bertram31.com

I own a 1982 31 Bertram with twin factory installed 3208 Cats. One of the tachometers has stopped working , because the film on the inside of the tachometer glass has fallen on to the pointer. The Tach, which I think was factory installed is an Auto Meter 4000 RPM with a 180 degree dial. The bottom half of the tach is blocked out by the Black film, which has separated and fallen onto the pointer.
I have contacted Auto Meter, and they no longer support the tach that I have.
The sending unit for the tach is attached at the front of the engine. The sending unit is referred to as a generator by Cat, because it converts a mechanical drive to a DC signal to the tach.
I would like to replace the tach I have with one which is similar in appearance, but I have been unsuccessful in finding one on the used market. One new tach and sending unit from CAT or an aftermarket supplier is $300 or more.
I thought it was worth my time to ask the faithful who have or had 3208 Cats in their Bertrams, if anyone might have an old working Auto meter tach in their spare parts bin..
If not, any thoughts or recommendations on a pair of replacement tachs would be appreciated. The hole in the instrument panel for the tachs is 3 3/8".
At this time, I am circling the wagons to define my options. I have found a tach repair tech, who feels that there is an 80% chance that he can remove the glass, clear the film from the pointer and replace the glass, without breaking it.
I also have the replacement part numbers from Cat.
Any thoughts please.

Fred

Fred,
I had a similar problem a few years ago. CAT had no replacement for them. I got some isspro tach's they have dip switches on back so they work with you tach drives on engines. Hope this helps.
Happy 4 the.

I know there are restoration shops that specialize in gauges for vintage cars---an internet search may find them.

Fred,
Try lauderdale speedometer in ft lauderdale.

https://www.lspeedo.com. I have a bunch of old instruments I'll look thru in the garage also.

Thanks for the ideas. I have contacted Lauderdale Speedo and ISSPRO. Will keep you posted. Lots of confusion on The Hull Truth and Boat Diesel on replacement of tachs for 3208 Cats.

Fred

Capt. Frank Did you ever determine the number of pulses per revolution your signal generator puts out? Or alternatively, the make of your signal generator? I am vascilating between an IssPro part number R8585MC and a Stewart Warner. In either case, it would be helpful to know the output of the pulse generator, which is not easy to access or photo based on the accessories surrounding it on the engine.

Cat is not at all helpful.

Thanks,

Fred

Fred,
According to isspro 134 tooth ring gear teeth. On the tach drive on front of engine. Just flipped switch on back and it was real close.

Capt. Frank: I don't understand what the tooth count on the flywheel has to do with the number of pulses per revolution from the pulse generator, which is mounted on the front of the engine.

I spoke with Isspro, and they said that the pulses per revolution was determined by the manufacturer of the pulse generator, which they provide with their instructions. So. for a Teleflex pulse generator, the number of pulses per revolution is 8 according to their instructions.

Am I confused?

fred

Here is a quick internet search--there are a few people out there that can rebuild the original:



http://www.bobsspeedometer.com/1/120/index.asp

http://www.williamsons.com/

http://dandmrestoration.com/services/

http://www.markclawson.com/

From page 5 the that came with my isspro tach. It shows #gear teeth, that what I used to set dip switches on back of the tach.
I know that it's a pulse generator but that's it. Had to get new gears (little plastic pice like on old speedometers.
I'll look to see with one but I ordered.

Anything with teeth count is off the flywheel that uses a magnetic pickup in the flywheel housing.
The 3208 uses a mechanical drive off the camshaft on the front of the engine to a pulse generator output to drive the tach. Camshaft spins 1/2 speed of the engine rpm. 2:1 ratio.

Fred , I might have one but if you can post a pic or text me one to see if I can match it if your interested.

Bruce: I have a good picture. Can I E Mail it to you?

Fred

Fred,
email it to me at bruce@southeastmarine.com