What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

'72 K5 - BYT - 1 ton swap

Overview Gallery Discussion
Most aftermarket tachs need some different wiring with LS engines. This is how I ran my VDO's and I believe autometers are the same
tach_circuit_fix.jpg


From Autometers site. There is an explanation at the bottom http://www.autometer.com/media/2650-1563.pdf
 
NorCalKid said:
Most aftermarket tachs need some different wiring with LS engines. This is how I ran my VDO's and I believe autometers are the same
tach_circuit_fix.jpg


From Autometers site. There is an explanation at the bottom http://www.autometer.com/media/2650-1563.pdf
Click to expand...


I forgot about using a pull-up resistor since I haven't had to use one on the swaps I've done (yet). Make sure to use 5 volts on the resistor, 12 volts will probably kill the PCM. May want to start with a 10k resistor as well.

If the pull-up resistor doesn't work then you'll need a tach adapter from Autometer.
 
I don't have any 5v reference wires run into the cab but it should be easy enough to build a voltage divider. I have plenty of room on the circuit board I built for the LED lights to add a couple of resistors for it.

I'll hook up a volt meter to the tach signal and see if anything is coming through. If I'm getting anything, I'll hold off on the fix until everything else is put together so that I can just leave it running and test various resistor setups.

On my check engine light staying on, I have a thought on what the problem is. The scanner isn't showing any codes, so the ground isn't coming from the PCM. I forgot that the light comes on whenever the key is on and the engine isn't running so I connected to the ignition switch like the brake light so that it would come on when you crank the starter. The brake light is connected to G1 on the switch and G2 was where I connected the engine light. Maybe it's staying grounded after start? I'll try disconnecting that tomorrow.
 
More progress:
6p0swap223.jpg

I got the TAC mounted to the inner fender well and the engine bay fuse box and the rest of the wiring in place. This area isn't as cluttered as it looks in the pic but it's not as clean as I'd have liked either. After I run it for awhile I may take a stab at prettying things up a bit more.

I also got the radiator support in.
6p0swap222.jpg

It might not look like a lot of time to put one in but the damn thing has 22 freakin' bolts. :eek1: If I do this again I'm getting someone to help me take the whole front clip off as one piece!

I've been going nice and slow putting the fenders and support back in place. The blazer rattled like crazy and when I took everything apart it was easy to see why. I had several bolts missing, and a few with the heads broken off or threads stripped. I took the time to remove all the broken bolts and re-tap all of the holes.

I replaced all of the capture nuts for the fender wells. The fender wells are aftermarket so not all of the bolt holes lined up and in some cases the holes were entirely missing. :doah: I redrilled the holes that were misaligned and added the ones that were missing so hopefully everything will be a lot more solid than before. :waytogo:

I also got a first hand lesson in exactly how flimsy the 1st gen cowl area is. I aligned the fenders to the doors as best I could first, then bolted the inners and radiator support to them. All of that was basically hanging off the front of the firewall/cowl with no connection to the frame yet. When I went to install the support body mounts I noticed that the support was sitting quite a bit lower than it should. I went looking around to see if there was any problem and realized the doors (which I had lined up to open/close perfectly) wouldn't close. The weight of the front clip was pulling the windshield area forward a LOT. I lifted the radiator support and was somewhat shocked at how easy it was to lift everything by hand.

Obviously once the support was bolted to the frame properly everything was lined up again and much more solid but it was still a surprise to see how flimsy everything can be.

Tomorrow, radiator, fans, battery and grill go in. At that point she's basically drivable although there are still a few things on the to-do list.
Rehang the front bumper. It wasn't done correctly before so it may take some time to fix it right to fit my body lift.

Build a bracket to mount my washer bottle where I want it.

Repair the hacked up trans cover. The tranny was moved forward so I need to fix the holes.

Build a bracket to hold the factory air box securely.

Fix the tach.

I think that's it other than taking it to the exhaust shop.
 
Nice work dude! It really is amazing how much things in these trucks can move around, even when they're rust free and all bolted together. I can't wait to get a cage in mine to stiffen the chassis and the body up. That new motor of mine is trying to kill the truck:haha:
 
Z71paramedic said:
Nice work dude! It really is amazing how much things in these trucks can move around, even when they're rust free and all bolted together. I can't wait to get a cage in mine to stiffen the chassis and the body up. That new motor of mine is trying to kill the truck:haha:
Click to expand...
Thanks man. I wasn't really planning on a cage but seeing how easily things move it may have to be in the cards some day.

More progress:
6p0swap224.jpg


She's drivable at this point. There's more to do still, but if the weathers decent I may take 'er around the block tomorrow. :D
 
ashman said:
Thanks man. I wasn't really planning on a cage but seeing how easily things move it may have to be in the cards some day.

More progress:
6p0swap224.jpg


She's drivable at this point. There's more to do still, but if the weathers decent I may take 'er around the block tomorrow. :D
Click to expand...

That's damn nice looking! Hope to check it out in person at Blazer Bash this year. :deal:
 
mrk5 said:
That's damn nice looking! Hope to check it out in person at Blazer Bash this year. :deal:
Click to expand...
Thanks man. Blazer Bash is in the plans for this year so hopefully it works out. I'll even have tow points this time. :whistle:
 
I didn't have a whole lot of time in the shop this weekend, but I did get another item checked off the list.

Since I moved my tranny, I needed to modify the tunnel cover. This is what I started with:
6p0swap225.jpg

Yup, a gaping hole and a piece of scrap aluminum screwed to it was my starting point. Evidently the shop that put the NV4500 in several years back didn't care so much what it looked like. :rolleyes:

6p0swap226.jpg

Hole cut to a more reasonable shape and paper template cut to match.

6p0swap227.jpg

Much better!

With that done I was able to button the interior back up and take her out for a spin around the block. The engine sounds and runs great! I didn't get on it much though since I haven't done the exhaust yet. Unfortunately It doesn't appear that my speedometer is working either. :( I'll have to figure that out too.

This evening I'll be putting the final touches on my washer fluid bottle bracket (pics later) and then it will be on to exhaust. For those of you that haven't seen my exhaust thread, Here is my starting point with that.
Exhaust1.jpg
 
Finished the washer bottle bracket last night.

paper template made:
6p0swap229.jpg


template laid out flat and ready to cut out in 18g sheet:
6p0swap231.jpg


bracket bent, welded and painted:
6p0swap232.jpg


bracket in place:
6p0swap233.jpg


6p0swap234.jpg


Not a sexy update, but something that needed to be done. Another item off the list.

Yesterday I was able to get a bit of work started on the exhaust as well. I went down to the shop where I bought the engine and they gave me a piece of the y-pipe from a 5.3 truck for $15. It's not usable as is but it is 2-1/2 into 2-3/4 and came with some 2-1/2 pipe with a couple of useful bends in it so all together a pretty good deal imo.

I was able to mock up some of the pipe last night as well and came to the conclusion that I will be using mandrel bent pipe. First of all, as mrk5 pointed out, mandrel bends are a lot easier to work with and second, all of the regular bend stuff I found locally is quite a bit thinner material. I think I could live with the regular bends if everything was equal but no sense doing all of this work on thin, cheap pipes.

Luckily, between what I had already and the y-pipe I got yesterday I think I can get most of the passenger side done. That will cut down on the number of new pipes I need to buy from summit by a lot.
 
Dykem and cardboard templates! :waytogo:

You have really stepped up your game and skills....


-G
 
You must log in or register to reply here.

Latest Posts

Top Bottom