Thread: Gear Drive, Gear Misalignment

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Many years ago when I still drank and partied, my friend Mike and I left his house in Watertown, SD on Friday afternoon to get some Kentucky Fried Chicken for Mike, his wife, me, and my girlfriend. Monday afternoon Mike and I called his wife from Minneapolis, Mn and asked her if she wanted regular or extra crispy!!!! Mike still has the same wife, for me, that was a lot of girlfriends ago....

My Engine builder will not use gear drives anymore either. They have shown on the dyno to cause more harmonicis in the valvetrain than a chain. Spend your money of a good double roller timing chain with torrington bearings behind the cam gear.

Another case in point, My friend built a 496 this year with a gear drive. it lasted 3 passes and caused him a huge failure.

Up to you, but i will never use one.

No, he wants a gear drive!

i have a big block in my shop came to me blown up the roller lifter were blown up cam trash it had a gear drive and the lifters that were the next to the gear drive were junk it will not have a gear drive in it when it leaves my shop the guy was thinking i was joking i told him NO way would he get that gear drive in that engine from me . they add hamonic so if it made 10 hp on the dyno i would not use one why? they break parts by adding hamonics i build stuff to say to gether i do not need a dyno for that

Originally Posted by pat mccarthy

I wonder if he will still run the gear drive?
I'll bet he thinks we are insane. :whacked ok i may have papers for that

yes....and yes.

You guys....are killin me. Like I'm talking to my dad and his nine twins...It is interesting to think what it would be like if all of you were in the same room together...and then I walked in with a gear drive in my hand....


I'll let you all know how it turns out...

Originally Posted by 65cayne

yes....and yes.

You guys....are killin me. Like I'm talking to my dad and his nine twins...It is interesting to think what it would be like if all of you were in the same room together...and then I walked in with a gear drive in my hand....


I'll let you all know how it turns out...

You do know what they say?
They say "Great minds think a like".

These guys get where you are coming from,but are trying to keep you from beating a dead horse .IMO that gear drive will make a better paper weight then a engine component.

Cayne, If you want to replace that gear drive, I will be happy to give you a hand. If it crashes your engine, I will be forced to let everyone here know about it.

Come to think of it, I bought my PJ gear drive from a ready to sell circle tracker when I was 20. Why did he want to get rid of it so?

And Denny had it right about us all being in the same room together

And I'll probably be long gone before you have problems with your street gear drive

And you'll get sick of it and sell the car before you change it out again

Best Wishes, Kitz

I always hear about the harmonics from a gear drive affecting the valve train but have never seen proof of it. If there are harmonics being produced from the gear to gear setup, then why are there no harmonics being sent to the distributor from the camshaft via their coupling gear? You would think that if these harmonics are that terrible they would have an effect on the distrubtor also. Maybe creating some type of spark scattering.

Originally Posted by mrbigg

I always hear about the harmonics from a gear drive affecting the valve train but have never seen proof of it. If there are harmonics being produced from the gear to gear setup, then why are there no harmonics being sent to the distributor from the camshaft via their coupling gear? You would think that if these harmonics are that terrible they would have an effect on the distrubtor also. Maybe creating some type of spark scattering.

well run them i have seen all the proof i need the distridutor is not a link to the crank it is to the cam thru a chain or belt drive and you can get spark scatter the firing of the pistons is not as smooth as one would think .plus the fact we are taking strait cut teeth with the gear drive with back lash. the dist gear as contact is better with the cut is of the gear. the gear drive will transfer harmonice to to the valve train .......period yes and do not forget the springs they love all them added harmonices

Originally Posted by mrbigg

I always hear about the harmonics from a gear drive affecting the valve train but have never seen proof of it. If there are harmonics being produced from the gear to gear setup, then why are there no harmonics being sent to the distributor from the camshaft via their coupling gear? You would think that if these harmonics are that terrible they would have an effect on the distrubtor also. Maybe creating some type of spark scattering.

Main reason there aren't as many problems on the distributor gear is that these gears are beveled gears, not straight cut gears..

As for proof of the damage caused by gear drives.... We used to run the Pete Jackson gear drives before the good double roller chain sets came out in our racing engines.... Had a lot of problems with valve trains, and strange wear on cam bearings and other valve train parts. We switched to the Cloyes double rollers when the came out, no more valve train or cam bearing troubles... Is this proof? Probably not. Just an observation.

Basic engineering will show that the chain will abosorb some of the vibrations, straight cut gears do not. If anything they amplify them.... The gear drives do not make timing more accurate then a high quality chain. All they really do is make noise.... To some I'm sure this noise is kewl.... To me the noise is just going to drown out any small ticks, clicks, or whatever's that I will never hear over the gear drive....

Sometime, on a car with a gear drive, when it's running put your fingertips on the timing chain cover.... You will feel some very strong vibrations... These vibrations (harmonics) will do nothing to improve performance in an engine...

If your lookin' for that coooool sound, just throw a blower with a 3" belt on it.

just put some playing cards by the spokes

Originally Posted by pat mccarthy

just put some playing cards by the spokes

You know I had a bad bearing in an alternator that made a "kewl" sound when I was about 16.
Dad tried to tell me about that also but I did'nt listen.
I was on my way home and the old bushing/bearing stuck and threw the belt right off.
I had to walk about a mile.
I got home late, got grounded and then still had to put on a new alternator and belt the next day.
OK,that was 24 years ago.
Now I am feeling old.