A-man930

iTrader: (2)

After MUCH reading, searching, and lurking I've reluctantly decided to post up my issues/concerns regarding proper oil pump selection. I feel it very important to fully grasp a concept before making a decision as important as this one and as expected I've found a large amount of hearsay, guessing, and plain bad logic coupled with an obvious lack of basic comprehension and not too much solid explanation/thinking. My goal is to as best as I can lay out my build specs, state my intended purposes of the vehicle, and relate what I've picked up about LS oil pumps to those two things in order to end up with an engine that will survive in this thing.

ENGINE:
'02 F body LS1.
9:1 static CR
hp/tq goal is somewhere around 500.
TWIN TURBO (not sure what kind of boost will be required to hit above goal.)
connecting rod side clearance: .026” (I've been told this is near max.)
connecting rod bearing to journal clearance: .0015” (clevite bearings)
main bearing to journal clearance:_____ (clevite bearings)
(take into consideration that we used plastigauge and feeler gauges with little experience. No access to dial bore or micrometer. So I'll assume there are likely some looser clearances in places)
lifters (stock replacement)
pushrods (stock)
polished crankshaft (stock)
connecting rods (cheap h beam replacements)

VEHICLE:
'69 IH Travelall.
4l80e with lockup converter
4:10:1 final drive
currently 37” tall tire (likely to decrease)
cruse rpm 1900-2000 rpm (until tire size goes down or gear goes steeper)
approx. 6000lb vehicle weight

The truck will be primarily used for road trips and work commutes with occasional 4x4 use and ego boosting. This is NOT an “all-out” machine but rather an exercise in creating a unique vehicle that suits my friend's desire to hear the whistle of turbos, see improved fuel economy (over the stock 345/tf727), have impressive passing power, and last many, many years.

Please correct me if I'm incorrect in any of my below statements.

A HV pump will move more oil per given engine rpm, giving you increased system pressure at idle and low rpm. It will also perhaps add heat and aerate the oil due to excessive bypassing. It should not pull any greater amount of oil out of the sump given equal “oil leaks” (bearing clearances etc.) and pressure relief spring. It seems that they are often used in an attempt to band aid worn out engines (not recommended I know).

A HP pump merely has a bypass spring of a different rating, allowing the pump to work closer to its potential volume wise. This is often more than adequite for most mild performance builds.
However, as mentioned before I am going to assume at least some margin of error in our measurements; making us “looser” than factory. This coupled with the low rpm powerband this things gonna make, the turbochargers and associated lines, and a hefty oil cooler make me very attracted to a high volume pump like the Melling 10296.
But horror stories abound about starving oil pans and sucking air and filling valve covers with oil. This is my primary concern regarding the 10296; no amount of high volume matters if the sump is empty. Is it worth getting a truck pan for the extra capacity? (clearance is likely not an issue.) Maybe the lifter tray drainback mod?

Help/opinions are appreciated.

A-man930

iTrader: (2)

Oops, forgot the mains. We measured near max factory clearance at .0025"

A-man930

iTrader: (2)

Here's one response to my own question I've run across.
https://ls1tech.com/forums/generatio...through-2.html

01cherryreds10

iTrader: (9)

I think you read into this way too much!

I think the only people who are starving their engine using the HV pump are the ones beating the daylights out of their cars at the road course.

In my 60k mile LQ4 I've got a TSP LS6 pump and it has given me absolutely 0 issues. The TSP is a ported and shimmed LS6 pump.

I would think with "loose" bearings so to speak you may want to go with a higher than stock pressure but I really can't see an untouched LS6 pump not being able to do what you need it to do especially since it's not going to be a high winding race car

Just my opinion

zzcamaro00

https://ls1tech.com/forums/8743784-post28.html

A-man930

iTrader: (2)

I've been accused of that before (overthinking). I think I'm gonna go with the 10296. Thanks for the replies.