I am installing my new cam (comp cams) with a gear drive. The gear drive instructions tell me to switch the dowl pin to the one supplied and I have done that. I slipped the cam gear on for a test fit and it seems like the gear is off center to the cam.. not only will it not allow the gear to slide over the cam but the bolt holes are misaligned. Who should I blame? Comp Cams or the gear drive company CAT? Can you enlarge the dowel pin hole on the gear for alignment?
Ignore this question. I took the old cam and pulled out the dowel pin and with the gear centered it still didnt line the bolt hoes. So, its the cam gear and nothing else.
CAT sounds like a chinese name for crappy parts? I still haven't figured out why anyone would want a gear drive....
Why run a Gear Drive......??????? if something Happens to the Gears BOOM there goes the Engine I raced Pro for Six years & ran a Chain set up at least if the Chain goes you can Salvage something! Just my 3.5 cents Live learn and Die a Fool
My friend Gary Silva had one in a early 50's Chevy Delivery that he drove for a long time that you could hear coming down the freeway from the other direction and know it was him before you could see the car. Unless it is a drag only car I can't see wanting to put up with the constant noise.
Is this a street car? If it is, I would think twice about the gear drive. I now refuse to install them for customers. 100% have asked for them to be removed after install, one even the same day. The noise will drive you nuts.
the kit should have an off set bushing kit for the pin, they are for changing the timing. here is a kit from jegs http://www.jegs.com/i/JEGS/555/20322/10002/-1?CT=999 if your timing set was complete the should be in there, they are usually color coded Paul
if the didn't supply a bushing kit then the replacement pin is most like offset +/- 4 deg and can be turned?
I like buying street cars that have a gear drive. I can usually get those cars cheap. The owners have a hard time selling anything that noisy. The first thing I do is remove the gear drive and install a regular timing chain setup. Then the car can be sold for a nice profit.
That's funny... There was a guy named Newberry in the town I lived in. He'd buy old heaps and throw a gear drive in every one. He sold cars like hotcakes to all the local kids...he'd tell them the engine was "built". He made an assload of money doing that.
If you dont mind the noise a gear drive is not going to hurt performance. Many years ago Car Craft magazine did a dyno with a small block Chevy,Ford,Mopar engines with gear drives and then switched to chains and I was amazed that the horsepower difference was within 1-3 horsepower. In highschool I ran a quiet Pete Jackson gear drive in my Nova and abused that 327 engine for 60k miles. I ran that Kendall GT-1 50w "green oil".
Been there done that with a gear drive won't do it again. What a POS. That noise will drive you crazy. From now on I only use a double roller chain.
My engine builder says the harmonics of a gear drive cause a lot of damage. They sound radical but the sound is actually doing damage.
This kit came from ebay. It was a good price so I gave it a go. I was hesitant in getting a gear drive but this is a father son project and my dad REALLY wanted a gear drive to go into it. According to the instructions supplied with the kit, I had to replace the dowel pin in the cam to the pin that came with the kit. With that done, I slid the cam gear on to find the holes were off by maybe .1 of an inch. Just enough that the threads wont start. Also, this is a OEM hydraulic setup so the cam gear has a cup that goes over the cam nose. I notice that the misalignment of the dowel pin hole wont let the gear go over the nose. Now I figure this is a sign that its time to go to double roller setup.
The "floating" idler gear drives have "some" harmonics...and the quality between the different manufacturers of these kinds vary alot... The more expensive FIXED idler gear drives are much better....and more accurate than chains.....hence their use in many race engines....reliable. And the SOUND isn't doing SHIT for damage....ever hear a straight cut trans??? Or an M-22, 4.88's, or blower whine??? If these kinds of sounds bother a guy......he ain't a hotrodder.....
At least you get 'something' for the noise with those sounds! I have had several friends install noisy timing gear sets only to help them change back to chain a little later. There was a guy in Hawaii in the late 80's with a gear drive in an OT Monte Carlo. It sounded like it had a blower, but was all noise, no go.
I like the gear drive sound personally... but never owned a car that I drove regularly with them. Now my dad on the other hand LOVES the sound. I was mainly doing it for him, but after this whole ordeal I am glad I have an excuse to go back to the double roller plan. The undue stress on the camshaft in this 4,000 motor will make me sleep better.
I was gonna jump in here to say I had a single idler gear drive in a bbc that actually sounded nice. Not too noticeable. But what the hell, I wouldn't buy another.
X2 - Like I said I abused my small block Chevy for 60k miles and often drag raced this car on weekends, best of 12.70 thru high school and then tore the block down years later and the machine shop never told me about any wierd damage from the gear drive. I only rebuilt it to turn it into a 383.
Never seen any other damage, other than getting stranded in a OT M-Code 351C Cougar, just outside of Bakersfield, when the idler assembly let go. I just cant abide by riding in the dentist's chair.
I don't have any pics, but I had a 350 that I built up. Mild hydraulic cam, aftermarket heads, TBI setup for a truck. First set of springs went about 3000 miles and it stranded me in Salt Lake City on my way to Nevada. 3 broken springs. I had a machine shop check everything out just to make sure I wasn't binding coils or otherwise doing something wrong. They put another set of springs in and gave it a good bill of health. The second set lasted 1300 miles. One broken spring this time as I heard it right away and shut it down. Another machine shop checked it over this time, replaced the springs and suggested I switch to a double roller chain. Absolutely no problems after that. It could be coincidental, but I doubt it.
I've ran both for a number of years. Gear drives because( I liked the whine)=younger,and double rows=older.And what kinda mileage are we talking about here? I've never heard of any kinda damage from dirrect gears,nor a chain. If it's a 100K mi stocker,of coarse the chain will strech,and we've all seen that. Dyno tests have proven a slight HP loss,but aren't there losses and gains throughout everything? it's just if you want the "whine". I've never had a quiet one,so I can't comment on that. Pro's and con's..... never seen nor heard of anything bad as a result of "gear drive",and have spent time as a machinist. Up to you if you can withstand the noise..... Cool for a while,but tends to get annoying..........Good luck with your choice.
Dual idler gear drives work by basically jamming the idler gear between the crank and cam gears. If the idler is really big, it would probably work ok. But in order to fit inside a stock timing cover, the gear is smaller than optimum. Big spring pressures on radical lobes and hi-volume oil pumps can add drag too, making the wedging of the idler between the other 2 gears even worse. They do put a lot of wear on the front cam bearing, and there have been cams that were bent as a result of excessively worn bearings (the bearing wears at the top as the cam gear is pushed up). If you have a dual idler drive and a locked out distributor, you can see the cam retard with a timing lite as the bearing wears. I've got a dual idler drive here that i pulled out of an engine that was way down on power. The drive looked ok, but turned out that it had about 1/8" of wear in the tie-bar holes, and allowed the cam to retard almost 20 degrees when it was rolled over. Even though there was a ton of wear at the top of the front cam brg, a simple swap to a double roller chain brought the engine back to life. If a person just put one in or was doing back to back tests, i doubt there would be a problem. But over time, i'll bet most dual idler drives will wear out the top of the front cam bearing.
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