I have a 84 KC 4x4 that my grandfather handed down to me. The truck has been sitting for 6 years and i'm just now getting to it. I found a 86 720 2wd that i'm robbing the motor out of and I have a couple of questions.
1. Are the transmissions the same between a 2wd and 4wd?
2. What is the biggest tires that I can fit under it at stock ride height?
3. I noticed that there is a drainbolt in the bottom of the gas tank and I took it out the other day and nothing came out. Is this a good thing or a bad thing? Would it be ok to go ahead and put fuel in the tank try and drive it or do I need to go ahead and drop the tank (something that I really don't want to do). As far as I can tell there is no gummy stuff on the bottom of the tank.
What are your suggetions?
Thanks for any help that anyone can provide.
84 KC 720 4X4 BUILD
Re: 84 KC 720 4X4 BUILD
Transmissions are the same, biggest tires you can fit with stock ride hight would be about a 235 75 R15 and anything bigger will rub the back of the fender when steering the wheel or if it bottoms out. You can gain maybe another inch up front by cranking up the torsion bars.
For the fuel tank, you really should drop the tank and clean it out really good if it's been sitting for any length of time or you'll run into very short lived fuel filters or even ruining the fuel pump if you don't run a filter between the tank and pump. what happens is rust and debris will fall off the sides of the inside of the tank and mix in with your fuel which will get trapped by the filter, then after driving it for about a week or so you'll notice the truck has no power at the top of 2nd or 3rd gear, this is because the filter is clogged and the pump can't fill the fuel bowl in the carb as fast as the engine is needing it and runnng the bowl empty, which if this early warning sign is ignored will eventually leave you stranded somewhere.
When I got mine last year, it was sitting for several years before I bought it and I cleaned out the carb, blew out all the lines to and from the tank, added in a new pump and put a filter before the pump and another one before the carb, I could go about 100 or so miles before it started bogging down on me, but with no time to drop the tank I was forced to just swap out the filter before the pump about once a week or so until I did have time to drop it and clean it out properly, but before I could drop the tank, it clogged about 5 or 6 filters and toasted a fuel pump.... all before I was able to put 1000 miles on the truck.
For the fuel tank, you really should drop the tank and clean it out really good if it's been sitting for any length of time or you'll run into very short lived fuel filters or even ruining the fuel pump if you don't run a filter between the tank and pump. what happens is rust and debris will fall off the sides of the inside of the tank and mix in with your fuel which will get trapped by the filter, then after driving it for about a week or so you'll notice the truck has no power at the top of 2nd or 3rd gear, this is because the filter is clogged and the pump can't fill the fuel bowl in the carb as fast as the engine is needing it and runnng the bowl empty, which if this early warning sign is ignored will eventually leave you stranded somewhere.
When I got mine last year, it was sitting for several years before I bought it and I cleaned out the carb, blew out all the lines to and from the tank, added in a new pump and put a filter before the pump and another one before the carb, I could go about 100 or so miles before it started bogging down on me, but with no time to drop the tank I was forced to just swap out the filter before the pump about once a week or so until I did have time to drop it and clean it out properly, but before I could drop the tank, it clogged about 5 or 6 filters and toasted a fuel pump.... all before I was able to put 1000 miles on the truck.
Re: 84 KC 720 4X4 BUILD
Thanks for the info. What did you use to clean the tank out with?
Re: 84 KC 720 4X4 BUILD
The best stuff I've found for cleaning out the inside of a tank is the KBS Aqua Klean and follow up with the KBS Rust Blast... I've done a few motorcycle tanks with this stuff and the Aqua Klean will get out all kinds of junk that you didn't think was in there... then the rust blast is a phosphoric acid solution that'll eat away the rust inside the tank.
They also make some tank sealer that can be put in after those 2 steps are done, but just cleaning it and getting rid of any rust that's inside it should be all you need to do as long as you drive the truck regularly and don't plan on letting it sit for long periods of time, also with all the gasoline today containing ethanol, most tank liner products won't last very long and can cause even more problems if the liner flakes off and gets into your fuel system. If you do want to line your tank, there's only 2 products out there that I know of that are ethanol compatable. Here's the KBS website for the Aqua Klean and Rust Blast... http://www.kbs-coatings.com/prep-products.html
You can use the Home Depot method with excellent results too... just get some industrial strength degreaser and just water if you just want to clean it up, but if you got any evidance of rust in there, muriatic acid will eat away the rust and leave the rest of the metal intact, Home Depot also sells this in the pool care section, it won't rust again after the cleanup as long as you don't let it sit for long periods as the gas sloshing around in the tank will help prevent it. You can still line a tank after doing this method of surface prep, but like I said, I don't recommend lining tanks anymore unless you can use the alcohol proof brands like the Bill Hirsch tank sealer.... Here's his web site... Lots of good auto restoration paints and coatings here as well... http://www.hirschauto.com/ . Like I said, you don't have to seal the tank with tank liner unless you got a pinhole or 2 (in that case, replacing the tank is really the better option anyway), but a good cleanup and acid etch will make the inside of the tank like new again. The acid etch is also optional, if there's no signs of rust inside the tank, you can skip this step, but if there is rust in there it does have to be removed and your fuel filters will thank you for it.
They also make some tank sealer that can be put in after those 2 steps are done, but just cleaning it and getting rid of any rust that's inside it should be all you need to do as long as you drive the truck regularly and don't plan on letting it sit for long periods of time, also with all the gasoline today containing ethanol, most tank liner products won't last very long and can cause even more problems if the liner flakes off and gets into your fuel system. If you do want to line your tank, there's only 2 products out there that I know of that are ethanol compatable. Here's the KBS website for the Aqua Klean and Rust Blast... http://www.kbs-coatings.com/prep-products.html
You can use the Home Depot method with excellent results too... just get some industrial strength degreaser and just water if you just want to clean it up, but if you got any evidance of rust in there, muriatic acid will eat away the rust and leave the rest of the metal intact, Home Depot also sells this in the pool care section, it won't rust again after the cleanup as long as you don't let it sit for long periods as the gas sloshing around in the tank will help prevent it. You can still line a tank after doing this method of surface prep, but like I said, I don't recommend lining tanks anymore unless you can use the alcohol proof brands like the Bill Hirsch tank sealer.... Here's his web site... Lots of good auto restoration paints and coatings here as well... http://www.hirschauto.com/ . Like I said, you don't have to seal the tank with tank liner unless you got a pinhole or 2 (in that case, replacing the tank is really the better option anyway), but a good cleanup and acid etch will make the inside of the tank like new again. The acid etch is also optional, if there's no signs of rust inside the tank, you can skip this step, but if there is rust in there it does have to be removed and your fuel filters will thank you for it.
Re: 84 KC 720 4X4 BUILD
I'm also going to replace the front timing cover seal and gaskets. Do you have to take the head off to do that?
Re: 84 KC 720 4X4 BUILD
The timing cover will come off without removing the head but it may be tough getting it to slide out the first time you take it off. I've had to change these gaskets before on my 280zx and the job wasn't that hard to do, you will need to remove the dizzy and the oil pump if I remember right but still pretty easy to do and I used Permatex Ultra gray to seal everything back up when I reassembled everything to prevent leaks at the timing cover/head and timing cover/oil pan areas.