Tacho

[AustHaflinger]

I have a small digital tacho in my Haffie that also doubles up as an hour meter. The display is hard to read and the revs displayed lag behind actual revs.

I would like to replace it with an analogue 2 cylinder engine tacho - I have searched on the net and found some 5" tachos that go up to 11000 rpm or higher but I am looking for a slightly smaller diameter version with max revs about 6000 rpm - as we all know the engine max rpm is about 4800 -5200rpm and tachos that go up to 11000-16000rpm mean the difference in revs in a haffie will not be noticeable.

Any ideas on where I might get something like this would be appreciated.

Garry

[HaffyHunter]

Hi Garry,
I am using a Drag Specialties (Harley-Davidson accessories) tach Part No. 2211-0057 (new# 2211-0119). It's got a 2.4" face and reads 0-8000RPM. The tach is very accurate and works like a charm. The price from DS is $73.95 USD. You can see it in the "2013 Oldbook" catalog on page 224 at DS's website.
Cheers,
Steve

[walderse]

This one should be more in keeping with the haflinger instrument panel.

http://www.egauges.com/vdo_ind.asp?Type ... PN=333-968

Hope this helps.

Take care.

Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

[AustHaflinger]

Thanks to both of you for your links - I have bookmarked them - my Tiny Tach really doesn't cut the mustard as a usable gauge.

Cheers
Garry

[AustHaflinger]

I was given a pointer for this one - about $130US

http://www.vdo-gauges.com/instruments/b ... 2-24v.html

What do you think??

Garry

[HaffyHunter]

Hi Garry,
That one looks like the cat's meow. I like the feature of setting the red indicator for rev limit and the range is 0-6000. For my taste only, it would be nice if it was a bit smaller and have a chrome bezel to match the Haf's petrol level guage but its other features kind of win out. Nice find!
Cheers,
Steve

[AustHaflinger]

As I do not have a governor I like the idea of the red light to catch the eye if revs get too high - could also be connected to a buzzer.

The instruments on my dash are already a mish mash so I do not need to match anything. I have a VDO fuel gauge, the standard speedo, an aircraft oil pressure gauge, an aircraft voltage meter and a Tiny Tach rev/hour meter and a hole for the original hour meter (might put a clock in there).

I like the aircraft gauges as they seem to suit the character of the Haffy and if I could get an aircraft fuel gauge and tach of the same style that would be great.



Garry

[Julian B]

This one should be more in keeping with the haflinger instrument panel.

http://www.egauges.com/vdo_ind.asp?Type ... PN=333-968

I have been doing some research into tachos, & found it quite hard to find one that they would guarantee would work with a 2 cylinder engine (including the one mentioned with a warning light). I finally bought one of the tachos that Jim mentionned above. VDO were pretty helpful, but as it was not available in the UK, I bought it from egauges in the USA and had it sent over. Not sure why, but there was no duty or tax to pay.

I have just wired it up very temporarily (one each to the battery terminals, and a third to the coil) to my 1970 Haf, and after flicking a couple of dip switches (to the "Ducati" setting) it seems to work well. I will now work out where to fit it, and the best way to run the wires etc. I am sure that purists will not like this, but if it helps preserve my engine(s) then I will be very happy. I will not drill a large hole in my dashboard, but will attach the tacho adjacent to it instead.

In another thread http://www.thehaflinger.com/viewtopic.php?f=23&t=669

The Series 1 engines are governed to 4500 RPM. The Series 2 engines are governed to 4800 RPM.

I presume that my 1962 "pre-series / early Series I" Haf (Weber carb, #2 cam) would also want to be governed at 4,500? Does anyone know for sure? I really need to ensure that the revs shown do represent what the engine is actually doing, but am not sure how best to do this. That said, it "looks" about right.

I have uploaded a short video here

[AustHaflinger]

The tacho certainly looks the part - having just got my Haffie back on the road today I found the the Tiny Tac that I have is really not up to scratch - like you I will most likely source from the US. Nice idle on your engine.

Garry

[HaffyHunter]

Hi Julian,
Your new VDO tach looks great. To answer your question, your engine would be governed to 4500 RPM.
Cheers,
Steve

[Julian B]

Thanks Garry & Steve; I'll post another photo when I have installed it & wired it in properly. [NB: For the record, the instructions call for two more wires (for the illumination), but this is not top of my priorities right now.]

[heinkeljb]

Julian,

I have a strobe gun which can show rpm and I believe it is accurate. If you want I can run it up to you some time?

John

[Julian B]

John, That would be really good - so long as you can show me how to use it to show rpm

Absolutely no rush whatsoever; now that I have got all my machines MOT'd, taxed & insured the pressure is off.

Speak soon!

Julian

[heinkeljb]

It's dead simple, connect the croc clips to the battery, connect the sensor lead to the left hand spark plug lead and run the engine! (It can be used to check the timing as well - bonus)!

I'll send you a text..

John

[Julian B]

Before anyone else rushes out to buy this VDO tacho, I have a slight problem with it. In anticipation of John's visit on Saturday I wired it up in my '62 Haflinger today and it is not quite right. Whilst it "looks / sounds" about right at tick over - in the region of 800 - 1,000 rpm - at speed it under reads significantly. It may be showing 50% rpm, as when doing 30mph / 50kph it reads about 2,000rpm, but I will have to do some more checks to be sure.

I have flicked the dip switches to "Ducati" (which I assumed would be a 2 cylinder engine), but more playing is obviously needed.



NB: Question: would tacho set up for a 4 cylinder engine but run on a 2 cylinder engine display 50% revs or 200% revs?

[HaffyHunter]

Hi Julian,

I just had a read through the instructions for your tach on the VDO website. It's interesting that the settings available only describe them as "Ducati" or "Rotax" with no real mention of the differing characteristics between them. I'd guess that the DIP switch setting you chose may be ok for the Haffy as it seems consistent with idle speed. The VDO instructions state that there is a potentiometer adjustment to be used to calibrate the tach between 30% and 100% of the RPM range. The instructions don't provide any indication of how much adjustment is attainable with the potentiometer but it's worth a try.

Typically a tach for 4 cylinder engines will read half the actual RPM when used on a 2 cylinder engine. This depends on the ignition system though. Single fire (1x coil per cylinder) versus twin fire (1x coil fires both cylinders) systems also single points versus dual points systems. As well, some models of solid state ignition system modules, e.g. MSD or Pertronix have unique firing triggers which won't signal some traditional tachs.

Cheers,
Steve

[AustHaflinger]

Thanks for all that information. This had prompted me to ask a few questions before I order the one I have decided on.

Cheers

Garry

[HaffyHunter]

Hi Garry,

I'm very happy with the Drag Specialties tach that I mentioned at the earlier in this topic. It's face and pointer are very similar to the Haf's original VDO instruments. My tach came with a little mounting bracket that I bent 90 deg. and bolted to the passenger grab handle so I didn't need to cut a hole in my dash panel. The tach is quite accurate and works perfectly right out of the box.

Cheers,
Steve

[Julian B]

Steve, My mounting bracket also came with a 90 deg bracket, which I straightened out and have clamped the bracket next to the dashboard. Sight lines are good, but it is also discreet, and easily removed should I wish to. (Forget the incorrectly mounted data plate which was done by someone meaning well but without my permission )

Hopefully I will be able to get the tacho to display the correct rpm over the weekend, but I'll keep you all updated in any event.

[HaffyHunter]

Hi Julian,
Sorry that this isn't a great photo but here's where my tach ended up (top right of pic). It's easily within my field of view at all times and sort of looks period correct as an original accessory .
Cheers,
Steve