Tachometers - converting mechanical to electronic

Tachometers - converting mechanical to electronic

Joined: August 25th, 2005, 5:45 am

June 22nd, 2006, 2:30 am #1

Our lower helm tachs were not functioning -- it was a combination of bad cables, plus some problems in the head unit itself. So like Paul did, we are converting to electronic tachs installed in the same Chris Craft trademark "Pods". Did one today; will do the other one soon:



I almost hate to say it (the purists will cringe), but I decided the conversion would look best if I could use the Chris Craft stock crome bezel -- so I ended up cutting the mechanical tach apart and using the bezel and part of the case in my conversion. So basically this mod is not reversible without buying a refurbished Chris Craft mechanical tach.

The electronic tachs are my preference, and I won't be converting back. However, before cutting the stock tach apart, I did some online research and found that refurbished Chris Craft mechanical tachs are available at quite reasonable prices -- so if some future owner wants to convert back to the stock mechanical tachs, that would be pretty simple.

In case anyone on the forum wants to replace a defective stock mechanical tach, here are pictures of a refurbished one I found on eBay for $115 -- very nice looking work:



Best wishes, Curt...
---

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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Joined: August 25th, 2005, 5:45 am

June 28th, 2006, 8:50 pm #2

Here are two photos -- one of a typical CC tach, and one of our modified tach:



The new tach, at first glance, seems smaller than the original CC tach. But that is actually not the case. The CC tach was quite small in diameter, but the big numbers and gauge scale silk-screened on the glass gauge front gave the illusion that the original gauge was bigger.

Here is one more pic, showing the mod in progress. In this picture, I had a bit of automotive Goop glue drying, which helps secure the chrome ring to the new gauge surround (which is a circular piece of sheet metal with a hole in it that the gauge slips into).



Best wishes, Curt...
---

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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Paul
Paul

June 28th, 2006, 10:30 pm #3

I'm one of those guys who is reluctant to make changes on a classic boat, or a modern classic like our Commanders. (Modern Classic as defined by ACBS as being anyting built before model year 1969)

Naturally some of the boats built in 1969 and 1970 are almost identical to those built in 1968, for instance, so I refer to just about all the early Commanders as "modern classics".

Having said that, I also changed out my tachometers to Faria electric gauges. I used a different method of creating a "bezel" but still utilized the modern electic tach because the old cable tachs were jumping all over the place, and I actually thouht some of the pulsation from the cable was translating into the distributor itself.

Your instllation looks carefully planned and executed, and I'm sure it's quite functional. I retained my old tachs, because I may want to have them rebuilt at some point and reinstalled in order to regain that true "original" look.

Regards, Paul
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Joined: August 25th, 2005, 5:45 am

June 29th, 2006, 7:17 am #4

It bothers me also to do a mod that isn't easily reversible, and I thought for quite awile about saving the old tachs vs. scavenging the wonderful original chrome tach bezels and part of the original tach cases for new electric tach mod (which basically required destroying the old tachs).

What tipped the scale is when I found that I could get totally refurbished (look just like new) Chris Craft tachs so cheap. That is when I concluded that the mod was basically reversible should some future owner want to do so. It is nice that Chris Craft used that same guage head in so many different boats for a bunch of different years -- due to the large total number of that gauge style produced, I believe refurbished ones are going to be available for many more years.

At any rate, I won't be going back to mechanical tachs -- just like speedometers in old cars, those mechanical cables get dry and kinked and get all frizzed up, and then they jump around just like you said, and become a liability. Also, having to drive those long speedometer cables probably puts some additional wear on the distributer.

I'll post a picture when I get the new tachs installed. I will probably install them some morning while on the boat for the upcoming blues fest. I have them temporarily sitting at the lower helm now and they look pretty sharp.

Best wishes, Curt...

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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Joined: August 25th, 2005, 5:45 am

July 3rd, 2006, 12:11 am #5

Our lower helm tachs were not functioning -- it was a combination of bad cables, plus some problems in the head unit itself. So like Paul did, we are converting to electronic tachs installed in the same Chris Craft trademark "Pods". Did one today; will do the other one soon:



I almost hate to say it (the purists will cringe), but I decided the conversion would look best if I could use the Chris Craft stock crome bezel -- so I ended up cutting the mechanical tach apart and using the bezel and part of the case in my conversion. So basically this mod is not reversible without buying a refurbished Chris Craft mechanical tach.

The electronic tachs are my preference, and I won't be converting back. However, before cutting the stock tach apart, I did some online research and found that refurbished Chris Craft mechanical tachs are available at quite reasonable prices -- so if some future owner wants to convert back to the stock mechanical tachs, that would be pretty simple.

In case anyone on the forum wants to replace a defective stock mechanical tach, here are pictures of a refurbished one I found on eBay for $115 -- very nice looking work:



Best wishes, Curt...
---

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
Yesterday morning while waiting for the daily blues festival music to start, we wired our modified tachs at the lower helm station:


The tachs didn't work right after we got them wired (needle going crazy). I pulled them back apart, and found the original Chris Craft ground wires that came up into those tach pods (used for the instrument light circuit) had about 4 volts on it when the ignition switch was turned on. So we abandoned those grounds and dragged in new ones -- that fixed the problem. Not sure what is going on with those factory grounds, but that old ground wiring is above the galley headliner and hard to reach, so we will chase that down some other time.

Best wishes, Curt...
---

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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Paul
Paul

July 3rd, 2006, 12:20 am #6


Hey nice job, very functional and suitable for service. I like the look of the old style tach, but I hate the jumping needle.

Someone out there is converting the old style tach to electric operation, not sure who or where, but I heard about it a while back. All it takes is money!

Faria makes some good looking instruments too, I used them when I converted my tachs a while back.

Regards, Paul
Last edited by FEfinaticP on July 3rd, 2006, 12:06 pm, edited 1 time in total.
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Joined: February 28th, 2007, 2:38 pm

February 28th, 2007, 2:52 pm #7

Yesterday morning while waiting for the daily blues festival music to start, we wired our modified tachs at the lower helm station:


The tachs didn't work right after we got them wired (needle going crazy). I pulled them back apart, and found the original Chris Craft ground wires that came up into those tach pods (used for the instrument light circuit) had about 4 volts on it when the ignition switch was turned on. So we abandoned those grounds and dragged in new ones -- that fixed the problem. Not sure what is going on with those factory grounds, but that old ground wiring is above the galley headliner and hard to reach, so we will chase that down some other time.

Best wishes, Curt...
---

1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
I really like the job you did on your tachs
I would like to duplicate what you have done on our 64 commander 38 hull 27 Miss Lily
I have looked at ours many times and I have no clue as what is the first step to remove them without damaging the housing
If it is not too much to ask could you give me a basic outline of your proceedure including the ground wire install and parts needed
your work is the best I have seen thats why I really wanted to wait intil I saw something that really looks good anyours are excellent!
thanks in advance for any help that you can provide
Dave & Lily

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Paul
Paul

February 28th, 2007, 3:33 pm #8

Hi David,

I agree, Curt did a VERY NICE job on his, but that's nothing new, because Curt does a nice job on everything he touches!!!!

The tach on your 38 is removed by a single screw in the very back of the tach housing (which faces the front of the boat). If you loosen that screw, the tach becomes loose and you can pull it out, with cable still attached, and light bulb power wire attached. It goes back together the same way!

Here is a thread to the INSTRUMENTATION files in our MASTER INDEX. At the bottom you will see two instrument restoration threads. Dale is presently restoring two instruments for me now, for a 20' Chris, I have a fully restored 38' Commander tach at the house now, and will probably get another one like it done too. The restored instruments are a lot better looking than the electric replacements, but I'm running electric FARIA now and they look and work fine. The restored tachs just look spectacular.

http://www.network54.com/Forum/503931/t ... 1149538237

You have several choices, good luck! Don't be a stranger!

Paul
Last edited by FEfinaticP on August 23rd, 2012, 6:23 pm, edited 1 time in total.
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Anonymous
Anonymous

February 28th, 2007, 4:16 pm #9

Thanks for the info
I am going to see if i can get to them today
I have been wanting to do this since Bought the boat three years ago thanks again I will keep you posted
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Paul
Paul

February 28th, 2007, 4:25 pm #10

Take photos of your work, your boat, and yourself!

Curt Hill got a starring role in a big movie contract due to the world-wide exposure he's gotten here on the forum. I think they have him playing General Patton or something. Just kidding.

Paul

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