Oilpump exchange during engine rebuild?
Thread Starter
Pro
Joined: Aug 2008
Posts: 744
Likes: 19
From: Salzburg Austria
Oilpump exchange during engine rebuild?
I´m wondering if I should exchange the oilpump during the engine rebuild. The old one works, but don´t know about the milage.
Should I keep the "old" one or rather buy a new one?
If new one, high volume or not and which brand preferably?
Should I keep the "old" one or rather buy a new one?
If new one, high volume or not and which brand preferably?
Burning Brakes
Joined: Aug 2013
Posts: 1,071
Likes: 322
From: palm springs ca
Oil pumps seem to be the first one replaced when rebuilding, but I look at the gears and any possible wear. If all looks good then you can shim the relief spring about 1/16" to get a few more lbs of pressure.
I will get a bunch of slack on what I said, but the pump is always running in oil.
I have never seen a oil pump that didn't work, maybe a few lbs less but still pumping.
Many will say why not spend the extra $, but if your pressure was OK then take a good look at your old pump.
Dom
I will get a bunch of slack on what I said, but the pump is always running in oil.
I have never seen a oil pump that didn't work, maybe a few lbs less but still pumping.
Many will say why not spend the extra $, but if your pressure was OK then take a good look at your old pump.
Dom
Le Mans Master
Joined: Dec 2006
Posts: 8,837
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I would use a stock Melling unit. $100. Use a metal collared pump shaft extension. NOT the nylon one. $10.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Never use a standard volume pump on a stock engine.
And if you spent $100 for one, you paid four times too much.
Remove the spring out of a stock M55 Melling....stretch it a bit.....massage the rear main cap by radiusing the inlet....then buy a quality 4340 stud to fasten it to the cap.
This is all you will ever need up to 6000rpm....and beyond.
Jebby
And if you spent $100 for one, you paid four times too much.
Remove the spring out of a stock M55 Melling....stretch it a bit.....massage the rear main cap by radiusing the inlet....then buy a quality 4340 stud to fasten it to the cap.
This is all you will ever need up to 6000rpm....and beyond.
Jebby
Race Director
Joined: Dec 1999
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From: Forked River NJ
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Melting Slicks
Joined: Dec 2009
Posts: 3,233
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From: Thunder Bay
This is one of those threads where you are going to get a hundred opinions. So I might as well give you a couple of mine. If the engine is built correctly, there shouldn't be any need for anything but a standard volume and pressure pump. A high volume pump can help with an engine that is getting a little tired and the clearances are starting to get a little large. I don't know what the indication is for a high pressure pump. So if you are going with a stock pump, then do you need to replace the one you have? I've never seen an oil pump fail in a Chevy. I'm sure it happens, but I've never seen it. Given the quality of the parts we are getting nowadays, I would think long and hard before I replaced the one you took out that you know was working. Was it making good pressure? If you do replace it, make sure you buy a name you trust.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Jebby
Le Mans Master
Joined: Oct 2007
Posts: 7,455
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From: RI, Now Franklin/Nashville TN
I used a Melling standard volume, standard pressure pump when I rebuilt/upgraded the L-82 in 2014. I use Mobil 1 0W-40 European Formula synthetic and my oil pressure at start up cold is 70-80 lbs at 50 degrees ambient and 45-50 lbs at idle hot and 60-65 lbs at high rpm....
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
oil shaft with metal collar...here you go..
Burning Brakes
Joined: Feb 2005
Posts: 894
Likes: 91
Hi Gunther, all you need is a conventional Melling M-77 pump with an M77020 spring installed.
Use a "steel-sleeve" driveshaft, no "nylon-sleeves"!
Thanks, Gary in N.Y.
P.S. We buy these components in bulk and put the package together in-house, we call it an M77-A pump here, it's the one Melling never produced. Can't tell you how many times I've recommended to my good friend George R. at Melling to consider offering this in their lineup!
Use a "steel-sleeve" driveshaft, no "nylon-sleeves"!
Thanks, Gary in N.Y.
P.S. We buy these components in bulk and put the package together in-house, we call it an M77-A pump here, it's the one Melling never produced. Can't tell you how many times I've recommended to my good friend George R. at Melling to consider offering this in their lineup!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Open the stock pump up and inspect it. If it is clean and doesn't have scoring on the bearing [plate] surfaces, it is fine to reuse for a stock motor with normal use.
You can stick a high volume pump in a stock motor...but it will just work hard to pump more oil through the same passages. It won't IMPROVE the lube capabilities of the stock pump (most surviving vintage Chevy cars have/had pumps that worked fine for 40 or more years WITH NO PROBLEMS). What would make you think that any other brand of pump would do better than that?
If you NEED a high volume/high pressure pump, go for it. If you don't, keep what you have, but replace the plastic tube before install.
You can stick a high volume pump in a stock motor...but it will just work hard to pump more oil through the same passages. It won't IMPROVE the lube capabilities of the stock pump (most surviving vintage Chevy cars have/had pumps that worked fine for 40 or more years WITH NO PROBLEMS). What would make you think that any other brand of pump would do better than that?
If you NEED a high volume/high pressure pump, go for it. If you don't, keep what you have, but replace the plastic tube before install.
Team Owner
Joined: Oct 2004
Posts: 81,241
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From: altered state
St. Jude Donor '05
Next motor will get a std volume high pressure pump
HV pumps are hard on the distributor gear
Ask your machinist to work over your oil passages, imo in most builds thats all you need. Esp if you run a heavier oil
HV pumps are hard on the distributor gear
Ask your machinist to work over your oil passages, imo in most builds thats all you need. Esp if you run a heavier oil