Oil pump choice for lt1 build
Thread Starter
TECH Regular
iTrader: (2)
Joined: Mar 2007
Posts: 412
Likes: 21
From: Southern Michigan
Oil pump choice for lt1 build Hey guys, I'm finally putting together my lt1 that's been down for several years. It's a forged 383 bottom end set up for nitrous with ported lt1 castings and an xfI 292. Motor will be street/strip and 7k rpm max. I purchased most of my parts years ago, and some of them before doing much research.
Well, long story short, I have a melling M155HV pump, a canton 7qt pan with a 3/4" pick up. My bearing clearances are as follows: mains average .0028", rods average .0026", crank end play .006" and rod side clearances average .021"
I realize now that pump is way overkill and am going to get something different. I think I am going to switch to a melling select oil pump, but am not sure if I need a +10% volume given my 'looser' bearing clearances, or just go with a standard volume. I'd apreciate anybody who's familiar with clearances and has first hand experience putting together motors to chime in. Thanks
Well, long story short, I have a melling M155HV pump, a canton 7qt pan with a 3/4" pick up. My bearing clearances are as follows: mains average .0028", rods average .0026", crank end play .006" and rod side clearances average .021"
I realize now that pump is way overkill and am going to get something different. I think I am going to switch to a melling select oil pump, but am not sure if I need a +10% volume given my 'looser' bearing clearances, or just go with a standard volume. I'd apreciate anybody who's familiar with clearances and has first hand experience putting together motors to chime in. Thanks
Last edited by nickp; Mar 3, 2017 at 05:40 PM.
TECH Regular
Joined: Nov 2011
Posts: 471
Likes: 14
From: Tucker, GA
TECH Regular
Joined: Nov 2011
Posts: 471
Likes: 14
From: Tucker, GA
The hardest job of the oil pump is getting oil to the mains and most stock pumps are good to 4500-5k. Once you rev beyond that or have larger clearances, things shift and you run the risk of cavitation in the pump. Cavitation = loss of oil pressure. The rod bearings don't help either since they're traveling in a circle and centrifugal force is pulling the oil out of the bearing. In my car, with an upper end redline of 6500 or so, a stock pressure and stock volume pump would be a bad idea since it would struggle against the spinning forces pulling the oil out of the bearings.
If your bearing clearances are tight, using a HV pump puts an increased load on the drive-gear because it is fighting against those clearances to get rid of the oil its pushing. Don't do that.
This is actually a touchy subject because there are loads of people that say a HV pump will also suck the pan dry if you're running a stock pan. I've never had this issue, myself, but YMMV.
Thread Starter
TECH Regular
iTrader: (2)
Joined: Mar 2007
Posts: 412
Likes: 21
From: Southern Michigan
I have a 7qt canton pan. And I laid out my bearing clearances in the op. I was hoping someone could tell me what pump to use based on my particular situation. I have no problem spending some money on a good oil pump.
Trending Topics
On The Tree
Joined: Jul 2013
Posts: 194
Likes: 0
High volume pumps come into their use when bearing clearances are larger than stock and spinning to high RPM's. With the bearing clearances the OP is running, a HV pump is pretty much required.
The hardest job of the oil pump is getting oil to the mains and most stock pumps are good to 4500-5k. Once you rev beyond that or have larger clearances, things shift and you run the risk of cavitation in the pump. Cavitation = loss of oil pressure. The rod bearings don't help either since they're traveling in a circle and centrifugal force is pulling the oil out of the bearing. In my car, with an upper end redline of 6500 or so, a stock pressure and stock volume pump would be a bad idea since it would struggle against the spinning forces pulling the oil out of the bearings.
If your bearing clearances are tight, using a HV pump puts an increased load on the drive-gear because it is fighting against those clearances to get rid of the oil its pushing. Don't do that.
This is actually a touchy subject because there are loads of people that say a HV pump will also suck the pan dry if you're running a stock pan. I've never had this issue, myself, but YMMV.
The hardest job of the oil pump is getting oil to the mains and most stock pumps are good to 4500-5k. Once you rev beyond that or have larger clearances, things shift and you run the risk of cavitation in the pump. Cavitation = loss of oil pressure. The rod bearings don't help either since they're traveling in a circle and centrifugal force is pulling the oil out of the bearing. In my car, with an upper end redline of 6500 or so, a stock pressure and stock volume pump would be a bad idea since it would struggle against the spinning forces pulling the oil out of the bearings.
If your bearing clearances are tight, using a HV pump puts an increased load on the drive-gear because it is fighting against those clearances to get rid of the oil its pushing. Don't do that.
This is actually a touchy subject because there are loads of people that say a HV pump will also suck the pan dry if you're running a stock pan. I've never had this issue, myself, but YMMV.
To the OP sorry to rant in your thread but I will stand by my reccomendation.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
If you check all the blueprinting clearances here http://www.goldsswagon.com/monster_lt1.htm you will find his clearances are where they should be.
Crank: .008-.0020 (1), .0011-.0020 (2-4), .0017-.0032 (5)
Rod: .0013-.0035 (service at .0030)
Blueprint LT1
Crank: .0020-.0030
Rod: .0010-.0030
assuming this is correct the OP's clearances would be on the "wider" side of spec but within spec noted in the link.....so a standard volume/pressure oil pump "should" suffice. However stock motors PCM program don't allow as high as RPM's as most do with aftermarket tuning so on this point wider bearing clearances and a HV pump can be more applicable.
IMHO HV pumps have there place with motors set up with wider bearing clearances than stock spec. Some builders do this and spec 20-50 wt oil to provide a thicker "wedge" of oil between bearing and cam/rod journal. In these situations a HV pump does not stress the pump drive gear or suck a pan (stock or otherwise) dry. Not convinced a HV pump can suck a pan dry but that has been stated on internet.
I have pulled the drive gear from a 45 k mi 383 that was set up with wider bearing clearances and it was pristine....YMMV
Some put the GM white spring (higher pressure) in a stock volume oil pump
Regardless of pump type used, get a solid oil pump drive shaft vs the stock one with plastic collar. The plastic ages and gets brittle and on "re-install" can crack/break. Also on the oil pump drive gear the plastic top also gets aged so be very careful on re-install to not over TQ or it will crack/break and that gear drive "lifts" up and then the gear strips....and then you have no oil pressure.
Thread Starter
TECH Regular
iTrader: (2)
Joined: Mar 2007
Posts: 412
Likes: 21
From: Southern Michigan
I do have the 242t, which I see is not a 7 qt pan. I bought it quite a while ago and thought it was a 7qt. I've been thinking about swapping that one for a moroso pan...
TECH Regular
Joined: Nov 2011
Posts: 471
Likes: 14
From: Tucker, GA
A high volume pump would only create excess wear on the drive gear. You are claiming a lot of knowledge yet you purchased an engine instead of building it. So youre not showing to even have trust in your own abilities. Just for the record I have been an ASE certified master auto tech for over 25 years prior to retiring. I have built many engines personally and I do know what I'm talking about. when you decide to qoute me and call me out you better have proof to back up what youre saying. Rant over.
To the OP sorry to rant in your thread but I will stand by my reccomendation.
To the OP sorry to rant in your thread but I will stand by my reccomendation.
You don't know me from Adam, so you're making wild assumptions about what I've done in the past and why I elected to buy an engine versus building one. And surprise, you're totally wrong about them, to boot. For the record, I bought an engine from Karl because I wanted (in my opinion) the best, and was willing to pay for it. And frankly, I'm at a position in my life where my free-time with my family is valuable, and I've got enough expendable income to not have to f with it unless I want to. And I don't.
Bigger clearances + higher RPMs = the smart builder would say "more volume needed". The Melling 10552 I've suggested above is a 10% increase in volume versus the 20-25% increase in volume of the M155HV the OP purchased. I'd not run the M155HV because its just not needed for his clearances. That being said, since they are on the upper end of what is acceptable for a stock pump, the extra 10% is a good compromise between load and delivery, and in my opinion, cheap insurance.
Stop with the personal attacks. This isn't Reddit.
Last edited by atlantadan; Mar 4, 2017 at 03:08 PM.
Thread Starter
TECH Regular
iTrader: (2)
Joined: Mar 2007
Posts: 412
Likes: 21
From: Southern Michigan
I am leaning toward the 10552. I just wanted to see what a few of you guys had to say. I feel the +10% volume would be a good match with my clearances and application. I didn't know if the standard volume/pressure would be quite enough. I do know the m155hv I currently have is overkill, which is why I'm not going to use that pump. Thanks for your input guys