jakemussman

iTrader: (3)

My buddy is having problems with his LT1 swap. He recently put a stroker kit in it, so its basically a 383 LT1. The problem is the all the teeth on the oil pump drive gear keep shearing off. This is the second time it has happened. We have heard since the install that high volume oil pumps are partially to blame (which is what came with the stroker kit). We have also heard that switching to an electric water pump can help as well.
I was just wondering if anybody has any experience with this issue and if we switched to a normal volume pump and an electric water pump would it remedy it?
I tried to find a oil pump drive gear made out of a harder material but haven't been able to find one?
Any help is appreciated!
Thanks,
Jake

New2Chevy

iTrader: (11)

That really sucks. I don't know why the teeth are shredding off, but I would stick with a new stock flow oil pump and would not switch to an electric water pump.

84redta

iTrader: (34)

I got a high volume running just fine for a year now, so not sure if that's to blame.

jakemussman

iTrader: (3)

Its really weird. I had heard of the housing part of the shaft breaking, and they sell things to remedy that. The housing part of the shaft is fine. It doesn't look stressed or anything. On the gear itself some of the teeth are broken clean off and the rest look like serrated wedges. The high volume oil pump may not be to blame at all it was just something I had heard. Supposedly an electric water pump should take some of the strain off of the oil pump gear, again only something I had heard so if that is a bad idea we won't take that route. I was thinking because the cam is made of a harder material then the oil pump gear that maybe thats why it is mangling them? After about a week since the rebuild was when this happened and the oil pump drive assembly was brand new, installed the same time as the stroker kit.
Jake

84redta

iTrader: (34)

Something has to be too tight and binding it, I don't even have a metal sleeve on my HP setup, did the factory nylon sleeve and know I'll regret that eventually, but for now, mine is doing fine. If you can take the intake off, can you turn the oil pump by hand with the tool?

hotrodln

i replaced the drive on my stock LT-1 last year on the recomendation of a friend...stock oil pump.....and those aluminum gears were as sharp as razors.....ready to shear right off.....i couldn't imagine how much stress a high volume pump would put on those flimsy teeth.....i put a high volume pump in my 84 TA....when i went to prime the oil system with my cordless drill......it made the thing SMOKE!....it's never done that before.....i'd ditch the high volume pump and maybe switch to synthetic oil....

Fei

It's actually my car we are talking about. I have an LE2 cam in it. I think it is an older Bret Bauer grind. I have the specs somewhere. Anyway. The first one I broke was a couple years ago. I had a HOT cam in the lt1 with stock oil pump. I think that was just an age thing with the added hp/tq that killed it.

Now I'm thinking the LE2 may have a harder cam gear in it. And I do have a HV pump in it. So I'm thinking that plus the even higher hp/tq killed it. Though I did start having some bad high RPM break up right before this died. So I'm not sure if the bad pump drive was causing the break up by creating some massive stutter from the drive engaging and disengaging rapidly or if the stutter sheared the teeth.

Does anyone know if a standard .491 drive gear will fit? and I guess I will just have to contact Lloyd and find out what gear works well with his older LE2.

hotrodln

do you have the opti spark? or did you add a distributor?

Fei

Opti.

hotrodln

so the opti runs off the crank, i wouldn't think that loosing teeth on the oil pump drive would have caused any misfires..........

Fei

no... opti runs off the cam. and either way cam and crank are still connected so a jolt in either will be sent to both. Though lessened between the two because of chain slack.

hotrodln

i thought the topti was wrapped around the crank pulley........

84redta

iTrader: (34)

Nope, crank pully is wrapped around crank, opti is actually under water pump and crank pulley mounted infront of cam. From the cam there is a sprocket that goes up and runs the water pump too, so really cam runs W/P and Opti.

hotrodln

well that's what i get for buying a slavage yard engine and NOT rebuilding it before i installed it! i hear allot of bad things about the opti spark, BUT an electrical engineer i know owns a 94 vette.......he drove it to 175k miles before it started running poorly....that's when he brought it in for it's first tune up!...has over 200k on it now....on nothing more than a good tuneup!

Fei

What's really funny is that i was always saying how good the opti has been to me. I used the original opti for over 100k miles between 2 builds and never had a single issue. Then a couple weeks ago I got this build running and that opti left me stranded. a little water got in it I guess from sitting for a couple years in a not so clean and dry place and a little rust formed on the optical wheel. luckly I'm so damn efficient at tearing this thing down I replaced that opti in an hour. Then this stupid oil drive crap happened.

hotrodln

i wonder if somebody makes a "hardened" gear for this?

Fei

Yea I can a steel gear for $40 or buy a composite gear for $100. The issue with that is if they are too hard then they will tear up the cam gear.

Fei

So I just picked up a stock gear from work for about $25. Everything runs good and high rpm break up is gone. Must have been causing the spark scatter. I may invest in a bronze if this doesn't cut it.

Fred G. Sanford

I have a 1994 chevrolet caprice L99 (4.3L) version of the LT1 I'm having a problem with turning the engine . As long as I remove the sparl plugs its spins free but when i reinstall the spark plugs it acts like its locking up. checked the timing it was off 180 degrees replaced it with new 1 still having same problem but all the valve train is fully operational im stuck can you help??? no lifters ,or pushrods stuck or anything

New2Chevy

iTrader: (11)

As far as the gear shredding, it's the high volume pump. Ditch that thing. You don't need it. All it does is cause problems and it can suck all the oil out of the oil pan before the oil circulates back into the bottom of the pan.

Also, make sure the drive gear on the cam is bronze material.

Just get a standard volume pump.

If you're autocrossing or road racing the heck out of the car, then you can keep the HV pump and use a bronze geared camshaft, but you should use a high volume oil pan so there is always a proper level of oil in the pan for the HV pump to keep circulating.

New2Chevy

iTrader: (11)

Start your own thread on this.

You mean you can't turn it by HAND or it won't turn over when you turn the key?

It's always easier to turn an engine by hand when the plugs are out because there is no compression in the cylinders.

New2Chevy

iTrader: (11)

I'd at least swap to an LTCC ignition setup.