• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Timing Gear Drives. Your opinions...?

70_Fastback

70_Fastback

Hell Bent for Speed
I'm sure most have read about my engine misfortunes up in Des Moines. I'm finally going to be able to tear into it Saturday morning.

But baring my assumptions about the gear drive set failing. Would you go back with another gear drive? I was running the Edelbrock Accu-Drive gear set:

350-7892.jpg

http://www.jegs.com/i/Edelbrock/350/7892/10002/-1


I've tried doing some research about gear failure statistics, but come up short. I do find timing chain failures though. But that could be because the 'general public' runs the conventional chain...?

If you were in my shoes, would you be inclined to go back to the gears (if that is the problem) or change and go with the more traditional double-roller chain?

Anyone else experience a gear drive failuer vs. chain failure?

Open for discussion; thanks.
 
I think I would have questioned the gear drive if the issue popped up during start up, I would have wondered if your compression ratio was putting a strain on the gears or something. Perhaps they cracked at start up and gave up the ghost while cruising. If you took a poll, how many people that built there engine or had it build and used gear drives as opposed to traditional timing chain what would the poll look like? If they weren't worth a $h!t, they wouldnt be on the market.
 
After seeing how robust that gear drive looks, I'm wondering if it might be something else. Maybe the cam pin sheared, or the cam bolt came loose. I guess you'll find out soon enough. If the gear drive did break, I'd switch to a double roller chain, as they are plenty proven. Good luck on Saturday Jeremy.
 
Hopefully it's something "smaller" but like Ryan said, I'd go with the chain. Those things may be top notch (I thought about them when doing mine) but my thinking is like this: The more moving parts you have, the more things there are to break. Just my $0.02 Not that my car is running right or anything.
 
If you find it is a gear drive problem, I'd go with a good dbl roller. It's worked for me so far.
 
A lot of dirt track guys use a fixed idler gear drive. The fixed idler gear drive is far superior to the duel idler for a few simple reasons . Number one , the idler has one gear that is slightly larger than the other , and that gear goes on the left side , and is wedged between the crank and the cam under acceleration . This causes a drastic power loss and wear on your cam bearings! The more valve spring pressure that you have , the more this gear gets wedged . With the fixed idler , your gear mesh is fixed , and will remain the same no matter how much spring pressure is used , if it's adjusted correctly by the person who installs it . Second problem with the duel idler is that fact that forward cam walk can't be controlled as well as with the fixed idler drive . Last but not least , the duel idler drive is just a sloppy unit ! Everything has room to just bounce around , and this is not good for obvious reasons . One of the most common failures of the duel idler drive , is broken retainer pins on the duel idler gears .
Also the crankshaft harmonics are very different than the camshaft and vice verse. A belt drive or chain has less friction and absorbs some of the shock to the camshaft and valvetrain associated with on and off the throttle driving/racing.
 
No question, I'd toss the gear drive. The big advantage of them was always that a timing chain can/will stretch. But gears wear, as do all the other friction points. Timing chain stretch is not much of a problem any more with the quality double roller sets out there today, and they have less friction. The cool noise that gear drives make is the sound of horsepower being used for something other than pushing the rear wheels.
 
Jeremy I would get rid of the gear drive. I have owned them and don't like them. I hate the noise they make and they rob horsepower. What I like to use anymore on a Ford is the Ford Racing Performance Parts double roller with 9 keyways in them. The 9 keyways make it very nice to degree your cam in when putting the engine together.
 
You must log in or register to reply here.
Back
Top