I am wanting to know if gear drives will stand up to the marine enviroment. I realize gear drives are more accurate and don't stretch like a timing chain. I am just thinking if they will stand up to higher rpms ( 5800 rpm) for periods at a time.. I am looking at the Pete jackson " quite" gear drive set to fit my factory roller cam..

any body else running gear drives?

any info is welcomed as usual


Travis

I think the gear drive would work, but there isn't much if anything to be gained. I would just stick with a good true double roller timing chain for the simplicity, price, and proven reliable performance. Just my 02.

stick with the chain

Travis, my opinion, absolutely NOT, one of the keys to longevity is to reduce variables.....ie harmonic vibrations caused by a gear drives. Sounds cool, but not on anything we build. You want it to sound like a blower, put a blower on it. If you want adjustability, quietness and reliability, put a Jesel belt drive on it.

Rod

Thanks boys.. That what opinions i wanted.. I will go the timing chain route.


Thanks


Travis

Hey RPM,
How many HRS do you get out of a Jesel and have you ever had one fail? JDNCA1 who frequently posts on this board had one fail this past season, luckily at idle so the damage was minimal. He went to a Cloyes true roller and they re dynoed the motor and showed no losses with the chain. He makes peak HP at 6800 RPM. Perhaps over 7000 RPM the Jesel starts to show some HP over the chain. Aside from harmonics, does a belt drive have a place on a low RPM marine engine?
Thanks,
Craig

Craig to answer your first question, no, we have never had a failure yet. All belts are replaced at the 200 hour topend freshen up so I am unsure of their actual longevity, but the cost is minimal at that point. We don't put mechanical roller engines in pleasure boats so the average customer will never see those kinds of rpms. We limit pretty much everything we do to 5600 max with most engines at 5400. In my opinion, the belt drive system has a place where ever reliability is wanted in a high perf, high $$$$ engine.

I have no issues with true roller setups at all, but if you want the added servicability and adjustability without any induced harmonics, the belt drive is the way to go.

Rod

You took the questions right out of my mouth Graig......?

so who should I use.. its toss up ...


crane or cloyes?

I went with a Cloyes Hex Adjust and a Comp 2 Pc. timing cover. When the motor was first broken in I checked the cyl pressures and retarded the cam a couple of degrees to get the cyl pressures down a bit. With 13.2:1 compression cyl pressures must be kept in check or detonation will eat something. I guess it worked. Cranking pressures are at around 200 and there are no signs of piston on my plugs. It runs good to!! With a standard cover I would have had to mess with the front oil pan seal and that is a ***** and even worse on a small block. Just an idea for ya.