[Tom Vaught]

Originally Posted by screamingchief

Nobody ever puts a larger checkball in the oil pump that I know of.

Most everybody that does this all put the smaller checkball in them.

They do that so the smaller checkball wont allow a small piece of "trash" to hang open the bypass like often happens with the OE checkball.

Shimming the spring is then used as the most practical means to compensate for the reduced OD of the smaller ball.

OD for the checkball in the "as delivered" pumps is 5/8".

Most folks that replace these drop to a 9/16" checkball.

Then you shim it like .065" or so to get the pressure back to roughly 60-70 psi.

FWIW

Bret P.

Save your typing, Bret. The "Wealth of all Knowledge" on how dumb Engineers are doesn't really understand why you do things on a Pontiac engine (much less be able to judge how smart or dumb Pontiac Engineers were). Has a good "bad mouth" game but nothing else.

"Badmouth" did not understand the check ball modification, how it was done, why it was done, or would figure out why you would need the spacer shim to get the pressure back into range with the smaller control ball diameter. Made a fool out of himself.

Pontiac Engineers DID do things for a reason, most people are just not smart enough (or have access to all of the information) to figure out all of the reasons why they did what they did. I am learning every day how SMART they really were.

Tom Vaught

[71 Ventura II]

Originally Posted by screamingchief

Nobody ever puts a larger checkball in the oil pump that I know of.

Most everybody that does this all put the smaller checkball in them.

They do that so the smaller checkball wont allow a small piece of "trash" to hang open the bypass like often happens with the OE checkball.

Shimming the spring is then used as the most practical means to compensate for the reduced OD of the smaller ball.

OD for the checkball in the "as delivered" pumps is 5/8".

Most folks that replace these drop to a 9/16" checkball.

Then you shim it like .065" or so to get the pressure back to roughly 60-70 psi.

FWIW

Bret P.

Your 100% correct it's the smaller checkball not the larger I mixed up the sizes!!! 9/16" ball with the shimmed spring is the way to go. The reason why people shim with a .065 washer is to compensate for the change in checkball diameter. Going from 5/8" to 9/16" is a .0625 smaller O.D., by shimming slightly more than the change in diameter you get a little more pressure. Pontiac Dude and Jim Liehart both shared this mod years ago. P-Dude has done it so many times he knows how the pressure changes depending on the shim thickness. I'd change it but PY doesn't let you edit the post now. Thanks for catching my error! JD

[71 Ventura II]

Originally Posted by PunchT37

What does pan capacity have to do with oil pressure?
What difference is 10 psi between a smart engine guy and a dumbass?

My 455 with a cross drilled crank has been run hard since 1985 or so with a 80# pump and the same inserts for 26 yrs. Runs fine today. No knocks, leaks, rattles etc. Still pulls 12`s to 12.40`s today in full street trim with all that age on the short block. That`s with solid motor mounts too.

The first point you missed: you posted seeing 100+ lbs of oil pressure clearly not 10 psi difference, as you tried to claim now.(60-70# vs 80-100+#) If you had more experience with building engines or read the reasons why professional builders found excessive oil pressure is detrimental to power output, parasitic power loss, and bearing wash would be beneficial.

The proper oil pump will provide between .8-1 lb of oil pressure per 1000 rpm's. Example: a 6500 rpm engine needs 52-65 psi of oil pressure, anything higher is a waste. Even on the "Safe" side it would need 60-68 psi.

Finally oil system capacity is directly connected to the oil pressure and or volume being forced through the engine. Running an oil pump pushing 100 psi with a stock oil pan capacity is not recommended period. If you have done it then your lucky. JD

[71 Ventura II]

Originally Posted by Tom Vaught

Save your typing, Bret. The "Wealth of all Knowledge" on how dumb Engineers are doesn't really understand why you do things on a Pontiac engine (much less be able to judge how smart or dumb Pontiac Engineers were). Has a good "bad mouth" game but nothing else.

"Badmouth" did not understand the check ball modification, how it was done, why it was done, or would figure out why you would need the spacer shim to get the pressure back into range with the smaller control ball diameter. Made a fool out of himself.

Pontiac Engineers DID do things for a reason, most people are just not smart enough (or have access to all of the information) to figure out all of the reasons why they did what they did. I am learning every day how SMART they really were.

Tom Vaught

Who pulled your chain? Are you now the "Engineer Police"? or just a guy who got their feelings hurt by the reality of the statements made? I admitted my error in getting the check ball sizes reversed, so what, the logic behind the modification is still sound.

Anyone who has worked on a vehicle in the real world not the virtual world knows how many brain farts "Engineers" have implemented over the years! How about the F series ford trucks running a turbo diesel where you have to remove the BODY of the truck just to service the gasket for the turbo??? I could go on forever with similar errors/mistakes made by engineers who design without the slightest concern for future service. Practicle application in the real world is lost on the engineers who live in the virtual world of computer aided drafting.... To defend a clearly flawed field just because it's your chosen profession is a battle in futility.

Engineers make compromises to protect the end user from themselves. In regards to the oil pump/filter bypass it's to protect the engine from owners to lazy to maintain the service on the vehicle. In this situation we are hopefully dealing with people who maintain their vehicles. If anyone reading this thread is not providing normal service intervals to their Pontiac, then by all means run the damn bypass valve since it was designed for you! At least do yourself a favor by getting a "NEW" aftermarket unit with all new components.

In closing I agree we need to continue learning by identifying those "Compromises" implemented by engineers!!! Again still no name calling unless your name is "engineer".. JD

[Cliff R]

If you want a good scare, leak test the pump check ball. They have a very poor fit at the seat, and worse when you change the size of the ball under the spring. The first time I tested one with soap/water mix and some compressed air, I couldn't believe the amount of leakage. Pulled two more off the shelf and they leaked just as bad if not worse. So there is a built in bypass in every pump right to start with, bypassing oil back to the oil pan the entire time the engine is running.....Cliff

[PunchT37]

Originally Posted by 71 Ventura II

The first point you missed: you posted seeing 100+ lbs of oil pressure clearly not 10 psi difference, as you tried to claim now.(60-70# vs 80-100+#) If you had more experience with building engines or read the reasons why professional builders found excessive oil pressure is detrimental to power output, parasitic power loss, and bearing wash would be beneficial.

The proper oil pump will provide between .8-1 lb of oil pressure per 1000 rpm's. Example: a 6500 rpm engine needs 52-65 psi of oil pressure, anything higher is a waste. Even on the "Safe" side it would need 60-68 psi.

Finally oil system capacity is directly connected to the oil pressure and or volume being forced through the engine. Running an oil pump pushing 100 psi with a stock oil pan capacity is not recommended period. If you have done it then your lucky. JD

You must have missed this;

Originally Posted by PunchT37

I run the 80# pump in my engine. I HAVE the bypass. When cold, I have to be carefull on rpms. The oil guage will wrap around to the peg on 0 if I rev it a lot when cold. This is on a 100 psi guage.

Originally Posted by PunchT37

When hot, it will idle at around 30 in park and 25 in drive. It goes to 80 and holds to redline. If you run the piss out of it, it will idle down to 20 and go to 70 or so. So, I believe my engine is not too tight and the pump relief is working.

The 100 psi comment was when COLD. After that, you stated that 80 psi is a waste and dumb. You gave wrong directions on how to get to 70. There`s your 10 psi difference. Why is 70 so great and 80 is a time bomb? Why not leave it at 60?

I have mine at 80 for the cross drilled, 3.25 main, crank. If I ran a 3.00 crank, I would have run the 60 # pump.

This motor was built back in the 80`s BEFORE all this forum knowledge. Talk to Jim Butler and others about oil pressure on 455`s, particularly on stock cranks. Hell, even the Pontiac engineers spec`ed a 80# pump for the 455SD. This engine runs fine, even today. It`s got the wrong cam for it`s heads now. I bought the cam in 1992 with 62 heads and 11:0 to 1 compress. It`s got 6x#4`s now. They were bought in 1996. They are hand ported by Dave at SD. This was before he had a cnc machine. The engine needs to have a different cam installed now for it`s 9.5 compress. But I`m gonna leave it alone. One might call this old motor, "Old Faithfull" as it has given NO trouble since it was built.

If I did that, and threw it in your car, it would rip. I decided to build a new motor to make 600 hp and have better street manners and to take advantage of the parts out there now that were NOT there back in the 80`s.

I`m building this one now. It`s more modern, has looser clearances and, like everyone, I have learned a little more since the 80`s and have applied to this motor.
I`m 48 yrs. old and have been earning a check as an automotive tech since 1985. So, I have learned a little since then. Do I know everything? Hardly. Does anyone? It`s all good man. Just relax a little.

[Cliff R]

The only difference between 60psi and 80psi for oil pumps is apprx 8-10 hp at the flywheel, and a tad harder on everything in the chain of parts that drive it.

We've got the stock Melling pumps with 60psi spring in engines we've built here to 750hp, spinning over 6500rpm's, zero issues anyplace with any of them.

The only engine failure we've ever had was knocking the lifter bores out of a block, and it had a brace in it.

With modern thinking/modern lubricants, and correct bearing clearances/rod side clearances, crank is straight and well prepared, straight hole thru the main bearing holes, etc, there is no need to run a lot of pressure, and the stock pump has PLENTY of volume to sustain these engines.

I'm actually surprised that such a simple topic went so far, and caused any contraversy, etc. The oil pump picks up oil from the sump, it pushes it thru a filter before it goes on to the bearings. If it meets too much resistance, the pump has a built in relief valve to control pressure and put any excess oil back in the sump. This is required because it is a positive displacement pump.

The "engineers" added a bypass at the filter housing, thinking there may be scenarios (worst case) where filter could be seen as a restriction (plugged up), and provided an alternate path to the bearings to make sure they could never be denied the oil they needed. Certainly dirty/unfiltered oil is better than no oil at all.

Blocking the bypass came about, because some folks felt that there could be circumstances when it could open when it really didn't need to be, and allow unfiltered oil to the bearings.

We've built enough engines here, at just about every power level and application, to know that you do NOT need the bypass in place and there to date have been zero negatives from doing this. So about all we get is the peace of mind that ALL of the oil that gets to the bearings in our engines is filtered, and probably helps me sleep just a little better at night........Cliff

[Tom Vaught]

Originally Posted by Cliff R

The only difference between 60psi and 80psi for oil pumps is apprx 8-10 hp at the flywheel, and a tad harder on everything in the chain of parts that drive it.

We've got the stock Melling pumps with 60psi spring in engines we've built here to 750hp, spinning over 6500rpm's, zero issues anyplace with any of them.

The only engine failure we've ever had was knocking the lifter bores out of a block, and it had a brace in it.

With modern thinking/modern lubricants, and correct bearing clearances/rod side clearances, crank is straight and well prepared, straight hole thru the main bearing holes, etc, there is no need to run a lot of pressure, and the stock pump has PLENTY of volume to sustain these engines.

I'm actually surprised that such a simple topic went so far, and caused any contraversy, etc. The oil pump picks up oil from the sump, it pushes it thru a filter before it goes on to the bearings. If it meets too much resistance, the pump has a built in relief valve to control pressure and put any excess oil back in the sump. This is required because it is a positive displacement pump.

The "engineers" added a bypass at the filter housing, thinking there may be scenarios (worst case) where filter could be seen as a restriction (plugged up), and provided an alternate path to the bearings to make sure they could never be denied the oil they needed. Certainly dirty/unfiltered oil is better than no oil at all.

Blocking the bypass came about, because some folks felt that there could be circumstances when it could open when it really didn't need to be, and allow unfiltered oil to the bearings.

We've built enough engines here, at just about every power level and application, to know that you do NOT need the bypass in place and there to date have been zero negatives from doing this. So about all we get is the peace of mind that ALL of the oil that gets to the bearings in our engines is filtered, and probably helps me sleep just a little better at night........Cliff

X2

Tom Vaught

[71 Ventura II]

Originally Posted by PunchT37

You must have missed this;
The 100 psi comment was when COLD. After that, you stated that 80 psi is a waste and dumb. You gave wrong directions on how to get to 70. There`s your 10 psi difference. Why is 70 so great and 80 is a time bomb? Why not leave it at 60?

I have mine at 80 for the cross drilled, 3.25 main, crank. If I ran a 3.00 crank, I would have run the 60 # pump.

This motor was built back in the 80`s BEFORE all this forum knowledge. Talk to Jim Butler and others about oil pressure on 455`s, particularly on stock cranks. Hell, even the Pontiac engineers spec`ed a 80# pump for the 455SD. This engine runs fine, even today. It`s got the wrong cam for it`s heads now. I bought the cam in 1992 with 62 heads and 11:0 to 1 compress. It`s got 6x#4`s now. They were bought in 1996. They are hand ported by Dave at SD. This was before he had a cnc machine. The engine needs to have a different cam installed now for it`s 9.5 compress. But I`m gonna leave it alone. One might call this old motor, "Old Faithfull" as it has given NO trouble since it was built.

If I did that, and threw it in your car, it would rip. I decided to build a new motor to make 600 hp and have better street manners and to take advantage of the parts out there now that were NOT there back in the 80`s.

I`m building this one now. It`s more modern, has looser clearances and, like everyone, I have learned a little more since the 80`s and have applied to this motor.
I`m 48 yrs. old and have been earning a check as an automotive tech since 1985. So, I have learned a little since then. Do I know everything? Hardly. Does anyone? It`s all good man. Just relax a little.

It's always good to see Pontiac V8's built and run hard! It's all good Thanks! JD

[Firebob]

I'm a little confused(surprise).

(Cliff)"I'm actually surprised that such a simple topic went so far, and caused any contraversy, etc. The oil pump picks up oil from the sump, it pushes it thru a filter before it goes on to the bearings. If it meets too much resistance, the pump has a built in relief valve to control pressure and put any excess oil back in the sump. This is required because it is a positive displacement pump."

Pump bypass drains the over pressured oil back to the pan and only oil that passes through the filter gets into engine circulation. It sounds like the rub is when the filter gets clogged and oil is recirculated back to the pan and not to the bearings. If the adapter bypass is blocked off then the only passage for oil is through the filter and if it's clogged it seems likely it will explode. The moral is don't let the filter get clogged. Seems to me you should be able to figure out at what pressure your pump bypass opens by how much oil pressure you have. If it just drains back out of the pump bypass into the pan what's the harm? As long as it has to go through the filter before the bearings anyway. The only trouble I've ever had is once a piece of something held the checkball open and I lost all oil pressure. Didn't realize quick enough and had to replace a couple rod bearings. I guess that's a vote for blocking it off if there's no downside to it.

Robert

[Tom Vaught]

Pretty Good Info here:

http://www.mgnoc.com/article_oil_filters_revisited.html

Logic of the by-pass valve in the oil pump

Logic of the by-pass valve in the oil filter

Full flow filtering vs by-pass filtering of the oil.

Tom Vaught

One other comment: If you read the link above you will see that the typical gear oil pump in a Pontiac is a Positive Displacement pump. It does not know anything except for volume per gear tooth void vs pump rpm. It has an internal by-pass valve that by-passes oil back into the inlet side of the pump if the restriction downstream gets too high. The only difference between the 60 psi pump and the 80 psi pump is the by-pass spring design and setting. The oil pump gear size (height and diameter) is identical.

So if the restriction in the engine (oil filter or oil passage flow) gets high due to cold oil or excessive rpm the oil pump by-pass will be open more often. If the oil restriction is still too high due to high engine rpm vs oil viscosity, the oil filter adaptor will try to by-pass the oil around the filter. If the the oil filter adaptor by-pass is blocked, then the oil filter itself must by-pass. If the oil filter does not have a by-pass or a poor by-pass design then the oil filter housing will balloon due to excessive pressures.

At some point the engine passages will have so much restriction fighting the pumps ability to pump oil, the forces on the pump drive will shear off the oil pump drive shaft tangs or shear the gear teeth or the oil filter will burst.

That means: the engine could still run for a bit with no oil pressure if the tangs sheared, or the engine will stop (due to bad timing) if the distributor gear teeth shear, or the customer will run over his engine oil if the filter blows.

I personally think the Pontiac Engineers designed the oil filter adaptor to protect the filter from expanding and possibly blowing the oil seal or the filter housing. Oil from the engine would naturally leak out of the engine onto the road surface and the vehicle could have quarts of oil under the real tires causing a crash. Dirty oil vs a person getting hurt in a crash.

JMO

Tom Vaught

[PunchT37]

Originally Posted by 71 Ventura II

It's always good to see Pontiac V8's built and run hard! It's all good Thanks! JD

Maybe a beer with Obama huh?

[PunchT37]

Originally Posted by Tom Vaught

I personally think the Pontiac Engineers designed the oil filter adaptor to protect the filter from expanding and possibly blowing the oil seal or the filter housing. Oil from the engine would naturally leak out of the engine onto the road surface and the vehicle could have quarts of oil under the real tires causing a crash. Dirty oil vs a person getting hurt in a crash.

JMO

Tom Vaught

Or a fire. Especially when most of us are running headers with a filter stuffed between 2 tubes.

[BGus16]

When our gear pumps are designed they use a term of cubic inchs of displacement per revolution. It takes into account number of teeth, min. diameter, max. diameter, corner breaks on the gear teeth and some other factors. Two other comments come to mind. Gear pumps are sized by the minimum flow required. That is the Pontiac engineers needed a pump to provide enough oil flow at IDLE rpms. Pump output of the gear pump will be almost linear except for any internal leakage around the gear teeth/housing. Once the rpms increase of course the pump output will have to increase upto and until the relief valve (check ball) opens and starts to bypass oil. You have to design the pump for minuim rpm flow and whatever that flow is will multiply at high rpms. Its a comprimise really. YOu cant size the pump output for both 500 rpm & 6000 rpm. When the relief valve is open it will increase the tempurature of the oil. If you actually locked the relief valve closed (we do all the time) i bet that oil pump would put out 1000 psi or until you blew the plate off the bottom of the pump. For how simple they are you would be amazed at the amount of engineering that goes into them.

Barry

[BAB]

I've plugged my bypass for 10 years and use a PF24 filter. The car hits 6000 RPM consistently and uses a 10w-40 oil. I've NEVER seen any signs of filter swelling that some have nor had issues with it plugged. If the bypass needs to open in the first place than you already have something wrong! If something is wrong I'd rather have the chance to catch it with the oil pressure gauge & save the rest of the engine by not sending metal or dirt to the rest of the engine, lifters, etc..I like the peice of mind the engine is keeping itself clean with 100% filter oil. Not a statement of right or wrong...just my experience thus far.

[Tom Vaught]

Originally Posted by Tom Vaught

Save your typing, Bret. The "Wealth of all Knowledge" on how dumb Engineers are doesn't really understand why you do things on a Pontiac engine (much less be able to judge how smart or dumb Pontiac Engineers were). Has a good "bad mouth" game but nothing else.

"Badmouth" did not understand the check ball modification, how it was done, why it was done, or would figure out why you would need the spacer shim to get the pressure back into range with the smaller control ball diameter. Made a fool out of himself.

Pontiac Engineers DID do things for a reason, most people are just not smart enough (or have access to all of the information) to figure out all of the reasons why they did what they did. I am learning every day how SMART they really were.

Tom Vaught

I APOLOGIZE JD FOR MY POST ABOVE.

You posted this:

The first point you missed: you posted seeing 100+ lbs of oil pressure clearly not 10 psi difference, as you tried to claim now.(60-70# vs 80-100+#) If you had more experience with building engines or read the reasons why professional builders found excessive oil pressure is detrimental to power output, parasitic power loss, and bearing wash would be beneficial.

The proper oil pump will provide between .8-1 lb of oil pressure per 1000 rpm's. Example: a 6500 rpm engine needs 52-65 psi of oil pressure, anything higher is a waste. Even on the "Safe" side it would need 60-68 psi."

What set me off was you were ripping into PunchT37 and his post so I ripped into you and your post. That was wrong.

Obviously 1 psi of oil pressure per 1000 rpm would be 7 psi to lubricate/ cool the engine at 7000 rpm. Ain't going to happen. Then you got into him about needing more experience with engines.

Yes, you are correct, Engineers do make mistakes, as do normal people like you did in your post. But I will say (and this is related only to Pontiac Engineering) Pontiac Engineers made very very few mistakes with our engines.

Your comment about "Ford Engineer Mistakes" was just a reaction to my post. That being said, do the job for 34 years and you will learn that there are a lot of compromises in "engineering" an automobile.

So again, I apologize for busting your chops for the posts you made.

Tom Vaught

[fiedlerh]

If you want a good scare, leak test the pump check ball. They have a very poor fit at the seat, and worse when you change the size of the ball under the spring. The first time I tested one with soap/water mix and some compressed air, I couldn't believe the amount of leakage. Pulled two more off the shelf and they leaked just as bad if not worse. So there is a built in bypass in every pump right to start with, bypassing oil back to the oil pan the entire time the engine is running.....Cliff

I'm sure you know one of the setup tricks:
Put the ball in
Use a drift and smack the ball into the seat.
Throw the ball away and use use a new one.

In response the Craig's response to my oil starvation experience; yes it could have been something else, but we'll never know. No other problems noted at teardown. Dan Whitmore said "It sure looks like it was starved for oil." The filter was a Lee MaxiFilter. 0.010 cleaned up the crank, so nothing was lost. I was on my way to impress a girl with my car, so Karma intervened, perhaps all for the better. You never know.

[Firebob]

Can you tell by looking at a filter, if it is a bypass design or not? Someone posted earlier in this thread that they didn't think any of the filters made for Pontiacs were the bypass type. Seems to me it would be better to have a working bypass in the pump and none in the filter. At least if the oil bypasses the pump it will still go through the filter. Whereas if it bypasses the filter you get unfiltered oil in the block. Is that fair to say?

Robert

[71 Ventura II]

Originally Posted by Tom Vaught

I APOLOGIZE JD FOR MY POST ABOVE.

You posted this:

The first point you missed: you posted seeing 100+ lbs of oil pressure clearly not 10 psi difference, as you tried to claim now.(60-70# vs 80-100+#) If you had more experience with building engines or read the reasons why professional builders found excessive oil pressure is detrimental to power output, parasitic power loss, and bearing wash would be beneficial.

The proper oil pump will provide between .8-1 lb of oil pressure per 1000 rpm's. Example: a 6500 rpm engine needs 52-65 psi of oil pressure, anything higher is a waste. Even on the "Safe" side it would need 60-68 psi."

What set me off was you were ripping into PunchT37 and his post so I ripped into you and your post. That was wrong.

Obviously 1 psi of oil pressure per 1000 rpm would be 7 psi to lubricate/ cool the engine at 7000 rpm. Ain't going to happen. Then you got into him about needing more experience with engines.

Yes, you are correct, Engineers do make mistakes, as do normal people like you did in your post. But I will say (and this is related only to Pontiac Engineering) Pontiac Engineers made very very few mistakes with our engines.

Your comment about "Ford Engineer Mistakes" was just a reaction to my post. That being said, do the job for 34 years and you will learn that there are a lot of compromises in "engineering" an automobile.

So again, I apologize for busting your chops for the posts you made.

Tom Vaught

Tom I accept yours and offer my own apology. Sometimes we get passionate very quickly and communicating via type doesn't allow people to see emotions or intention. I truly want to avoid waist full or hurt full posts going forward. It's all good and thank you for your links and information in this thread. JD

[grivera]

Originally Posted by BAB

If the bypass needs to open in the first place than you already have something wrong! with 100% filter oil.

Does this mean that if the engine is built correctly and nothing is wrong, the bypass won't open?