'86 chevy 3/4 ton...got some questions...semi urgent - Team Camaro Tech
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post #1 of 11 (permalink) Old Mar 17th, 03, 04:42 PM Thread Starter
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Finally got a chance to work on the recently aquired 3/4 ton today. This is the one with the 305/700r4/3.23 combo (strange IMO). Anyway, the feedback q-jet was shot, the exhaust system was shot, and the valve covers leaked horribly. I gutted it down to the long block today, and removed all the smog stuff and about 5 miles of vacuum lines. I then bolted up an old weiand 8004 intake I had laying around, plus a set of headers, and will be installing my old 600 edelbrock carb. All this is temporary until I take delivery of my buddys van I bought (400sbc/th400). Anyway, now for the questions...

1) The stock 305 distributor that I thought wasn't computer controlled apparently is. It is a vac advance big cap HEI but on the backside of the housing are 4 wires that connect into a bigger harness on the passenger side firewall. The mechanical advance is frozen solid at about mid advance. If I can get the advance unstuck, will this distributor function "normally" disconnected from the computer? If not, I have another spare HEI laying around that also has its advance froze up. What is the best way to free them up and keep them from sticking again?

2) On a '86 truck, what controls the convertor lock up function? Will I need to get an aftermarket lockup kit, or is there another way?

3) How do I adjust the TV cable for the 700r4? I've got an edelbrock bracket for hooking up the TV cable, but there is about a mile of adjustment in this bracket.

4) Will a recently rebuilt (stock spec) 700r4 live behind a mild 400sbc? Mild as in stock longblock, with headers, intake, and a mild cam?

5) What rearend is in this truck? It is a 14 bolt, but I have found there are 2 versions...a 9.5" and a 10.5". I assume it is the smaller one but how do I tell for sure? What is a decent posi unit for these rear ends that doesn't cost a fortune?

I expect to have this thing up and running tomorrow (minus an exhaust system) so any help would be appreciated.

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post #2 of 11 (permalink) Old Mar 17th, 03, 06:49 PM
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Virgil
 
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Man, did Chevy change from 84. I know they put a 305 in 81-82 3/4T, but I thought they dropped it in 83. Also, I've never seen a 3/4T rear end numerically lower than a 3.42 (I've only messed with 87 and earlier)
On to the questions,(the ones I CAN answer) to see if I can help.
1) On the old ESC distributers, you can unplug the 4 wire plug, and jump 2 of the wires and it will run. But I don't remember which ones.
5)To id the rear, does it have full floating axles? Or C-clip? Full floater will have a hub sticking out with 8 bolts to hold the axle in. The floater is the 10.5

Hope this helps,
Virgil
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post #3 of 11 (permalink) Old Mar 18th, 03, 01:37 PM Thread Starter
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I appreciate the reply. But, I still need to know about the tc lockup and TV cable setup. Anybody else?

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post #4 of 11 (permalink) Old Mar 18th, 03, 05:12 PM
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I have a 86 1/2 ton with a 4.3L carbed. If my memory if right, I think you have to jump the A & C terminals on the distrib side to get it to run without the ESC(electronic spark control) hooked up. You will have to adjust the timing a little to get it to run well.

i took some shots of my 86 chevy service manual for the TV cable problem: click here

check this for the tv cable http://www.hotrodders.com/cgibin/ubb/16/000345


JIM
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post #5 of 11 (permalink) Old Mar 18th, 03, 09:53 PM Thread Starter
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Thanks a bunch Jim. Sounds like a total PITA to me Hopefully it will quit raining long enough tomorrow for me to take a shot at it. Of course, the 600 edelbrock didn't come with the correct linkage piece for the TV cable hookup, and their catalog doesn't show one either. Guess I get to do some more hunting.

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post #6 of 11 (permalink) Old Mar 19th, 03, 05:20 AM
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If you're not sure which pins to jump for the distributor, just replace the 5-pin module to a 4-pin like I did for my '86 C10. Plugs right in.

I'd be a bit worried about the 700R4 with a 400. That's gonna make a lot of torque. I guess if you go easy on it, it should live.

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post #7 of 11 (permalink) Old Mar 21st, 03, 05:53 AM
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Mike
 
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travis,

In 86, the unlocking of the converter should be computer controlled. However, there are kits out there that let you use the brake pedal switch to unlock the converter once you step on the brake. The computer also has some control over when it locks up, but if you want to grenade the computer, go ahead and just look into getting the lockup kit which includes the wiring.

For more info and for the kit check here: www.700r4.com

Also, painless makes a kit as well

Good luck! [img]graemlins/hurray.gif[/img]

Mike

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post #8 of 11 (permalink) Old Mar 21st, 03, 06:51 AM
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I can't get my converter to lock up. I don't know what the deal is. I'm not sure how to test the solenoid-thingy in the trans...maybe it doesn't have a lockup converter?

Matt Jones
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Art Morrison Ent. Inc.
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post #9 of 11 (permalink) Old Mar 21st, 03, 07:58 PM
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David Pozzi
 
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That four pin distributor uses the computer to control advance, it has no mechanical advance. Some did have a vac adavance though.
You'll probably have to use the other one. Soak it in solvent for a while and remove the shaft from the distributor to free it up.
The shaft can get varnish on it on the lower part of the shaft which can make removal from the distributor body very difficult.
David

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post #10 of 11 (permalink) Old Mar 22nd, 03, 09:45 PM Thread Starter
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The distributor in this engine is just like an older HEI...mechanical and vac advance, but it has a 4 wire harness coming out the back side and plugs into another harness that goes into the firewall. Irrelevant at this point anyway...I tried to dissasemble it and mangled it in the process. All the advance mechanism was so rusted up it practically crumbled under a little pressure with a screwdriver. I picked up an Accel replacement HEI for $125. Everything is on now except for a few minor odds and ends. I have to figure something out on the tc lockup though, and I need another bracket for the throttle cable.

On the tc lockup, I found several kits thru different manufacturors. Prices range from about $70 to $170. If I understand correctly, the torque convertor locks up automatically...the problem is getting it to unlock (thus the aftermarket brake switch doohickeys)??? I dunno. I do know this thing ought to run WAY better than before. I kinda wish I would have put a cam in it now.

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post #11 of 11 (permalink) Old Mar 23rd, 03, 09:36 PM Thread Starter
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It's alive once again! Other than getting an exhaust system installed and the tc lockup taken care of, it is done. Finished bolting everything up today, dribbled a litte gas in the carb, and it fired as soon as I bumped the starter. That had to be the quickest fire up I have ever had And the throttle response is so unbelievably much better than before. Pretty sad though, that the stock cam in base 305's is so small that even with open headers it isn't very loud

I have another question but will open a new topic

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