will use anything to not spend a nickel for a cotter pin! No toothpicks though!!!

Notice the chamfer on the spool valve goes into the pump body bore first, do not reinstall the spool backazzwards!

 

[Michael Mayben]

Check the free length of the pressure regulator spring to determine if it's within specification. This one comes in at 2.256". Robert already trained us that the spec for the free length is 2.250"...perfectly within spec.

If the spring was somewhat under the spec in free length, then that indicates it's "collapsed" over time and the shimming data he extrapolated will be skewed.

 

[Michael Mayben]

Here's the typical oem "shim" used in these oil pumps...nothing special, just a washer. Idea is to provide a "seat" between the spring end and the retainer/cotter pin...not to "calibrate" the regulated pressure of the pumps individually. This ain't even close to rocket science!!!!

 

[Michael Mayben]

The washer in this sii pump has a nominal thickness of 0.040".

The od of the washer is 0.680"...basically a 1/4" grade 8 sae flat washer!

 

[Michael Mayben]

This is where ya gotta do that hard shit called "math" before ya go to 7-11 for a big gulp and some washers.

Use Robert's data found in post #15 to determine what thickness shim ya wanna use!

You can stack another shim on top of the oem, ya can toss the original out and go with a thicker shim/washer, ya can do mix-and-match all ya want to come up with the total thickness (spring pre-load) ya wanna end up with (within reason of course!).

Whatcha see here is two "ideas" I use sumtime. The darker item is a metric 8mm plain old flat washer (black oxide finish), the lighter item is plain old 1/4" sae flat washer. Either of those will have to have the od reduced onna grinder until they fit inside the bore of the pump in a kinda "sloppy" fashion.

Actually...if yore gonna make a shopping excursion for some washers, then look for a 7mm flat washer, those are kinda unusual but used in many applications, I find stuff like that in the hardware assortments at the local farm supply or even them bigbox home supply operations. A 7mm flat should be just right in od and ya might wanna use two of 'em depending upon actual thickness..always take calipers when ya go shoppin'! Looks real trick stuck in yore pocket protectors.

 

[Michael Mayben]

Don't forgit to re-install all this stuff before ya re-hang tha pan! Otherwise you will be real disappointed in this mod and yore wife will look at ya like this!

 

[Robert Kenney]

Ahhhhhhhhhh fuck man!!!!!! I think I am going to blow chunks all over my key board............................................................................

Mayben you gotta warn us before posting your girlie pictures.

 

[Michael Mayben]

At my age...ya don't cull dude...neither does/did tiger!

 

[Greg R]

...neither does/did tiger!

Sumbuddy's been up the holler way too long!

 

[Scoutboy74]

Hey! Iz that'n still availuhbull? I bet sheez even got sum uh her teeth yet!. Hail, sheez an upgrade over what jerry's been grab-assin' lately. Hook me up mayben! You kin be my best man!

 

[Dave Clifton]

Its early, I'm trying to finish what coffee I haven't spewed all over myself after catching first view of the right hand seat passenger above , I know I need to find a net and re-capture some missing brain-cells...

Just to confirm adequate absorption:

shim required to increase oil pressure 1 psi = .009"
shim required to increase oil pressure 5 psi = .044
shim required to increase oil pressure 10 psi = .089
shim required to increase oil pressure 15 psi = .133
shim required to increase oil pressure 20 psi = .176

if the oem washer is .040" and I want a 10 psi increase I need to add to or replace the oem in whatever combination so that I obtain around .090" tst (total shim thickness: oem + additional). Thanks! Michael the photos help!

Ok. I'm gonna go clean up my spill now. Happy Friday!

 

[Robert Kenney]

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

For a 10 pound relative increase in regulation pressure +/- 10% add .090" is what I calculate and this correlates with engines I have built /rebuilt.

I have always left the factory shim and added thickness to increase pressure. Just happened that my washer selection gave me what I need in a combo type of dealy-o and that is how I posted it.

 

[Robert Kenney]

at my age...ya don't cull dude...neither does/did tiger!

She/it kinda looks like there outa be a place to add air with the big blue eyes, fake lookin hair and, strange stretch marks around the mouth. I gotta stop or I'll be liken to dirty my desk at work.

 

[Michael Mayben]

The best thang about the blow-up chicks...ya just stick a pin in 'em if they cease to be amusing and they fade away with no backtalk. That fit's in right along with jerry don't it???

And...ya kin store 'em on the shelf right alongside the carb kits, spark plugs, oil filters, and woredown rocker shafts!

Think we'll ever hear from dave agin????