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1984 Chevy Silverado - 4BT Swap

92K views 720 replies 23 participants last post by  T_Swindler 
#1 · (Edited)
I am finally taking the plunge into the 4BT swap. I have learned quickly that the venture is not for the faint of heart. I am looking to get out under 7K. I purchased by 4BT in 2011 and 4L80E the same year. Then it sat in my garage as a dream that would not die. Ahead to 2019. My transmission is at Monster Transmission in Florida. My engine is a Harbor Engine and Grinding in Corpus Christi. Member Rube Bonet is manufacturing a new and stronger wave ring for the build. DieselTuff will be receiving both my injectors and injection pump. In short, I want a good drive train to start the build off right. Anyway, I wanted to introduce the build. Lastly, to thank all the advice along the way. 🍺 I mean this especially to char1355, who has inspired my build with his knowledge answering the various questions on this forum. (Certainly, others are have been great contributors as well.)

T. Swindler

I added pics of my truck which normally sits with my neighbors truck. Mine is the blue/gray 1984 Chevy Silverado 1/2T 4WD. His is a Red/Silver 1984 Chevy C20 3/4T. Both run the 6.2 diesel engine.
 

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#623 ·
I decided to update the thread:

CONDENSER: Still looking and doing more research. I cannot find the condenser (Period!). Every parts store wants to sell the 16x 26 or 27 inch version while mine is closer to 31 inches. I will have to use the existing one (or so it seems at this point).

RADIATOR: I purchased a smaller radiator (for the same truck with a 350 gas engine). It is three row aluminum and should fit. Sorry for the project delay, but I have been plain stumped over this. Is a smaller radiator to be, or not to be... that was the question.

Saying all that, I have no timeline on the truck (other than my better half continually asking me when the project will be done). I do believe she wants her backyard back. The other factor is the south Texas heat. I cant stay too long out there on any given day. The word "BRUTAL" sums that up. I am jealous of those of you who work out of a big garage. In the end, I hope to have a daily driver.
 
#624 ·
Tom,

If you use the existing condenser, it will need to be flushed to clean out the lubricant oil. The oil used for F12 is not compatible with R134A.

The smaller radiator should work OK. My 4bt runs cool with the replacement radiator specified for a 300 CID Ford gas engine (I did buy the slightly thicker AC version).

Note on both of the above: The condenser has dual electric cooling fans, helps a lot.

Russ

EDIT: p.s. Single pass R12 condensers are not as efficient as the same size triple pass R134A condensers. Using the bigger R12A condenser "probably" compensates... All my AC installations used new condensers (never had a good original condenser).
 
#625 ·
The system was converted to R134A from R-12 years ago. I would like to find a condenser that would work, but so far nada. Here is my last thought... This is a universal condenser for the chevy 81-87. I do not need the drier though. I like the fact that you can choose which side of the vehicle the compressor is on when choosing the condenser. It routes the compressor discharge to the proper side without having to run a length of tube/hose to reach it.

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#626 ·
Russ,

Before I disassembled my truck the AC system was working until I broke a line on my compressor. (the compressor mount broke and the solid aluminum part of the hose broke due to vibration). Not sure if this makes a difference, but I suspect the condenser is usable. It needs to be cleaned up and some of the fins straightened.

Tim
 
#628 ·
Tim,

If the condenser worked before, it should work now. Just give the coils a flush.

Russ
 
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#630 · (Edited)
Time to update the thread after the hot summer months are waning. I have worked on fitting a smaller radiator, not just because it was recommended, but to allow me to fit my intercooler piping. I ran into a few snags on the way.

First, the radiator (from Amazon) stated it was for the 6.2 Chevy but was way too short.
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You can see the radiator doesn't reach the supports.

So, I worked on this issue:


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#631 · (Edited)
I was able to use the stock lower radiator support hose. It looks great. Even though the radiator is shorter, it fits because the length was knocked off of the driver's side. With the shorter radiator, the intercooler piping will fit as intended.

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The upper hose looked great too.

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I moved my heater return hose to the drain on the driver's side so I could use the stock drain location for the low coolant level sensor. I still need to hook up the transmission cooler lines though.

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After the radiator was in, it felt fairly solid, however, was not satisfied. I decided to shim up the lower supports and that is in progress. I also decided to start the intercooler mounting. That is in progress too.
 
#633 ·
Started the day with a 2-mile walk on Shoreline Drive in Corpus Christi. Caught the sunrise in front of the American Bank Center.

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The hump hose came in. Note: I chose a hump hose as it allows for up to a 20-degree bend if case the ends are not in line with one another. This completes the inner cooler piping. On to the cold air intake.

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I put the passenger inner fender on temporarily to figure out the air intake to the HX30. I just need to see how I will make it fit.

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#634 · (Edited)
Worked on the Cold Air Intake some more, but I still need a support bracket or two.
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To fit everything up I installed the inner fender, the coolant overfill, the AC line to the Evap, and the battery support to ensure the location I chose would not interfere with anything else.

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I also put some time into the transmission oil cooler lines

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but was curious about the transmission cooling lines and (on the transmission) which port was an outlet and which was the inlet for the 4L80e. Found a good picture online:

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#635 · (Edited)
Worked on the transmission cooler brackets today (one bolts to the transmission cover and the other to the front of the engine.)

The front mount (shown below) looks like a musical note. This is coincidental.

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The musical note mount is attached to the engine forward of the front engine mount (below). Since the mount and transmission cooler line is the same color (black) they blend in the picture.

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This is the mount (below) attached to the cover of the transmission.

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The rear mount (below) is attached to the transmission dust cover.

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Cooler lines connected to the transmission inlet and outlet (below)

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This is where I left off for the day. I have to bend both 90 degrees and connect hoses between them and the trans cooler on the radiator.

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Came back the next day and finished connecting the transmission cooling lines to the transmission with hose.

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#636 · (Edited)
Worked on the Oil Filter Mount bracket today. I am still trying to design it on the fly. This is what I have so far. The mount bolts to the engine mount hole on the passenger side front block. The other mount points are under consideration.

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Next day update:

Bolted a plate to the alternator support to serve as a support for the filter bracket. I also being up some bars to connect this plate to the oil filter support.

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#637 · (Edited)
completed the Oil Filter Mount Bracket. The mount bolted right in. I just need to connect the oil lines. I scuffed the AN fitting a bit upon installation. Ordered the correct tools to prevent that from re-occurring. It looks good though and the filter is easily accessible.


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Later on in the evening: Thinking about this setup, which appears okay at first glance; I may add a removable guard in case the belt ever breaks. I would not want the broken belt whacking the oil filter.
 
#640 ·
Started looking at the wiring today. I purchased a normally open 160-degree sensor. The plan is to connect the sensor to ground. The ground will complete the circuit of the KSB and radiator fans to power them on through a relay. Just thinking out loud at this point but I like the idea.

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Started looking at the wiring requirements as well and found a cool chart to assist with determining the size of wire needed to complete the wiring harness.

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#641 · (Edited)
Started working on schematics to figure out the relays. The starter relay is to disable the vehicle with a remote. The purpose is to interrupt the wire to the starter if the ignition is turned on. The device has a two-minute delay so once the vehicle is parked after driving, it can not be restarted unless you have a remote. I added a bypass switch just in case the remote should ever fail for the remote relay (eBay stuff).

Looking at the drawings, I updated the thread and put the A/C into the mix. The fans should be on when the AC is running.

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I still have to put this in the truck. But I feel it is better to have a plan when I go out there. :geek:

11/20/21: I have edited the first diagram. Grounding the fan relay is the best trigger out there. I have three ways to activate the fans. It is done by grounding the fan relay with the toggle switch, 160-degree thermostat, or the trinary switch.

On 11/21/21 I added two relays 1) parking/running lights 2) Ground timer. This will allow the lights to shut off on a timed delay after the ignition is de-energized (key pulled out) Added the timer relays to the light circuits so they will time out probably 10 seconds to a minute after the key is turned off.

On 11/22/21 I saw some rather large issues with my schematics. The timer relay on the lights was not a good setup. Much better now. Also, I am wondering about the KSB and whether that needs to be on its own circuit. The setup looks good until you figure out if the AC is running, the fans are running and the KSB is energized. so the KSB can be energized while the engine is cold. I need to reconsider this and come up with a solution. I rewired the lighting schematic as well.


Here is a great video on how the system works: How To Wire A Trinary Switch To Your Car's Electric Fan - YouTube. It is a simplified and explained version of my wiring schematic.

Here is another on relays: How To Wire An Automotive Relay - YouTube

How to select a fuse: how to CALCULATE how big of a FUSE you need in your circuit (STEP-BY-STEP) - YouTube
 
#642 ·
When I disassembled the truck, I was dismayed about the number of issues I was having with unbolding the front clip. The nuts were breaking off inside the fenders. Today was the day I dealt with the issue.

On this fender, five nuts broke off. This left empty square holes with no nuts on one fender and two missing nuts on the other fender.

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I welded some nuts to flat bar

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And cut the bar up to make small tabs to weld the nuts to. (of course, I pre-drilled the holes before hand.

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So with the flat bar tab with a nut welded, I drilled through the inner fender and tapped the hole for a machine screw to secure the nut in place.

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Cleaned it up and paint the inner fender with flat black.

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#643 · (Edited)
TRINARY SWITCH OR BINARY SWITCH (LOW-PRESSURE AC SWITCH).

Trying to figure out my wiring, I ordered and believed I needed a Trinary switch. However, you can rig another relay and use the regular (Low Pressure) switch (also called a Binary Switch). I have added two diagrams to show the difference. Originally, I was going to go with a Trinary Switch, but picked up a harness that will allow me to use the regular Binary Switch.

TWO DRAWINGS TO SHOW A TRINARY SWITCH SCHEMATIC VERSUS A BINARY SCHEMATIC.

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The basic operation for both is relatively straightforward. The relays have 12v from the ignition (when on) and 12 v from the battery/fuse panel. The trigger on both schematics is the ground. The ground is activated by 1) the temp switch 2) a toggle switch, or 3) the Trinary Switch or the AC relay. Once grounded the power can go through the relays to the fans and turn them on. From the earlier design, I added another relay to control the second fan through an independent relay. I also removed the KSB which will now have its own harness.
 
#644 · (Edited)
Here is the KSB (wax, earlier version). The power is from the ignition switch to the relay which is the input to activate the relay. Power through a fuse will be the input to the KSB. The ground switch is a temp switch (the same type as the one used on the fan circuit) which will complete the relay circuit and activate the relay to send 12volts to the KSB which will melt the wax and retard the engine a bit. I decided to mount the temp switch for the fans at the back of the engine and the KSB on the inlet of the engine from the radiator.

11-27-21 I added a resister to the outlet of the relay to the KBS to reduce the current. This was based on char1355 and his comments on post 645 and the following four posts.

11-28-21 I added a drawing without the relay. This is simply a 12 volt wire that uses power from the ignition (tapped in on the fuel shutdown solenoid) and ran through the resistor to the KSB. It is simpler in design.

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Note the two wiring scenarios. The drawing with the relay uses the ground (-)
to activate the 12v (+) to the KSB and the non-relay uses 12v (+) to active through the temp switch.
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#645 ·
Have you checked the wiring specs for the KSB. Those wax motor types have a special wire that has a built in resistance. Not sure who's bright idea that was but it's not just a normal copper wire. There are even instructions in the service manual about testing it to be sure it is functioning correctly. It's is also a darn expensive little piece of wire harness.
 
#646 · (Edited)
#647 ·
From my understanding, the wire is supposed to have a certain amount of resistance to make the KSB function correctly. Here is a link to a Cummins service manual you may find very useful. It even shows part numbers for things like sensors and wiring harnesses. This manual is over 1000 pages long. The KSB info starts here on page 947 and up. https://constructionexcavators.tpub.com/TM-5-2420-230-24-2/TM-5-2420-230-24-200968.html
 
#648 ·
Thinking about this, I only need to know the amount of resistance the wire has and add a resistor to my harness. The instructions state ensure the reading is less than 10 ohms. The KSB shown uses a 3-ohm resistor, but that doesn't mean that is the resistance required for my harness.
 
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