anyone use them? ive heard you cant use the noisy version but i was wondering about a quiet one. i wonder if the knock sensor would pull timing because of it, what do you guys think?

 

There's a few posts about it but the search is down. Basically there is the possibility that the gear drive could throw off the knock sensor but nobody has been able to step up with knock counts before/after to prove it. There are a few guys around here running the quiet pete jackson setup with TPI and no issues. But the noisy version, eh nobody has verified it works no issues from what I've seen. But hey keep in mind if it did cause issues you could change the knock sensor to one that senses a different range of harmonics or you could modify the PROM to act differently when it gets knock counts.

 

Tim Burgess runs the noisy PJ.

 

hehe...so i crawled under my car today (people look at you funny when you do that at a parking lot outside the dorms ) and my knock sensor isnt even hooked up...looks like the wire got old and fell out.

anyway: more than likely a quiet one will work?

 

More likely that your ECM is never completing KS testing and you're running with less than full timing.

As for the gears, they're heavier than a chain, create noise, and may require extra lubrication:

 

gear drives cause harmonics, quiet or noisy version. No amount of harmonics is good, whether or not the knock sensor picks it up. Why would you want one? Unless you're running HUGE(over 300lbs seat) valve springs there is no need. - Plus, it takes more power to turn 2 gears(crank turns idler which turns cam) than a good roller chain. So again, why?
- we've got a blower car thats running a billet double roller. The springs are 330 seat, around 1300 open, plus the cam driven fuel pump....so,obviously, nothing wrong with a good chain.
- I have nothing against a gear drive if its needed(proper application), but otherwise I see no point. A street car just isn't the application....

 

only other reason I can see using a gear rather then a chain is timing accruacy over time. the gears shouldn't stretch out like a chain would and stand even less of a chance of braking then a chain I would think. but then again that is why we maintain the cars also. so stuff like this doesn't happen.
plus chains can last quite some time plus they don't break that easily

 

the reason for why is because i came across one cheaper than i can get a timing chain, so i was just curious.

 

Thats the reason I threw it on my engine when I rebuilt it. Just one less thing Id have to worry about down the road...plus I was keeping it pretty stock and didnt care about the weight. Plus they sound cool :-p

 

I know there are more than a few 300,000 mile timing chains lurking around here. Chain sets got a bad rap when the factory was using nylon toothed cam sprockets to make them even more quiet - As if chain noise was ever a problem.

A timing chain (typical set) has to stretch to the point of actually skipping a tooth before it has enough slack to lose even 5.5° of timing. Considering variations in grinding, pinning cam snouts and drilling sprockets, broaching keyways, installation, and the fact that most people don't even care enough to degree their cams when they install them makes use of a gear set about as sensible as driving through McDonald's for two quarter pounders with cheese, a super-size french fry, two apple pies, and a DIET Coke. Unless you're **** enough about valve timing to the point of using an eccentric bushing, checking everything for accuracy, and knowing what you actually want you valve timing to be, using a gear drive for "accuracy" makes about as much sense as the "low-calorie" trip through McDonald's. You're trusting too many vendors and suppliers to get it right for the "super accurate" timing to even matter.

And if you're that concerned, you'd be running a HTD belt drive instead of a gear set. Don't fool yourself with gears thinking they are "accurate". If you want the noise, just admit that you want the noise. By the time you get the engine tuned just right, you'll be tired of the noise anyway. But don't take my word for it.

 

what a CAS for timing accuracy?

 

I've been using the Pete Jackson "quiet" gear drive for 13 years now. It's still pretty noisy. My scantool shows a few knocks but nothing that affects performance.

 

i guess ill just pass it up then, a guy i know was going to sell me one that was only slightly used for $20 so i was just curious.