Tach connection
Thread Starter
Racer
Joined: Feb 2012
Posts: 421
Likes: 27
From: Harrisburg PA
Tach connection
If I have removed the HEI in favor of an MSD ready to run and blaster 2 coil, can I simply run the tach connection in my '77 off of the (-) coil terminal without causing damage to the tach?
The MSD ready to run that I have does NOT have a separate tach lead...
Thanks
The MSD ready to run that I have does NOT have a separate tach lead...
Thanks
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I think the tach needs a filter first. It looks like a big distributor condensor and is usually bolted to the intake with two feed lines. w/o the filter, the tach may read too high or sporatic.
Last edited by HeadsU.P.; May 5, 2018 at 09:45 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Using a condenser may do the trick
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
Thread Starter
Racer
Joined: Feb 2012
Posts: 421
Likes: 27
From: Harrisburg PA
Using a condenser may do the trick
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
No ignition box--the MSD dizzy is the "ready to run" version. I do have the tach connected up right now, and all is well, at least out of the gate...Interesting looking at some diagrams...the "tach" connection on the HEI is listed as the coil (-)...
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
YES...your engine came with an HEI distributor and the tach connection is in the distributor cap. And GM also has a filter between the wire from the main wiring harness and the cap.
DUB
DUB
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Using a condenser may do the trick
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
.
I do know that the company that makes the tach boards that is inside your tachometer says that there is not need for the filter once it is installed. Or at least the company of the ones I get..and I do not know who that is right off the top of my head.
SO..not knowing if you have already serviced your tach board which are well known to get a burn spot in then and make them act crazy. I would call this company and explain what you are doing and see if it is acceptable to NOT have tach filter or you MUST ahve a tach filter.
You did not mention if you were using an ignition box...like a 6AL...which does have a wire for the tach if I am not mistaken.
DUB
All reproduction and original tach boards can read either the square or rounded signal.
Personally... I'm taking the MSD blaster coil, 6AL box and distributor off my 72.... I hate it!!! I'm putting in a generic tach drive HEI distributor or putting the original distributor in there, I've not decided yet. But MSD has been a nightmare for me on this car....
Willcox
