Short post, I'll have more on it over the weekend.

THIS IS AIMED DIRECTLY AT THE ENGINE BUILDERS/ASSEMBLERS!!!!!!

If "missed", it COULD cause a catastrophe for certain. And it appears a random sort of deal now! It MAY come down to "stacked-tolerances", or not!

While the components, we're talking new CAM here, are out of the unit, trial fit the distributor (driven) gear INTO the teeth on the cam drive gear. There should be no noticeable "gap" at the "root" section between the gears. You will need to hold the cam and gear at a very specific angle to check it out with some good lightning in the background!

(Add) This is going to be a possible issue ONLY with the cams using the "pressed" on rear gears, "steel cams" and cast dist gear! But at this point I would check them all right at this time!

(Add) The photo below shows (as good a shot as I could get) the heat generated at the dist drive gear. I would ask you not to try to analyze what you see, we've already made the "fix" with a cam change while in the dyno room! I will add this for now, this was a "customer-supplied" piece and he had been forewarned NOT to use it, but for a different reason! We could not have "picked-up" on this issue before today! This is a retro-hydraulic, but it is NOT our ususal Comp Cams "stick". Initially, Dart even got in the "mix" here for a short conversation! IT IS NOT A BLOCK ISSUE! That finally proved out!

Once again, I'll come back with more later, I have a very specific reason for "no-names" (really not allowed anyhow) at this time!

Thanks, Gary in N.Y.

P.S. There are some "people" very aware of this situation, and it's one of those "keep it quiet for now" issues!

Double P.S. This issue MAY explain some premature distributor gear failures, we just don't know yet???

http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/th_CamDriveGear-A.jpg (http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/CamDriveGear-A.jpg)

Gary,thanks for info and i/we will be waiting for your update on this situation.

Scott

Hi Scott, here's a partial copy of a response to a member up here, another builder, who I've just contacted.

(Quote) The distributor gear disintegrated on the dyno after 4 tests. Ruined the dist shaft, bushing, caused the rotor to contact the cap and took the cap out!

We, 3 of us with over 130 years of experience, suspected the cam but needed more proof!

Installed a new distributor, removed the plugs, run the unit "on-the-starter", removed the dist and found the new gear already heading south!

Could not believe it! First thing comes to mind is the block. Brand new 10.200 T/D Dart, fully "probed" on the Haas, but not the dist area. This is when I called Steve at Dart to confirm any reports of "bad" blocks. He said no and I took him at his word. Later proved to not be the block!

Pulled the cam, replaced it with the customer's original, and the unit is fine. Not a single issue, it's scheduled to be picked up Tuesday night!

Have that cam and 2 others on the bench with a brand new dist gear, this was the "shocker". The new gear fit "snug" into the root section of both my own cams when held in the installed position (as it would sit in the block) BUT it would not get anywhere near the "root" section of the failed cam. There's an "air-gap" of about .015" between the 2 gears. This was causing very high "side-loading" on the dist gear and housing by not allowing the dist gear to go in deep enough to "float". Hence the "burned-out" dist gear and the other parts.

I can't give you all the specifics just yet but I'll give you this much, the gear is N.G. (dimensionally) on that cam, again, regardless of that "heat" pattern!

I've gotten Comp involved in this, it is not one of their cams, AND one other "major" player in the "marine" environment, whose cam it happens to be. I've gotten nothing but the usual denials from the cam supplier but was able to confirm our suspicions some with Comp's help!

As I said, we replaced the cam and the unit runs fine now!

The nice part of this story for us (if there is one) is the customer was adamant about using this cam he supplied, I really tried to talk him out of it, but we are "off-the-hook" and he's paying the add'l labor in the dyno room! (His old cam actually made more power than the one he supplied) (End quote)

I'm adding NOW, this as an "after-the-fact" thought, what I first suspected as the "heat-damage" may be normal during the cam manufacture, I have never seen it before and due to the conditions that we were seeing I surmised it too be related?

Turns out to be a moot point either way!

There is a "run" of "bad" drive gears (these are mounted on the cam) out there and this HAS been confirmed!! How many, not sure, BUT, we now know how to spot them on the bench using the "gear-fit" test beforehand!

Thanks, Gary in N.Y.

P.S. Most vendors just love to go into "denial" or use the old cliche, "we have no problems, you've got the only "bad" one". Not sure how many times I've gotten that reply!

I brought this back to "confirm" this is a "very real" problem.

If any builders have "connections" out there try to do some behind the scenes homework.

Took 2 days to fabricate a "crude" checking-fixture, and we now know EXACTLY what went down on this unit!

Remember, this is "customer-supplied" cam here, NOT one of ours! It IS a "steelie"/cast drive gear option!"

Thanks, Gary in N.Y.

P.S. I've got to let the "dust settle" for now, when I get some more answers (only a couple) I will have more! I'm very certain many other's are aware of this! Actually, I would "bet-the-ranch" on this one!