Hi Guys,

Yes, I have read other threads on this subject but it doesn't appear to help me.

My friend has a 82 Firebird that has had a 327 V8 put into it, and the tach is reading much too high. I installed it into my 82 Trans Am and it confirms that it is indeed the tach and not the car.

Comparing the two tach units (the V6 and my V8 one), all the electronics appear to be the same, except for the black microchip used. The V6 has a 8110 and the V8 has a 8143.

As I said, all the other components appear to be the same, resistors are the same, and all other components have the same values. I'm stumped as to what it could be. Any clues?

One thing I do note is that the needle on the V6 tach moves very freely, but my V8 tach is "rigid" by comparison.

I hope some kind person can help solve the mystery!

Thanks!

 

Did you read the thread on swapping the capacitor in the V6 to make it work on a V8?

 

Yeah I did. I saw that and thought it would solve my problem, but when I actually removed my tach and got hold of my friend's V6 tach I checked for the capacitors. I was surprised to find they were of the same value.

 

blackbeauty

I have a 1982 T/A cluster if you need one

 

I'll tell my friend about your generous offer. How much would you want for it?

Thanks

 

blackbeauty

the whole cluster is free, I replaced it with one from a 87, all the gauges were working when it was removed from the car, odometer was at about 88,000, you will have to pay for shipping though.

 

Yes, they are the same value. You need to put in the NEW capacitor, it is a different value that will make a V6 tach work with a V8

 

Ah!

I gave it a try by putting in the requried capacitor but it ended up making it worse, not better. Just for a test, I've gone the other way and will find out tonight what effect that has. Do you think maybe because the damper appears to be shot that this could affect the accuracy of the gauge?

If it doesn't work out, Jproz1167, I'll be looking at taking you up on your generous offer of your 82 dash cluster. Could you let me know how much freight to New Zealand would be please?

Thanks,

Steven

 

The resistor chip on the board is probably bad then.

 

Is that the white chip?

 

It should be the one that has a different number than the V8 tach had on it.

 

Ah, that'll be the black chip. I tried looking up on the web for info on them but I wasn't able to dig up anything useful.

I altered the capacitance again and it seems to be have made no difference. Reckon it's poked good and proper. Reckon I'll have to email JProz1167 for his cluster.

Thanks for your help.

 

OK I am an FNG here. I am going to be doing the same swap here shortly. I have an 8000rpm tack from a v6 that is going into my v8 car (87 TA) I searched this whole sight and didn't find the thread dealing with the modification needed to make the tach perform correctly. Can you let me know how to do this mod or point me in the right direction?

Thanx

 

It's here...

https://www.thirdgen.org/techbb2/sho...ght=tach+fixed

 

Thanx for the info!

 

You're welcome. I'd be interested in hearing how it goes.

 

I will let you know.