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Mechanical tacho drive

Started by _accomotors_ , Jul 23 2011 06:10 PM

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14 replies to this topic

#1 _accomotors_

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Posted 23 July 2011 - 06:10 PM

Hey there everyone. This question sort of spans numerous category so I thought it best to post in this sub-forum.

I am looking at installing a mechanical tachometer in my Kingswood. The main question I have is regarding the many Group C Toranas run when new, as most of those I have seen photos of seem to run a 'Jones' brand mechanical tach. Where abouts do these cars take the drive for the tacho from on the Holden V8? Is it from the front of the crank, or maybe the front of the cam? Or do they run special distributor add-ons to have a mechanical take-off?

I am hoping that someone who maybe has one of these cars will be able to shed some light on the situation and even post some photos of specific areas?

Thanks guys.

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#2 EunUCh

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Posted 23 July 2011 - 07:42 PM

The only mech tacho i have seen was run by cable from dizzy,short one for outside fit up,long one for inside the one i saw had a tell tale needle as well so that the max revs the eng went to was recorded.
The tach/dizzy i saw came off an A9X that ran at bathurst in the 80s

Edited by NOBALLSUC, 23 July 2011 - 07:43 PM.

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#3 WhaleOilBeefHooked

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Posted 23 July 2011 - 10:15 PM

That's correct most of the mechanical tach's work off cable connected to dissy, so you not only need the mechanical tacho but also a suitable distributor to run it and naturally the cable to join em both together...

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#4 _accomotors_

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Posted 23 July 2011 - 11:28 PM

Thanks for the replies guys. I knew that some were driven off of the distributor such as fitted from the factory on many American automobiles. Some had drives fitted to the generator or the crank too. Many aftermarket distributor manufacturers make items with mechanical tach drives built-in, but not for Holden. If the Group C Holden V8s ran the mechanical tacho off of the distributor, which distributor were they using?

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#5 EunUCh

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Posted 23 July 2011 - 11:49 PM

I think the one i spotted was a 'scorcher'twin point job, might have been twin coil as well,not 100% sure,its not mine and been a
while since i have seen it.i try and sus it out to be sure.The bloke that owns it was offered pretty good money for it over the
phone,it may be gone.

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#6 EunUCh

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Posted 24 July 2011 - 06:56 PM

The one these guys were using was a 'scorcher',twin point,twin coil set up,forgot to check out what type of tacho
but apparantly they were good and exp. at the time,some one on this site would surely know a bit more about them.

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#7 _accomotors_

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Posted 25 July 2011 - 05:57 PM

Thanks for going to that effort NOBALLSUC, I appreciate it.

From what you are saying here, it appears that the twin coil, twin point L34-style distributor made by 'Scorcher' had a mechanical drive on it for a tachometer.

Is anyone else able to confirm this?? How about factory L34s run in circuit racing, anyone else?

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#8 Struggler

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Posted 25 July 2011 - 09:17 PM

Hi James, as I said on the other forum, I have only seen the Mallory dizzy with the cable drive. I haven't got any pics but the car is currently owned by a member here who may still have that dizzy in the car (it has passed through a few hands since I owned it and people seem to hold onto weird stuff like that !).

Good luck finding one !

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#9 Litre8

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Posted 25 July 2011 - 09:40 PM

Ring Scorcher Ignition in Victoria and ask them.

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#10 EunUCh

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Posted 28 July 2011 - 09:04 AM

thats right accomotors,the tach drive came off dizzy,might be a bit difficult obtaining something
like that now,Scorcher might know if some of the old school staff are still around.

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#11 _accomotors_

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Posted 29 July 2011 - 04:34 PM

Thanks for the info and effort it took in acquiring it there boys, much appreciated. I inquired about a new L34 dizzy to Performance Ignition a while back, but it was WELL out of the range of what I was looking to spend, so it looks like I'll put that one on the back burner a while!

Anybody wouldn't happen to have a photo of such a distributor in-situ would they, give me something to visualize??

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#12 EunUCh

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Posted 06 August 2011 - 09:36 AM

Hope this is ok,tacho is Jones item

Edited by NOBALLSUC, 06 August 2011 - 09:37 AM.

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#13 _outer control_

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Posted 05 December 2013 - 02:06 AM

Does anybody know when these were first used on the race cars i understand Gown Hindaugh developed them under their name scorcher. HDT used a Mallory item and a Smiths gauge that worked backwards

Edited by outer control, 05 December 2013 - 02:10 AM.

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#14 Shiney005

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Posted 24 November 2024 - 03:27 PM

I bought this mechanical drive M.Mallory tacho from a former owner of the second Patterson's L34, which was converted to A9X specs around Sept '77. Whether or not it was given to Brock by Harry I don't know.

The car it came from is the front one.

Screenshot 2024-11-24 131909small.png 1.39MB 3 downloads