Mac's sells two nylon timing gears. One a standard timing gear, the other saying a 7.5 degree timing advancement gear for greater low end power and a wider power band. What is up this this?
Does anyone run this 7.5?
Yes. Seems to help on the hills. But hard to tell as my engine got new pistons, rings and rods, and a straight through Marvel carb.
There's no magic here. Advancing the timing gives more low end torque and less higher RPM torque. Retarding the cam timing gives you the opposite. Neither can give you a "wider power band". Advertising hyperbole is believed by those who don't know any better.
I installed a advanced timing set on my '81 351m in my old f150. It made a BIG improvement. Better torque AND better fuel economy
I have not tried it on a T yet but I do own one. The gear I have is double drilled so you can use it standard or advanced
Can U accomplish the same thing with the "spark" lever??
As Royce stated cam (valve) timing and spark timing are two different animals.
As Royce alluded to, you can't get something for nothing. It is always a trade off, but, changing your cam timing could give you a wider "useful" power band. I have heard experts say that as far as cams are concerned anything below 3 grand (rpm) is low end. If that is true, Model T's are all low end.
I have put them in several engines and like the low-end power increase. I don't care how fast my T's will go (unlike some here, such as the MT 500 guys), but I often climb hills in my T's so the low-end bump is a big plus.
What about mating that 7.5 advanced gear to a Stipe 180 cam? Is there already some advance built into that cam?
Seems to me a cam can be designed to take more advantage of that +7.5 deg. it were designed with such a gear in mind, such as one of the reground cams made by Ford-N-More in Spokane.
I have thought about giving a T engine variable cam timing.
My thought is to trim the width of the cam gear (take 1/4 the width of both sides). Then modify the front cam bearing to allow the cam to be slid lengthwise as you drive. It wouldn't work with a New Day timer but the other timers should be OK
Timing change aside, I would never use any nylon timing gear under any circumstances.
I would even be LESS inclined to do so if you have a generator on a the Model T engine.
Ron the Coilman
And yet I've run a fibre gear for 30 years and probably 25,000 miles WITH a generator on my '27. Gear mesh is everything in my experience
Les do U have a generator?
Yes, please re-read my posting
And you know I am just a "cobbler"
OH...I have a skim problem and I miss things.
How do you gear mesh? I just shove the gen in the hole and hope for the best. I agree that the better things mesh, the longer they will last..
The generator bracket (and generator) need to be trial installed prior to installing the front cover. The mesh can then be "tuned" by the gasket thickness of the bracket. I also use a "link" between the "dummy" camshaft and the line boring bar to ensure precise crank to cam gear mesh. It is a total "package"
Macerated fibre gears from long ago are way better for wear resistance than any of the modern fibre gears - might be O.K. for a non-generator car.
Here's where a good babbitt job is important. I haven't worked on that part of the engine in a long time. I guess I should remove the front plate and check it out. I'm running an oil pump instead of a generator. Thanks Les
Here's the oil pump (for the inserted mains): Thanks again Les
I personally would not use or recommend Nylon timing gears.
I understand the reasons and care with which you use them, but few are as knowledgeable and careful as you.
Others and their successors no so.
Ron the Coils
Been running the advanced nylon gear out of PA for 3 years now on two cars with one with a generator and one with an alternator without issue. The one fiber gear that was in one of the cars I bought did not last at all. Be interesting to see how long the nylon ones last. Sure seemed to help out low end.
Steve, you mentioned macerated timing gears as being OK. it was my understanding that they are the ones which DO give problems. My tudor is down with a stripped gear at the moment. I was under the impression that the LAMINATED fibre gears were the good ones, but they disappeared a good while ago.
I have use aluminium gears exclusively for all my re-builds, to avoid any problems.
Allan from down under.
I've been using a Nylon gear in my MT 500 car for 5+ years, and put one into my wife's 500 car 3 years ago. I have an aggressive cam in both and just last year I started running a generator against them. I have had no problems and I recommend them to anyone who want to have quite timing gears.
I like the AC compressor. What can you tell us. I assume that is the B210 oil pump? How do you like it?
I might have it backwards ?
Granted it wasn't a T, but I once spent an unscheduled extra week in Trinidad Colorado thanks to a nylon timing gear. I'm with Ron on this one.
As for fiber,
Tell you the truth, I've had problems with most of them, Most of my problems were related to too much cam. I've replaced many fiber gears running against generators. Most of my failures have been stripped out center hubs...the cam driving pin holes typically become slots in the aluminum gears. I have seen two failed nylon gears, only one kept the car from running. I've yet to see a ruined bronze gear unfortunately my experience has been you can hear them coming from half a mile away. (They're noisy like the aluminum gears)
I think in a stock cam situation the nylon, bronze, or aluminum gears are all good choices.
BTW the first batch of nylon gears had the tooth pitch wrong. Those I believe were made by Performance t parts, this problem has been corrected with the gears sold by Snyder's.
Model a's and flat head hot rodders use an off set key to get the same advance result. I'm thinking you could make an offset key and be better off than using the unreliable fiber gear. Keep in mind, you can improve the low end torque or the hi end power but you can't do both at the same time via the 7.5 degree gear.
I forgot, Stipe sells and adjustable timing gear.
I agree with Ron, I learned the hard way.
Brass Car Guy — one can also re-drill the metal cam gear of your choice to provide the 7.5° advance. This is not my graphic, but is what I used to drill the bronze gear in my '26 touring, which could well use any extra low-end torque.
Oh, horrors! A noisy Model T? We can't have that!
Are you using a Nylon timing gear in a non-generator Model T engine? You posted some time ago of changing out a bronze gear to Nylon because of noise. If you are running a Nylon gear....is it holding up?
I bought an advanced Nylon gear for a replacement engine I'm building for our 13. The new engine sports a new SCAT crankshaft.
I have replaced the Nylon timing gears in 350 & 454 Chev. engines with double roller timing sets. Those engines have much more valve pressure compared to what a T runs. The load area on a T timing gear is much larger compared to the Nylon gears in a 350 or 454 Chev.
Has anyone had a Nylon Gear fail in a non-generator engine? I would not run a fiber gear...and do not consider them being comparable to a Nylon gear.
Can i ask a very simple question to the use of a nylon gear? Is it simply the idea that it is much quieter compared to a stock gear? If that is the case, i guess all those other squeaks,rattles and groans that occur every time my T comes to life and drives needs a complete plastic overhaul.
I have been able to check the generator gear for proper backlash in an assembled engine through the oil filler hole by reaching down in the hole with a finger and seeing if the generator gear can be rocked back and forth. One of the free generator gear teeth can usually be found by feel and by pushing against it a good hold can be obtained on the gear. It should rock back and forth just a slight amount and produce a slight clicking sound as the gear teeth come in contact with each other. If it can't be moved it is too close and a thicker gasket needs to be installed between the generator mounting plate and the engine.
This method may not work with Nylon cam gears.
Les, The oil pump works great and I installed an electric oil pump with check valves to pre-oil the mains before I start the engine and the engine driver pump takes over. I don't know the model of the pump but it works great and maintains 40psi. The compressor is one that we installed on the Geo Metro a few years ago. (My shop used to install aftermarket air in new cars for the local car dealers.) It's smaller than the the normally used 10 inch Sanden. The oil pump runs on the aluminum cam gear without noise so I think it fits pretty good. My luck with the other than a metal gear is not as good as yours. AND for everyone that thinks that compressor drags too much power, you can hardly tell when it is turned on.
What would be interesting to everyone would be more information then I stripped the timing gear! How fast were you going, what was your RPM approx what modifications were made to the engine if any.
Keeping that in mind I will try and post as much info when and if my nylon 7 1/2 gear or the one I have installed in a customers car strips.
I have the nylon gear in my '15. No problems so far, about 11,000 miles. No generator, but it does have a Stipe 280 cam.
Thanks for responding, I was also planning to use a Stipe 280 cam which is presently in my old engine. Is the Nylon gear you are using have any added advance? If so, did you notice better low end torque?
What I think would be really interesting is what was the exact crank to cam spacing? Is it the 3.937" that the gears are designed for? The camshaft bearing bores in T blocks have a LOT of vertical variation. Many guys who line bore T's locate the main bearings only by a horizontal guide. I used to do this and found that gear mesh would be all over the place. Fortunately then you could buy oversize fibre cam gears. With the right cam gear you could get good mesh (which corresponds to loooong fibre cam gear life). In the last 15 years I have been locating the mains using a 3.937" long link between the dummy cam and the line boring bar. Now I get perfect gear mesh with standard size gears. And that is another "cobbling" trick.
To add to that, are new generator and crank gears being used? In my case, maybe a couple of thousands miles on both in the other both new.
The gear I bought is straight up. It has all the torque I need at any speed. The high compression head adds a lot of torque.
"BTW the first batch of nylon gears had the tooth pitch wrong. Those I believe were made by Performance t parts..."
Absolutely, 100% correct! I bought 4 of these junk gears. Of the 4, the pitch diameters varied as much as .015 and pitch diameter runout was .011. What garbage!