gjohnsonws6

iTrader: (12)

Need some help guys.Now for the second time i have shredded the oil pump drive gear and the housing is cracked.first time it went 4500 miles,this time 2500.This is a forged,353,cam only. Is this from the High Volume pump? Running the melling 155,supposed to be the stock replacement.Found it by chance this time(changing to different cam) At least it did not go all the way like the first time and lose all oil pressure. Im bout to push this muthafuka out the door and burn it maybe time for LS1

fergymoto

iTrader: (129)

You may need a bronze drive gear. Talk to the cam manufacturer to see.

shbox

If it is the 155HV, then that's your problem. HV pumps have been known to shred the drive gear. Rarely do you need an HV pump in an LT1.

gjohnsonws6

iTrader: (12)

A bronze gear would never work in this application,running the stock melonized gear as instucted to do by comp.I have thankfully come to realize the root of the problem,and will be instlling a GM pump/pick up STOCK! un modified no BS Hope this does not happen to anyone else.This needs to be noted somewhere.

JAKEJR

I TOTALLY AGREE!

I've posted on this several times before after going through several drive gear failures. After a lot of research, the common denominator was the HV oil pumps I was running. Even GM's melonized gear died.

I feel your pain.

Jake

West Point ROCKS! Nation's TOP COLLEGE per forbes Magazine!! Graduation Day Parade 20 May 2010!!!

Mighty Whitey

I've had a few friends have problems with the oil pump drive gear shredding the teeth off when they were running a "billet" cam. specifically the GMPP hotcam.

97Z28SS

iTrader: (5)

Check out Shon Herron's site, I believe he's a vendor here he has a "billet aluminum oil pump drive housing" that should eliminate the problem of the cracked plastic oilpump drive housing and hopefully stop the gear teeth from shredding.

97LT1

iTrader: (3)

I am running a 10% overdriven pump soon with canton pan. Hope I dont have any issues. You guys are making me nervous. At the time I couldn't find a stock volume pump with the select casting that was stronger. I did however make a steel backbone style bracket for the oil drive to reinforce it.

shbox

The housing has nothing to do with the shredding problem from the drag of an HV pump. It will stop the housing from cracking, though.

SPEED#1

iTrader: (14)

JUst swap out the pump, so it dont re-occur.

gjohnsonws6

iTrader: (12)

The billet piece from Herron is nice and I have looked into that,however as shbox stated it will do nothing to stop the drag created by the HV pump.First time this happened to me(4500 mi) The housing was not cracked,but the gear on the cam and drive were gone.Now this time housing is cracked,and gear on cam and drive are gone.I have lost alot of time and money due to this,and would hate to see this happen to anyone else.This pump is the melling stock replacement... So after re building it after the 4500 mi incident I used another new "melling stock relacement" So where is melling located cause im gonna shove this pump up someones ***!

ADM

Why did you not get a GMPP replacement stock volume high pressure pump?

shbox

It's not Mellings fault, if you put in an HV pump (which is really not clear).

BTW, Melling makes the GM pump.

I would recommend the following:

Melling Select 10554 pump (std vol/std pressure 3/4" inlet. Should come with Melling IS-55E shaft).
GM white spring 3848911 for higher pressure.
GM pickup tube, 12550042.
GM oil pump drive gear 1103868 (if needed).

gjohnsonws6

iTrader: (12)

I have used new oil pumps with every incident,these have been the pump that melling has listed by part number as the stock replacement pump for the LT1,I do not remember the part number.I was just trying to do the right thing by using their intended stock replacement for the application lised.If you ask for a replcement pump from melling for this application you will end up with a HV/HP pump.I was unaware that using a HV pump in an LT1 would cause such a problem,but i do now.Have all new GM stuff going back in,had to pull out the tranny to remove pan as well.Thank you for the part #s shbox.All im saying is i would hate to see this happen to anyone else.Maybe those part #'s should be posted in a sticky thread somewhere

lt170chevelle

iTrader: (2)

I made the same mistake a few years back. But mine lasted the better part of a year and a half before shredding.

ADM

I didn't have to pull the trans when I pulled the pan out for the oil pump swap, unless thats exclusive to manuals?

97LT1

iTrader: (3)

BTW what high volume pumps are causing the failures. ( I mean what percent of overdrive?) Is it only the 25 percent overdriven pumps?

Burning Rubber

iTrader: (1)

I had a melling pump and a factory GM pump in my last two motors and they both shredded the gear.

97Z28SS

iTrader: (5)

I guess the real question is does anyone make a better drive gear that won't shread? I've built and run many hp sbcs in my day and I've always used hv/hp oil pumps and never had problems with the gear teeth shreadding. Now I do know when I went to a billet steel sr cam I had to install a bronze distributor gear back in the day but they would fail also after awhile. Then the melonized distributor gears solved those porblems.

Also to the OP and everyone else whose had a gear failure, when you built or re-built your engines or modded them did you reuse the existing oil pump drive or did you guys install new ones? I'm asking because if you reused one from a high mileage engine, maybe it was just worn out and that's why it failed.

Lonnies Performance

iTrader: (16)

Anytime you change a cam, you should use a new drive gear. It has already developed a wear pattern & changing to a different cam can change the contact area of the old gear & cause accelerated wear. For something that is rather cheap & so hard to replace when it fails (plus filling your engine with shavings), I always recommend a new one with a cam change.