[Nite Life]

I am planning to put a gear drive setup in my Formula. I have heard that they can reduce HP, that they can cause excess wear on the valvetrain due to transmitted vibrations, etc. But I have also read that many knowledgable mechanics swear by them. I am a little torn. I would be buying one for 2 reasons: a) I love the sound of a gear drive. They are just frickin wicked. and b) I have had difficulties with timing chains and stretch in the past. I would love to eliminate this part of the equation.

Your thoughts?

[Nite Life]

After noticing the many other threads involving this topic I believe I have come across the answer I was seeking...

Thx.

[DoubleVision]

I`ve never used one and likely won`t. Only reason I would use one if there can be no exceptions in the cam timing, and since I`m not building 600 horse engines there will likely never be the need. Since you only said Formula, what year formula? is the computer still active? if so a gear drive can`t be used with a computer, the knock sensor will pick it up as detonation and retard the spark timing until it won`t run. If not, run your gear drive as you wish, but if timing chain stretch worry`s you get a Cloyes true roller set, heat the chain with a propane torch and throw it in a bucket of STP oil treatment, the heat causes expansion and the lube works it`s way into the rollers. I`ve removed chains with little to no stretch after over 50,000 hard miles and reused the set.

[Nite Life]

Hi.

Firebird is a 1976, running a 1969 400 block, 143 heads.

[Nite Life]

I think this one got buried.

[CptKaos]

it didnt get buried, you effectively ended it with you second post.

Larry

[WDCreech]

Originally Posted by Nite Life

I am planning to put a gear drive setup in my Formula. I have heard that they can reduce HP, that they can cause excess wear on the valvetrain due to transmitted vibrations, etc. But I have also read that many knowledgable mechanics swear by them. I am a little torn. I would be buying one for 2 reasons: a) I love the sound of a gear drive. They are just frickin wicked. and b) I have had difficulties with timing chains and stretch in the past. I would love to eliminate this part of the equation.

Your thoughts?

A gear drive will transfer harmonics to the vave springs and they will loose pressure. If you want a chain that doesn't stretch, get the Australian RollMaster. Believe me. Been there, done that!

[Studebaker]

Yes gear drives work, however this is in race engines that see minimal long term use. Most of these engines are rebuilt almost every race. A gear drive is a very accurate way to stabilize cam timing at sustained high rpm use (if properly set up). They are however very troublesome for everyday street use. they wear excessively, do transmit high frequency vibrations to the valvetrain. There is nothing wrong with a high quality chain. Yes, Chains do stretch, but are simple, easy to set up and very durable. If any of you are old enough to remember "Grumpy's Toy" pro stock 352 CID Vega. (destroked 400 /400 with small journal 327 crank with home made thick spacer bearings). He used stock gm timing chains and ran the engines to 9800-10,000 RPM with no failures. Of course he changed them out after each race.

[Hippie]

Originally Posted by Studebaker

Yes gear drives work, however this is in race engines that see minimal long term use.

I'm truly disappointed in an answer like this from someone with the user name "Studebaker". Studebaker's used gear drive timing sets until the early 60's, the one in my 289 is 52 years old with who knows how many miles on it and still works just fine.

[1ownerT]

Doesn't the Chevy inline 6 use gears no chain?

I believe that many racers especially NASCAR use a belt drive.

[RPM]

Originally Posted by Studebaker

Yes gear drives work, however this is in race engines that see minimal long term use. Most of these engines are rebuilt almost every race. A gear drive is a very accurate way to stabilize cam timing at sustained high rpm use (if properly set up). They are however very troublesome for everyday street use. they wear excessively, do transmit high frequency vibrations to the valvetrain. There is nothing wrong with a high quality chain. Yes, Chains do stretch, but are simple, easy to set up and very durable. If any of you are old enough to remember "Grumpy's Toy" pro stock 352 CID Vega. (destroked 400 /400 with small journal 327 crank with home made thick spacer bearings). He used stock gm timing chains and ran the engines to 9800-10,000 RPM with no failures. Of course he changed them out after each race.

I remember that. Jenkins claimed the stock aluminum gear with the plastic on it made the most power.

[Studebaker]

No offense Hippie, You are correct, the Stude V8's did use timing gears, however this was a two gear drive making the camshaft reverse rotation.. the gears were not straight cut and this allowed the gear to provide slight rear pressure to keep the cam from moving back and forth. What I WAS refering to in the above post was the the cheap idler type gear drives (Cam gear, Crank gear and two floating idlers) that they sell for SBC and BBC. These are not very effective and usually cause more problems than they solve. . It's nice to meet someone else that is into Studebakers. I had a 63 Avanti with Stude 289. That was a great designed engine. Long stroke forged crank, reverse rotation solid lifter cam w/ adjustable shaft rockers. It was surprising how much torque the small 289 made! Most people don't know Stude had a 289 before Ford, Better design in my opinion. The Avanti body was less than desirable fiberglass Quality, but for 1963, hey it's the best they had. And I know of no other american made cars in 63 that had front disc brakes! I currently have a Stude 50 R-2 truck But I repowered with 355 chevy-t-350 and ford 8" rear. It drives very well. Those Studes were way ahead of there time, both in engineering and style. Stude's forever!

[Hippie]

Originally Posted by Studebaker

No offense Hippie, You are correct, the Stude V8's did use timing gears, however this was a two gear drive making the camshaft reverse rotation.. the gears were not straight cut and this allowed the gear to provide slight rear pressure to keep the cam from moving back and forth. What I WAS refering to in the above post was the the cheap idler type gear drives (Cam gear, Crank gear and two floating idlers) that they sell for SBC and BBC.

I was just funnin' ya', I couldn't pass that one up. I have a '55 Commander C body Coupe with a 289 out of a '56 President or Sky Hawk. Mine is an early '55 and originally came with a 224 V-8. Don't know who put the 289 in or when but I'm glad they did.

[y112]

I've personally used Pete Jackson Gear Drives since 1981.
You can see my Vettes and customer engines that I've used gear drives in. I never had any problems because I followed the instructions and bought undersize idlers when I needed the specified clearance. 9.20's with the 69 Vette and 8.70's with the 90 Vette. Gear drives do rob a little horsepower, and create harmonics, but for 150+ in the 1/4 mile with no power adders, I think they work fine in most street cars. I would NEVER run the noisey drive, and I personally like Pete Jackson because of idler availability.

[chrismac]

Here i my experience with a gear drive on the street. Yea the noise is cool, but also can trick you because it is not always constant. My lock plate allowed the bolts to come out, yes it was my fault because I didn't use lock-tite, but the plate should have stopped them from moving. Accurate timing, guaranteed but how much rpm are you going to see, and most timing chains are good to 100,000 miles that is if you get a good set.