oh no
Replaceing oil pump
Drifting
Joined: Jun 2013
Posts: 1,269
Likes: 226
From: Cocoa FL
New oil pumps ARE cheap...because most of the new ones are just a POS gypo part!!!
What you already have is a 'tried and true', original GM, no :BS:, working oil pump. You already know that it works well over a considerable period of time. Those pumps were made to last FOREVER...unless you run some metallic trash through it or run it dry
.
Youngin's only understand "replace the old stuff". Older folks understand that C3 equipment was made to much more rigid standards and specs back then. The design and fabrication paradigm was much different 40 years ago. Today, they just want stuff to last through the [almost nonexistent] warranty period.
BTW, what is the warranty period for a "new" oil pump from "The ZONE"? 90 days, at the most. And you already have one that's worked flawlessly for over 40 years....
Hey, the pistons rings and bearings are 40 years old, too. Why not just buy "new" stuff for everything that's OLD in the engine?
What you already have is a 'tried and true', original GM, no :BS:, working oil pump. You already know that it works well over a considerable period of time. Those pumps were made to last FOREVER...unless you run some metallic trash through it or run it dry
.Youngin's only understand "replace the old stuff". Older folks understand that C3 equipment was made to much more rigid standards and specs back then. The design and fabrication paradigm was much different 40 years ago. Today, they just want stuff to last through the [almost nonexistent] warranty period.
BTW, what is the warranty period for a "new" oil pump from "The ZONE"? 90 days, at the most. And you already have one that's worked flawlessly for over 40 years....
Hey, the pistons rings and bearings are 40 years old, too. Why not just buy "new" stuff for everything that's OLD in the engine?
I do understand the "cheap insurance" position, but I feel that these oil pumps are pretty bullet proof. I like to think of it as "if it's not broken, then don't fix it."
Racer
Joined: Sep 2011
Posts: 408
Likes: 1
From: Ormond Beach Florida
For what little they cost I agree with replacing the pump. If it's your neighbors beater then maybe not.
Use a Melling Select pump.
I would also clean the pickup screen very well. Melling even had a paper on this alone.
For broken plastic collars, I've replaced them in a pinch with a 1/2" dia copper sweat coupling and a couple have lasted over 100k miles+.
BTW, the oil pump is the ONLY internal moving part that uses unfiltered oil.
Use a Melling Select pump.
I would also clean the pickup screen very well. Melling even had a paper on this alone.
For broken plastic collars, I've replaced them in a pinch with a 1/2" dia copper sweat coupling and a couple have lasted over 100k miles+.
BTW, the oil pump is the ONLY internal moving part that uses unfiltered oil.
Exactly right 
Melting Slicks
Joined: Dec 2009
Posts: 3,224
Likes: 652
From: Thunder Bay
I used to share the 'cheap insurance' philosophy and replaced a lot of parts that probably had a lot of life left in them. In the last few years, however, I've had just too many crappy parts that weren't as good as the ones they were replacing. With parts being manufactured in Mexico, China, and God only knows where else, I've been a lot more careful about replacing parts that are still good. So I guess the lesson is if you're going to replace the pump with a new one, make sure its the best part you can buy. If it fails, its going to take a lot of expensive parts with it. I'd re-use it.
As far as the drive shaft is concerned, the aftermarket shafts with the integrated metal collars are good parts, and well advised if you are using a high pressure pump.
One modification you may wish to consider is a stud and nut to replace the bolt holding the pump in place. The stud will engage more threads in the bearing cap. I have had the bolt pull the threads out of the bearing cap. Very annoying when it happens when you're installing the bolt. A disaster if it happens when you're driving the car.
As far as the drive shaft is concerned, the aftermarket shafts with the integrated metal collars are good parts, and well advised if you are using a high pressure pump.
One modification you may wish to consider is a stud and nut to replace the bolt holding the pump in place. The stud will engage more threads in the bearing cap. I have had the bolt pull the threads out of the bearing cap. Very annoying when it happens when you're installing the bolt. A disaster if it happens when you're driving the car.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
One modification you may wish to consider is a stud and nut to replace the bolt holding the pump in place. The stud will engage more threads in the bearing cap. I have had the bolt pull the threads out of the bearing cap. Very annoying when it happens when you're installing the bolt. A disaster if it happens when you're driving the car.
If you tore out threads doing this, you had an amazingly wrong bolt or seriously over torqued it
This is where this "while I'm in there" thinking goes really sideways...
Melting Slicks
Joined: Dec 2009
Posts: 3,224
Likes: 652
From: Thunder Bay
If you look at the bolt and pump carefully you will be surprised at how few threads engage the casting. Oil pump studs are readily available from ARP, Milodon, etc. and are a good idea. Loctite the stud in place (I'm not sure red is necessary) and you can sleep better.
As far as distorting the bearing cap, if that were a concern, then we would be line honing the block with the oil pump in place, and I don't think most guys are concerned about that. Regardless, distorting the bearing cap is far less of a concern than having the oil pump fall out.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I've never seen it happen - and the oil pump is only torqued to 30#, I think. Not saying it didn't happen, and I use the ARP studs on all of my builds...but what you're recounting seems very rare to me as I've never experienced or heard it before. I've also never seen an oil pump fall off.
I have seen a few engines where the pump has broken, but in each case they were the crappy over-the-counter pumps and the engine was making over 1.2 HP/CID.
My shop absolutely has the pump torqued in place when doing an align-hone.
The bottom line IMHO is everything you mess with on a running engine simply increases the risk. If it's running and not making metal, leave it the heck alone. 'nuff said, I think the OP has all the opinions he needs to make a decision
I have seen a few engines where the pump has broken, but in each case they were the crappy over-the-counter pumps and the engine was making over 1.2 HP/CID.
The bottom line IMHO is everything you mess with on a running engine simply increases the risk. If it's running and not making metal, leave it the heck alone. 'nuff said, I think the OP has all the opinions he needs to make a decision
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
The metallurgy of the new over-the-counter pumps is absolute junk - so if you haven't been using Melling Performance pumps...yeah, you've been rebuilding with POS pumps 
http://www.mellingselectperformance....n-Oil-Pumps#GM
http://www.mellingselectperformance....n-Oil-Pumps#GM
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Keeping the old pump has nothing to do with "cheap insurance" It has to do with the "reliability" of manufactured components. When many thousands of stock Chevy oil pumps perform their function for 4 decades [or more] and are in perfectly good condition when finally removed for a complete engine overhaul, it 'tells' you that it is almost foolish to change one....unless the stock design is no longer adequate for the engine's needs [ie, rebuilt for racing engine that requires high pressure/high flow].
Nothing "cheap" about that.
Nothing "cheap" about that.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Neither.
High volume is never required. It's been covered in-depth before, but the summary is that HV pumps are intended for very wide bearing clearances due to design (no longer done) or wear (crutch).
High pressure is also not typically needed, and the Melling pumps come with both springs.
We now return you to your regularly scheduled thread
High volume is never required. It's been covered in-depth before, but the summary is that HV pumps are intended for very wide bearing clearances due to design (no longer done) or wear (crutch).
High pressure is also not typically needed, and the Melling pumps come with both springs.
We now return you to your regularly scheduled thread
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I have the oil galleys drilled for extra spray on the timing chain and the distributor slotted for constant spray on dist/cam gear.
I use a 10% over HV Melling Select pump to make up the flow loss and still never run over the pump relief because of the HV pump, so all is well.
Oil flow is also about heat removal as well as lubrication.
The Select series pumps are much better designed than the stock/oem series.
I use a 10% over HV Melling Select pump to make up the flow loss and still never run over the pump relief because of the HV pump, so all is well.
Oil flow is also about heat removal as well as lubrication.
The Select series pumps are much better designed than the stock/oem series.
Drifting
Joined: Jun 2013
Posts: 1,269
Likes: 226
From: Cocoa FL
Keeping the old pump has nothing to do with "cheap insurance" It has to do with the "reliability" of manufactured components. When many thousands of stock Chevy oil pumps perform their function for 4 decades [or more] and are in perfectly good condition when finally removed for a complete engine overhaul, it 'tells' you that it is almost foolish to change one....unless the stock design is no longer adequate for the engine's needs [ie, rebuilt for racing engine that requires high pressure/high flow].
Nothing "cheap" about that.
Nothing "cheap" about that.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
My point was that keeping the original pump is not just being frugal, in my case. IMO, unless the engine NEEDS something 'special', the OEM pump is the BEST way to go. Just clarifying my intent...
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
I just cant encourage someone to size up a oil pump clearance from under the car - on a creeper, bolting up the pump then install the gasket, lay up some clay, bolt up the pan, remove the pan, adjust the pick up screen, lay up some clay, install the pan, remove the pan adjust the pick up screen, lay up some clay, install the pan. Now u have the clearance? Do u know how to braze? Can u stake the PU tube?
Now check the clearance again. Adjust the clearance again if needed.
Yes all this is done from the creeper under the car. Fun, fun, fun.
Have i done this on a creeper? Yes!
Can i even suggest this to someone else and claim im trying to help them. I dont have to answer that.
If u get the chance replace that plastic collar with a metal one. Leave the pump with only 20k mi on it alone.
Fix the seal that was the problem in the first place - u dont need anymore problems.
Geeze,
cardo0
Now check the clearance again. Adjust the clearance again if needed.
Yes all this is done from the creeper under the car. Fun, fun, fun.
Have i done this on a creeper? Yes!
Can i even suggest this to someone else and claim im trying to help them. I dont have to answer that.
If u get the chance replace that plastic collar with a metal one. Leave the pump with only 20k mi on it alone.
Fix the seal that was the problem in the first place - u dont need anymore problems.
Geeze,
cardo0
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Sorry about the confusion.
I rebuilt the engine about 8 yrs and 20k miles ago and I recently developed a rear main seal leak. The pump and oil pressure are fine. The replacement pump was disassembled and blueprinted and the pick up was brazed to the pump. I will remove and replace it as is,
I was just trying to go over the job in my mind and get all the required parts before starting. And I was wondering if there was any new types of seals or if the pump shaft plastic bushing was up dated or whatever?
I bought a 1 piece FelPro pan gasket and a National Nitrile rear seal.
The only question now is, replace the plastic shaft bushing or buy a 1 piece shaft with intragal socket??
1 vote for the new shaft.
Any other thoughts?
I rebuilt the engine about 8 yrs and 20k miles ago and I recently developed a rear main seal leak. The pump and oil pressure are fine. The replacement pump was disassembled and blueprinted and the pick up was brazed to the pump. I will remove and replace it as is,
I was just trying to go over the job in my mind and get all the required parts before starting. And I was wondering if there was any new types of seals or if the pump shaft plastic bushing was up dated or whatever?
I bought a 1 piece FelPro pan gasket and a National Nitrile rear seal.
The only question now is, replace the plastic shaft bushing or buy a 1 piece shaft with intragal socket??
1 vote for the new shaft.
Any other thoughts?
