Results 1 to 14 of 14

Thread: 4 Cyl ---> 6 Cyl Tacho Swap.

  1. #1
    Toymods Club Member #194 Conversion King Lambolica's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    2,111

    Default 4 Cyl ---> 6 Cyl Tacho Swap.

    This was a commolnly asked question on the old forums. Why does my 4 cyl tacho read funny now I have a 1J in there?? The answer is simple 6 cyl engines send more signals per revolution compared to a 4 cyl. meaning that you tacho will read approx 1/3 higher than it is supposed to.

    There are several ways around this.

    1. have the tacho calbrated to suit (TA22 tacho's off the top of my head can be modified)

    2. Install Monster Bling Bling Tacho (which have switches to read 4, 6, 8 Cyl)

    3. Don't have a Tacho

    4. Try this swap. (ie install a 6 Cyl tacho in to existing 4 cyl)

    I have done this to the Sprinter and it works a treat. this example is for Stitts "Dubbo or Bust" mobile which never had a Tacho (except for the Coupe and thus is uber rare and exy)

    The Theory is simple Find a suitable tacho and swap it in. The reality not as simple as there are a few factors to concider. For the photographed example here There was no tach. so a suitable tacho face had to be found. in this case a TA22 tacho is the doner face. being 4 cyl still another 6 cyl unit had to be found and it has to have the same sweep as the TA22 face (ie the face of the TA22 tacho goes from 0 RPM to 8000 RPM through a 260 degree sweep. so a trip to pick and pay less was made to find a 6 cyl tach with the same sweep. A Crown MS112 is the doner.

    In the case of the AE86 tacho I couldn't find a suitable sweep 6 cyl tacho so I found a 6 cyl tacho and face and swapped the whole lot.



    This is the TA22 tacho that donated the face. it has the same rasied letters and points as the rest of the guages



    This is the 6 cyl tacho unit from the MS112 which is screwed through the face of the tach with 2 screws (you can see this on most toyota Tachos) It appears that most Toyotas use the same 2 mounting bolts locations on the face on nearly all tachos from 80-mid 90's so there is a huge number of cars that can be a doner.



    The TA22 face had an older style mounting system that was ground off using a dremel and the 2 mounting holes were re drilled to suit the new doner tacho unit.



    The tacho unit bolted through the face of the TA22 gauge ( the pipe thing is a light that the TA22 uses (in this case will need some grinding down to suit the new housing as the Light will be reused)



    The tacho unit and the face bolted together and the needle in place ready for test fit and installation back into the Dash Cluster.

    ( Note for Stitts Wagon now powered by p00 I have taken the liberty of using the old brake light from the TA22 and converted it to a BHG warning light. I have studied wiring diagrams, Surfed the net and found everything that happens in a p00 motor that contributes to Blowing headgaskets and done some special wiring so that when ANYTHING that happens that endangers the headgasket, the light will illuminate warning the driver that BHG is Immanent..... It is wired to the ignition switch.)



    Test fitting back into the guage cluster it the new Tach doesn't look out of place keeping the theme of origonality for the car. All that needs to be done is the old clock that used to be there will be doner for the mounting brackets and clear plastic cover to make it fit as good as origonal.



    This is the completed Sprinter Tacho. this was much simpler. the doner tacho unit was out of a JZA Supra and I used the Face as well as the unit and trimmed the face to suit the oil Pressure gauge and the Hi beam light. Here you can see 1 of the 2 screws that hold the tach unit to the face under the tail of the needle. this was basically pull the 4 cyl unit out put the 6 cyl unit in, even the wires reconnected with out issue. If you look closely you can see the outline of the Tacho face card over the origonal.

    So basically what you have here is a cheap simple option for a 6 cyl tacho after you have done a conversion from a 4 to a 6. The same wouls apply for any other swap as well 6-4, 6-8 etc. Not bad for about $15 and about 2 hours of my time....
    Beige.... The new Black!!!

  2. #2
    Junior Member Domestic Engineer myne's Avatar
    Join Date
    Dec 2005
    Location
    sa
    Posts
    629

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    I dont want to make your impressive achievement seem pointless, but was there a reason you didnt try to recalibrate the sprinter tach?
    http://www.mindspring.com/~jayk3/toyota/tachmod.htm

  3. #3
    Toymods Club Member #194 Conversion King Lambolica's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    2,111

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Yes I did look at that site, However Not haveing a "reliable 6 cyl Tacho" to read from to get the accuracy and I had all of these parts on hand, and I didn't have the equiptment to do it as the site sugests I did it this way.
    Beige.... The new Black!!!

  4. #4
    Junior Member Domestic Engineer
    Join Date
    Dec 2005
    Location
    nsw
    Posts
    593

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    i sell signal converters that can adjust
    4cyl to 6
    6 to 4
    etc etc
    and they can be very finely adjusted for exact calibration

  5. #5
    Toymods V8 Member Too Much Toyota CrUZida's Avatar
    Join Date
    Aug 2005
    Location
    WA
    Posts
    8,214

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    I gave my tacho to a guy to recalibrate.
    Cost me $25
    Peewee
    1985 MZ12 Soarer - 1UZ Powered
    2013 86 GTS

  6. #6
    Official Off Topic KING! Conversion King stradlater's Avatar
    Join Date
    Oct 2005
    Location
    Vic
    Posts
    2,121

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    I bought bling.
    it cost me $400
    heh
    Facebook | LinkedIn

    1976 RA23 Celica - 1UZFTE ???rwkw - Earlier: 11.6 @ 116.9mph But Now: ??
    2014 Aston Martin V12 Vantage S Coupe - 421kW 0-100 3.1.....
    2005 Mercedes Benz SLK 350 - 200kW...

  7. #7
    Junior Member Conversion King timbosaurus's Avatar
    Join Date
    Feb 2006
    Location
    Melbourne
    Posts
    2,037

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Great how-to mate!!!

    I'm also not trying to depreciate ur work, but just for anyone else thinking of other options... i can add 2.

    The first is to use Jaycar's adjustable speedo kit (which is pretty expensive and bulky in my opinion) which can adjust speedo (squarewave) signals +/- 100%. I dont see why this wouldn't work with a tacho.

    The second, much cheaper and smaller (and doesn't need calibration) option is to use 2 logic chips (74HC02 and 74HC74) and a voltage regulator (LM7805) which adds up to a pricely sum of $3.05, and convert the signal down by one and a half using flip-flops. I haven't actually done it with a real tacho, but have done the same thing with a squarewave in a completely different application... it shouldn't be any different. If anyone really thinks they would benifit from it, I could build it and confirm that it works. let me know.

    Might prove a lot easier than the conversion mentioned above if u have a 4cyl tacho already in the dash and 6 cyl engine already under the bonnet.

    Cheers
    t.

  8. #8
    Toymods Club Member #194 Conversion King Lambolica's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    2,111

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Yes... i should point out that I am Aware of most of the above ways of doing this.

    The reason for the conversion in the photos is the Car doesn't have a Tacho and one needed to be put in. the TA22 was suitable but not operating, So I did it this way.
    Beige.... The new Black!!!

  9. #9
    Junior Member Conversion King TheStitt's Avatar
    Join Date
    Jul 2005
    Location
    Act
    Posts
    2,735

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Good to see it going together thanks mate

    As said its another way to do it
    ST177 UZS131 Crown Royal 'G' the pimping limo like daily 1UZFE 144rwkw

    DST17T MS53 68 Crown Custom Wagon 7MGTE 266rwkw

  10. #10
    Junior Member Conversion King timbosaurus's Avatar
    Join Date
    Feb 2006
    Location
    Melbourne
    Posts
    2,037

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Quote Originally Posted by Lambolica
    The reason for the conversion in the photos is the Car doesn't have a Tacho
    Kinda makes modifying the original tacho difficult then, doesn't it?

    Good job Lambo.

  11. #11
    Junior Member Grease Monkey
    Join Date
    Nov 2005
    Location
    ACT
    Posts
    52

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    The RA23's have a little potentiometre type thing on the back of the tacho. I just adjusted that till it matched up with my Dwell/tacho metre when i swapped from 4 to 6cyl! Easy!

    Dylo

  12. #12
    Junior Member Carport Converter SL666's Avatar
    Join Date
    Nov 2005
    Location
    ACT
    Posts
    1,809

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    anyone done it in a hilux?

  13. #13
    Toymods Vice President Chief Engine Builder TheToyman75's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,224

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    Now this info is Gold.
    1971 2T-B Celica TA22 ST.
    1973 2T-G Celica TA22, aka "The Unicorn".
    1975 2T-G Celica TA27 GT
    1976 2T-G Celica TA23, aka "The Colonel".
    1985 3F Auto FJ62 Landcruiser
    1989 7M-GTE MA70 Supra, aka "The Poopra"

    History: Rods Classic Celica Sampler thread.

  14. #14
    MR 18RG Chief Engine Builder The Witzl's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,164

    Default Re: 4 Cyl ---> 6 Cyl Tacho Swap.

    I find these ideas intriguing, I'd like to subscribe to your newsletter....

    Nice work
    I should also note, for those who have converted to the likes of a 1JZ or 4AGZE and your factory tacho isnt working, there are a couple of SIMPLE mods you can do to fix up the tacho rather than buy a tacho booster...

    Link to fixing JZX70 tacho - http://masa-ya.jp/bike/jzx70g/tacho.html
    ** cant find link to doing the AE86 tacho, but the user "JP" on here has it on his webspace somewhere



    Timbo, i've got a new topic to post that i'd like your input included please.
    link - http://www.toymods.net/forums/showthread.php?t=18393
    Last edited by The Witzl; 30-01-2007 at 09:46 AM.
    ...... butt scratcher?!


Similar Threads

  1. ST162 3SGE Swap (Photo Diary)
    By buck naked in forum Tech and Conversions
    Replies: 56
    Last Post: 07-10-2007, 10:38 AM
  2. RPM Tacho Wire
    By Cuzzo in forum Tech and Conversions
    Replies: 12
    Last Post: 10-01-2006, 09:38 PM
  3. 1GEU > MTEU + Auto > Manual in GA61 swap
    By KwS in forum Tech and Conversions
    Replies: 15
    Last Post: 06-12-2005, 01:36 PM
  4. Supercharge a 2.2 4y (na) motor or engine swap
    By steve_t647 in forum Tech and Conversions
    Replies: 2
    Last Post: 22-11-2005, 05:22 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •