Gear or chain??

[trularin]

Up until very recently I was a fan of going to gear drive for CAMS.

But I have heard one story where someone blamed vibration from the gear drive as a failure in their engine.

So I am not really interested in damaging my engine by the possible vibration from a gear drive.

Then again, the consistant timing of the gear drive and the lack of chain stretch appeal to me.

So I was wondering what you all think about gear or chain.

Please post your opinions.

[Ron61]

Tru,

For mostly street driving I would go with the chain drive. The gear drives are noisy and are really more suited for racing in my opinion. We put one in a friends car some time ago and then after about a month he took it out and went back to the chain. I have used chain drive in all of my High Performance cars and have driven them hard and have never had any problems.

Ron

[Fordzilla]

I vote for a quality double roller chain

[Bobcat]

I`ve never heard of vibration from a gear drive damaging an engine . If you want to see something scary , look at a video of a timing chain taken with a high speed camera . The guys I know that use gear drives on their Late Models have never had that problem .... very noisy , yes .

[ERA Chas]

You would need to race-abuse your engine to [i]need [i] a gear drive and at that you'd check it every season. Danny B makes an excellent belt-drive system with none of the hardships. Makes cam adjustments a snap. But how often you plan that?
Double roller chains serve street/strip cars long and well before needing attention.
Also your tune-up must be perfect and remain so because you sneeze it once, you broke it.

[D-CEL]

Gear drives were “*****en” back in the 80’s! LOL, But now they are all but extinct.
Current wisdom is that Belt drives are the best, with chains seconded as they ad a level of dampening between the crank and cam.
The applications where gears are used are pretty limited. I think the Top Fuel guys still use them because of the super high valve train loads, but that’s about it.
It is interesting to me that they still sell gear drives for street applications.
They are known to actually amplify the crankshaft harmonics and transmit them into the valve train.

Jason

[joyridin']

Get a quiet gear drive. The noisy ones are a menace. I've run a few and never had a problem. I had no vibration issues.

Can't really say which is better though. For a mild cam on a street car, I'd probably go with a chain.

[undy]

Nothing beats a good quality timing chain.

[blykins]

Double roller timing chain.....Ford Racing makes a nice one for around $50-60. It also has a ton of keyways in it, so you can really dial in your cam timing.

[FWB]

i've always used chains even on our full race high risers. a good quality double roller will out last the valvetrain. there is no hp advantage to a gear drive. bear in mind your building a car not the space shuttle.

[Sharroll Celby]

Gear drives DO have that extra racecar "sound" that lot of people like.

[marcalan]

My preference is a good quality double roller timing chain

[Aussie Mike]

From what I've read the double idler ones can cause problems. The 2 idler gears are floating between the cam and the crank. As the power is put through them to drive the cam there is a fair amount of thrust upwards on the cam that can cause cam bearing failure. The gears also move around in relation to each other so they don't mesh very well and that's why you get so much whine from them.

A good single idler setup where the idler is fixed to the cam cover or the block is a far superior setup. The gears stay correctly meshed and the thrust load on the cam is reduced. They also run quiet.

I've been planning on fitting this setup to my motor.





Cheers

[RICK LAKE]

trularin It depends on the money you have. If you are looking for a little extra HP? If money is not a problem, a belt drive wins out if you have a cover for it to drive on the roads. It will last 50K without any problems, is quiet, eliminates alot of engine harmonics, you can adjust the cam timing in 10 minutes, adds life to the motor. You can also pickup about 2-5 hp because of better control of the oil windage in the oil pan and timing cover. If you do many camshaft swaps this saves a ton of timing with only removing water pump and intake. No oilpan needs to be touched. Price is in the $800.00- $1,100.00 range. Alot of cars on the road today run belts without any failures for 100K miles and turn 7,000 rpms.
For noise and maken the most HP, gear drives. Setup is important and a good oil supply to the gears extends their life. This is more for 1/4 mile race cars or someone who wants a blower sound under there hood without a blower. Takes time to correctly setup timing of the camshaft and crank, may need to get special offset shims for the camshaft gear for the correct timing to the crank. Timing always stays perfect, just noisy.
Timing chains, True double roller and steel gears, will last 100K miles without any problems. Over this time period you will get a little stretch of the chain. They are the cheapest of the 3 and just as strong. Advantage is being quiet and dependable. Good oiling of the chain will extend the life for god knows how long. No plastic gears for this setup. Timing is good between camshaft and crank, over time you will see a change in the power of the motor from the chain stretching. Timing marks jumping 5-10 degrees is no out of the question and the car still running ok. If I was running a chain and had room in the timing cover I would add a tensioner to the chain so the slack is taken up on the back side of the chain.
I have 10 years of racing with a Cloyes timing setup and it is still tight. I am going to use a Danny-Bee belt setup on my 498 motor in the future. This will be with a lightwieght valve train.
Bottom line, It's all about money and where to get the MOST bang for your BUCKS. Unless racing, spend the money on Head work, Intake work, exhaust pipes, or carb. You don't need that gear noise under the hood to hear your motor running and it only will give you about 3-8 HP at 6,000 rpms and up. Stay with a chain and gears, 98% of the cobras are running them without any failures. If the chain broke, most times something locked up and broke it. Rick L.

[elric]

I run a single idler Milodon gear drive on 427SOHC between the stub cam and crank with a chain sprayer for the long timing chain. It's so quiet you would never suspect it has a gear drive.