Maximum Incline

great answer,didnt know that

Simple Summary!

All good practice comes from a sound theory--' Oil pump inlet must not be dry'

Brilliant!

Thanks, Shadetree, that is my understanding as well. Problem is I need documentation from GM of this to refute a competitors claim. Having trouble getting spec from our engine supplier - was hoping someone would know of a direct GM source for this performance spec.

More than 22% down hill grade will render oil pick up dry.

At about three hundred feet with engine revving high then it quits and at about 1/8 mile brakes start to smoke speed increases regardless of pedal pressure and the easy button falls off.

If you're thinking of running this engine in much more of a position than it's "normal position", and for any length of time, and you're going to run a wet sump, you should look at a gated oil pan. You'll do a better job of keeping oil around the pickup tube. Stock pans are notorious for allowing oil to flow away from the pickup, even in mild performance applications.

No possibility of running a dry sump? Far better for oil control. I speak from experience as a NASCAR engine bullder and engineer.

Application is an off-road utility vehicle. Competition claims ability to climb 100% grade (45 deg). Having difficulty getting performance spec from our engine supplier. Was looking for a source to a GM spec to validate the literature the sales guys write to answer competion claims.

Would love to go to a dry sump, but hard to justify until we have evidence that we can't match competition claims.

Sounds like you're stalling no pun intended.

Dry sump is the choice in your situation.

I agree, but knowing it and proving it are completely different.

Uh, uh, proving it would seem not so difficult. Unless you demand to experience all possible results yourself but if you appreciate the trials of others and learn from their experiences, the following may be of help.

Begin with the criteria for usage of a wind age tray and incorporate the data about oil swirling and foaming towards implementing a dry sump which is far superior method guaranteeing a successful lubrication than oil bath. I say oil bath because after the wet sump has lost pick up oil bath is essentially what you've got.

www.circletrack.com search for dry sump. Sweet info here

www.drysump.com/drysump.htm and these S.A.E. guys have done the leg work and the head work.

No, I don't need to experience it all for myself, but none of these resources are specific to the GM 4.3L and, more importantly, are not GM endorsed. What I need is a source to the GM testing on their 4.3L that gives allowable operationg parameters. All I need is a statement from GM that says at what angle the oil-pickup becomes starved or the rear cylinders become engorged, but it has to be a GM source specific to this engine. As I stated, the direct supplier for these engines does not seem able to supply this data, so I am searching for an alternate source. Certainly, I could perform my own tests, but without GM's stamp it's worthless to me. I know our machine will climb a 100% grade for as long as we need it to (we've done it numerous times), but I need a GM source that says the engine is rated for this; or I need a GM source that says only X% is allowed and we'll install a dry sump, but I need the data from GM to justify the decision.

Good luck with that,

I'm trying to think like a corporate liability lawyer (a somewhat twisted place to be) and can't think why it would be a good reason to publish that data. Think of the idiots that would put that to the test (and the lawsuits).

It would seem a greater liability not to publish an operating limit. For example, if a customer over-revs and blows the motor and is injured, then the lawyers can at least say "look here, we published the rev limit and you exceeded it at your own peril". Why would this operating limit be any different, besides not being as commonly encountered?

Like I said I was trying to think in lawyer.

Good point...

I happened to think of an avenue you might approach this from. Try looking in some automotive manuals such as Motors or Chilton etc. If they have this info they may reference a manufacturers tech sheet. You might also contact them for help getting what you need.

That is a brilliant idea! Thanks!

Whoa up there Guest,

No intent to disparage you.

Perhaps a direct enquiry to general motors technical library would benefit your endeavor.

No worries - I did not feel disparaged, only that the intent behind my inquiry was lost. Forest for the trees sort of thing!

Do you have a link to the GM tech library? Sounds like just what I'm looking for, but my direct inquires to GM have resulted in little progress. Gate-keepers and voice-mail trees are such a nuisance!

Yes but due to information restraints imposed by interlopers if you get my drift. You should begin a the Chevy dealership; service department and yes they will help verify the integrity of GM engineering.

Years ago the info could be had via a phone call but now information can lead to off shore competition.

Go see Mr. Good wrench...

May be a visit with S.A.E. is in order