Timing Gears?
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Joined: Sep 2006
Posts: 74
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From: Beckley WV
Timing Gears?
There is a lot of knowledge on this board and I'd like your opinions on something. What's your opinion of using a timing gear set instead of a timing chain setup? Is there a benefit or drawback or going one way or another? Thanks.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
The only drawback I know of is the noise. They are not quiet at all, and have a very distinct gear clatter / whine.
I would suggest finding someone locally that has the gears and listen to his engine before you buy and install them. It's soooo much work for you to go through if there is a chance you won't like the sound.
I would suggest finding someone locally that has the gears and listen to his engine before you buy and install them. It's soooo much work for you to go through if there is a chance you won't like the sound.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
We just pulled the gear drive setup out of one of our Vettes out here and installed a good timing chain set instead - just got sick and tired of the noise. There was no change in performance after the swap. So... advantages to the gear drive: None. Disadvantages: You'll get fed up with the whine pretty quickly after the novelty of it wears off.
Le Mans Master
Joined: Apr 2005
Posts: 6,357
Likes: 427
From: Seattle Area WA
I've ran several Donavon and Milodon type gear drives on high HP blown motors. These fixed idler designs do not give you that annoying noise like the floating types ie Pete Jackson types. They do have a distinct sound though. Gear drives do suck HP so you are better off with a Cloyes good true roller for your average street motor. Another issue that will come up with a short leg water pump is the tight clearance or lack of clearance between the back of the water pump and the gear drive case.
Racer
Joined: Apr 2004
Posts: 401
Likes: 0
From: IL
I will add that if your thinking of going to EFI (using a knock sensor) in the future it'll give the ECM problems. There are rare cases where setup is required depending on the block casting tolerences around the front cam bearing boss when installing some gear-drives.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Engine masters did a comparison of cam drives, milidon fixed idler
gear drive, cat brand dual idler gear drive, jesel belt drive,
comp cams timing chain. they used a fairley stout 440 chrysler
for the test. chain timing set 633.5 hp/595.4 torq.,
milidon fixed idler 636.3hp/596.3 torq., dual idler cat 634HP/596.3 torq.
jesel belt drive 633hp/594.2 torq.
average hp chain 511.7, milidon fixed idler 511.2, dual idler cat 511.0
jesel belt 510.7. there conclusion makes no difference what you use
power is almost identical.
gear drive, cat brand dual idler gear drive, jesel belt drive,
comp cams timing chain. they used a fairley stout 440 chrysler
for the test. chain timing set 633.5 hp/595.4 torq.,
milidon fixed idler 636.3hp/596.3 torq., dual idler cat 634HP/596.3 torq.
jesel belt drive 633hp/594.2 torq.
average hp chain 511.7, milidon fixed idler 511.2, dual idler cat 511.0
jesel belt 510.7. there conclusion makes no difference what you use
power is almost identical.
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
While a gear drive is not needed on most street engines they do have thier place for sure. Most floating gear drives for the street have been made to make more noise because people wanted it to make noise. But "test" show no horsepower change fine, that is with all parts new with no chain stretch, and they all stretch with use and change timing enough to change power out put. The other very inportant reseason to use a gear drive would be in the case of extreme valve spring peasures that break chains and stretch them big time. Another big need would be in a race application for a gear drive is in dirt track cars where they are on and off the gas hard all the time. But no need at all for most street cars! Manuel
Melting Slicks
Joined: Jun 2001
Posts: 2,340
Likes: 2
From: Moro IL
Something else I heard about gear drives, which may or may not be true but does make sense to me. Is that they tend to transmit more harmonics into the valvetrain then your normal belt or chain drive.
Pat Kunz
Pat Kunz
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Aside from most gear drives' obvious noise (may also foster smirks & smuggery from more experienced within earshot) ... Gear drives tend to push down on crank snout and front main cap & bearing ... chains pull up ... there's a LOT LESS support in cap than there is in block. Unless there's true race car HUGE valve spring pressures and / or blower drive ... gear drive not needed. Suggest do NOT use gear drive and DO use a good quality chain.