Ken Cemo

This is driving me mad. 1000 miles on a completely rebuilt LT1 with bullet proof everything and the water pump drive gear is disintegrating. I spend the $376 on a Cloyes #9-3151 timing set and have spent the last 2 months trying to find out why their is metal shavings on my magnetic drain plug every time I checked it and why their is a loud clattering sound at high rpm. The motor started blowing oil out the timing cover and that's where we found the trouble. The gear that drives the water pump looks like it has 200,000 miles on it and the gear that it meshes with(waterpump shaft) looks perfect as does the timing gear on the crank and cam and chain. Where did I go wrong??? The maching shop even drilled holes in the small freeze plugs on the oil galley holes so that we would have plenty of oil in their. I don't want a repeat of this nightmare. Why would this happen???

96LT1TX

I just had the exact same problem. I replaced the LT1 stock timing set w/ another stock timing set w/ my cam install, and 500 miles later the water pump gear gave out... heard nothing about replacing it until now. (a little too late)
I now am probably going to get an electric waterpump to avoid this problem completely, I hope someone finds the problem w/ this, please post the fix, I am now considering getting a new gear or the new wp, sorry I wasn't much help but the stock LT1 replacement is perfectly fine, no problems w/ it (all the teeth are still there)

my cam and mods are in sig, it put down 318/332 (rwhp/rwtq) on the dyno and didnt go past 4800 rpms because it was bucking so hard (now I know the timing set was F"ed)

Ken Cemo

So you replaced the stock LT1 timing set w/the same? Or did you replace the stock w/the Extreme Duty (#12361410)? Either way it sounds like you didn't change the water pump gear?

My personal nightmare is still not over. The Machine Shop and Cloyes are still trying to figure it out.

SSNoMad

I'm not sure about him, but mine was the Extreme Duty. I'm going to an electric waterpump and use the new Cloyes HD set that does not have the gears for driving waterpump. It uses the same chain and crank sprocket as the Extreme Duty set. The cam sprocket doesn't have gears on back. It's $80 at Summit

96LT1TX

I replaced my timing set w/ a stock LT1 timing set, and it is fine... I kept the water pump gear stock, and that is the teeth I found in my intake manifold

quicksilver97ta

Wow, it seems there are some problems with the ED timing set. That's what I used when I did my heads and cam, I even used the new w.p. drive gear provided. Not long after that I installed an electric w.p. and right after that I began to hear a very slight knocking noise from the t.c. cover while idling. Metal on the drain plug was evident. I tore it down and found the w.p. and back of the cam gear chewing on each other. Not severely but more wear than the 60k stocker. I guess I caught it early enough, I couldn't find anything else wrong so I removed the w.p. gear and put it back together. She runs strong but I can still hear the noise. I posted about it and received an email from someone who said they're e.d. set was out of round .004.

Paul94Z

so what is the consensus here? ED set is bad? I just got an ED cam gear and wanted to buy the chain and crank sprocket to complete the set.. I only searched because I wanted to see if I needed a new pump gear or not..

dmoor88

whats another option for us who want to retain our stock waterpump yet want something strong?

Z95m6

I'm running the LT4 ED set. Its been on for 20k+ and no problems. I just reused my old stock water pump gear and a cloyes over sided gear for the crank. No problems here and it see 6500.

Paul94Z

ok.. that makes me feel better about the water pump gear.. so the gmpp and cloyes cam gears are the same? can I purchase the oversized-crank gear and new chain individually.. anyone have part numbers? EDIT! I found someone who claims the components (crank and chain) in GM 12371043 "ZZ4 HD single roller" are the same as the LT4ED kit minus the cam and new waterpump gear.. can anyone confirm this?

Mikey97Z

OMG this is exactly what happened to me! Same exact parts. It was the water pump. I used a Bosch pump and it was tough to turn, compared to a GM, and it wore all the teeth off the gear!

Did yours look like this?
http://z28.reanimator.org/stuff/camgear1.jpg

I had to buy a new timing set, and a new water pump. PepBoys got me a full refund on the pump. Their policy is *exchange only* but I told 'em I was gonna FREAK on their asses for making me tear down my motor and everything, just give me the refund.

Don 97 SS

I can't confirm that information, but I would not be a bit surprised. GM doesn't make all or even most of these parts. They source them out to manufacturers that specialize in the particular components. GM may sell parts with a GM label but most are made by somebody else.

Paul94Z

can anyone find individual part numbers to compare the ED vs the ZZ4 set?

got_hp?

so can i call up cloyes and order a complete matched LT4 ED set?

SSNoMad

You can call Cloyes and talk to their Tech line, I think they only sell through distributors. I used ThunderRacing, you could also use Summit Racing or Jegs.
Rich