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Old 11-18-2009, 02:36 PM   #1
Dave Clifton
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Default Oil Pump Relief Valve Shimming

Hello mr. Mayben!

Could you either point me to the proper thread or take this opportunity for a short treatment on the title subject?

Touch on:

1. Proper procedure. I have read that improperly done it can raise pressure too much.

2. Theory of operation. I have also read opinions that shimming it does nothing for increasing pressure except in over-pressure situations which should be very rare or non-existent in properly built and operating motors.

I'm dropping my oil pan for re-gasketing and thought it might be a good chance to perform the shimming. My psi is ok. Pretty average numbers with 20w50 oil. I wouldn't mind seeing a little more than 8~10 psi at idle on a fully warmed up engine. I also get about 10 psi for every 1000 rpm on the same warmed up sv 392.

My searches of this (and other) forums have been frustrating. I need a once-and-for-all from the IH sv guru!

Thanks!!

Dave clifton
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Old 11-18-2009, 02:50 PM   #2
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Default Re: Oil Pump Relief Valve Shimming

I think that would be a great idea too dave. Your psi numbers are spot on though. Are you sure you're not trying to fix something that ain't broke? And now a message from the professor.........
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Old 11-18-2009, 04:49 PM   #3
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Default Re: Oil Pump Relief Valve Shimming

Quote:
Originally Posted by dave clifton View Post
hello mr. Mayben!

Could you either point me to the proper thread or take this opportunity for a short treatment on the title subject?

Touch on:

1. Proper procedure. I have read that improperly done it can raise pressure too much.

2. Theory of operation. I have also read opinions that shimming it does nothing for increasing pressure except in over-pressure situations which should be very rare or non-existent in properly built and operating motors.

I'm dropping my oil pan for re-gasketing and thought it might be a good chance to perform the shimming. My psi is ok. Pretty average numbers with 20w50 oil. I wouldn't mind seeing a little more than 8~10 psi at idle on a fully warmed up engine. I also get about 10 psi for every 1000 rpm on the same warmed up sv 392.

My searches of this (and other) forums have been frustrating. I need a once-and-for-all from the IH sv guru!

Thanks!!

Dave clifton
Where tha hail ya been dave??? I thought ya gave up??? Were we cool in the engine bay all summer????

Both your bullet points are bullshit regurgitated on other boards over and over through the years and then they take on a life of their own. I don't beat around the bush as you know!

I'm currently shimming the oil pump relief valve (both I-4 and sv apps) using a ballpark 0.070">0.100" shim. Whatever washer that ya have around that will match the I.d. Of the hole and in that range is just fine, nothing special. That should give you a net increase of "hot" oil pressure or about 12psi. Any more than that is certainly unnecessary.

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!

I'll have some meaningful oil pressure numbers (shimmed pump) tomorrow after we crank the sonjamotor for the first time (we didn't get the engine bay prep finished today):

http://www.forums.IHPartsAmerica.com...tor-lives.html

I've personally observed oil pressure in Jeff's 345 in his white sii over and over. That motor was built with a 0.170" shim iirc. It runs an instant and solid 60 psi goin' down the road and has for many years.
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Old 11-19-2009, 06:31 AM   #4
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Default Re: Oil Pump Relief Valve Shimming

I'm comfortable with my present psi numbers.

I guess all the hype on the forums about oil pressure in sv motors and the, from my vantage point, uncertainty surrounding the oil pump shimming has added a level of curiosity I was hoping to resolve with mr. Mayben's expertise.

I, in particular, so seldom drop the oil pan that this May be the last time for another decade or more that I will do so. If warranted I was and am willing to add a washer to the valve for sits and grins. I certainly don't want to harm anything in a perfectly running set-up.

Michael, all I can say is that life certainly throws curve balls. I'm still in the batter's box though and swinging for the outfield. I've taken Scout off-road once This summer! Stayed close to home the rest of the time (wife's 2 knee fixes) and concentrated on my new, somewhat iffy job situation.

The Scout ran beautifully until my front drive shaft contacted the lip of my 727 oil pan and peeled it down enough to cause a serious drip (or should I say pour??). I was in a severe articulation angle (obviously), and going in reverse. A balance weight on the shaft was just in the wrong place at the wrong time turning in the wrong direction. Luckily bad weather at 12,000 feet had already started my decent and return home (whew! If not that would have been bad considering how far up I would have been. In the stratosphere without a tranny).

Now I have a new smaller diameter front shaft. The previous one was just too big in od. I always suspected it and was finally proven correct.

In 4xlow pulling a long grade Scout never got over 210. I'm still gonna make one more change to the derale fan that lou has spec'd. I want that added fan to core clearance.

Oh yeah, I always run the napa gold (wix) filter with 20w50 oil.

Would shimming affect the psi in a linear fashion? From idle to highway? Or just the high end? (my "theory" question)

dave
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Old 11-19-2009, 09:00 AM   #5
Michael Dimock
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Default Re: Oil Pump Relief Valve Shimming

On my 196 that I just rebuilt, I shimmed the pump with a washer that mayben suggested/gave me. granted it doesn't have really any drive time on it yet, but it runs around 20 psi hot idle, and 60 psi hot cruise. Cold fast idle is around 65 psi. Hope this helps.
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Old 11-19-2009, 09:35 AM   #6
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Default Re: Oil Pump Relief Valve Shimming

Dave,

without a calibrated, high resolution oil pressure gauge and the ability to vary engine rpm using a micro-adjustable throttle control, it would be hard to develop actual hard numbers regarding increasing relief valve spring pre-load by shimming. But I'm sure we can come up with some seat-of-the-pants data. My gut feeling sez that "yes", any change in relief spring pre-load will affect pressure in a linear fashion.

We also need to have a typical "stock" oil pressure relief valve spring tested so that we know what it's curve is for comparison. Since there are at least three different variations of the oil pump body/end plate used throughout the I-4/sv production run, that adds to the mix also. So sample springs from each version would need to be tested in order to determine if any variables are present there also.

Only one I-4/sv oil pump is currently available new, so we'd need to test one of those as well for comparison. Since we can't source new springs for each variation through the oem parts source, that is not an issue...but we May be able to find/develop springs which accomplish a conservative increase in pressure without the need for shimming old, unknown parts!

Hopefully over the winter, I'll have a test mule engine running on a stand that will be used for playing with stuff like this. Not a dyno, though I do plan to incorporate a 10kw harbor freight alternator into the scheme to use as an apu around the place here when the juice goes away on occasion. And the engine is just a tired 196 that is "typical" of what many folks are running every day, and has more than adequate oil pressure numbers in it's current form even though one cylinder has a somewhat "flat" cam lobe, an affliction common on the I-4 motors with an oem cam.

Oil pressure numbers displayed on the gauge are controlled/affected by many variable in any single engine. The pump output pressure at any constant test rpm is determined by the end clearance between the rotors and the cover plate (along with rotor tip clearance between the master/slave). That is why multiple mylar shim-gaskets are included with the melling pump rebuild kits.

But due to the design of the I-4/sv engine lubrication scheme, the greatest "control" point regarding oil pressure is the condition of the cam bearing running clearances, unlike many other engines where oil pressure is grossly affected by the main and rod bearing clearances.

And in stock form regarding an engine which exhibits no internal wear, the ihc-designed lube system is certainly adequate for an engine running at 2800>3500rpm, 24/7 in an industrial irrigation pump application...or heavily abused by an inexperienced school bus driver!
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Old 11-19-2009, 07:47 PM   #7
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Default Re: Oil Pump Relief Valve Shimming

If I May, I'd like to add to the info already well posted and has been documented. There's a lot of emphasis on pressure, but it's a part of what the bearings need. Flow is the main thing that keeps bearings slick'umd up. They constantly bleed off oil, and that's needed to carry away heat. A good flow replenishes that oil and supports the hydrodynamic oil wedge which is what supports the journal in the bearing. In a sense, the lubrication system is a system of orifices; bearing clearances, drillings, galleries, etc. Volume and pressure are interelated. Jack up the pressure and you get more volume to a point; beyond the point it's just more pressure as the system is only gonna pass so much. Many engines can actually run on way less pressure that we're accustomed to, but the extra poundage you could call a safety factor. More pressure than spec'd on the specifications sheet for a street/stock engine is robbing horsepower.
Viscosity of the oil is a major factor in the flow/pressure formula. I'll cite a documented example* in short form:

"taking figures from an actual case, the oil pressure is 10 psi with the engine hot, and this is felt to be too low. The oil is changed from an sae20 to an sae30. The pressure is now 13.5 psi. What effect did this have on flow? The flow actually dropped slightly. The increase of pressure merely reflected an increase of system resistence to the thicker oil.
In another case the engine operating temperature was increased from 160*f to 190*f; with a corrsponding increase in oil temperature. The oil pressure at full load and speed fell from 25 psi to 21 psi. The viscosity of the oil fell over 40%, from 121 ssu to 75 ssu(saybolt seconds universal). The drop in system resistance more than counterbalanced it so the rate of oil flow to the bearings increased by 17% it is, of course, possible that in another engine this reduction in pressure might imply a reduced oil flow, but the pressure gage is not a true indication either way"

gauges are a necessary tool in figuring an oiling system's performance, noting differences or changes from the ordinary or fluctuations from spec say to signal time for maintenance. High readings could be from a stuck relief/regulating valve, cold thick oil or oil sludged up from an overdue change(way overdue), choked/coked galleries and the like.
Low pressures could be restricted intake screen, a wornout pump, oil diluted with fuel, the regulating valve stuck open; and as previously shown in other threads, worn bearings and particularly the cam ones.
Specs for an sv and slant 4 show 10-20 psi @ idle to 40-50 psi at 1800 rpm with sae 30 oil at 200*f. Good reason to stay with the recommended or equilvalent oil. Just my view, but for an unmodified stock engine anything beyond that is wasting horsepower. They don't come broke, and if they were maintained; we get them 40 years old and still runn'in. Whether spring adjustments can be linear is hard for me to get my head around. Too many variables; viscosity, temperature, speed. Mike's test mule at known conditions should bring that out.

I hope this goes well with folks. The intent is to add to and not a "instead off" form of contributing. While the book May be old, the principle is the same and what the engineers use. I also included a link from melling's website, enjoy.

Link from melling pumps:tech tip videos

Bib. * "industrial lubrication practice", paul d. Hobson
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Old 11-20-2009, 06:54 AM   #8
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Default Re: Oil Pump Relief Valve Shimming

This weekend I'll take some closer measurements of my oil pressure and post the results. We can use them as a comparison against michael's test engine and other contributor's engines.

I've a v392 with around 20,000 miles on it (well broken in). It's pretty strongly built with a schneider cam and efi. This engine was built for me by a friend and professional mechanic. He's extremely thorough and plasti-gauged every bearing clearance to insure it met spec. We installed a re-built oil pump iirc. Probably straight out of the box. funny but wade has always felt my pressure is a little low but he attributes that to this being an IH sv and he's comparing it to GM and others.

I'm running an autometer mechanical oil pressure gauge and an autometer mechanical water temp gauge. Both gauges are plumbed into the stock IH positions for those sending units. Sorry but I can't measure my oil temp. Napa gold (wix) filter and valvoline 20w50 motor oil with moa and zinc additives. (switching to straight swepco next change, but uncertain of viscosity choice. Need results and answers to this thread for that decision.)

I'll measure pressure at idle, 1000, 2000, 3000, 4000 rpm cold and at 195f (thermostat setting, after a drive to insure the oil is fully warmed up) and post the chart.

I've already started to learn some new things here. I'm very interested in how this thread will end. "if" I decide to shim I'll repeat the exact test again and post those results.

Thanks for everyone's contributions! Interesting stuff!!

Dave
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Old 11-20-2009, 09:12 AM   #9
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Default Re: Oil Pump Relief Valve Shimming

It will be interesting to see the numbers you get.

Re oil temperature...

I really do not think this is an issue with "water-pumpers" -- unless your cooling system fails...

I thought oil temp was an "issue" in a corvair (at least something I decided to "monitor") and when I had an engine built from the "ground up" in 1977, I had the mechanic add an oil pressure and an oil temp gauge (electric, of course).

Having an oil temp gauge was a "bust" from my viewpoint -- maybe because the needle hardly moved when it was "up to temp".

The gauge read 220 - 230 "all" the time - seemed high to me (the gauge is not hooked up now.).

But, the engine lasted 140,000 miles - no oil related failure.

Oil pressure / flow -- for corvairs the aftermarket offered (still offers) a hi-volume oil pump kit -- longer pump gears / housing extension -- for the "hot rod" / dune buggy crowd.

My corvair mechanic did not "like" these used on a stock engine -- to make real use of the higher volume pump, he felt the oil passages had to enlarged to handle the additional volume.
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Old 11-20-2009, 04:53 PM   #10
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Default Re: Oil Pump Relief Valve Shimming

Quote:
I really do not think this is an issue with "water-pumpers" --
Hey Robert! How've ya been?
To answer your concern, oil temperature is critical for all engines. Run 'em too cold, and ya get mayonaise in the pan(cold sludge the white goo), too hot and the cheaper blends can coke up the rockers and the life of any lube is greatly shortened. The optimum engine temperature is 180*f for a water cooled, I'm sure you can translate that to air cooled. It comes down to longevity as well. The sae did some tests in the 60's that correlated cylinder wear with engine temperature. What they found was that the cylinder wear rate decreased a large amount by having a minimum cylinder area temperature of 160*f. This meant the overall engine temperature or thermostat selected was best around 180. This was back in the days of 160 and 170 degree thermostats and before "permanent" antifreeze. I have actually held in my hand and read the sae abstract on that; the library at work had one as the dept of engineering and the sae go back many years. That was over 20 years ago, I hope it's still there.

200 to 210*f is a real good oil temperature, and my engines typically run that range; 220 to 230 ain't real bad, I start worrying when it approaches 240 though. It helps provide a good flow through the lube system, provides the needed film on cylinder walls and good oil ring scavanging , and the biggest point in favor of that temperature is it will drive out the moisture; that's good as engines produce water during the combustion cycle. I could go on, but that's the short and sweet.

Clifton, you'll be real happy with swepco oil. Most people that use it, including me, find the 15-40 an excellent choice for our type of driving and service. My lifter tick at start up has disappeared, and overall pressure has stayed constant Throughout the 5k mile service change. It also has the recommended zinc(antiwear) additive.
We need the oil moderator here! He could fill you in on the details.

Last edited by Greg R; 11-20-2009 at 08:46 PM..
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Old 11-21-2009, 04:09 PM   #11
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Default Re: Oil Pump Relief Valve Shimming

Clifton,

I've been sitting by reading the posts on this thread with great interest. I'll tell you that the information michael, Robert and greg have given is right on the money and wanted to see where this was going. (thanks for the push, greg!)

in chosing the weight you are going to use in your engine, please remember that it was originally designed for a straight 30wt oil. Back in those days, the straight weight Oils were common as the technology had not yet developed to a point where the multi-weight oils needed to be. With that in mind, this is one of those cases where I actually go against the oem recommendation for straight weight because of the much better protection afforded by the multi-weight oils. With the fact that you are in Colorado, sae 20w50 engine oil would not be my first recommendation, instead sae 15w40 should fit the bill just fine. You mentioned going to "straight swepco" - and that is the reason I zeroed in on the multi-weight, even though swepco also makes a straight sae 30wt oil as well.

It has been estimated that 80% of wear occurs at start-up and you will get much better start-up protection from the lighter end of the 15w40, but at the same time have the protection of the 40wt oil at the top end. 15w40 weight oil will have a wider ambient service range than practically any other weight, from close to 4 degrees f to 122 degrees f.

The swepco 306 - 15w40 supreme formula engine oil is rated as an "sl / ci-4" oil, it has a full-bodied additive package, including a high amount of zddp and detergents. You do not need to, nor do we want you to supplement this product with any other additives such as the ones you mentioned in your post, doing so can throw off the balance of the chemicals which are blended to work synergistically for the full effectiveness and protection of your equipment.

Jeff at ihon stocks 10w30, 15w40 and 20w50 swepco engine oil... You can find it on the purchase page under lubricants, or by going to the "sticky" on the oil tech page.

If you visit some of the earlier posts on the oil tech page, there are several which refer to the change in oil classification which occurred in late 2006 when the epa got involved and mandated a reduction in zddp to save catalytic converters, so please make note that you do not want to use an oil which has a label of "sm / cj-4" even tho it might state that it is backwards compatible and meets the "sl / ci-4" service rating. It might be backward compatible, but it doesn't mean it is the best to use in older engines.

Thanks for your consideration in using swepco engine oil, if you have any other questions, please let us know about them.

Swepco
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Old 11-22-2009, 12:25 PM   #12
Dave Clifton
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Default Re: Oil Pump Relief Valve Shimming

Ok, my test results are in:

baseline info:

IH v392, fresh rebuild with 20,777 miles, so... "broken in".
Autometer mechanical oil pressure gauge.
Ambient air temp (garage) this am in beautiful Colorado, 46f.
Crankcase has 7 qts of valvoline 20w50 + moa + zddp.
Oil filter is napa gold (wix) #1452.

This oil + filter was last changed July 4th 2007 but only has 1,810 miles on it (what can I say? Not an everyday driver!).

Oil pressure (psi):

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

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

Other items:

sorry to admit this, but this Scout is pretty much a "garage queen" in the winter. If it weren't, I would already be running lighter weight oil. The only reason I am running 20w50 is because without exploring any other variables, this was the quickest & easiest way for me to get my summertime pressures up where I felt they were adequate for protection of my v392 investment.

I do not recall what my 10w40 pressures were in the summer 20,000 miles ago. I recall at the time thinking "oh crap" this is on the low pressure side of things. Thus my switch to 20w50 with my mechanic friend's approval.

This said, and I'm not 10% the mechanic that all of you are, I feel from all I've read that the above psi numbers are good targets For an IH sv motor. I would gladly run 15w40 or even 10w40 if this same target range was met.

Thus my interest in shimming the oil pump. Is it possible (or likely?) that shimming would result in a similar range of pressure for thinner weight oil?

Advice? Do I shim?? Then switch to 15w40??? Or...

"there's nothing broken dave, don't mess with it!"

I'd still like prof mayben to post shimming instructions. I suppose I can read my service manual for the disecting part but his photos are super!

Thanks fellas!!!!!!

Dave
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Last edited by Dave Clifton; 11-23-2009 at 02:31 PM..
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Old 11-22-2009, 04:57 PM   #13
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Default Re: Oil Pump Relief Valve Shimming

Personally dave, I'd leave the oil pump alone! Those numbers are outstanding actually and indicate no issues whatsoever!

And I go back and forth over time between 15w-40 and 20w-50 oil as it strikes my fancy...I see no difference in anything related to oil viscosity...only the oil filter selection as far as oil pressure numbers cold and hot/clean or dirty.

If you wanna add a nominal 0.070" shim to create additional regulator valve pre-load, it will cause no problem and is one of the easiest things you can do while the pan is down for re-seal. A simple flat washer of the nominal thickness and approximate diameter of the relief valve bore. Be sure to use a new cotter pin! I have an oil pump in the soak tank now for clean-up, I'll post a how-to regarding this in the next few days.

Today I ran the sonjamotor for about two hours (we got it started last nite). The idle oil pressure numbers (cold and hot) are outstanding but this is a function of a new engine build with tight bearing clearances, a fresh oil pump, etc. Shimming the pump spring should have no effect on idle oil pressure! But the hot numbers at various rpm points are very encouraging for now, but this motor needs accumulated hours before making and determination if this was a valid mod. Robert and I talked at length about this today, he'll be doing some relief spring testing soon also so we can better understand and relate to the data found in the various service manuals.

And...we're running an oil that is contaminated with assembly lube and ant-seize, along with a filter for which I have no previous pressure data. We'll run this about 500 miles and the change oil/filter for taking a look-see at the real numbers we're gonna live with.
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Old 11-22-2009, 10:27 PM   #14
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Default Re: Oil Pump Relief Valve Shimming

Dave, to ditto as Mike posted; your pressures look okay. If it were my engine, I'd have no worries.
One thing that affects overall pressures from idle to load are the pump's clearances themselves. On prior rebuilds I did years ago, not IH, maintaining a minimum spec and not a wear limit was the one thing that really kept system pressures up through the range from idle to load. I never really played with valve shimming per se except to up the higher rpm pressure which later on I learned and posted earlier
a thing that surprised me the most was that the swepco oil upped my pressures in the truck and the Scout at the idle to about 1,500 rpms. Driving rpm hot pressure pretty much stayed the same at around 40 to 45. The 266 went from just above 10 psi to now it seems to hold below 20. It's a 0 to 80 psi gauge, so the resolution is a bit rough in the lower ranges. The other surprise was that the pressure stayed consistent towards the 5k mile change. I used to be a off the shelf fan, chevron was one I especially liked. But it seemed as it got older towards 3,500 miles; my pressures seemed less. Lifter tick seemed more often if it sat for a couple of days, especially on a cold morning.
I haven't seen a change like Mike with the filters though.
I've stuck only with wix or purolater, usally the purolater gets 1st preference.
I tried the swepco, believe me it was gonna be a one time deal for the cost of it. Not now, I really did see a change for all the reasons I've given. Damn, I didn't mean to have this seem like a durn sales pitch, but that's real world for me.
This thread has me going to bed with all sorts of ideas in my head about measuring pressures, delta p's, filter loss, and flow gotta see flow etc, etc.
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Old 11-23-2009, 01:19 PM   #15
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Default Re: Oil Pump Relief Valve Shimming

Like michael wrote, he and I jawed about the oil pump shimming for a spell. We decided that I would do the calculations of the shimming/pressure curve. It just so happened that I was in the middle of a performance 392 build and that I would do the measuring for the dealio while I had the pump apart in my hands.

All sv/4 bangers have the same oil pump relief valve telemetry. Eg spring rate, free length, test length and force, relief poppet diameter and, spring length at which the relief valve poppet begins to relieve or open the return port. Below are my data points. Some are values from the fsm that I verified using a force scale and caliper.

Spring free length (fsm) = 2.25" (new)
spring test length (fsm) = 1.812"
Deflection @ test length = .438"
Spring load @ test length (fsm)= 13.31
Spring rate =30.35 #/inch
Spring force/.001" of deflection .0335
Oil pressure/.001" spring deflection= .113
Relief point spring length =1.812"

Shim values are rounded to nearest .001" and based on relief valve cracking pressure and a new spring. Increased rpm can/will increase oil pressure as poppet compresses spring further. The shim should not effect idle oil pressure. An engine with a large overall amount of bearing wear May never reach relief valve pressures even at high rpm.

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


Hth


s
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