I was cruising to work this morning at around 7 am, enjoying the drive. Not really honkin, just cruising. Then the engine died suddenly. The oil pressure dropped to zero simultaneously. I coast to a stop and I was like a FORD, Found On Road Dead. When I crank the engine the oil pressure isn't comming up, so I guess timing chain or that the button allen screws that hold the timing gear to the LT4 Hot Cam had come loose. A coworker picked me up and I called AAA from my office. I was very clear, Corvette, Flatbed. But when the driver arives, he takes one look at my car and refuses to tow. I said that I would sign a waver, the plywood splitter protects the spoiler, but he wanted no part of it. I call AAA and they can't get anyone out till noon, so I go back to work. I finally get the car home around 1:30 pm. I pull the cap and crank. The rotor is not moving. Timing chain of course. So I spend the rest of the afternoon pulling the front of the motor apart. Electric water pump, serpentine belt, harmonic balancer, etc. But when I pull the timing cover off, the timing chain and gear look perfect. WTF? I think about it for a minute and a light goes off. I bet that hydraulic roller came ate the dizzy gear. I was told many times, and I read many times that with the GM LT4 Hot Cam, you did not need a special distributor gear. I geues they were wrong. Check it out.
Bee Jay

 

hey Brother!! it was me last week with my wires burnt out... now you... sorry buddy

the 72 Jeep cj5 did the same thing last year, the boys and I had to pull the whole front of the engine apart to replace both the distributer gear and the timing change gear and chain (AMC 304) ..


better find all the shavings buddy.... don't want them working into anywhere they should not be....

 

Was it a roller or solid cam button? It possibly wasn't clearanced correctly?

Possibly the rear cam plug driven in too far? There would be wear or even a hole in the cam plug if so.... maybe an oil leak as well.

 

I think I have to buy a melonized distributor gear. I didn't think it was necessary with the LT4 Hot Cam.
Bee Jay

 

Ouch! looks chewed up. Hope the shaved off particles were tiny and didn't eff anything up in the motor.

 

The dist that say you can use a normal / stock gear say that because you can, other wise they would be negligent in their advertising and the represnent headaches as well as potential payments to people like yourself.

Dose you cam have the normal / stock dist. gear ? If is is a billet roller and the same for cam gear this will happen.

Also cam walk will cause this to happen, as the cam turns on the dist shaft it wants to pull away, that is why the 6-8 thou cam movement spec is important, I run mine slightly less as I feel thing wear in and never had a problem.

If you are running stock pump with lighter oil then thing won't happen as often. Buy high viscosity oil and high pressure / volume pump then when the cam moves forward you will start to chip teeth. I use a $250 timing chain cover with a roller button, some say over kill but one less thing I worry about Not saying however that is your problem or what the cause was.




One thing that is imperative is the cam gear is compatible with distributor gear

I am sorry for your misfortune and I hope you get it up and running soon.

I may see a flat bed on Weds night as I am leaving the line wheels up ( if I can get the drag radail tomorrow and shifiting at 7 grand

Look into the Comp Cams composite gear, expensive but won't break or wear out

One more thing it is not the distributor manufacturer that dictates the type of gear to use it is the cam manufacturer

 

dam unlucky break there BJ . that gear really did get chomped on. i think you posted once somewhere that you got your hotcam from a friend or on a special deal as it had low miles on it? i might be confused with someone else and probably am but if not is there any chance that the cam had already suffered damage. by that i mean...............

as im quite sure you are correct that the lt4hotcam does not need a melonised gear is it possible previously the cam was used with a melonised gear and when you got the cam it was not visible to the eye but the damage was done and eventually even though you had compatable parts once you installed it, it was like using old unmatched lifters to a different cam.

you do have me scared though. i have crane cam 119661 and when i put it in i was also advised that the gear on my msd ready to run was suitable without a change. i may do some research once again.

 

Yes, all GM roller cams require a melonized gear. I've been using one on my ZZ502 for 3 years now. I used the same melonized gear for 2 years before that on a CC solid roller cam. No problems at all.

Check your cam gear for damage. I hate to think where all that metal ended up.

 

Did you get that camera mounted so we can watch the rear end ? We like videos.

 

Yes, videos of catastrophic devastation.

 

LT4 hotcam is steel as are all genuine GM roller cams that fit C3 era sbc/bbc. Use the melonized genuine GM gear with those.

Suggest a bit of proactive policy work on that refused tow situation. There could be a next time; what if similar were to happen while stranded in a dangerous location?

BTW ... seen similar symptoms as yours but NOT related to yours ... timing set ok ... dist gear ok ... but dist no rotate ... cast cam broke in two

 

Yep, I was informed of this when I was buying all of my parts. I got a billet steel cam and had a iron dist gear pressed on so it would be compatible with the dist iron gear drive. I did not want to have to use a weaker metal gear on the dist and have to replace it all the time.

 

A melonized gear is not "weaker", and you'll never have to replace it.

 

What is a melonized gear? Is it just made of different metal?

 

I just got off of the phone with Scoggins-Dickey tech. Yes, the melonized gear is required for the LT4 Hot Cam. They have them in stock for $36. The local Chevy dealer does not stock them but can get them to me in a day for $80. I'll wait for Scoggins-Dickey. I should have the gear by Friday, and wrench this weekend. I can put the harmonic damper, water pump and pulleys back in the mean time.
Wait for it...........................here it comes.
While I'm in there I may as well pull the intake and heads and install the head studs and super thin head gasket I've got laying around waiting for the perfect opportunity to install.
Bee Jay

 

are you going to cross your fingers and hope those chunks of gear don`t find their way to your bearings?

 

Since I unecessarily pulled my timing chain cover, I have to drop my oil pan with it's one piece gasket. I'll clean it out, clean out the oil pump screen, change the oil very soon, and hope for the best. I'm really not ready to buy that World Products aluminum block just yet.
Bee Jay

 

good luck with the repairs BJ sorry to hear about the problems with the tow truck.

 

No ... it's a surface treatment process
http://www.northeastcoating.com/SaltBathNitriding_1.htm

another surface treat process that yields really durable gears is REM & its equivalents ... parts end up appearing as dazzling chrome ... but there's not any chrome or other plating. BTW, All nascar ford 9" R&P have rem or similar treat. Lotsa guys around here get 1-race nascar sets & run em in regional circletrack ... they LAST! ... rather commonplace.
http://www.remchem.com/

 

Jackson,
Thanks for taking the time to post the links. In a nutshell melonizing seems to be a way to harden the distributor gear.
Regards Pete.