No Go

You seem to have it in for Cloyes...they are about the best in timing chain setups...my experience such as a request for a slightly larger crank sprocket for my line honed LT4 was met with no problems-out the next day in the mail-fit like a glove. I would not expect to get that grass roots service from many aftermarket companies...

Really tough to diagnose the culprit if more than one item is damaged destroyed...

I've used two ED chains and no problems. I'm glad they are available as not much available for a high reving LT type engine. I would not trust a stock LT4 (or LT1) setup for 7000 rpm shifts where the rpms don't drop below 4000 for 45 minutes and 300 degree oil temps. It is a proven setup by many.

I'm surprised you haven't commented on Chevrolet with their deficient product that spins rod bearings when put on the track. Many LT and LS engines with that issue.

MSR

i already know i have that, and that at least some of the shavings are steel (since i have a magnetic plug). but this is also consistent with a few other failures.

again, i wish i could tear it down soon to add to this thread, but i just don't have time.

-michael

sothpaw2

Sorry Michael, but I think you have what I have. I don't know what else would do that, but then, I don't know motor like some.

Heck of a coincidence though if you have some mileage on the ED chain set.

sothpaw2

MSR,

If I really had it in for Cloyes you'd see a post with the title "ED timing set is junk--Cloyes makes bad product". Here, Z28 forums, etc etc.

All I've done here is ask if others are having a problem and report on mine. I am greatful for all the support that I have received.

Tough to diagnose the culprit--only one component was destroyed, and that is the ED cam gear, and that only where it meshes with the water pump. Yes, the water pump itself is a little messed up, but it still functioned.

Plus, you have a scientific measure of hardness (we took several hits) and a comparison between an EXTREME DUTY gear and a plain Jane LT1 gear. The LT1 gear was much harder.

You have the opinion of a licensed metalurgist who saw the damaged gear.

As for Chevy--I wouldn't hold them accountable for that. It's a passenger car. It wasn't designed to do that stuff. I would hold them accountable if the bearings spin under their normal useage segment on the street.

Now, the Cloyes gear is different. It is advertised as EXTREME DUTY, so it's normal useage segment is by definition EXTREME.

I never said "Cloyes sucks, don't buy things from Cloyes"--but it appears to me that this was a defective product.

Maybe others would benefit from reading this--you can run an electric water pump or you can do a hardness test on the gear you get new and see if it's acceptable.

tjwong

Here is what I found after a little research. I spoke with the Cloyes engineer this morning. One thing he told me which I found was interesting is that the LT4 ED set from GM is assembled as a set by GM using their OE parts supplied by Cloyes.

The crank gear is also used in the GM 4.3, 5.0 and the 5.7 P (LT1) and truck engines. So this means that the crank gear is made to GM OE Specs. The cam gear of course is LTx specific. The water pump drive gear went through several iterations. Staring when the LTx engine was first conceived, the gear was made with NO HOLES drilled into the gear. Later in 1993 it was upgraded to having 6 holes. Then in late 1994 it was upgraded to having only 3 holes. GMs engineering is saying that the holes provide additional oil splash to lubricate the water pump drive gears. Through all three iterations at no point was the hardness of the gear changed. Damn I didn't ask what that spec was but I am sure he would have told me

Another point that is interesting to know as well is that Cloyes manufactures their LTx ED set as a tested and rolled set. Each individual timing set is tested with a 110lb weight attached to simulate valve train loading. Also the crank gear is made so that it is .014" larger in OD so that there is NO SLACK in the chain with it is assembled on the engine. GM maintains a OE spec that is .014" smaller, but Cloyes manufactures the gears that is supplied to GM on the outer limits of the GM Spec to assure a tight chain fit in our engines. But it will not be as tight as their matched set from Cloyes. With the additional time that it takes to manufacture and test the CLoyes timing set, this is why their set cost a considerable amount more than the GM set. In my thinking it maybe worth the extra cost.

The Cloyes engineer did mention that he has heard of a few failures. Some blame as pointed to the water pump, another was the pump drive shaft bearing failure. And another was with the old gear setup with no holes in the water pump drive gear. I personally have not seen one failure, I have a GM ED chain setup on my engine with 2 years on it, with no hint of noise.

Another note is that he mentioned some people have changed the shaft drive bearing to one that is sealed. I am not sure if that is good or bad. I lean towards the good side because the shaft assembly is installed with a retainer plate like that of the cam retainer plate. It shields the bearing from splash on the cam sprocket side. On the intake valley side it would have to rely on splash from the lifter galley, here with the spider in place there would be limited splash. But so far I have never seen a bad bearing. Even in high milage blocks where I have removed the bearing it was still good. So thats another maybe on that one.

I called Cloyes because I was worried about the two LTx engines I have just assembled with a new GM water pump drive shaft and gear assembly. I didn't install the ED gear that was supplied with the set because the new shaft came complete with a gear, shaft and bearing. Cloyes assured me that the gears were the same as they supply them to GM, same hardness, same gear pitch and diameter......so for now I am not going to worry about them.



Just my two bits worth on this subject.

Dan Parker '96

I've been running the ED set with the stock (now 116K) waterpump drive gear for the last 13K miles on a '96 A-4 with the LT1 ->LT4/Hotcam conversion.

The car is just a toy and is brought out to be abused on sunny days. Shift points are a tick over 6500rpm and I run it up there every chance I get. I've nabbed the rev limiter (6700rpm, being a dumbass) at least 2 dozen times over the past 3 years. Over the past 12 months I've actually been hoping it will blow up at these settings so I have a reason to do a 396. But it continues to deny me (even with a 120RWHP shot of nitrous).

I've had zero issues with the ED timing set combined with a (very old) stock waterpump gear.

Sorry for your misfortune. I've been there before as well.

sothpaw2

Dan,

So you never changed from the LT1 gear or the bearing that goes with it? Did the ED set come with a bearing, or just the new waterpump gear?
What do your oil temps get to?

Interesting. Thanks .

sothpaw2

Twong,

Sounds a lot like my conversation with Cloyes.

That's interesting that he mentions the waterpump and drive shaft bearing.

Here's why: When I recieved my stock '96 LT4 cam gear from GM, the hardness numbers were same as the ED gear! Not very hard. But I don't believe this could be a coincidence. 2 bad gears of different design is not believable.

So: the gear wore that way because it was softer than the waterpump gear, but it never should have wore at all, no one else's does.

This brings to the fore front poor oiling. Metalurgist mentioned that. It would explain why failure was right after a track day.

I suppose there is also the possiblility of just a partially seized pump against a really soft gear. Or maybe bearing failure, which could have even resulted from the install (perhaps a mild scoring? Or mismatch between LT1 bearing and ED gear?)

Twong, did you use the special GM tools to get the gear on and off the bearing? And they were 6 hole LT1 water pump gears with matched bearings and shafts? I don't think the ED kit comes with the bearing or the shaft.

tjwong

No, I actually used a bearing tool to remove the gear from the shaft. I start out with a new shaft mainly because the old ones will have a groove worn into them by the seal. I used to just measure the depth of the old gear on the shaft and press the new one onto the new shaft to the same depth. Now I have made a tool that is the correct depth to press the gear on. It is very simple to make, I used a peice of heavy wall 1.25" OD tube, cut it too length on a lathe, the gear is placed on top of the tube, with the shaft inserted into the gear, I press the shaft into the gear until it bottoms against the press table.

MSR

here's a follow-up on my engine:

i honestly didn't think i had the same problem, but turns out i do. i purchased the HD set from gmpartsdirect back in late 2002, i think, it would be interesting to see how that correlates to any others that have failed.

the bearing on the pump drive shaft is intact, and the water pump also seems solid. i'm fairly certain my timing chain set was defective. perhaps it missed being hardened properly?

i never thought to check backlash when i installed it all. i know my machinist didn't do anything to change the cam location in the block, so the cam to water pump drive distance should have been the production value exactly. has anyone actually measured backlash from cam sprocket/gear to water pump drive gear? (i do remember rotating everything freely, so it didn't start out binding.)

short of spending big $$$ for a cloyes set, now, what are my options? who has actually broken an OEM LT4 set?

thanks.

-michael

sothpaw2

Michael,

I would still be interested in hearing the details of what you found--what does each gear look like, was there metal in the pan (I recollect so) and are your bearings (rod&main) ok?

As for spending the big $$$--the real issue is cleaning up all the metal from the gear. Here I tried to avoid getting screwed but I still did. Based on hindsight, I would advise you to either 1) clean the engine in-car if the crank is not scored or 2) if you really want to do it right, pull the engine and clean it out-of-car, but DO NOT have it disassembled and hot tanked because if you do, most machine shops will just BS you into new pistons, which means a rebalance, which is a complete rebuild you might not need/want. Which is maybe $1000 short of a 383 shortblock. Anyway, just clean it up yourself or have them power wash & use new cam, rod, & mains.

As for the timing sets--I measured the hardness of the LT4 stock, the LT1 stock, GM ED, and the Cloyes pricey set, which appears to the eye as exactly same as the GM set except for the waterpump gear.

What I have to tell you is this--all 3 cam gear hardnesses were same--very soft--RC 28. The matching waterpump gear is RC 42 (only measured the cloyes). The design IMHO is a disaster looking for a place to happen, but if the waterpump is ok, it doesn't find that place.

Since I can't guarantee the quality of the *** water pump bearing (no joke), I went with the Electric water pump which eliminates this stupid design all together. An LT1 gear set is also much harder (RC 42 for both gears) but you don't get a roller chain.

MSR

there was metal in the pan, and in the lifter valley. (i guess it was being flung through the front holes in the valley wall.) all the metal was metal slivers roughly the length of the contact area from cam sprocket to water pump drive.

the gears show definite signs of wear, with the points of the contact areas being worn razor thin. still, i caught it relatively early, so not a terrible amount of wear.

i don't think much metal, if any, made it through the oiling system. the bearings are all in great shape, the crank looks brand new. i got lucky on all that.

i will go with an OEM water pump, to make sure this wasn't caused by my rebuild having its bearing slightly off center. still not sure what to do about the timing chain, but i'll probably go with one directly from cloyes with the slightly larger crank sprocket.

-michael

sothpaw2

Might consider new lifters if it was in the valley. I've heard they will probably be ok but certainly ingested some powder which IMHO can not be a good thing. I was going to chance it but I have changed my mind.

I guarantee you that the Cloyes set has a crank sprocket just as soft at the ED one. You're not solving the problem unless yours was even softer than the 3 I tested.

I don't see how you could screw up the gear alignment. Look at the grooves in the teeth and see if they are even and also if wear is on one side of a tooth or both. If both you had a lot of backlash, which in my case I believe was the pump.

Also--all the wear was on the cam gear, no wear on the smaller, waterpump gear? My wp gear was perfect, not even the slight mark or shiny color to it. That's because it's so much harder than the big gear.