1981 Camaro Z28

[MP81]

Had to change a small amount to my previous routing of the lower cable, and figure out what the best way was to route the upper cable down, but it is connected now. I also popped under the engine to address the plug wire situation and it turns out the three-wire separator mounted to the block was there, just covered in shit, so I didn't see it before. Was able to pop a couple wires there, and playing with them, I think even if the one on the oil filter rotates, the point it may naturally gravitate too will still be off the exhaust.

So the car is back down on the ground - just need to reinstall that trim plate at the front of the carpet inside to cover the hole/firewall up (I was far too disgustingly filthy to be inside the car, which is clean - and was being eaten to death by mosquitoes, because it was nearly dark again when I started...). Planning to do that tomorrow, hopefully when it is light out, then I just need to reconnect the battery, and it'll be time for a test drive.

I still need to coat the bottom of the ICM with di-electric, but I think that can wait until after dyno day.

[MP81]

Car is back together, finally got to take it out on the road for a test drive annnnnnnnd...speedo doesn't work.

Sooo...other than that little tid bit...the car ran and drove pretty well. The on-center dead spot in steering is terrifyingly enormous, and the synchros aren't the best, but it was fun.

Car was too hot to go attempt to see what the issue is, and I don't really care after all the work right now. It's going to dyno day tomorrow, then I can try and troubleshoot it.

The speedo itself spun by hand when it was apart, as did the speedo cables...so I'm not quite sure what is the issue.

[MP81]

Got up early to look into the speedo issue. Disconnected the upper and lower cable from each other, and by spinning the end of the upper cable, the needle on the speedometer would move. So the upper cable is good. Thank God.

I was also able to spin the female end of the lower cable, which I should not have been able to. With the rear on stands, running in gear, it did not spin. I reconnected it and took it to dyno day first (I wanted to run the car, speedo or not), so that it could cool down at home while I ran the Cobalt after. When I got home, I pulled the trans-end of the lower cable off and found it to be in the same condition as the old cable I removed - the end was sheared off and in the converter box, and the "end" was partially unraveled. When I spun the end of the cable, the speedometer needle moved.

So, somehow, the converter box is snapping the end of the cable off and then unraveling the cable...which I find confusing. If the box didn't work (I was able to turn it by hand when I had it out of the car), it simply wouldn't turn the cable. But it does work...but then breaks the cable? Any thoughts?

On another note, dyno day!




Run #1
https://www.facebook.com/kyle.paulse...13149467645436

Run #2
https://www.facebook.com/kyle.paulse...57653494871409

So, I had predicted somewhere between 80 and 100 wheel horsepower, given it's a 35 year old, 120k mile Cali-emission, AC 305 that hasn't been driven regularly in 20 years or so.

So it was much to my surprise when Phil called me over after the first run:

146.3 HP and 238.69 lb-ft of torque. The second run was similar at 147.54 HP and 231.69 lb-ft.

The car was only rated at 165 HP and 245 lb-ft of torque - and even at a 15% drivetrain loss (and I'd expect it to be higher than that) - this old girl is putting out more power than originally rated for, 35 years ago.

Sounded great, too!

Driving the car to and from dyno day was a blast - it's certainly not fast, but man is it fun to drive - especially when the air intake flap opens.



So, with that - I have a few things I'll need to take care of. Obviously I need to figure out this issue with the speedo and why it ate up my new lower cable. Also, the rag joint (my guess) is in need of replacement with how giant of a dead zone on center I have. It also scrapes something (thinking the wheel liners) up front when making certain turns, despite having factory-sized tires.

[1BADAIR]

there is a preload adjustment you can do on the steering box. If you go to far it wont come back over center tho

[MP81]

Is that easy to get to?

[1BADAIR]

Should be right on top of the steering gear. A big nut with a screw in the middle . Loosen the nut(lock) and adjust the center then tight the nut back up to lock it

[MP81]

All right, cool.

So do you think that is the cause, or the rag joint - or both? It's a pretty sizeable "slop" zone.

[MP81]

On another note - assuming the culprit of the speedo issue is the converter box, where would I find the proper replacement. I have the full part number, so that helps to at least know what I need.

[JoeliusZ28]

[MENTION=709]bri2203[/MENTION] might be able to help you source that part?

[MP81]

Yes.

For reference, it is a Stewart Warner correction box: 666F Z12 8241C

[bri2203]

Why does it have a correction box?

Bobs Speedometer can make you another one if you need it.

[MP81]

Why does it have a correction box?

Bobs Speedometer can make you another one if you need it.

Had one from the factory, according to my uncle.

[MP81]

Here's what I found: http://www.gmpartswiki.com/getpage?pageid=14337

Since it's a 3.42 4-speed car, with a 225/70R15 tire, from the factory it comes with the box I have, Part number 3950352, 0.8242 ratio, C-stamping.

Looks like now that I have the part number (and from a quick google, the superceding part number of 15635472), I may be able to search it that way.

[MP81]

Bought one with the superceded part number last night, and a new lower cable this morning. Hopefully this does it.

[MP81]

Got the new box today.

New Delco vs original SW corrector box. Looks like they were able to make it quite a bit smaller - and lighter. The old box didn't seem to have any issues rotating.




Installed the new corrector box and a new lower cable. I routed it what is most likely the intended way to route the able (used the clip bolted to the bottom of the bellhousing that the cable clipped into perfect. Allows it to tuck above the frame rail and attach to the box at a much better angle - without having to tie it up with mechanics wire.



Popped the rear up on stands, fired it up, popped it into gear and got a reading on the speedo! Dropped it back down and took it for a few laps - speedo works now. It bounced a bit at first, but seemed to settle down shortly thereafter.

So I don't know if the box truly was bad (seemed to turn pretty smooth), or if it was just having routed the cable wrong caused it to bind for a second, and the correction box snapped the end off and unwound it.

Either way - it works now - probably for the first time in, I'd guess, 20 years at least?