TE Cortina Tacho, 4cyl to 6cyl

[Kevaclone]

Anyone have the tech info on converting.
ie. what's involved and what components needed(specs/values)

All I can find is everyone having it done by instrument techs but nothing else

[vdo]

You will need to use a wave form generator to recalibrate the tacho.

[supershifty]

Kev, I'll share my experience with my TD Cortina.

She was a 2 litre with the sports dash, I upped it to a 250 xflow. Amongst all the little differences to be sorted, I was concerned about finding a 6cyl dash as I liked the factory job. I went to the wrecker I'd sourced most of the parts from and asked him to find me a 6cyl dash. He asked me what was wrong with mine, I said it's a 4cyl dash, he said there was no difference between the 4 and 6 cyl dashes.

I went away disbelieving but had other stuff more important to do to get her back on the road. Eventually got her back on the road with the 4 cyl dash still resident - bugger me, the tach read the correct revs!

I don't know how or why, defies logic, I assure you it worked fine apart from every so often I'd start the car and the tach would sit on zero for about 5 secs then jump up to indicate revs.

Cheers!

[vdo]

That's just spooky..! In all my years of instrumentation I can't say I've ever seen a tacho do that. Are you positive the readings are correct..? There's not a HUGE difference, bit there is a difference. A 4cyl tacho connected to a 6 cyl engine running at actual 1000rpm will show approx 1500rpm on the tacho, and the difference increases dramatically as the revs increase. Now I'm all creeped out..!

[supershifty]

Originally Posted by vdo

That's just spooky..! In all my years of instrumentation I can't say I've ever seen a tacho do that. Are you positive the readings are correct..? There's not a HUGE difference, bit there is a difference. A 4cyl tacho connected to a 6 cyl engine running at actual 1000rpm will show approx 1500rpm on the tacho, and the difference increases dramatically as the revs increase. Now I'm all creeped out..!

I fully agree with you. I admit I didn't check the tach readings against my DMM with the 4cyl engine, but it "felt" about right. I did however check them with the 6cyl, and the dash tach was pretty well correct up to the 3.5k I took it to sitting in the driveway.

If the wrecker was wrong, then just maybe I had the 6cyl dash in the first place. The car was used when I bought it and that was the dash that was in it.

Yep, creepy much!

[Kevaclone]

besides the wave form generator, what do I need to physically do/change first?

[vdo]

Nothing else. Just remove the tacho from the cluster and hook up the WFG onto the connectors on the tacho and adjust the trim pot located on the back to selected frequencies to display the correct rpm. Do you have access to a WFG..?

[Kevaclone]

Thanks vdo, replied to your PM