#1  
Old 04-08-2020, 12:47 PM
SusieQ SusieQ is offline
Member
 
Join Date: May 2018
Location: Metro Detroit
Posts: 32
Default OIL PUMP PSI

I have a 1967 GTO with the engine out of it.

Back many moons ago when I started this project, the advice I got at that time was that for my stock 400, an 80psi oil pump would be a smart upgrade. So, many years ago, I purchased a Melling 10541:

https://butlerperformance.com/i-3164...h.html?q=10541

Now I'm not entirely convinced that the 80psi is the best choice.

I've read a lot of forums and it seems that the general consensus is that 80psi is unnecessary, and can even be harmful to a degree. Some people are of the opinion that it can put unneeded stress on the gaskets, can wear the cam/distributor gear prematurely as well as other parts, and will rob horsepower.

Just as I was coming to the point of considering buying a 60psi pump, I spoke to Dale from Melling tech who disagreed with all of this and said that the 80psi "shouldn't" cause any problems and the upgrade would be fine.

What do you guys think?

While I'm at it, let me ask a couple of other questions.

What is the best way to tack the pickup tube so it doesn't fall out or shift out of place? There seems to be a WIDE range of opinions on this.

Should I buy a hardened oil pump drive shaft? I think it could be cheap insurance. I'm looking at this one:

https://butlerperformance.com/i-2445...-opds-std.html

Any other advice?

Thanks for your help everyone!

SusieQ

  #2  
Old 04-08-2020, 01:33 PM
racegto65's Avatar
racegto65 racegto65 is offline
Chief Ponti-yacker
 
Join Date: Nov 2002
Location: Las Vegas,Nevada
Posts: 570
Default OIL PUMP PSI

Oil pump choice depends on a lot of factors, bearing clearances,rod side clearance, crank end play and intended max rpm. If this is a stock build with close to factory clearances the 60 psi pump should be fine. Also the hardened drive is good insurance for either pump.

  #3  
Old 04-08-2020, 01:54 PM
Joe's Garage Joe's Garage is offline
Senior Member
 
Join Date: Oct 2016
Posts: 215
Default I'd agree with Bill that 60psi should be more than adequate.

If your engine is fairly stock, with 'normal' bearing clearances, 60PSI is plenty.

But you don't need to purchase a different pump to get to 60psi. Just change out the relief spring assembly to a 60psi setup.

And, YES, get the hardened driveshaft. One less thing to have an issue with.

  #4  
Old 04-08-2020, 03:15 PM
Dragncar Dragncar is online now
Ultimate Warrior
 
Join Date: Mar 2004
Location: Humbolt County California
Posts: 5,917
Default

Few things. You must use a hardened shaft with a 80lb pump. But, do not use that shaft in the link. I do not see the little 'dimples" or a clip to prevent the shaft from being pulled up too far when your distributor is removed. Its made by AP. And their shortened shaft that comes with the IA2 block does not have those either so I will not use their shaft.
That shaft gets pulled up and falls off the pump it will more than ruin your day. Nightmare makes the proper shaft for IA2 blocks so I am sure they make the correct one for stock blocks too.
And there is no reason to run a 80lb pump in any Pontiac that is not some loose big power beast. And even then most do not use them.
Your pump, I have a Dyna Gear 80lb pump and it comes with a kit to turn it into a 60lb pump. Also came with the right hardened shaft with C clip. I bet Melling has the parts needed to turn it into a 60lb pump. Might want to ask. Folks did use to cut either .75 turn or 1.5 turns out of the spring to drop the pressure. But I would not do that, hit or miss.
BTW, I have a 455 with 60lb pump forever. Crosses the line at 60lbs, no need for a 80lb pump.

  #5  
Old 04-08-2020, 03:51 PM
78w72 78w72 is offline
Ultimate Warrior
 
Join Date: Nov 2007
Location: iowa
Posts: 2,732
Default

keep in mind the unofficial rule is 10psi per 1000 rpm. unless you plan on running 8000rpm, or over 6000 rpm frequently, the 80lb pump is overkill & not needed. especially if you live in colder climates &/or run thicker oil.

  #6  
Old 04-08-2020, 04:50 PM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 28,410
Default

1) You can take a spring and cap from any normal Pontiac Oil Pump and swap the parts with the 80 psi spring cup and spring. I used to buy the 80 psi spring cup and spring from Melling for about $4.00 and convert the stock 60 psi pumps to 80 psi pumps.
So going the other way, if you have your old pump laying around should work unless the pump had 150,000 miles on it.

2) Pure street vehicle I would run the 60 psi pump parts too.

3) The hardened Driveshaft is a good idea if you run the 80 psi pump but I have never seen a stock 60 psi driveshaft fail in normal usage. Not Racing stuff with thick oil.
Maybe if you got a chunk of material inside the gears of the pump from a crappy oil pick-up design.

4) I would run the later oil pan with the baffle welded in the pan. Helps on right hand turns off freeway ramps.

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

John M and BAE just created a billet block for John, bye, bye 5.80s
  #7  
Old 04-08-2020, 06:05 PM
Steve C. Steve C. is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Liberty Hill, Tx. (Austin)
Posts: 8,727
Default

Concerning the parasitic loss from a 80 lb pump. This from Jim Butler on the subject....

"We've never seen a noticeable performance loss from the added load," says Butler. "Racers will sometimes run a 60-psi pump to reduce parasitic drag and free up a few horsepower. While that's acceptable in a dedicated race engine that's frequently torn down, it's certainly not something we recommend for all engines."

Curious, anyone have testing data with the difference in power/torque loss on a engine between the two pumps ?

https://www.hotrod.com/articles/hppp...-observations/


.

__________________
'70 TA street car / 505 cid 10.63 @127 mph / 3750+ lbs (96 degrees / 48% humidity / 30.14 )
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE
The Following User Says Thank You to Steve C. For This Useful Post:
  #8  
Old 04-08-2020, 07:00 PM
coonhunter70 coonhunter70 is offline
Senior Chief
 
Join Date: Aug 2015
Location: Southwest IN.
Posts: 262
Default

60 psi

  #9  
Old 04-08-2020, 07:06 PM
Steve C. Steve C. is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Liberty Hill, Tx. (Austin)
Posts: 8,727
Default

Every so often, someone comes along and proposes reducing oil pressure to free up horsepower..............


https://www.eng-tips.com/viewthread.cfm?qid=350063

Interesting read, not for any endorsement but offered for general interest.


.

__________________
'70 TA street car / 505 cid 10.63 @127 mph / 3750+ lbs (96 degrees / 48% humidity / 30.14 )
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE
  #10  
Old 04-08-2020, 07:37 PM
formula kid formula kid is offline
Senior Member
 
Join Date: Mar 2005
Posts: 233
Default

Built a 73 block to SD specifications Nunzi did all the machine work. He asked me what rpm the max was for the engine. I said max 6K to 6.2 K. He asked about the oil pump, since it was a block I got from the junk yard I told him it was new. I gave him a NOS SD pump, he switched the spring to 60 psi and did work to the pump gears. He said no reason to run a 80 psi pump.

  #11  
Old 04-08-2020, 08:28 PM
Steve C. Steve C. is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Liberty Hill, Tx. (Austin)
Posts: 8,727
Default

So for a 6000-6200 rpm street engine... who is correct Butler or Nunzi. NOT to insinuate either is 'wrong'.



.

__________________
'70 TA street car / 505 cid 10.63 @127 mph / 3750+ lbs (96 degrees / 48% humidity / 30.14 )
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE
  #12  
Old 04-08-2020, 08:32 PM
SusieQ SusieQ is offline
Member
 
Join Date: May 2018
Location: Metro Detroit
Posts: 32
Default

Good stuff guys.

I like the idea of switching the spring to convert it to a 60psi. That's a big help if I decide to go the 60psi route. I was thinking I had to buy an entire new pump.

I'll look into the cost of the spring and then make a decision on what I'm going to do.

The collective wisdom is that the 80psi isn't necessary, and would "probably" be fine, or "shouldn't" cause any problems. I'm not a big fan of doing things that have disclaimers such as "probably and "shouldn't," especially when there's no clear advantage, so I'm leaning towards changing that spring.

An added advantage going with the 60psi is I don't really need to spend money on a hardened driveshaft.

Thanks again guys!

  #13  
Old 04-08-2020, 09:02 PM
Jay S's Avatar
Jay S Jay S is offline
Senior Chief
 
Join Date: May 2018
Location: Nebraska City, Nebraska
Posts: 467
Default

The first time I ever tried an 80 psi pump the new engine started and ran then quit. Pulled the distributer cap off and the rotor wasn’t turning. Pulled it out found nothing wrong. Pulled a valve cover off and the valves were not moving. Found that the key on the cam sheared. Replaced the key and it start up an ran, when we rev’d it up the cam key sheared again. Grrrrr...20 some years later I can smile about it. We weren’t back then. We pulled the engine and put in a 60 psi spring and never had any trouble after that. Not saying it will happen to you. But Pontiac didn’t exactly overbuild the cam gear or the cam drive.


Last edited by Jay S; 04-08-2020 at 09:02 PM. Reason: Edit
  #14  
Old 04-08-2020, 11:07 PM
Dragncar Dragncar is online now
Ultimate Warrior
 
Join Date: Mar 2004
Location: Humbolt County California
Posts: 5,917
Default

The hardened shaft is needed for a 60lb pump. Thats what Dan Whittmore sent me with my pump. I asked him about it and was told you can still twist a shaft with a 60lb pump on a cold morning. Just do it, peace of mind is worth the 30 or so bucks.

  #15  
Old 04-08-2020, 11:14 PM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 28,410
Default

Quote:
Originally Posted by Dragncar View Post
The hardened shaft is needed for a 60lb pump. Thats what Dan Whittmore sent me with my pump. I asked him about it and was told you can still twist a shaft with a 60lb pump on a cold morning. Just do it, peace of mind is worth the 30 or so bucks.
Not saying that Dan Whitmore was not telling the truth on that cold morning deal but honestly, my car/engine for example has not been started on a cold morning in almost 20 years and I live in Michigan. I have a Truck or an Escape for those cold mornings. Not my 1964 GTO convertible.

SusieQ, your info does not say what part of the USA, I assume, you live it.

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

John M and BAE just created a billet block for John, bye, bye 5.80s
  #16  
Old 04-09-2020, 12:39 AM
formula kid formula kid is offline
Senior Member
 
Join Date: Mar 2005
Posts: 233
Default

One of the main problems with the 80psi SD pump was that in the north when it middle of winter a few SD cars blew the oil filter on cold morning starts.
If your car is outside and has an engine block heater pugged in keeping the oil warm in the winter no problem. Yes I also had the hardened shaft for
extra insurance.

  #17  
Old 04-09-2020, 06:17 AM
steve25's Avatar
steve25 steve25 is offline
Ultimate Warrior
 
Join Date: May 2008
Location: Westchester NY
Posts: 10,868
Default

Ask yourselves this in regards to the need for oil pressure that being
On the 60s 421 SD motors ( same diameter mains as a 455 ) that ran the banked ovals at 6200 rpm near constantly how much oil pressure did they run?

__________________
Epstein was murdered!
The Following User Says Thank You to steve25 For This Useful Post:
  #18  
Old 04-09-2020, 07:05 AM
Cliff R's Avatar
Cliff R Cliff R is offline
Ultimate Warrior
 
Join Date: Nov 2000
Location: Mount Vernon, Ohio 43050
Posts: 16,445
Default

"What is the best way to tack the pickup tube so it doesn't fall out or shift out of place?"

I would NOT weld the pick-up to the pump for any reason. I see this recommended a lot, but I've had enough engines come in here where the weld broke off a piece of the pump and the pick-up ended up in the pan to avoid that deal altogether. While on the subject NEVER weld the retaining ring on a TH400 drum for the intermediate sprag either, get the 4L80E spiral lock. Seen WAY too many of those have the sprag knock the welds off the ring and the trans looses second gear and has to come out for repairs.

Several much better methods to accomplish that task. For deep sump pans with the taller aftermarket pick-ups I weld a strap to the pick-up then put the other end under one of the pump cover bolts.

For stock pick-ups they are driven in place, then I drill a small hole thru the pump and pick-up about 1/4" from the edge and tap it for a hardened allen drive machine screw, usually 8-32. This is done in the shop vise, then the cover removed to blow out any chips that may have fallen inside.

With either method the pick-up can't fall out or turn and you aren't putting any heat on the pump from any type of welding operation........Cliff

Attaching the pick-up didn't happen from the factory, but the material those OEM pick-ups were made from was better. Aftermarket pick-ups are "soft" metal and don't have any "memory" to keep them in place, so it is imperative that you take the extra time to make sure is doesn't fall off and end up in the assembly.......Cliff
Attached Thumbnails
Click image for larger version

Name:	Super Duty (5).JPG
Views:	141
Size:	133.6 KB
ID:	536767  

__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran!
73 Ventura, 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile)
  #19  
Old 04-09-2020, 07:14 AM
Cliff R's Avatar
Cliff R Cliff R is offline
Ultimate Warrior
 
Join Date: Nov 2000
Location: Mount Vernon, Ohio 43050
Posts: 16,445
Default

As far as oil pressure goes with correct bearing clearances and proper crankshaft main bearing alignment, correctly sized rod big ends, and correctly assembled the stock pump with the 60psi spring is more than adequate for what you are doing.

Even on the higher HP builds we've done, several over 700hp the stock Melling pump was used and we've never had a single issue anyplace related to bearings or engine failure due to a pressure lubricated parts. Matter of fact the only engine I've ever lost was a "high-end" build before the aftermarket blocks were available and it broke a piece of lifter bore off the block even with a brace in it. The problem with that engine, IMHO was that the camshaft was just too big and aggressive and side loading things beyond the capabilities of the lifter bore design. It had previously led a good life for over 10 years at a lower power level with a pretty hefty flat solid camshaft in it pushing the car to low 10's. The solid roller upgrade with a butt-ton more spring pressure and super aggressive lobes was good for 17 drag strip runs before it gave up, and the aftermath wasn't pretty!........Cliff

__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran!
73 Ventura, 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile)
  #20  
Old 04-09-2020, 09:41 AM
SusieQ SusieQ is offline
Member
 
Join Date: May 2018
Location: Metro Detroit
Posts: 32
Default

Here's the take from Greg at Butler Performance tech:

It should be OK to use as the stock ram air 4 and super duty cars came stock with the 80psi pump

I donít have a different spring all I can offer is a complete 60psi pump

ugh lol

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:00 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 

Cold Case Radiators

Cold Case Radiators is a Max Performance company that produces high end aluminum performance radiators at a price point that won't break the bank. Polished and stamped tanks. 2 rows of 1" tubes. Lifetime Warranty.

GTOG8TA.com

GTOG8TA.com is a Max Performance company that manufacturers parts for the 04-06 GTO, 08-09 G8, and 93-02 Firebird/Trans Am platforms.

Copyright © 2017