Tach installed....now a question

[Colorado Boy-74-FJ40]

Installed a cheap tachometer on the rig last night. Looks good works good. Does 3000 RPM sound right for a pretty tight "red line". At 3K she is screaming pretty good and I wouldn't want to push her a whole lot past that. I thought when I rapped it up it was doing in the neighborhood of 4000 - 4500. I was kinda surprised that 3K was her crying point. Is it because she has a gozillion miles or is that the nature of the F engine?
BTW the mileage on the odometer is misleading. She was missing her speedo cable for about 15 years or so. I would guess she has about 175K or better

 

[ibejamie]

I just put the same tach in mine- same spot too . My 2F cruises down the highway at 70 mph at 3000... I haven't had the urge to go any faster than that- she starts really screaming at ~3500 rpm...

Hope that helps.

 

[highlandcruzer]

That's about all I want push my 2F, normally. With 33's and stock gears I think that puts me around 65 to 70 mph @ 2800 to 3000 rpm's IIRC.

On occasion, in the mud, I'll tach her up past that in low gear, just to spin the tires. But I wouldn't cruise on the road, past 3k myself.

Besides, you've petty well peaked your powerband. No point in turning faster. my .02

 

[FF LC FREAK]

IIRC, peak horsepower is at 3600 RPMs for the F engine. I usually shift around 3000. I have the same tach, and I set my redline at 4000. I've never been that high, but I have been to 35-36k a few times. You can definitely feel the HP kick in above the 3k mark.

Good luck!

 

[Colorado Boy-74-FJ40]

Thanks, I was just wondering of the tach was working properly

 

[highlandcruzer]

I thought when I rapped it up it was doing in the neighborhood of 4000 - 4500. I was kinda surprised that 3K was her crying point.

That's funny, I remember thinking the same thing before, and after installing a tach on my 2F. "Huh, that can't be right"

It's right. Nature of the beast... Tractor motor... It's a lugger, not a spinner. If you're used to running V motors, or even Heep I6's, it just doesn't seem right at first.

 

[highlandcruzer]

You can definitely feel the HP kick in above the 3k mark.

That's interesting, I guess I've never really tried it on the road. Too scary above 70 ! lol I do turn it, pushing four grand intermittently off-road, but I mostly do it for the tire speed in 2nd low gear .

 

[Degnol]

Thanks, I was just wondering of the tach was working properly

Just make sure you have the tach set a 6 cyl, not 8cyl

Ed

 

[FF LC FREAK]

You can definitely feel the HP kick in above the 3k mark.

That's interesting, I guess I've never really tried it on the road. Too scary above 70 ! lol I do turn it, pushing four grand intermittently off-road, but I mostly do it for the tire speed in 2nd low gear .

Granted, this is relative to F engine HP. Its not like the HP of a big block kicking in. But it is noticeable. There is a definite difference between stomping on the accelerator at 2k vs 3k RPMs.

YMMV.

Oh, and you don't necessarily have to be in your top gear (3rd or 4th depending on your tranny) to test this out.

 

[Colorado Boy-74-FJ40]

It is

Just make sure you have the tach set a 6 cyl, not 8cyl

Ed

set on six, Thanks anyway

 

[Degnol]

Just make sure you have the tach set a 6 cyl, not 8cyl

Ed

set on six, Thanks anyway

It has happened. Just checking.

Ed


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[Spitpatch]

Put the same tach in my '71. Offset it on the steering column at about the 1:30-2 o'clock position, so my high beam indicator and all guages visible.

With the newly rebuilt motor, and standard tires (LT235-75R-15"), it ran at 3000 rpms at 64-65mph. (3spd tranny). Now with 31-10.50 tires, at 2800rpms, (motor not screaming as it was at 3000), speedo shows 60mph, but I figure I'm probably really going about 64-65mph. Have not "paced" it yet with a friend in a rig with an accurate speedo. That'd be the true test, or find a friendly cop (oxymoron?) with a radar gun, or one of those reader boards they put out occasionally.

The 31 inch tires got me where I wanted to be for rpm's on the highway. (2800rpms for 64-65mph). She seems to sing that harmonic happy sound at those rpm's. Most cops will tell you 64-65mph is where they set their radar guns to give them a signal beep for a potential solid ticket in a 55mph zone. If I wanna go faster on the hiway, I'll fire up my '67 Fairlane with a 289, modified suspension (and radar detector): that is a true driveable 100mph car, but not much of a hunting rig.

 

[Spitpatch]

Deleted a duplicate here. (Couldn't find how to do it in the edit mode)

 

[Degnol]

Try this....Gear Calculator

 

[KOOTENAY KRUZER]

Probably easier and more accurate to just borrow a handheld GPS unit to check your speed.

 

[highlandcruzer]

If you can't borrow one.................I've got the GPS service on my cell phone. It works great to track my vehicle speed, real time. Very accurate, and cheaper than buying a separate unit.

 

[Big Todd]

I have one mounted in mine. I knew my speedo was off, but it was off farther than I thought.

I got a Magellan Sportrac at Radio shack for $129.
It also has a trip meter in it.

 

[brider]

Colorado Boy:

Did you fab up the tach mount, or did it come with some bracketry to mount on the column like that?

 

[Colorado Boy-74-FJ40]

Included

Colorado Boy:

Did you fab up the tach mount, or did it come with some bracketry to mount on the column like that?

It was in the kit. I didn't need to fab anything. Much like the one in the pic. The only thing was the wire that attaches to the coil wasn't long enough so i had to splice in some additional

 

[brider]

OK, I'm searchin' for the SunPro II in the pic you posted, but what brand is yours, and where did you get it?