Gear Drive Preferences

Fullchat289 · #1 (**permalink**) 12-11-2003, 03:52 AM

Does anyone have preference towards some of the gear drive timing sets I'm seeing on Ebay? I am considering plans for a 289 rebuild and wanted to fish for some insites. If it helps for any of your responses, the car I'm looking to build would be mostly used for street with the occasional track or hillclimb day thrown in. I would like to build a well breathing engine that will rev freely to around 7,000 without too much problem.

Thanks!

blykins · #2 (**permalink**) 12-11-2003, 06:14 AM

Which ones are you seeing? I'd go with a good name brand....Pete Jackson....Edelbrock...

Fullchat289 · #3 (**permalink**) 12-11-2003, 06:29 AM

Maybe to clarify a little bit - I suppose I'm looking for opinions on differences between going with gear drive vs chain set-ups.

blykins · #4 (**permalink**) 12-11-2003, 06:52 AM

Oh...

Well the big plus on a gear drive is that it will probably last a whole lot longer than a chain will. Also, when it comes to power transfer efficiency, a chain is supposed to be one of the lowest forms.

The drawbacks (if you can call them drawbacks) are: they're really really noisy...and they sound like a roots blower when you get the engine spinning.

Waters Racing · #5 (**permalink**) 12-11-2003, 07:09 AM

Well here is another opinion. Milidon also makes a gear drive. You can buy these in quiet, normal or extra noisey. Yes you can get some loud ones. I love the one's that I have used and will be replacing a brand new timing chain set on this new cobra with an extra noisey one. Nothing like rolling down the road with the sound of a blower......

Ebay has some cheapo stuff on there, I have never used any of it but who I am to say it is not any good. I will say I know what I am getting with a name brand. I believe about everyone makes a quiet one now if that is what you are looking for.

GREENSNAKE · #6 (**permalink**) 12-11-2003, 10:00 PM

I put the Edelbrock Accu-Gear Drive in mine. Its Not too noisy or too Quiet but there are some loud ones out there. I really like it Its great for track and street Held up Quite Well there is some Machining involed on the inside of your timing cover really just grind off the Oil catching lip untill there is only about .030 left Quite simple . (greensnake)

Traveller · #7 (**permalink**) 12-12-2003, 08:20 AM

None of us will ever drive our cars enough to wear out a timing chain so that's not an issue.

However, a gear drive will transfer more vibration to the valve train and will reduce it's life.

The only reason I can see to using a gear drive is because you want the sound.

Mr.Fixit · #8 (**permalink**) 12-12-2003, 09:25 AM

I know reputable engine builders that will refuse to warantee a motor with a gear drive. There is no reason to ue a gear drive instead of a chain, but there are reasons not to use a gear drive. Why do you want a gear drive?

DonC · #9 (**permalink**) 12-12-2003, 09:41 AM

Fixit:
Can you share some of the reasons NOT to use a gear drive other than that given by Traveller? Having had a car that broke a timing chain I'd rather not experience that kind of repair again. Always trying to add to my information about stuff.
DonC

niles · #10 (**permalink**) 12-12-2003, 12:50 PM

They are normally spur gears. spur gears are only in contact one gear thooth at a time, then transmits the load over to the next come with an "impact"; this causes shock load to go thru the teeth, this is what causes the noise. Also since all the torque is supported by one tooth the stress is much higher; ie failure rates.
As opposed to a chain that has multiple teeth taking the same load. Also the slack in the chain flexs and dampens out some of the shock loads. This comes at the expense of less accurate timing and timing scatter.

If you want the best of all worlds there are hi-tech cog belts drives made by serveral folks(jesel, beesy bee?), that solves all the cons.
One tends to think of chains as crude; actyally they are extremely effecient, cheap and reliable.
gn

Fullchat289 · #11 (**permalink**) 12-12-2003, 02:43 PM

Everyone:

Thanks so much for your insites and perspectives.

Off to the States in the a.m. for a little Holiday visiting. Will be checking the site occasionally for additional banter.

Best wishes to all!

RICK LAKE · #12 (**permalink**) 12-13-2003, 03:05 PM

Fullchat289 Hi Al. What about a Dannybee belt drive? I think they cost about 700.00$ Clog belt can be spun to 10,000rpm as a tensioner on it. The belt should last 40,000 mile of hard abuse and help stop harmonic of the engine running. They use this kind of belt on most overhead cam motors. I am building a 484 or 496 Shelby and are going with a Danny bee for this motor. I like the ability to change the cam timing in 15 minutes if needed while on the dyno to set the motor up for the best tork and hp numbers. As far as I know the belt gets no service. The water pump covers it to protect it from harms way. You could build a cover or shield if you wanted. Hope this helps Rick Lake