In January I put on new heads and LT4 Extreme timing set and a new Bosch waterpump.

Last week my engine started knocking so I'm tearing it apart.

I think I found the problem. The waterpump drive teeth are worn off my cam gear. In this pic you can see some are totally gone! So why did this happen? I even installed the pump gear that came with the set! I don't think I installed it wrong. There's really no other way to install it. I'm guessing that the Bosch pump put too much drag on the gear maybe? If you look at my stock set (65K miles on it) it had almost no wear. Any ideas?

I don't want to put on a new timing set and eat it up again! I think I'll get a GM waterpump. What else could it be???

 

I would say there is a probem with the pump.Does it spin freely?

 

What Joe said.

 

It definately does not spin freely. It's kinda tuff to turn with your fingers. Should it spin easily? It's felt like this since it was new. I shoulda got a GM pump for the same price.

 

That's an expensive gear to be tearing up because of the water pump. Even my leaking water pump would turn relatively easily (though it made an awful noise).

Another question is "where is all that metal?"

 

I found a lot of it stuck to the oil drain magnet. Are there any other magnets in the oil pan? I'm going to look in the filter too.

I already have estimates for a new forged 383, but if I can just put on a new timing set and water pump, that would be good too. I wasn't really ready to pull the engine out this month.

Any recommendations on cleaning the metal out of the engine?

 

Is the WP shaft hard to spin? That will make me think twice about buying a Bosch WP. WHat about the WP shaft assembly and the bearing that is located in the block? That bearing and shaft are wear items and should be replaced. That could contribute to the problem.

 

Yes it's hard to turn the input shaft on the Bosch WP. It felt just like this when I put it on 7 months ago. I ordered a new GM pump, and when it comes I'll see how stiff it is. The shaft and bearing in my block look good and spin nice and smooth. My timing gear was always so noisy, now I know why. I hope the metal pieces got filtered out of my oil

 

Man I hope it works out for you... I hope this is all that the problem was...

And for what its worth, my stock GM pump that was failing input shaft spun easily, as did my ASC (Autozone, lol) replacement.

 

Mikey97Z,

Sorry to butt in but I just got the extreme timing set and was wondering if there were any special tricks to change that water pump drive gear?

Thanks for any help.

Tim

 

when i had the water pump replaced a couple weeks ago i went to two different stores and the bosch and some other knock off had really, really tight shafts, could barely spin the bosch and the other one was seized. went and found another pump that worked a bit better. i wonder if there are many of the bosch pumps that aren't functioning properly??

 

I just used the stocker with the Extreem set before I went to an electric pump....didnt really see the need to use the extreem piece.

 

i didn't replace my waterpump gear either with my extreme duty.

 

When I replaced my oem timing set with the GMPP ED set, I had already purchased a WP Shaft assembly ( GM#10219554 $37.31 & 2 "O" rings GM#12553792 @ $1 ) that had a pressed on gear. Having learned that that part (gear/shaft bearing) is a normal wear item, I decided in advance to replace it when I went in to replace the cam and lifters. Yeah, it was a few more bucks, but I was pleased I didn't have to fuss removing and press fitting that ED gear. I don't have a press or tools to do that work. I just wanted to post so guys know that there is a GM P/N for the assembly.

The ED WP gear is slightly different than the regular gear. The side corners of each tooth is cut off at a 45 degree. I'm not sure why. But there is a slight beveling of the teeth. The shape and size of the grooves are identical. ALso the ED WP gear had a slightly different look as if it was hardened or something. Maybe this is just a minor manufacturing difference. Again, I don't know.

 

What I did is use a socket extension and hammer to tap on the back of the WP shaft and gently knock it out the front of the block. The bearing will stay in there (leave the retainer plate on the front so the bearing doesn't come out with the shaft). Then I took the shaft and ED gear to a local shop (because my bench vise couldn't open wide enough to do it at home) and they easily pushed the old gear off and pressed the new one on. They didn't even charge me cuz it was so easy (but I tipped em good) Then you just gently tap it back into it's bearing in the block. My bearing is still solid and spinning smoothly at 70K miles.