My oil temp rarely gets above 210, and if it does it is for such a short time. With the BeCool radiator, 160 stat, it runs really cool. It is also under very little load most of the time. Nothing like road racing would do to it.

 

This is one of those sitsuations where a batch of metal wasnt given enough cure time befor the following treatment was given. There might be a small percentage of these soft gears out there. When I told the speed shop of my concerns on the ED set they kinda gave that ,"this guys a whack job look". They said they install at least 100 of these in a year and never had problems with it. I wasnt taken any chances and went with LT4 set. I didnt realize you found that one also to be soft or I wouldnt of done it. As for the truth, I believe you or I would of gone with ED set

 

I hardness tested 3 Cloyes gears (1 failed GM ED, one Cloyes ED made to better tolerances, and one LT4 stock) which were manufactured during vastly different time periods (LT4=1996, GM ED=purchased 2003, Cloyes ED=purchased late 2005) plus the stock LT1 gear back to back in a laboratory, on more than 1 occasion. Only the LT1 cam gear is hard, compared to its mating wp gear, all the others are much softer than their own mating gears.

If it was a bad batch, the Cloyes I purchased in 2005, 2.5 years after the failed one, should have been good. What are the odds of two bad batches out of two purchases 2.5 year apart?

I know what you mean about the builders--I talked to them in 2005 after this happened--they are clueless. My conviction is that few if any of their clients road race their cars, and street/drag racing use will take a long time to make this show up. My gear lasted me 15,000 miles, but suspiciously, 3 days of road course were in the last 1,000 miles. Even with some road racing, RichS had some bad wear but only found out because he was tearing the motor down for another reason, it would have taken him much longer to wear the gear completely down.

The ED gear might last 60,000 miles on the street /drags, how many of those 383's have that much mileage? And when they find that it's a problem, 6-8 years later, will they come back to the engine builder? I really doubt it--no feed back does NOT mean no problem.

 

Being a Tool&Die maker for 30 years I was wanting to know what the Rockwell #s were from highest to lowest. I have my orginal 96 LT4 gear set in my shop. I will take it work and grind two small flat spots and see what the points on the press read. This is gear and chain has 80,000 hard miles on it, most from Street and Drag racing and it still looked Ok.
Thanks
Louis

 

Timz06, are the galley plugs at the front of your block
stock LT1 plugs or have they been replaced at some time?
In either event, do they have drilled bleed holes?

In another thread, I mentioned lubrication from drilled
galley plugs could help reduce wear by lubricating the
gear set. RichS confirmed in post #12 that his LT4 had
already had OEM drilled plugs, but his injured 396 did
not have these.

"LARGE" pics of worn Extreem duty timing gear

If I understand correctly, RichS swapped a gear set he had
used successfully on the LT4 for 6000 miles to the 396
only to have it fail soon after. tjwong wrote in post #45
below about how the WP drive gear design went through
revisions over the years as GM changed the number of holes
in the gear in an effort to optimize lubrication.

Help: anyone with LT4 extreme duty chain!

Also, has anyone considered whether the change in oil
formulation to reduce ZDDP (zinc) may be a factor? It is
causing rapid wear of flat tappets & their cams, maybe
the high pressure loading of these gear teeth results in
similar increased wear without the ZDDP additive?

.

 

Quote from an earlier post by sothpaw2:


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.

http://forums.corvetteforum.com/show....php?t=1163505

 

The standard SBC Meziere is rated at 35 GPM (free-flow) and normally
draws 7A. The High Flow is rated 55 GPM (free-flow) and normally
draws 12A.

I do not know the flow capacity of the LTx design, but flow through
a earlier stock SBC is said to max out at about 65 GPM (this would be
under load, not free-flow). For endurance racing at 500+ HP, one
recommendation is to provide for 100 GPM flow capacity.

96GS#007's first-hand experience with the issues of extended operation
with an electric pump would provide invaluable lessons for anyone
planning to go this route for a track car. In addition to the coolers,
perhaps he has boosted GPM by running higher voltage, changing the
coolant path or through some other approach?

.

 

Thanks 42 RC is really not that soft as tool steel Rex 95 that we grind to make special cutters for the lath is 65 RC. I wonder if he measured where the teeth were cut as that place would be softer as the more material you remove the softer the metal is under where it is hardened. As much as the Cloyce set is you would think all of the metal would be hardened correctly after rough machinig was done.

If I ever go with a EWP I will go with a Duel Row roller chain like the 1970 LT1 350, 370 HP I had (back in the day) and have my computer remapped.

 

Yes, the RC 42 was in the teeth of the waterpump gear. It is softer as you go away from there.

Yes, RC 42 isn't super hard, but it is very different from RC 28-29 that I measured in the cam gear teeth and even away from the teeth.

As quoted, I'll restate that mating a gear of RC 42 with one of RC 28-29 is just begging and pleading for trouble. In 2005, I went so far as to look into design literature for gear making. The rule of thumb is to keep the gear teeth at a similar hardness. The wp gear is smaller,so it's teeth see more contacts, so you'd make that a little harder.

As for the holes--my car had the holes, it was a stock LT1 block and all I asked the mechanic to do was swap out the heads & cam and change the timing set. He did this in-car. I don't see him going to the trouble of plugging up the holes.

Also, Michael (MSR) in those threads states that his block has the holes and he still has the wear.

There was also a gentlemen from Florida with this problem on a stock
LT1 block.

No connection that I see here with the holes.

 

I wonder what the hardness is on the drive pin for the water pump?? My guess much softer than the gear teeth. I hate this design as I agree that having two sets of different styles of gear theeth on the cam gear for the LT4 is a weak and poor set up. Next year(still paying for the new engine) EWP and a Duel Row roller cam chain and gears.