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1989 Crew Cab Tow Rig Build

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82355 said:
Doesn't the ECM want to see a VSS anyway? I know on my 1987 V10 it gets the VSS from the speedometer.

I forgot about your crew cab having a fixed yoke.

Martin
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Nope, when doing a full stand alone harness on an LS, the motor doesn't need any VSS input. If I was running an electronically controlled tranny, then yes the computer for the tranny would need a VSS signal, but not the motor with a manual behind it

TBI needs a VSS to help the ECM control other sensors, but not LS
 
Id always just assumed having it on an LS engine would be similar to TBI where it would go into "cruise mode." Learn something new everyday!
 
RootBreaker said:
OOOOH CAN WE HEAR HER ROAR!!!!!????
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Hopefully soon. The last real things I need to purchase is wiring harness and air intake setup. Everything else I have already purchased to make it start, just gotta find some time to get it all in. And you better believe I'm going to start it up with open headers...cause I want to, haha.

I have all the cooling system stuff, fuel lines just showed up in the mail today, and headers are waiting to bolt on. All of that will be at least two weekends to get in. Then wiring and air intake and it should go "Vroom"

I'll try to get a video of it running once that happens (that will be a glorious day for sure) :saweet:flagwaver
 
Kay86K5 said:
Hopefully soon. The last real things I need to purchase is wiring harness and air intake setup. Everything else I have already purchased to make it start, just gotta find some time to get it all in. And you better believe I'm going to start it up with open headers...cause I want to, haha.

I have all the cooling system stuff, fuel lines just showed up in the mail today, and headers are waiting to bolt on. All of that will be at least two weekends to get in. Then wiring and air intake and it should go "Vroom"

I'll try to get a video of it running once that happens (that will be a glorious day for sure) :saweet:flagwaver
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sweet... so question.. why 8.1L? I am contemplating the 6.0L swap but now looking 8.1's are not too bad priced...
 
RootBreaker said:
sweet... so question.. why 8.1L? I am contemplating the 6.0L swap but now looking 8.1's are not too bad priced...
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I plan on towing with mine quite a bit and the 8.1 is a torque machine especially at low rpm's. Also, the 8.1 is actually a little easier to swap into a square than a 5.3 or 6.0. I showed earlier that the 8.1 has mounting holes for stock square body big block or small black motor mounts. So no need for conversion mounts. My brother has a 6.0 Burban that he completely went through the motor with redone heads, new cam and pistons and all sorts of stuff an he finally feels like now it tows pretty well. A bone stock 8.1 with just a tune will still outdo his 6.0. So since I have towing in mind, that's why I went with the 8.1.
And honestly his 6.0 isn't going to get that much better mileage than mine. This 8.1 will probably get 11 or so empty and 10 mpg's towing. My brothers Burban gets 13-14 empty and about 9 towing. So not breaking the bank at all here
 
wow cool stuff... so if you buy the stuff from a donor truck what is really required to do the swap? is there an article showing what wires, etc? i have no clue on this part... will do my research eventually... actually wait for you to post up how to do it.. LOL
 
I haven't paid much attention to them but isn't the 8.1 block set up similar to the oldschool big blocks? I've only seen them while I was upside down in a boat trying to put the drain plugs back in so I don't know the design?
 
RootBreaker said:
wow cool stuff... so if you buy the stuff from a donor truck what is really required to do the swap? is there an article showing what wires, etc? i have no clue on this part... will do my research eventually... actually wait for you to post up how to do it.. LOL
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When I started doing research on the 8.1, most of the best info I got was from here:
https://ck5.com/forums/threads/l18-8-1l-swap-resource-thread.308019/


F.S.F.W said:
I haven't paid much attention to them but isn't the 8.1 block set up similar to the oldschool big blocks? I've only seen them while I was upside down in a boat trying to put the drain plugs back in so I don't know the design?
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Essentially, yes. As far as the block and everything is concerned, it's pretty much the same as any older big block. Pretty much they took the vortec 454, stroked it to 496 (hence the increase from 7.4l to 8.1l), and then put an LS type injection on it. There are a couple other differences here and there, but that is the gist of it. I purchased headers off a mid 80's style big block and they fit right on the 8.1. Pretty cool really
 
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That's awesome. I kind of figured that but I never looked into it. Do you know if you can use a early bbc intake?
 
F.S.F.W said:
That's awesome. I kind of figured that but I never looked into it. Do you know if you can use a early bbc intake?
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I don't think so, the heads don't swap over since the head bolt layout is different. From what I understand it's just the exhaust port layout that is common hence the reason why the exhaust manifolds can be shared.
 
skunked said:
I don't think so, the heads don't swap over since the head bolt layout is different. From what I understand it's just the exhaust port layout that is common hence the reason why the exhaust manifolds can be shared.
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This is correct. The intake side of the heads and the bolt patterns are completely different (meaning it's more the LS style). It's really just the block side that shares resemblance and like skunked just said, the exhaust ports are the same as the previous years big blocks
 
Got some work done on the truck this last weekend.

Got my headers installed. Went with mid-length Headman Headers. They seem to work pretty well and fit pretty good. I just went with a mid-80's BBC header (as they fit on the 8.1 just fine) and will add some O2 sensors to the little extension to weld the exhaust tubing to (was included with the headers) that comes off the header when I get those. I also installed my coil packs and new plug wires





I then started on the fuel system. This is how I moved the bed back to get access to the pumps



I now realized why the passenger tank wasn't working :eek:. The pump was completely burnt up and the intermediate hose was completely gone



So, I decided I would get a brand new sending unit for the driver tank (as this is going to be my main tank that feeds the motor) and also installed my new EP381 fuel pump. These pumps are for the 1997 Tahoes with the vortecs. They put out the necessary ~60 psi but have the same dimensions and fit inside the hanger of the TBI sending units



New sending unit/pump installed into driver tank (yes I put a new screen on the pump before installing...the pic above doesn't show that)



Since the crap pump/sending unit pictured above wasn't really up to par, I decided to take the good used sending unit I pulled out of the driver tank, and I know that pump was working cause that's the tank I was driving on before pulling the motor, and I threw that whole pump/sending unit into the passenger tank



And yes the ports are facing the opposite way on purpose cause that was the only way to get it installed (these sending units are side specific on the dual tanks). But I really don't care cause I'm using this passenger tank as a storage tank. I'm going to run a line from the passenger tank feed line to the driver tank, and then hook up a little toggle switch inside the cab that will turn on the fuel pump and transfer fuel from the passenger to the driver. This way I can keep duel tanks and have more fuel capacity if need be. Haven't run the line to the driver tank yet, but when I do I'll take pics of it

I started working on the new fuel lines up to the motor, but realized I got the wrong fittings for the tank and also the 8.1 fuel rail. I have already figure out what I need and ordered the parts (luckily the fittings are cheap) and should have those before the weekend is out. I'll take some pics of those when I get them done
 
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are you concerned with the plug wires burning up being that close to the headers?

I like the fuel "storage" idea.
 
skunked said:
are you concerned with the plug wires burning up being that close to the headers?

I like the fuel "storage" idea.
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Yes, I'm actually thinking the plug wires will burn up the way they are right now, but it will do for now. I've seen a couple places who make the plug wires specific for running headers, so I'll probably get some later on down the road. But at least I'll be able to start it up with those when I get to that point :D
 
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Kay86K5 said:
But I really don't care cause I'm using this passenger tank as a storage tank. I'm going to run a line from the passenger tank feed line to the driver tank, and then hook up a little toggle switch inside the cab that will turn on the fuel pump and transfer fuel from the passenger to the driver. This way I can keep duel tanks and have more fuel capacity if need be. Haven't run the line to the driver tank yet, but when I do I'll take pics of it

I started working on the new fuel lines up to the motor, but realized I got the wrong fittings for the tank and also the 8.1 fuel rail. I have already figure out what I need and ordered the parts (luckily the fittings are cheap) and should have those before the weekend is out. I'll take some pics of those when I get them done
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That's an easy way to avoid messing with the duel tank switch and all that mess. Maybe that's what @bent72 needs to do.
 
mrk5 said:
That's an easy way to avoid messing with the duel tank switch and all that mess. Maybe that's what @bent72 needs to do.
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Yeah, it should be pretty simple. I'm going to run the line to the driver tank overflow port (right next to the filler tube). I will take some pictures of the hoses when I get them hooked up, hopefully this weekend The only thing that you will have to remember is to turn the switch off to the pump since it will be manual, that way you don't run the pump dry.

According to my research, this was the easiest thing to do with my 8.1 liter. I guess the computer does have the capability to run dual tanks, but then I would run into the issues of finding an actuator that would accommodate the feed and return line sizes needed, and most likely double the cost of fuel lines to get it hooked up. That's when I decided this would just be a whole lot easier to do then messing with all that stuff. Plus, for me, I will only really use that every once in a while. For instance, going to Blazer Bash it would be nice to fill both tanks up and not have to fill up again until I get to Moab. For normal towing to the trail on Saturday, or just weekend fun stuff, I would just fill up the driver tank and go.
 
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