ch@0s

Did someone Say LS? I aint never hear of dat beafur. Lets do it!!

ch@0s

lt4obsesses

What's an optispark?

lt4obsesses

Well, I just ran out a ran the engine for a bit. Basically through a full heat cycle. I varied the rpms, slow increase/decrease, rapid increase/decrease, slow +/rapid - etc. A couple of blips to 4K, held for a couple of seconds etc. With my stethescope on various places, over rockers, exhaust ports, block et al, I heard nothing unusual. No knocks, pings, anything other than the typical sewing of the rockers, and of course the chatter from the trans (smf).

The oil looked clean of course, but no specks or anything like that. At least not that I could see. So we'll see. But that metal came from somewhere, and engines are not self healing. These are the only true facts I know at this moment.

ch@0s

I had my dizzy gear chewed off once. Scared the crap out of me. Maybe its not deadly.

Tom400CFI

Sounds promising, so far....


LOL!!! I thought that was a local commercial!

383vett

What difference does this make? The copper babbet material of bearings is not metallic. If the bearings are shot, copper metallic particles will show in the oil but not be attracted to a magnet.

Midnight 85

It really doesn't matter where it is coming from, it is getting imbedded into your bearings. You can change the oil & filter 100 times but the fact is the POSSIBLEdamage is already done

JrRifleCoach

Time to cut that filter open and inspect for pieces.

Klondike

If it is in the oil you can see, it's been through the bearings on it's way to the filter. The filter may have stopped the larger pieces but something is worn past it's hard load bearing surface and shedding it's softer under-surface. I'd look at rocker arms & pushrod tips first and then lifters/cam.

Tom400CFI

Oil goes pan > pump > filter > bearings (cam).

HlhnEast

Much to early to throw in the towel yet. As long as it isnt smoking, knocking or has zero oil pressure I would keep driving it. I dont know about the LT4s but drive it easy, change the oil out again as suggested before making your decision.

Good luck!

lt4obsesses

Either way, it needs a rebuild. Or replacement (LSx). I really just need to get a storage unit where I can spend some time on it. Chaos offered up some garage space, but it seems our work schedules are about the polar opposite. Just need a space where they don't really care about people working on cars too much.

The only part of the path of the oil that really matters is between the valve train and the pan. That is where the problem is.

cudamax

Don't run the motor at all. Take some of that old oil in a little bottle to the closest big truck place you can find. With a semi engine they always do an oil analysis on all of their own truck fleets and for anyone looking to buy a rig. Doesn't cost much and it tells you a lot about the motor.
If its running rich and exactly what type of metals are present in the oil. It will tell ya if its bearings, metal. Then take it from there.
It could be in the oil pump/dist drive gear.
Have you been buzzing this up around or over 6000 rpm?

http://en.wikipedia.org/wiki/Oil_analysis

cv67

Dont think he has a distributor: with JR cut the filter open it will tell the story.

cudamax

Just got it through his name. Don't LT4's chew up oil pump drives and now and then. Not hard to inspect and maybe if it don't look good upgrade to a billet

https://www.corvetteforum.com/forums...ump-drive.html

http://ls1tech.com/forums/lt1-lt4-mo...questions.html

lt4obsesses

This is true, and did happen to me over four years ago. It is an issue on both LT1 and LT4 engines. The mount for the drive gear in the lifter valley is made from plastic. These can crack or break, which would cause the gear to be unstable.

When my pump was replaced, it was a standard Melling OEM unit. The gear was modified to increase oil to the gear and the mount was steel.

cudamax

Kool so it should be good

mtwoolford

this happened to me; long story short, don't try to reuse the stub shaft gear; replace it with the proper GM "mellonized" (fancy word for hardened) gear; btw the stub shaft "shaft" is a slightly smaller diameter than the traditional shaft found in a distributor, so make sure you get the right one, otherwise they look identical;

now something else, was that oil the original rebuild oil? there's a lot of anti seizes and assembly lubes / greases that are copper or molybdium based which certainly show up in the oil as "metallic"

lt4obsesses

Checked the new oil from the dipstick today. Dripped it onto a plate and took it inside for a closer look. It definitely has metal in it. Should have seen the sparklies run towards the magnet!

If I were the type to hazard WAG's, I would say that my oil pump drive is shredding. I only say this because when it's hot, the oil pressure gauge jumps a bit, and when the engine lugs, like pulling into a tight parking spot, it's nose dive for a second.

My other majot WAG would be a camshaft lobe getting wiped, but I still cannot hear any definitive lifter ticks, so IDK.

Without the benefit of taking stuff apart, it could be anything. But there is metal falling off of something, no doubt, no question. This engine has not healed itself.

So, I guess it's time to start part shopping. Given the mileage, I just think trying to fix one issue is pointless. Might as well rebuild now. Thinking classic 383, what do you guys think. (Unless I can find a good turnkey LS2 or 3, for cheap) Suggestions or leads are appreciated.