Page 1 of 1
Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 1:15 pm
by Reno Speedster
I have a great old tachometer that reads in hundreds of RPMs that I am using on my speedster. A while back I saw a tachometer drive that ran off the fan belt in a picture of an English car, but I can’t find the picture and have never seen another. Have any of you made, used, or seen a belt driven tachometer drive on a T or other car? If so, I am interested in any information on what works and how to make one.
Re: Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 1:58 pm
by Steve Jelf
I don't know about belt drive, but tachometers are a common item for sale on the net at a wide range of prices.
Re: Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 2:40 pm
by DanTreace
Older post on tach installs
Scroll down and photo of fan pulley drive using an o-ring as drive belt.
https://www.mtfca.com/discus/messages/1 ... 1296400655
Re: Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 2:59 pm
by Craig Leach
Hi Morgan,
A while back someone was looking for info on adjusting the speed of a tach drive that came off the back of the generator. But no on the fan
which will maybe need the same ratio change made.
Craig.
Re: Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 3:16 pm
by Reno Speedster
I like the one that runs off the fan hub. That would be a simple way to do it and using a rubber drive rather than the belt would be simple. I would need to do some calculations to get the ratio right. The mounting is pretty easy as well. The only difference is I am using the 1926 water outlet/fan hub.
Re: Any tips on a fan belt tach drive?
Posted: Tue Jul 15, 2025 3:21 pm
by Henry K. Lee
The ones I have seen Morgan used a rubber wheel as you are stating with light spring pressure from an arm. Turned out it was pretty accurate.