Oil Pump and Cam
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
I run a Melling high pressure pump with the standard spring in my 403 because it's a better pump than the stocker - even ported. That's reason enough for me. I run Manton pushrods because they are better. A Cali's crank because it's better, Wiseco pistons because they're better. Morel lifters because they are better. See a trend? Cheap tires will keep your rims off the ground but better tires will perform better and give you more peace of mind.
It's a major pain to replace the oil pump. Why not put in a better pump while you're in there. It's not a lot of money.
Just my $.02
It's a major pain to replace the oil pump. Why not put in a better pump while you're in there. It's not a lot of money.
Just my $.02
I installed a G5-X3 cam in my 02 Z06 after about 21k miles a lifter broke (43k miles on the car). The cam had a lot of grooves worn into it. With a stock motor, installing a high lift cam is obviously making it work harder than it was designed and tuners will usually bump the rev limit on the motor a little. AT THE VERY LEAST, replace your lifters with LS7 lifters - which I heard are the replacement for all LSx motors (perhaps not the LS9
) Then a very mild upgrade to your oil pump would be another good choice, not a Melling but a ported LS1 would be fine to help the oil flow a little better throughout the motor.In my current forged 418ci motor I'm running all the same stuff as WKMCD above: Melling, Morel, Wiseco, Cali. but I am using Manley pushrods. After experiencing what a lifter can do if it breaks, I look at the weakest and sometimes the least expensive link and upgrade it if it makes sense.
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
WKMCD,
I’m not knocking your choice to change out items you have chosen to install on your engine. If you don’t mind, what I would like to know is what primary features or design aspect make the items you have picked better than the ones they replaced? My highest interest includes the oil pump and the pushrods.
Eric D
I’m not knocking your choice to change out items you have chosen to install on your engine. If you don’t mind, what I would like to know is what primary features or design aspect make the items you have picked better than the ones they replaced? My highest interest includes the oil pump and the pushrods.
Eric D
It's just a matter of using the best parts in your budget and understanding the value per $. There are more expensive parts than I used in some areas but I spent what I felt was indicated for what I want and reasonable cost-wise.
The Melling oil pump has the best reputation and history out there. I've never heard of a problem with one. I picked up 8 lbs of idle pressure with the Melling. The spring has nothing to do with that - only high RPM oil pressure where I picked up 10 lbs. The cost difference between a Melling and a ported or even stock oil pump is not that much.
The pushrods were made by Terry Manton. They are 11/32 w/ .120 wall thickness. They are also 3 piece with hardened machined tips. The normal aftermarket upgraded pushrods are made in nominal legths - usually in .025" increments and are .080 wall thickness. Terry made mine up in 7.414 and 7.437 length with gives me exactly the preload I want to run. I run Morel bar lifters, the Manton pushrods and PAC 1521 springs shimmed to .050 of coil bind. Probably a better and more exactlng setup than most but I like the idea and results of knowing it's done right. BTW: My cam has .660 lift and I run YT Ultralight rockers.
Hope that answers your questions.
Kevin
Last edited by WKMCD; Mar 31, 2009 at 04:00 PM.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Kevin.
Thanks for the write up and the photos. Very nice looking engine compartment!
With the amount of cam lift that you have I can understand the beefer push rods. I guess I'm not sure why you would want to be so close to coil bind. What do you have your preload set at? You have me a little confused here as spring preload is normally set by shimming the valve springs, what does push rod length have to do with it? I know having the right push rod length is important for proper geometry but I haven't heard of it being used for valve spring preload.
The spring on the oil pump relief valve will make a difference in idle oil pressure on cold start, not some much once the engine is warm. I don't doubt that the Melling is a decent oil pump, but I don't agree that running higher than stock oil pressure or volume is a good idea. Doing ether just adds parasitic loss in power without adding anything to engine performance.
Thanks for the reply,
Eric D
Thanks for the write up and the photos. Very nice looking engine compartment!
With the amount of cam lift that you have I can understand the beefer push rods. I guess I'm not sure why you would want to be so close to coil bind. What do you have your preload set at? You have me a little confused here as spring preload is normally set by shimming the valve springs, what does push rod length have to do with it? I know having the right push rod length is important for proper geometry but I haven't heard of it being used for valve spring preload.
The spring on the oil pump relief valve will make a difference in idle oil pressure on cold start, not some much once the engine is warm. I don't doubt that the Melling is a decent oil pump, but I don't agree that running higher than stock oil pressure or volume is a good idea. Doing ether just adds parasitic loss in power without adding anything to engine performance.
Thanks for the reply,
Eric D
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
Eric,
The pushrod length has nothing to do the rocker geometry. That is set by shiiming the rocker if necessary. Once that is set correctly as indicated by the wipe pattern you need to set you lifter preload. That is done with the correct push rod length.
Setting the spring installed height to .050 of coil bind is recommended by PAC for maximum performance of the 1521's.
BTW: I never mentioned anything about a higher volume oil pump.
Kevin
The pushrod length has nothing to do the rocker geometry. That is set by shiiming the rocker if necessary. Once that is set correctly as indicated by the wipe pattern you need to set you lifter preload. That is done with the correct push rod length.
Setting the spring installed height to .050 of coil bind is recommended by PAC for maximum performance of the 1521's.
BTW: I never mentioned anything about a higher volume oil pump.
Kevin
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Kevin,
Ok, I understand now, I thought you were talking about valve spring preload, not lifter set point.
Yeah, I know you didn't mention a higher volume oil pump, but the only way you can have higher pressure compared to the stock oil pump is if you increase the oil flow or run higher viscosity oil.
Regards,
Eric D
Ok, I understand now, I thought you were talking about valve spring preload, not lifter set point.
Yeah, I know you didn't mention a higher volume oil pump, but the only way you can have higher pressure compared to the stock oil pump is if you increase the oil flow or run higher viscosity oil.
Regards,
Eric D
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
I agree this will increase pressure and it will push more volume to the lubrication system. The oil that was being dumped by the relief valve is now routed to the pump output port.
The down side of this, more isn't always better.
The down side of this, more isn't always better.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Don't disagree. Mine sat apart on the work bench for a week while I decided on whether or not to shim the pump and ramp up the pressure a bit. In the end I spoke to Tony Mamo and he affirmed he didn't think it was necessary.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Pro
Joined: Oct 2005
Posts: 733
Likes: 0
From: Vanceboro NC
Kevin.
Thanks for the write up and the photos. Very nice looking engine compartment!
With the amount of cam lift that you have I can understand the beefer push rods. I guess I'm not sure why you would want to be so close to coil bind. What do you have your preload set at? You have me a little confused here as spring preload is normally set by shimming the valve springs, what does push rod length have to do with it? I know having the right push rod length is important for proper geometry but I haven't heard of it being used for valve spring preload.
The spring on the oil pump relief valve will make a difference in idle oil pressure on cold start, not some much once the engine is warm. I don't doubt that the Melling is a decent oil pump, but I don't agree that running higher than stock oil pressure or volume is a good idea. Doing ether just adds parasitic loss in power without adding anything to engine performance.
Thanks for the reply,
Eric D
Thanks for the write up and the photos. Very nice looking engine compartment!
With the amount of cam lift that you have I can understand the beefer push rods. I guess I'm not sure why you would want to be so close to coil bind. What do you have your preload set at? You have me a little confused here as spring preload is normally set by shimming the valve springs, what does push rod length have to do with it? I know having the right push rod length is important for proper geometry but I haven't heard of it being used for valve spring preload.
The spring on the oil pump relief valve will make a difference in idle oil pressure on cold start, not some much once the engine is warm. I don't doubt that the Melling is a decent oil pump, but I don't agree that running higher than stock oil pressure or volume is a good idea. Doing ether just adds parasitic loss in power without adding anything to engine performance.
Thanks for the reply,
Eric D
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Upgrading the oil pump with a cam change came about largely for two reasons...
The first, the early LS1 oil pumps were not quite as stout as the later model LS1s (and LS5s). They've been revised slightly from the very early models.
Second, it's one of those "while you're there" thought processes. Getting TO the oil pump is quite a bit of work, so if you have any question as to it's integrity, when digging in for a cam swap, that is the perfect time to replace it.
My 01 made great oil pressure before the cam, it makes great pressure after. I had no reason to want more oil pressure, and I did nothing external to need more flow capacity.
No, you don't need to change it if yours is working good. The cam and/or hp level does not require more oil pressure. People do it for peace of mind mostly...or in some cases to compensate for external accessories like an oil cooler, remote filters, etc.
The first, the early LS1 oil pumps were not quite as stout as the later model LS1s (and LS5s). They've been revised slightly from the very early models.
Second, it's one of those "while you're there" thought processes. Getting TO the oil pump is quite a bit of work, so if you have any question as to it's integrity, when digging in for a cam swap, that is the perfect time to replace it.
My 01 made great oil pressure before the cam, it makes great pressure after. I had no reason to want more oil pressure, and I did nothing external to need more flow capacity.
No, you don't need to change it if yours is working good. The cam and/or hp level does not require more oil pressure. People do it for peace of mind mostly...or in some cases to compensate for external accessories like an oil cooler, remote filters, etc.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Hey I hope your cam change goes well and you enjoy the added performance.. Keep us posted on how it all works out for you.
