I will the extreme duty timing chain and sprockets work with the stock waterpump gear? If not, does anybody have a part # for the waterpump gear that comes with the lt4 set (12370835)?

 

I believe it comes w/ a new one w/ the set.. not sure though..

 

Yes, but you should replace the original wp gear at the same time. The ED timing set comes with a WP gear, but it requires press fitting on the rest of the assembly. I can't do that at in my garage. Fortunately, I already had a complete replacement assemby w/gear so I used that instead.

 

im not getting the set, its going to be two sprockets + the chain. Waterpump gear is not included, but i have a new waterpump already. I was wondering if i could just bolt everything together or if i need to get the waterpump gear that would have came with the lt4 timing chain set. Gmparts direct doesnt tell what the part# is for the waterpump gear in the set.

 

If it's in the budget, get an electric water pump. I saw the Summit brand for $179.95. Looks just like the Meziere. Part # SUM-314351

 

12551727 sdpc2000.com says thats the lt4 ED waterpump gear # but look it up in GMPD and all it says is "shaft". I have an oversized crank sprocket from thunder and ill be buying the rest from GMPD. Should i get that WP assembly w/gear instead?10219554 should I go with the lt4 gear, the stock assbly, or both??? think ima start a thread

 

When I installed my GMPP ED timing set, I also replaced the WP gear and everything related.

If you get the WP Shaft assembly GM#10219554 $37.31 the gear comes attached (pressfit on the shaft). I got a separate WP gear with my ED set so now I have a spare. Removing the WP gear from the shaft assemby will be tricky if you don't have the tools to do it. Plus the assembly has the caged bearings (if I recall correctly) that go into the the block. They are a wear item and buying the shaft assembly gets all the parts replaced and not just the WP gear that comes with the ED set. You also need 2 "O" rings GM#12553792 @ $1 to replace on the WP shaft.

Get the shaft assembly and do the complete job right!

 

Somehow, someway.. when I did my cam swap I forgot to replace my water pump gear when I installed the ED set. No problems here 14k miles later

 

Extreme duty comes with a steel water pump drive gear that is supposed to be used with the steel cam gear. I bought a new w/p drive assembly and then pressed of the gear and installed the E.D. gear.
But get this- after 3500 miles my ED timiing gear has 1/3 of the cogs totally eaten off and the other 2/3rds of the teeth are half eaten away, the w.p gear looks perfect.
I also used the oversized crank sprocket from Thunder Racing.
No warranty on GMPP parts.
I can send pics
Rich

 

I am going with your exact timing set up, and now im worried. Do you have any idea about how this happened? Do you think it was'nt installed right, or maybe the oversized crank had something to do with it? Anyone have ideas? This shouldnt be happening to such an expensive timing kit.

 

OK Here's the latest.
Cloyes is the manufacturer for the Extreme Duty Set. GM would not stand behind the failed part. I located a guy from Cloyes and emailed pictures to him. He could read the numbers on the gears and was surpised mine were some of the first made for GM on an ERO (Engineering Request Order).
He said they were 10 years old. They must have been in some parts warehouse, because I bought them last year!
Although they were made to specs they may have not been a matched set and he is sending me a new matched set for free, that includes they oversize crank sprocket.
I think they all come this way if you buy the Cloyes parts instead of going with GMPP. Also Cloyes stands behind their parts and GMPP doesn't.
Sorry I don't know the Cloyes number but I'll find out soon.
In any case if you buy the matched set now, you should be OK.

 

That was a very interesting report. I am glad you are getting that matter resolved and to hear that Cloyes stands behind their products.

 

I noticed on my ED timing set that the cam gear and the water pump gear
had hand etched numbers. This may be how they identify a matched set.
I did not write the numbers down or take a picture. Hopefully mine will last
a long time.

Other than a bit more gear whine the ED set is working great.

 

I bet you spoke to Wayne the tech guy at Cloyes, he is super, he also told me how to tell if my wp gear was pot metal or billet steel. The billet steel gear has 3 or 6 holes drilled throught the gear front to back for oil passage. My 97 has the 6 holes, and spun good, he said I was in good shape for the ED set, so I am sending back the "dinky" LT4 set that I bought.

 

I went through the exact thing. I also talked to Cloyes and he even told me that Cloyes manufactures the GM Extreme chain gears with powdered metal. AS per GM's request to try to cut down on noise as he said the Billet gears can be a tad louder then normal. Cloyes brand gears are made with Billet steel.