RAFTRACER

I have been observing some bizarre oil pressure issues on my new solid-roller 387 (4.125 x 3.62), which has me concerned. I have heard that there are oil pressure issues with solid rollers in these motors, but I have never heard exactly what some of these issues are. I did a search last night on this board for these problems but never came up with what they are besides someone just having low oil pressure constantly.

My problem is low oil pressure but it is somewhat different than what I have seen posted. Here are the oil pressure specifics of my motor...Fire then engine up cold and all is fine 45-50psi @ idle (1300rpm), and oil pressure will increase 7-8 lbs per 1k rpm, maxing out around 80 psi. All seems great huh.....Well when the engine warms up I start losing oil pressure on the gauge in the cluster coming from the top of the engine. Hot pressure would be around 25 psi @ idle up to a max of around 36-38 psi @4500 rpm, not so good. I dont like that fact that it will not build pressure when warm as it does when cold. This is a roadrace Corvette so oil temperatures will get to 265-270 when runnning, and I am sure the really hot oil temperatures will further reduce oil pressure and additionally cause catastrophic engine damage sooner than later.

In my analysis , I have checked oil pressure with an adaper in place of the oil filter with a manual gauge and additionally have removed the stock engine oil pressure sensor and installed a manual gauge in that location also. When it is cold both of the readings between gauges match both higher pressure and both fluctuating higher with increased engine speed. when the engine gets warm the oil pressure taken from the oil filter adapter will be significantly higher than the one taken at the top of the engine block in the stock location. The differences when hot are this, @ idle the OP at the bottom of the engine will be 30-ish and the one at the top of the block will be 23-24-ish. This is where it gets wierder... as engine speed increases the two reading become further apart to as much as 25 psi difference @ 4.5-5k rpm (35psi or so on top and 60psi or so lower).

Since the camshaft and lifters are priority fed, I am really scared of what is going to happen to the bottom end.

The specifics of the motor are this , brand new ls2 block sleeved by ERL in New Albany , Indiana. Block does have the crappy D.O.D. bosses is the lifter valley . Lunati crank and rods, Wiseco pistons. The camshaft is a .650/.650 260/270@.050 on a 110. I believe it is a standard base circle camshaft, but I would have to call Jud @SAM to find out . It has Lunati solid roller LSx lifters from what I understand are either like the Morel, are are built by Morel and sold by Lunati ( not real sure, if someone can clue me in..they were acquired about a year ago ) with an .842 diameter and the lifter bores have not been "bushed". The engine has a ported, shimmed and springed LS2 oil pump. The engine has AFR 225's and Jesel solid roller rocker shafts.


Do any of you with solid rollers have anything like this occur with your motors, I'd love to hear about it. I dont get why the oil pressure changes from top to bottom when the engine gets hot as pressure should be a constant in all of the loil galleys, cold or hot. I dont think I am looking for some restrictions in the galley that leads up to the camshaft, since when it is cold the pressures are the same. Does the increase in valve lash adjustment when hot cause the oil pressure to drop ???? I am assuming that valve lash grows approx .010" hot vs. cold. This is the only thing that my feeble little mind could come up with as a cause for the difference in pressures hot vs. cold. Do the new style "metered orifice" lifters help this situation ????


I am going to drive myself crazy, someone please help I'll rip those heads off of my car and replace my lifters with something else if it'll defineatly help/cure the situation. Unless I have a striking revelation, I'll have to go back to hydraulics ( which I would rather not do)


TIA............................................

Bink

Danny - good to see you posted here. I was going to link to your CF thread when I saw this one.

Have you talked to Shirl Dickey...MrEracer on CorvetteForum?
He's run solids in some of his track cars ....I think. Google his name - he's in Arizona now...famous for aircraft/aviation. He runs with Arizona Corvette Racers ->http://www.redracervette.com/. Also, he runs Shirl Dickey Enterprises in Ariz.
FWIW.


joel

Bink

Check the CF thread.

...interesting accusump info by Kurt/W2W and Shirl ->

https://ls1tech.com/forums/generation-iv-internal-engine/685940-accusumping-ls2-block.html .

ChucksZ06

iTrader: (9)

I would look at how the lifters are when moving to the top of the lifter bore and make sure you are not losing oil in this area. Maybe pushing too much oil up the pushrods also. Good luck.

racecar

So you have great pressure at the filter, but not good at the top end. The pump must be working fine. Do you have the plastic barbell plug in the back of the block, drivers side.
BTW, I have a C&R radiator with a built in oil cooler, never see oil temp over 240, even on a hot day in 25 minute SCCA races.

RAFTRACER

Yep, plastic barbell is installed , I wish it were that simple.........Installed crower solid roller lifters which are edge orifice restricted units, and that didn't help......Looks like I will be pulling and reinspecting the entire motor soon, I am finding copper in the oil......F$%^ !!!!!

Bink

^^^That sucks!!


RAFTRACER is a noted GM/Corvette preparation specialist (he'd say he's a mechanic) - especially roadrace/autocross Corvettes.
He has won 4 or 5 National titles (SCCA) as a driver and seems to set class record at most roadrace tracks he's visited.

His post number is not indicative of his vast knowledge.

racecar

I have Morel lifters also, they work fine. Two things that I have run into: 1. my oil pump pickup was on the bottom of the pan, that caused strange oil pressure, sometimes good, sometimes bad. 2. Cam bearings on these motors seem to be way out of tolerance even on new blocks. First thing that I do with a new block is to check clearances. .002- .003" is acceptable. .0035 is not. How you can have different pressures in one motor is a real mystery.