80 720 Lowering ?

[izzo]

This is actually two questions. First, when I am cruising down the road at 40mph, I am really doing 50. Goes for all speeds, speedo reads 10 lower than actual speed, is that tire size? And can i get it fixed with a new speedo cable?

 

 

As for the lowering, its at stock height now. I would like to get it lowered at least 3-4 inches. Give it that look, id like the front to be an inch or two lower in the front. So i suppose 4 in front and 2 in back. It has stock suspention on it now. Anyone know of a kit I can get, or parts for other vehicles i can get to put on there? (Like 510 springs etc...)

 

:confused:

[jesusno2]

Turn the torsion bars down and go to the auto parts store and pic up a 3 inch lowereing block kits install it and your done. Total cost without frt end alignment about 40.00 bucks

[SickDrift]

This is actually two questions. First, when I am cruising down the road at 40mph, I am really doing 50. Goes for all speeds, speedo reads 10 lower than actual speed, is that tire size? And can i get it fixed with a new speedo cable?

 

How did you verify how much exactly your speedo is off? If your tires are the cause then your speedo wont always be off by ten mph, rather, the faster you go, the more it will be off; so 5mph off at 30mph, and 10mph at 60mph. If it's just off 10mph off all the time, it could just be the speedo itself?

[izzo]

I had my girl driving behind me on the way home from picking it up. I was doing 60 on 167 south, and blowing by people. She called me up and said i was speeding LoL....

 

 

So i tested various speeds, all were 10mph off. Also, not sure how to adjust the torsion bars. I will get some pics of what I have under there soon and post them.

[SickDrift]

I had my girl driving behind me on the way home from picking it up. I was doing 60 on 167 south, and blowing by people. She called me up and said i was speeding LoL....

 

So i tested various speeds, all were 10mph off.

 

So, if your speedo is indicating 5mph, you're actually driving 15mph? Yeah, your tires wouldnt cause a change 10mph across the board like that. Curiously though, what size tire do you have on?

 

Do you see it physically jump when first moving from a standstill? As it is mechanical, if it is always 10mph off, at all speeds, I would say the problem is at the speedo. If it were a gearing issue (tires, differential, speedo cable) the issue wouldnt be uniformly wrong, but rather graduating.

[izzo]

I will check that and let you know the outcome. Never looked at it from a stand still,just after I was going down the road a bit. I am surprised I have'nt backed it into anything yet since reverse is where first is :D

[SickDrift]

I will check that and let you know the outcome. Never looked at it from a stand still,just after I was going down the road a bit. I am surprised I have'nt backed it into anything yet since reverse is where first is :D

 

I know what you mean. My Subaru is a 6speed and it was wierd getting used to 6th being where reverse usually is.

[]2eDeYe]

Also, not sure how to adjust the torsion bars. I will get some pics of what I have under there soon and post them.

 

There lot's of pic's and instructions for torsion bar lowering in the FAQ in General Discussion (or you can click the link in my sig) ;)

[izzo]

I see the torsion bar guide, and pics. I dont really get how it works, for some reason i thought it would be different. I will get under there this weekend and poke around a bit. I dont remember seeing something like that when i was under there.. Then again i didnt look to well. Thanks for the help and the link to the faq, I will use it as the datsun bible lol

 

 

Also, that guide looks like it was for re-indexing instead of just adjusting, is that the same thing?

 

And once I get to that point, is it one click clockwise or counter clockwise?

[]2eDeYe]

Same thing, mostly. You only need to re-index if your lever arm ends up below the frame rail.

 

Tighten the bolt to raise the truck. Loosen it to lower. (I could have this backwards)

 

It's really simple once you figure out how it works. Just jack it up and turn the adjusters, set it on the ground and see where she sits, adjust for desired ride height.

[izzo]

Sounds good, ill try and make it to the bbq on the 13th and just have someone point it out so i can be sure. Then if i goof it up at home ill post some pics of what i did and maybe someone can tell the noob what to do :D

[jesusno2]

What's funny is that reverse is where 1st normally is I'm guessing that is a dogleg datsun trans please correct me if I'm wrong here? If ya do a search for my screen name you can see some pics of my 720.

[turbojunker]

That truck didn't come with a dogleg 5 speed. I'd imagine that's the reason your speedo is always off, the drive gear is wrong for the speedo.

[datzenmike]

But again, it would be out a percentage not a constant 10MPH.

 

Some of the 720s had a short tail tranny in them, the dogleg is typically a short as well, so easy to swap. I've tried to figure out which models had the 'shortie' but could find no common reason for this.

 

h2theizzo can you post a good picture of your tranny.??

[SickDrift]

That truck didn't come with a dogleg 5 speed.

 

I kinda thought that was the case, but didnt want to say anything and sound more dumb than usual if I had been wrong.

[jesusno2]

Of coarse it did'nt come with a dogleg, but being a 80 model it was a l motor truck it's possible somebody swapped trannys at some point in time. That's my guess why the speedo is goofy or tire size is wrong or someone has swapped rear diffs who knows?? the truck is 28 years old, prolly passed through many hands.

[slodat]

I've heard of a shot tail dogleg 5 speed on the Z motors in 720's. I think the guy said it was an '83 4x4.

[datzenmike]

I've heard of a shot tail dogleg 5 speed on the Z motors in 720's. I think the guy said it was an '83 4x4.

 

Me too! He got a rebuilt tranny put in and found the gears all moved around. I asked a lot of questions and concluded it was indeed a dogleg. I did some research and think it might have been from an '80-'81 HLa510 with the NAPS Z20S motor.

[izzo]

For sure, my camera needs to go in the shop (lense stuck) But i have a crappy HP photosmart camera i can craw under there and snap a few off.

[izzo]

this is about the best i could do for now. probably doesn't help much

 

And i know there is rust, The guy who owned it before me welded in a new floor plate so its safe :D

 

[izzo]

ill try again this weekend to get up in there and take some better pictures. i will need to get some ramps or something

[datsunaholic]

That does look like a dogleg (smooth bell, no spacer between the gearbox and extension housing) but there was a fairly rare longtail dogleg (was used in the 810). Still would throw the speedo off by a certain percentage. The fact that the trans has junkyard markings (yellow writing) on it shows that it was replaced at some point. The truck probably had a 4-speed originally.

[SickDrift]

The fact that the trans has junkyard markings (yellow writing) on it shows that it was replaced at some point.

 

Good call.

[izzo]

Yeah soon as i saw that picturei knew it was a junkyard trans lol..

 

and it probably was a 4 speed, does the ID plates anywhere say? Or would i have to decode the vin

[datsunaholic]

I'm not sure the dataplate will have the trans type on it- they did in 1981, but in 1980 at least early on they were using the older plate that didn't list the trans. But there is a possibility. If it is anywhere, it's on the dataplate on the passenger side inner fenderwell.

 

Decoding the VIN won't really help, as the trans type wasn't part of the code.