Tach adapting for V8

Waggoner5 · 08-18-04, 03:06 PM

I noticed a lot of people are looking for the potentiometer value for making the 6cyl FJ60-62 tach work on a V8. Here is a picture of the install. The pot value is 200ohm. You only use 2 out of 3 lugs. The outer as you maybe can't see, is not used. Attach an aftermarket tach and calibrate yours as needed.
Gary

cahilc · 08-18-04, 10:11 PM

While we're talking about tachs ... Doesn't the tach run off of the coil ? If so, wouldn't it be possible to rig a hidden anti-theft 'kill switch' from the tach by taking it to ground, thus grounding out the coil and stopping the truck from starting ?

Real curious, been chewing on this idea for a while,

Thanks in advance,
Cahil

Tinker · 08-19-04, 05:27 AM

Why do you want a 4K tach on a engine that turns over 5K?. I'm trying to adapt a cheap Auto Meter 6K tach to my 84 FJ60 5.7 Vortec/4l60E - looks like it'll fit (just got info from Painless on the correct harness wire).

woody · 08-19-04, 08:03 AM

adapting is nice for the clean-stock look, and honestly, I can't recall the last time I took my 350 up to 5k....

Does the AM tach drop in the "stock" spot? pop up pics and info, would like to see that one too!!

Options are always good....

Waggoner5 · 08-19-04, 11:48 AM

Other than maybe climbing a dune, when would you see over 4-5k RPM? My truck will break major parts at 5k. Come to think of it, my truck will break everything under it, at 5k.

Woody, the tach rests where it should and is correct all the way to 5k. Its an option for someone who doesn't want to spend even cheap $ on an aftermarket tach. This mod costs 2.79, and fits.

DirtyLittleSecret · 12-27-07, 07:06 PM

...and where might one get the "fancy" little 200 ohm potentiometer you have there?
NAPA - nope
Radio Shack - nope
REM - sold out

Waggoner5 · 12-28-07, 08:23 AM

I bought some at Allied electronics. They are a chain, but not sure in your area.

ad20k · 12-29-07, 03:38 AM

might try www.digikey.com. I think there is a $25 min order.

DirtyLittleSecret · 12-29-07, 04:06 PM

$25, would buy about 25,000 of these lil' buggers...
I guess I'm kinda confused as to why a potentiometer rather than just a regular 200 ohm resistor? I mean, there's no reason to adjust it is there?

Ah, I see...You're using the aftermarket tach as well to calibrate it and get "visually close".

rover67 · 12-29-07, 05:53 PM

i rev mine up to 6k almost weekly.. sometimes daily. (the 5.3 liter engines are good for that no problem). too much fun not to.

I originally did the potentiometer thing too after i did my swap, but ended up doing the 6k rpm autometer tach install.

but yeah, that motor reallys like it up in the revs... especially when i'm passing an fj cruiser headed up to the slopes

DirtyLittleSecret · 12-29-07, 06:40 PM

Quote:

Originally Posted by rover67

i rev mine up to 6k almost weekly.. sometimes daily. (the 5.3 liter engines are good for that no problem). too much fun not to.

I originally did the potentiometer thing too after i did my swap, but ended up doing the 6k rpm autometer tach install.

but yeah, that motor reallys like it up in the revs... especially when i'm passing an fj cruiser headed up to the slopes

Hey now, I sold a new FJ Cruiser, and stepped up to my FJ62. Pretty soon it'll be an even better move.

Dirty Toad · 02-10-08, 10:53 PM

Quote:

Originally Posted by rover67

i rev mine up to 6k almost weekly.. sometimes daily. (the 5.3 liter engines are good for that no problem). too much fun not to.

I originally did the potentiometer thing too after i did my swap, but ended up doing the 6k rpm autometer tach install.

but yeah, that motor reallys like it up in the revs... especially when i'm passing an fj cruiser headed up to the slopes

Where did you put the new Tach? Got pics of it?

08-18-04, 03:06 PM	#1
Waggoner5 IH8MUD Lifer Join Date: Sep 2003 Posts: 2,203	Tach adapting for V8 I noticed a lot of people are looking for the potentiometer value for making the 6cyl FJ60-62 tach work on a V8. Here is a picture of the install. The pot value is 200ohm. You only use 2 out of 3 lugs. The outer as you maybe can't see, is not used. Attach an aftermarket tach and calibrate yours as needed. Gary Attached Images __________________ Gary Waggoner Golden, Co 1989 FJ62 SOA, 502 Mercruiser, ARBs Sold 1987 HJ61 SOA, Cable Locks, 39k miles Sold 1983 FJ40 sitting broke since 89 1965 FZJ45 Pickup on modified 80 chassis 2003 Tacoma, ARB, OME, SC, TRD TLCA 10689 LSLC 2000 Rising Sun 2007 www.powerplayracing.net Last edited by Waggoner5; 12-28-07 at 08:24 AM.

08-18-04, 10:11 PM	#2
cahilc IH8MUD Addict Join Date: Mar 2004 Location: Silver Spring, Maryland & Daytona Beach, Florida Posts: 800	hijack - but relevant to tachs ... While we're talking about tachs ... Doesn't the tach run off of the coil ? If so, wouldn't it be possible to rig a hidden anti-theft 'kill switch' from the tach by taking it to ground, thus grounding out the coil and stopping the truck from starting ? Real curious, been chewing on this idea for a while, Thanks in advance, Cahil __________________ ..... 67 Red FJ40 - SBC, Holly, NV4500, SOA 87 Blue FJ60 - Cummins 6BT, NV4500, OME, SUA ..... coupla' parts rigs too ...

08-19-04, 08:03 AM	#4
woody Admin Join Date: Jan 2002 Location: Appleton, WI TLCA# 1548 Posts: 9,444 Blog Entries: 1	adapting is nice for the clean-stock look, and honestly, I can't recall the last time I took my 350 up to 5k.... Does the AM tach drop in the "stock" spot? pop up pics and info, would like to see that one too!! Options are always good.... __________________ Brian 'woody' Swearingen Lead Driver, Toyota Trail Team (Central) '07 FJ Cruiser...Revtek, 285 BFG-AT's, ARB/Warn, BudBuilts, 93k miles... '74 FJ40 'The Raisin'...TBI350, mVB 700r, 4:1 32-spline D300, SOA/ellip 4-link, RoundEyes, 8274-50/WinchLine, 30-Longs, 37" PBR's/TR's... '95 HZJ75...1HZ, H55F, mine bed, BFG-MT's... '96 FZJ80 'Gretchen'...OME, E-loks, 285 FCII's, ARB/T-Max10k/WinchLine'd, MetalTech'd, 4x4Lab'd, IPOR'd, Slee'd, UltAir'd, INTI'd... '03 Chevy 2500HD Dmax, Diamond Eye 4", Diablosport, Bose, 285 Nitto TG's, B&W... '08 ABU 14,000# 32' gooseneck car hauler... '?? buggy ??...5.3 Chev, 700r, Atlas, axles?, SAW's, 7075/QA-1's...design phase 1... Glock 17C - Kahr CW9 - Sig Mosquito - Davis D-32 - Remington 7600 - Marlin 30AS - Ruger 10/22

08-19-04, 11:48 AM	#5
Waggoner5 IH8MUD Lifer Join Date: Sep 2003 Posts: 2,203	Other than maybe climbing a dune, when would you see over 4-5k RPM? My truck will break major parts at 5k. Come to think of it, my truck will break everything under it, at 5k. Woody, the tach rests where it should and is correct all the way to 5k. Its an option for someone who doesn't want to spend even cheap $ on an aftermarket tach. This mod costs 2.79, and fits. __________________ Gary Waggoner Golden, Co 1989 FJ62 SOA, 502 Mercruiser, ARBs Sold 1987 HJ61 SOA, Cable Locks, 39k miles Sold 1983 FJ40 sitting broke since 89 1965 FZJ45 Pickup on modified 80 chassis 2003 Tacoma, ARB, OME, SC, TRD TLCA 10689 LSLC 2000 Rising Sun 2007 www.powerplayracing.net

12-27-07, 07:06 PM	#6
DirtyLittleSecret IH8MUD Lifer Join Date: Sep 2006 Location: Troutdale, OR Posts: 1,176	...and where might one get the "fancy" little 200 ohm potentiometer you have there? NAPA - nope Radio Shack - nope REM - sold out __________________ 1988 FJ62 (Toylet): LT1 350, 4L60e, IPOR seats, 3" OME HD w/ 4+ Ubolt flip, 1" body lift, 33x10.50 BFG KM's, Aussied, ARB/Warn 8000, Thule'd. Waiting to go on: Longfield 30's, Knuckle kit, TG sliders, and other goodies.

08-19-04, 05:27 AM	#3
Tinker IH8MUD Lifer Join Date: Apr 2004 Location: Larkspur, CO Posts: 2,175	Why do you want a 4K tach on a engine that turns over 5K?. I'm trying to adapt a cheap Auto Meter 6K tach to my 84 FJ60 5.7 Vortec/4l60E - looks like it'll fit (just got info from Painless on the correct harness wire).

12-28-07, 08:23 AM	#7
Waggoner5 IH8MUD Lifer Join Date: Sep 2003 Posts: 2,203	I bought some at Allied electronics. They are a chain, but not sure in your area. __________________ Gary Waggoner Golden, Co 1989 FJ62 SOA, 502 Mercruiser, ARBs Sold 1987 HJ61 SOA, Cable Locks, 39k miles Sold 1983 FJ40 sitting broke since 89 1965 FZJ45 Pickup on modified 80 chassis 2003 Tacoma, ARB, OME, SC, TRD TLCA 10689 LSLC 2000 Rising Sun 2007 www.powerplayracing.net

12-29-07, 03:38 AM	#8
ad20k IH8MUD Junior Join Date: Jul 2007 Location: Houston, TX Posts: 105	might try www.digikey.com. I think there is a $25 min order.

12-29-07, 04:06 PM	#9
DirtyLittleSecret IH8MUD Lifer Join Date: Sep 2006 Location: Troutdale, OR Posts: 1,176	$25, would buy about 25,000 of these lil' buggers... I guess I'm kinda confused as to why a potentiometer rather than just a regular 200 ohm resistor? I mean, there's no reason to adjust it is there? Ah, I see...You're using the aftermarket tach as well to calibrate it and get "visually close". __________________ 1988 FJ62 (Toylet): LT1 350, 4L60e, IPOR seats, 3" OME HD w/ 4+ Ubolt flip, 1" body lift, 33x10.50 BFG KM's, Aussied, ARB/Warn 8000, Thule'd. Waiting to go on: Longfield 30's, Knuckle kit, TG sliders, and other goodies.

12-29-07, 05:53 PM	#10
rover67 IH8MUD Regular Join Date: Sep 2006 Location: Lafayette, Co Posts: 376	i rev mine up to 6k almost weekly.. sometimes daily. (the 5.3 liter engines are good for that no problem). too much fun not to. I originally did the potentiometer thing too after i did my swap, but ended up doing the 6k rpm autometer tach install. but yeah, that motor reallys like it up in the revs... especially when i'm passing an fj cruiser headed up to the slopes __________________ 85 FJ60 240k H55, LM7, HomeBrew Bumpers, sliders, SUA and 35's

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