Mine seems to be fine after two years running. Haven't seen much about them on the forum lately. Was wondering if they are reliable?
OK after 7 years....so far.
Has extra locator holes for advanced valve timing.
I think a lot depends on how well they are “meshed “. Perhaps only as good as the skill and knowledge of the person doing the linebore and installation of the generator.
The type made some years back had the helix cut on the wrong angle. The newest ones are cut correctly, and since they have been supplied, I have heard of no failures.
I've heard the new ones have been holding up well as well. Still, in my mindset I've never liked the idea of nylon on steel contact. I've been setting aside parts for an engine rehaul on my 26 Coupe next Winter. I Ordered all new gears from Dan McEachern, and went with a bronze cam gear that he advanced 7 1/2 degrees for me. It will be a little louder, but I have peace of mind.
You may not want to trust my opinion, as I have been running a fibre gear since 1978 on my 27 roadster for many thousands of miles. I am just installing another one. But I do my own line boring
My unhappy experience with a nylon timing gear was in a Chebby, not a Model T, but I'm sticking with bronze or aluminum.
Problem is, not all synthetic materials are born equal, and generic descriptions can be misleading. The materials and methods used to produce "fiber" (phenolic) gears recently have not proven to be the equal of such gears made 40 years ago (and more). Similarly, not all "nylon" gears are actually nylon, or made of resin materials appropriate to the application. Over 50 years ago, I worked in a shop where gear boxes which employed nylon (the real thing) gears were designated - the gearing ran quietly and gave superior service. In repair, we rarely replaced either the nylon gears or the steel gears they mated with.
Rich, that's exactly the reason why I don't use them. I have no doubt that properly made nylon gears are every bit as sturdy and reliable as bronze or steel. It seems like there's just too much guesswork though on the varying quality of the nylon gears. Who made it? Did they get the hardness and other factors right? Etc. It's why I went with bronze, no guesswork. Funny thing is I work for a plastics company. We utilize PTFE in some of our products which is very sturdy and has remarkable heat resistant qualities. Plastics if made right, can be very sturdy.
I share Steve's experience with nylon.It didn't fail me as it was still running when I decided to check it at 256,000 miles.I will be running metal gears of some variety in my T's. I just can't bring my self to be offended by a bit of gear noise in a 100 year old engine.
305 chevy gear.Yes I cut my thumb on 1 of the aluminum teeth as the nylon was Gone.
In your old blue/green Suburban Steve? Sounds right. Mack, that brings back memories! You made it many more miles than I.
I had my hot 70 Pontiac and my nice 67 Cadillac spit their teeth off right here at home for me to fix when starting them.
A model A welder engine spit his teeth off the fiber cam gear in the same way here too.
A 70's Chrysler left us stranded after a stop on a gravel road. Spit those quiet Plastic teeth off the alum gear just like the others.
That mix of Aluminium and Plastic wasn't such a good idea yet Matthew's right. In the right situ, Plastic is superb.
Stock T gears or McEachern gears for me but I'm tainted Nevin!
Yep. Chev 350. Had to hike down I-25 for several miles to find a phone. I spent a week in Trinidad waiting for parts from the outside world.
Generator failures seem to cause "soft" cam gears to shell out.
A fiber gear made in 1978 or earlier is probably a good one. My 25 Touring has a fiber gear most likely made in the 50's, if not earlier. It's been in there since 1975 and going strong. I have had several failures however with gears made in the last 15 years or so. Yes, installation has much to do with it. I won't match my mechanical skills with yours, but that said, I'm no slouch either.
Fiber cam gear in my T was most likely installed when the restoration was turned out back in '02 (I think). No generator to run, it was spontaneously de-laminating. I replaced it with an aluminum gear.
If you look at a fiber gear, and it looks like woven material, it is better than one that looks like chopped material, both types were made in the past, the woven type were original equipment, the chopped type were the cheapest aftermarket. That was my experience. Dave in Bellingham,WA
Thanks for all the feedback. It looks as though there has been little in the way of failures as yet. I think my fibre gear lasted ten years before losing it's teeth, and I'd never want another one! Guess the jury is still out....
Back in the early '70's I had a '72 Chevelle SS 454. The nylon teeth on the aluminum gear, like Mack's and probably Steve's, "came from together", to quote a previous poster. Those teeth then dropped down into the oil pan and plugged the oil pump pickup, which then promptly caused the crank bearings to spin. Had no idea what happened until I tore it down. Back then, I was told the reason those teeth came off was that timing chain links had worn enough to stretch between the teeth and caused them to break off of the gear. Made sense to me. Needless to say, I never used a nylon gear after that. I used a roller chain setup on anything I put together after that. I never really understood the "silent timing chain" thing, I never could hear anything from the roller chains. Same with the stock timing gears on a T, too much other noise to hear the timing gears. That being said, I still won't use nylon or fiber gears on a T, or anything else. It just doesn't make sense to me. Why chance it? JMHO Dave