5genflcracker
Well-known member
Does anybody know wich is better and why? Thanks for any input.
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timing chain vs gear drive
- Thread starter 5genflcracker
- Start date
timing chain is less expensive but will strech which will retard your cam timing over time. The gear setup is tricker to set up depending which one you get and is louder which on an airboat is not realy a problem. If you use a 2 gear setup you have to use a different cam because it is turning backwards as compaired to a timing chain. If you use a 3 gear setup you have to drill and tap for the idler gear. There is also a setup with a pair of gears that ride between the cam and crank gear. they are easier to set up but more expensive. Those also can use a standard rotation cam.
Tim
Tim
I would use the timing chain over the gear even though the gear to gear last a little longer. The gaer to gear loses a little hp. Where the chain does't. Use the chain set up but use the high performance timing sets. Such as Cloyes. Also if you are going to perchase a timeing set up check your engine year. If your engine is later than a 1972 model the cam has been retarted to cominsate for unleaded fuel. They did this to get rid of valve ping. So if you redegree your cam you will increase throttle response and increase torqe and hp. Just my 2cents.
I personally would recommend the Comp Cams double roller chain timing set.
They have three keyway positions already ground into the cam sprocket, and they're factory ground with 2 degress advance built in to accomodate for initial chain stretch and the wear-in that will occur on both sprockets during break in.
After a few hours running they settle in at TDC. Classy piece of work in my opinion, and they're not expensive.
olf
They have three keyway positions already ground into the cam sprocket, and they're factory ground with 2 degress advance built in to accomodate for initial chain stretch and the wear-in that will occur on both sprockets during break in.
After a few hours running they settle in at TDC. Classy piece of work in my opinion, and they're not expensive.
olf
robert4570
Well-known member
Buddy had a 500 Caddy which he ignored the timing chain problem that was coming and it finally went . We left the boat were it died and returned the following weekend to install the new one , pain in the a$$ .
I prefer gears on a car motor , just reliability sake.
I prefer gears on a car motor , just reliability sake.
fatboy0054
Well-known member
I KNOW CAD CAMS WALK MORE THAN SOME ! UNLESS YOU HAVE A BUTTEN ! WHICH MOST POEPLE DONT ! TIMING MATAINECE IS IMPORTANT ! ON CAD S !
A
Anonymous
Guest
Gear drive will transmit more crankshaft harmonics to your cam.
I'll stick with a chain, unless maybe one day I can afford a Jesel Belt Drive.
Just don't get one of the $20 cheapo "roller" chains.
A good roller timing set should cost between 50 and 100 bucks.
I'll stick with a chain, unless maybe one day I can afford a Jesel Belt Drive.
Just don't get one of the $20 cheapo "roller" chains.
A good roller timing set should cost between 50 and 100 bucks.
Waterthunder
Well-known member
I have ran gear drives on tons of motors actually in a lot of airboat motors to without a single problem EVER. I see no problem with them in an airboat. I actually prefer to use them on anything with a cam over .650 lift. The constant revving and deriving of an airboat kills timing chains. You will stretch a chain in an airboat twice as fast as a standard shift car. As for the harmonics it's not an issue in an airboat here is why. Most all of the people who dislike timing chains and where most of the negative info comes from is the circle track guy's. They have two main reasons they don't like them. The valve train harmonics everyone gets concerned about usually occur around 7,500RPM and up this obviously is not even an issue in an airboat. And second they run in a extremely narrow RPM range. These harmonic take a very consistent RPM to occur so unless you run your airboat at 8,000RPM for 30 seconds at a time There is absolutely nothing wrong with a timing gears, If I owned a caddy or DD I would run one. Matter of fact I will install one in my LS1 if someone makes them. On a DD you have the add timing chain stress of crank walk on top of revving and deriving. The purple boat in my pic's had a .650 lift roller with A Pete Jackson geardrive that boat logged years of service with a radical valve train and not one single problem!
Waterthunder, others: No gear drive is now nor has ever been available for the Cadillac. Only the single roller cloyes chain. A friend of mine built one, which was a huge pain since the distributor shaft is in the front and poorly placed to design a gear drive. It was fine, but a one off custom piece. The weakness in a Cadillac is the very small crank sprocket-----if you tap it on with a hammer, it will run from 1 second to 3 hours before it shatters. You must use a concentric ring of some sort and Eeeeaaase the bottom gear onto the crank. Charles
jdotson
Well-known member
Charles that is info I could have used several years ago as I shattered three gears in a relatively short time. I only "tapped" the first gear on and believe my other two problems were from harmonics. Shortly after the three gear sets came several flex plates and one crank hub....all while running direct drive with composite prop. Now that I've got a balanced rotating assembly and gear box...no more problems except head gasket failures that happen every once in a while. Currently 100 hrs on last gasket but I am starting to get suspect each time I add coolant. Next Caddy build will be o-ringed block and copper head gaskets...unless Potter gets those copper gaskets he mentioned some time ago.
Waterthunder
Well-known member
Have you tried placing the timing gear on a bearing hot plate. They work wonders I use them on press on bearings and 80% of the time you can just slide them on by hand wearing a glove of coarse!
Great idea thunder---I will try it next time. I have usually just taken some jewelers strap and polished the crank and used a bolt and huge washer to ease it on. But it is really a design problem---the keyway isnt placed correctly on the crankshaft snout by the factory so the woodruf key grabs about half the gear----which is so narrow, that it gets badly stressed. If you backfire a Cadillac from water in the fuel or otherwise, many times the crank gear will shatter. Best, Charles
When you're having them made you'll be able to correct the deficiencies you mentioned with the keyway. Potter might even be interested in buying a dozen or so ...... :wink: .
I'd look for the best machine shop I could find and tell them that if they're willing to work with you there may be a lot more business for them in the future.
olf
I'd look for the best machine shop I could find and tell them that if they're willing to work with you there may be a lot more business for them in the future.
olf