Tachometers

What are you guys using?

I'm thinking to upgrade. I'm currently using an AutoMeter SportComp Monster with shift light. I'm questioning the accuracy of this one. When I hook up a Snap-on timing light it reads 6250 when the tach is at 6000.

 

I have always used Auto Meter tachs in the cars that I ran at the track and they performed well. They were accurate as well because I used them in conjunction with MSD 6AL ignition and the tach would read the same RPM as I had the rev limiter set in the ignition box.

I'm using a old style tach in my Maverick that looks like the old 3 3/4" Sun tachs that I got from Summit or Jegs.

 

If your timing light is a dial-back type I would suspect that before the tach.

 

Unless it is really old or has been beat around a lot,that is a very good tach,probably the most used one at the track.

 

Thanks guys. I think I'll plug in another spare tach to see if there's any difference.

 

Do you shift off the light or the tach ?
RLB

 

I shift off the light.

But, the car seems to be getting soft going through the lights. If it's really at 6250 rather than 6000 then it may be getting into valve float. It floated them at 6200 on the engine dyno when we built it.

I get to run it again on Wednesday. I'm going to put some new plugs in it before I go out. I've been running the same plugs all season. That's 52 runs on this set. It may be just a plug problem.

 

Did any of the numbers change 60 ' 330' 1/8 1/4 ? You could check a couple springs and if they are down some add a shim. Look for a broken spring.
RLB