Z95m6

I'm going to add an electric pump but i plan to keep my LT4 chain. If i ever have my e-pump break down in another town or something, it leaves me the option of going to the local parts store and picking up a stock pump and getting home.

SSNoMad

My waterpump drive was brand new.

SSTAT

OK I give up. Ive read this thread 3 times now and a few others on this subject and I still dont get what combo is safe. To summarize this thread:

1. Seems everyone that swapped out there WP drive gear for the ED (in their ED set) toasted them. Are you guys saying we should use the ED set but leave the stock WP gear? (or ideally buy whole new assembly).

2. One guy in the thread says this is the whole assembly with the ED gear already installed (12551727) while another guy says this is the whole assembly with the ED gear already installed (10219554). Surely one of these part numbers must be the replacement with the stock gear, and one with the ED gear but which is which?

3. Both guys suggest you should use the ED set and buy the whole WP assembly with the HD gear already installed, (one of the part numbers above) but why would you do that if that is the gear that keeps failing - see #1.

3. Then I think three guys chimed in who used the LT4 ED set with the stock WP drive gear and did fine but then someone else said that the gears between the LT1 and LT4 drives were completely different??

Help a guy out!!

BTW I road race with NASA - EWP is not an option

SSNoMad

I can see why you are confused. It does seem that most all of the failures were when using the Hardened WP drive gear, however, it is the large gear on the back of the large sprocket, that fails.
When I bought mine there was not an assembled hardened drive gear available. The set came with a hardened gear that needed to be pressed on to the shaft. I bought a new water pump drive gear assembly and had my builder remove the new standard gear and install the hardened gear.
The LT4 comes stock with a single row roller timing chain, it looks similar to a bicycle chain so if you order the LT4 timing set that is what you will get. I think it is a 10mm single roller.
I almost sent mine back when I got it, it looked wimpier than a stock LT1, but I have run it successfully on 2 engines with no issues.
The LT1/LT4 ED is an after market only GMPP Off Road use only chain, this means no warranty through GM. I think it is 1/2" single roller. Cloyes also makes this same setup without the large gears on back of the sprocket, but of course this means EWP only. That is the way I went- the Mezier HD flows more coolant than the cam driven WP even at 6K rpm.
I really don't know what to recommend for you, but I wouldn't buy the HD again myself.
Rich

2QUIK6

Yes, there is conflicting info in this post...
Some left the stock wp gear and no probs.
Some left the stock wp gear and had problems with the wp gear chewing up...mine made a terrible grinding noise and there was strange wear marks on the cam gear....
And at least one person, tim95, had the cam gear show alot of wear from just 2k miles with the ED wp gear...he's is the only one I have ever heard having an issue with the ED wp gear with the ED cam gear.

And tim95's gears look different than any LT4 ED gears I've seen, just in color and texture/appearence.

I listed the part#s eariler in this thread for the ED wp gear already pressed on the shaft assembly from GM if you don't want to hassle with getting gears pressed on and off..plus you'll have new bearings and all.

If you look at the 2 wp gears, the teeth are clearly a little different, I think the pics in the link in the post with the part#s earlier show that.

So, IMO, I've read more about failures using the stock wp gear than using the ED wp gear (only the one in this post from tim95)...so I'd put in the ED wp gear when doing the swap..Mine has about 10k miles on it now and no issues thus far....I'll have it apart in a few months for a cam swap and will evaluate it at that time...I know that doesn't help your current decision though.... Maybe you should start a new post saying..."post up any failures using both the ED wp gear and LT4 ED timing gear" and see if you get any more bites.

SSNoMad

Mine failed using the ED WP gear, and the ED cam gear.

2QUIK6

ok there's another, I didn't catch that in your previous post.
I'm just going to throw this out there, don't take it the wrong way. But did you see the parts originally installed to make sure that your builder put in the right components the first time around?
I ask only because I did not see the componets installed in mine and just assumed that the builder used the LT4 ED set, both gears.... Not until it was making the grinding noise did I take it apart myself to find that the wrong gears were used by an experienced LT1 builder.

If you verified that the correct parts were used, that would be enough for me to consider just using a stock LT4 replacement when I do my cam swap later since I'm going to a smaller lift. I have a stock LT4 gear set on my truck with a 530/560 lift cam and its been in there almost 60k miles just fine, so that may be your answer as to which gear set to use .... I do not know what the "limit" on lift and spring pressure would be for the LT4 stock set????

quicksilver97ta

I can't remember how long ago I subscribed to this thread but I had problems w/ the ED set as well. I installed it, I had the new ED wp gear pressed on, I know it was right. BUT it had abnormal wear in a short time so I yanked the wp gear and went electric. I'd stay far away from an ED set if running a stock wp.

Dave1980

This thread makes me want a EWP that much more.

It just seems that the GM ED is junk with premature wear, with issues on both styles of WP cogs.

Z95m6

I wouldn't worry about it and give it a try. I bet the reliability on this chain is better than many other companies products. You read about a handful of failures and I'm sure 1000's have used this setup. You read about way more Comp Cam failures than you do these chain setups but everyone still uses Comps stuff.

2QUIK6

I also remember someone saying that when their gears had the excessive wear, they had also replaced their wp when they had it all apart with a Bosch wp. Their was a recall for the bearing in these pumps being extremely tight, seems like there were a few where the pump could barely be turned by hand. If you replace you wp with a Bosch pump, be sure the pump spindle spins easily by hand.

Z95m6

I do remember that as well. The new pump was to tight and killed the gears.

SSNoMad

I appreciate your thoroughness, I'm the same way.
The hardened WP drive is easily identifiable and was scribed ED also, pictures and emails were sent to Cloyes and they were aware of the problem. It was definitely a new ED gear pressed on my new WP drive assembly.
All this being said- my waterpump was a rebuilt from O'Reilly and it did fail about 300 miles before the gears were trashed. However, they had been making a racket ever since install and everyone seemed to say it was typical noise for the ED gears.
It is possible that the WP sold by O'reilly was defective and caused this. So much for lifetime warranty on a WP, I'd only buy GM from now on if I didn't have an EWP. The impeller on WP was spinning free on the shaft and the input shaft was hard to turn.
Also-When the O'Reilly pump failed, I was in the middle of no where coming back from Vegas to Texas and the closest town was 30 miles away in Los Cruces, NM and had an AutoZone. It was 300 miles or so after installing the AZ WP that the gears started making a terrible noise and I shut it down.

SSTAT

Maybe I'll start this as a new post, but Im just curious... has anyone EVER heard of a new stock LT1 timing set failing on an LT1 with a aftermarket cam? Ive just never heard of it, and im wondering if all this aftermarket stuff is worth it in the first place. I mean we all like the idea of a heavy duty timing set, but is there evidence out there that it is needed - I mean we already know of all kinds of ED sets failing (so to speak). Anyone know of a case FIRST HAND?

SSTAT

Hmmm, maybe Im on to something...