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.

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 that 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. :eek2:

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 lifter 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 pressure 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 :bang: 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..................................... .......

 

I suspect the lifters are the culprits.

I've had success with three company's solid lifter offerings - Isky, Crower, and Shubeck. Oh, also Jesel but you need to bush the lifter bores to use theirs.

Good luck

 

Thanks Charlie for you input. Have you ever had problems with solid rollers in lsx blocks ???? If so , what were the problems , and whose lifters were they. I have been researching the Crower (hippo) and the Jesels (way too much dough) and the Morels.....

Does the upper end losing pressure and not the reading at the filter make any sense ???? I thought pressure should basically be maintained through out. Low pressure up top= low pressure at the bottom. Weird as hell how it changes from hot to cold too.

Thanks for your advise........

 

I had issues with Comp Cams and Morel. Some others I know had issues with Cranes.

Comp Cams would not allow the upper end to develop any significant oil pressure. The Morels acted the same as you described - good pressure right off the pump and a 20 -30 PSI drop at the the back of the lifter galley.


Isky made us a set of rollers without an undercut in the middle of the body and plugged one of the oil entry holes. Worked great - no drops in pressure.

Crower built us several sets of their edge orifice lifters and they also worked great - no pressure drop.

For road racing I'd be careful not to pull the sump dry and advise a bushed block or at the very least, a set of Smith Brothers pushrods with an .035 restrictor.

Hope that helps.

 

Danny,
I have had the same problems with solid roller LSx engines... Comp solid rollers were totally unacceptable and they refunded my money as they are aware of the OP problems with their lifters. I switched to Morel solid rollers and they were better but still have lower than desired OP. The engine is a street/drag Darton sleeved LS2 and we are converting it back to hydraulic lifters. I am not a fan of solid roller lifters for road race engines, at least in LSx engines... If the engine had priorety main oiling then I don't think the pressures you are seeing would be a problem. Unfortunately, this is not the case with GM LSx engines. I have seen oil pressures in the low 30's (6500 rpm) at the end of some road race sessions with no problem. Lower than that and the main bearings will suffer.
Sounds like Charlie has some real world success with Isky and Crower solid lifters. You might follow his lead on them if you intend to stay with solids.
As to the difference in pressure at the different locations. This is not surprising in a dynamic system. The stock sensor location is fartherest from the pump and the lowest pressure point in the engine... OP would be higher everywhere else.
I do not think the restricted flow push rods will help your OP problem as the Morels have restricted flow to the pushrods built in. I highly recommend restricted flow pushrods in hydraulic lifter road race engines as the limited oil flow to the top end prevents flooding of the breather system and subsequent heavy oil discharges to the catch can... They also keep the oil in the pan where it needs to be rather than pooled in the top end, starving the sump.
Shirl Dickey

 

If you end up considering a return to hydraulic lifters, the GM racing caddie lifters are used in the CSRV program in destroked engines that turn 8500 rpms. And they're pretty cheap, too.

 

Thanks......I have a set of Caddy lifters @ work already that I had for another project, but had to use LS6 lifters instead because they were unavailable.......I'd still rather sort this solid-roller thing out, but I am getting sick of working on this thing I can tell you.

 

Danny,
I consulted with my friend who builds LSs (about two a day) for Nascar Busch teams. He is in a somewhat unique position because he gets most of the motors back after races and they tear them down again and again.
Some things to think about:
*Cam bearings- If they are not factory stock one may have moved. They do not have good luck with aftermarket.
*Oil pump- Try a stock one
*Pressure relief in oil pan.
* and the lifter issue- They have tried several and run them in most in iron block motors. Aways issues and lots of variables. They run stock LS7 encapsulated hyd lifters with their "standard" higher lift GA cam to ~8500 rpm routinely in LS1/2s. This with stock rockers. What most often fails is Ti after market valves and mandated after market retainer clips. His opinion is with all the solid roller variables it is not worth it.
I can put you in touch if you like-
Bruce.
meltn@new.rr.com

 

Thanks Bruce for you and your buddies insight......I may take you up on the offer to speak with him a bit myself. This has been a frustrating experience for sure....All I want to do is race, and all I have been doing is working on this damn motor. ( it does sound NASTY though )


Mr.Eraser......nice talking with you this evening, the pleasure was all mine. We'll be talking more after all of this for sure..


Anyone with a striking oil pressure revelation ???? I'm good for the help, I swear. I would rather stay solid ( alot of time and money already invested )

 

What solid roller lifters are you running?

Sorry if I may have glanced over it....it very well may be the case as others have said and in fact its the most probable cause.

Running the Crowers for two years without issues....

Tony

Edit....Just looked at your first post and saw you running the Lunati's. Haven't seen their design so I cant comment on how effective they would be. Anyway for someone to post some pics?

 

Thanks Tony.......appreciate your insight. I just fire-mailed a set of Crower edge orifice lifters......The ones I have are Morels sold by Lunati, which are also supposed to be restricted, but in going over the technical data with both companies there are significant differences....I am keeping my fingers crossed. Off come the heads...........again. If that doesn't work, high volume oil pump for me......I am stubborn.

 

Stubborn is GOOD!!

 

If you go the high volume route then take double head of RPM's response above about not drawing the sump dry.

Friend using a Melling pump was seeing pressure fluctuations during HPDE at Texas World which is a very high speed track that has some nice long sweepers. On these sweepers he would see the pressure run up then fall off fast and get a low oil warning light. It freaked him out as this was a new LS2 402 but not a solid roller motor. We looked it over and the only leak we saw was from the line out of the catch can. We opened it and it was full of new oil, not the frothy crap you usually see. During the highspeed sweepers the oil was pooling in the valve covers, flooding the catch can and not returning to the pan which the Melling pump quickly pumped dry.

 

I think he runs a 3 quart Accusump to circumvent the dry pan.

 

Stubborn is a double-edged sword my friend............

Heads are off....... awaiting the fire-mail delivery driver

 

I am all about keeping the oil in the pan where it belongs. Thats why I am doing the lifters first. Even if I have to resort to using the HV pump, the top of the motor is already going to be restricted, and there are other ways to restrict it more if needed. And as Bink had mentioned , I have 3 more quarts in the accusump ready to fire straight to the bearings. Wish I could afford a dry-sump.....I've already spent too much money

 

Danny,
A word of caution with the HV pump... Even if you restrict the oil flow to the top end, the HV pump is going to pump the extra oil somewhere. I know you want it to go to the bearings, however, I have discussed concerns with other LSx engine builders that all the oil pumped past the bearings ends up on the cylinder walls over powering the rings and their ability to seal... This is especially true with low tension racing rings. High oil consumption is the result. I think your problem is elsewhere and a HV pump is a bandaid with some unpleasant side effects... FYI, I'm changing my HV pump out and replacing it with a stock pump...
Shirl

 

This is some good stuff...

 

Its common to have the lifter bores bushed. Make sure that the lifter is not opening the larger oil hole in the lifter bore. Some smaller base circle cams allow that orfice to become a big bleed, causing low oil pressure. Search LS1tech, its common over there and this issue has been covered more than a few times.

My question to you danny, is Why all this trouble? You have raced long enough now to have 3 drysumps on the shelf On top of that, why a solid roller? There isnt much power there over a properly setup hydraulic unless you are running pro stock lift

Just think- sell the Solid roller rockers and you are 1/2 way to a drysump

 

I agree with MrE on the HV pump. Probably not the answer and likely another problem.