Well, this is a two part thread. Lost all oil pressure this morning, just cruising to work in a ~45mph zone and not doing over 2k rpm. Started hearing a ticking noise, thought it was an exhaust leak, got a little louder and I banged a u-turn to start heading home. Noise got louder and more intense, looked down, 0 oil pressure, shut off engine, coasted to a turn off. Checked oil and it was fine, started it back up (2 seconds)to see if I had sucked the pan dry, nope kept ticking. Towed home. I pulled the intake and found the oil pump drive gear stripped almost flat on one side. It appears to be steel and not bronze.

First question - I have a Comp Cam p/n 07-000-8 and read that a "-8" cam should not eat drive gears. Why did mine?

Question two - How much damage do you think I did to the lower end. Engine has ~10k miles since build.

My intention now is to replace the gear, put it back together and run the engine to see if I am knocking a rod etc...

Ooops, third question, what gear would you recommend with this cam? I do not know for sure what gear I have on the cam and I didn't see anything on the cam card.

Any help would be appreciated, thank you.

 

According to comp cams, -8 are made to mate to OEM gears. Was your pump drive an old one? Maybe it had wear and thus too much lash. I assume it didn't get frozen in one spot and still rotates freely.

Once you had even a few seconds on a rotating engine with no oil flow, it's wiped out the bearings. LT1's are notorious for spinning bearings, now it's just a matter of time if you didn't already. If you do as you plan, it could only do more damage and if you wait to do it right, it may take more parts with it and cost you even more to redo then. In other words, the longer you wait, the more it might cost to fix.

I would discuss the problem when you get round to fixing it with an expert from a cam company.

 

Agreed, didn't know these things are prone to spinning bearings, good to know. So what do you think caused the failure, especially after 10k miles. What do I replace it with?

 

They are not prone to spinning bearings, they are prone to owners who can't seem to understand much though which leads to vast amounts of bad information being passed around. Besides that whatever they are known for stock no longer applies to your fully built engine.

Some of us have spun bearings, but when it happens it is usually making at least 50% more than stock power and revving at least 10% past the factory rev limit, and has been opened up possibly exposing it to dirt contamination to do the mods necessary to hit those power levels. The fact it can handle so much more than stock power and elevated rpms is proof it is a good motor.

I would plan on replacing the bearings, cheaper to do it now than risk the results of running it again if it is damaged.

Far as why it happened, seems like this is a "known occurrence" with the Comp cams. I would not say common, but we have seen it before on the forums and seems like Comp is often the cam maker.

 

Here is a link to my thread on ls1tech http://www.ls1tech.com/forums/lt1-lt...ump-drive.html

 

Are you by any chance running a high volume oil pump?

 

Fred, I am not positive if I bought a HV pump or not (been a few years and a ton of parts at the same time). I am going to assume that I did and will change it to stock when the motor comes out. In searching this subject, I noticed HV's eat gears but a good combo should last more than 10k miles, which were all DD miles. I don't take this to the track, just the occasional tuner with a fart pipe and primer grey ground effects. I am looking for another OP drive gear but not sure what I should buy. I've seen the polymers but only in .500 and .491 but not our .427. I know I can machine a bushing but I really didn't want to go thru that if I don't have to. Any ideas what I should put in there?

Henry - Thanks for the links I hadn't seen these before. Should I run a bronze gear? I would have thought the tougher the better.

 

Lunati has the everwear gear for LT1.

 

OK, new gear from Lunati is in. I am going to start taking the motor out tomorrow. When I was replacing the gear however, I dropped the 2 "washers" that go on before the gear. So my question is...... what are they and how do they go back on?? One "washer" has tangs on in and the other is flat. I believe the tanged one goes on first then the flat one and finally the gear. If this is correct, is there an alignment for the tangs against the pump drive assembly? If anyone has pics, i would be greatful!

BTW, I am going to try taking the motor out from the bottom, never done that before........

 

Anyone?? I don't want to put this back together wrong, especially after going thru everything to get it out of the car (out of the bottom, not bad but not fun).

 

http://www.ls1tech.com/forums/lt1-lt...-1k-miles.html

 

You have the washers correct the flat one goes on second, the other one will just line up; you will know then it is on correctly. I would not be too worried about the problem wrd1972 is having; a lot of guys are running this gear with no problems, he seems to be the first and only exception.