What have you done to your square lately??

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
1,387
Reaction score
4,320
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
Awesome.
Cooper Cobras bring back high school hot rod memories. Lol
Had a set of 275 60 15s on my Impala.
And a set of 33 12.50 Cooper Discoverers on my Blazer plow truck!

A long long time ago
Yep! Same here. My pops always swore by them on the Corvette. I can still hear him telling me, “ you really want that sidewall, 70 series is where it’s at”. I think a set of 275/60 would’ve looked great on it. He’s probably rolling over in his grave right now with me saying that, haha.
You must be registered for see images attach
 

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
1,387
Reaction score
4,320
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
I installed the LMC headlight relay kit today in my '81 C10 6 cylinder. I spent about 5 hours working without hurrying, pretty easy job. And best of all, it actually worked correctly as intended with no troubles on the first try!
What this accomplishes is to remove the electrical load (current draw) of the low/high beam headlights from the headlight switch and low/high beam foot switch. These stock items become the control system selector devices for two 30-amp power relays mounted on the inner fender. These relays send direct battery power to the low/high headlamps when activated. This system will have less voltage drop to the headlights, making them brighter. Also the dash switch will now have much less current passing through its headlight contacts.

Quality seems to be good, and I am satisfied. Notes: You can install the relays on drivers or passengers side, but passengers side is probably easiest if you only have the stock battery. You can remove the entire stock headlight wiring from the split loom that goes between both headlight and stuff in the new harness wires if desired. But I decided it was too much work and zip tied the new harness alongside the stock split loom.
You must be registered for see images attach

The wiring diagram on the package:
You must be registered for see images attach

Since my headlight sockets were brittle and crumbling, I spliced two rubber covered 90-degree headlight connectors onto the LMC harness, I like these alot despite the wire color mismatch with the harness:
You must be registered for see images attach

I also deleted the LMC harness headlight male plug and butt spliced the low beam and high beam signal wires directly to the appropriate relay control wire. Everything gets hidden in front of my dual batteries and the two relays are mounted to the inner fender next to the stock battery, no clearance issues.
Drivers side:
You must be registered for see images attach

Passengers side where most of the wiring is performed:
You must be registered for see images attach

The two red wires on the right are the main power wires that go to the battery. I did attach them directly to the battery positive post temporarily while I get the auxiliary fuse block installed. The aux fuse block will be used for low beams, high beams, fog lights, bed light etc.
On to the next project.
Thanks for the pics- lots of people have posted favorably about this conversion, so I’m going to do that too. I don’t plan on driving too much at night but it seems just better (and safer). While I’m at it, I’m going to finally get around to changing to a new battery style so the terminals are reversed. That way, if I ever get hit hard in the front end, the battery positive terminal won’t dead short on the radiator core/headlight support.
 

legopnuematic

Licensed Junk Dealer
Supporting Member
Joined
Oct 27, 2016
Posts
2,615
Reaction score
6,889
Location
MO
First Name
Spencer
Truck Year
1971, 1̶9̶7̶4, 1976, 1979,1̶9̶8̶5, 2002
Truck Model
Dart Swinger, Sierra 10, C10 Cheyenne, C10 Big Ten, Silverado 10, Ram 2500
Engine Size
225/6, 350 c.i., 350 c.i., 5.9l Cummins
Compliments of a tech at my work, we evacuated and recharged the ac in Goldie. Crazy, but only pulled like 2.5 lbs out and put in 4.5 of the same R134.

R12 sticker called for 5.25 lbs.

Funny thing is that I can't tell it blows any colder ... :think:

High side around 250, low around 70.

I don't get it.

Bad condenser, maybe ?

Receiver sweats a lot more now.
Serpentine or cross flow condenser?
 

FireTruck1984

Full Access Member
Joined
Jan 7, 2019
Posts
2,988
Reaction score
9,946
Location
Michigan
First Name
Ted
Truck Year
1984 and 1984
Truck Model
High Sierra K1500 350. Sierra Classic C1500 305.
Engine Size
350, 305
Wife bought me a GT3 Retro wheel and new radiator for our anniversary. Thought it was a nice gift.
You must be registered for see images attach
Very thoughtful gifts! She’s a keeper
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,622
Reaction score
28,872
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Compliments of a tech at my work, we evacuated and recharged the ac in Goldie. Crazy, but only pulled like 2.5 lbs out and put in 4.5 of the same R134.

R12 sticker called for 5.25 lbs.

Funny thing is that I can't tell it blows any colder ... :think:

High side around 250, low around 70.

I don't get it.

Bad condenser, maybe ?

Receiver sweats a lot more now.

Those pressures are too high. What was the outside temp and humidity?
 

Goldie Driver

Full Access Member
Joined
Mar 19, 2018
Posts
4,054
Reaction score
6,685
Location
Houston, Texas
First Name
Britt
Truck Year
1980
Truck Model
GMC K1500 Suburban
Engine Size
350
Those pressures are too high. What was the outside temp and humidity?
Approx 95 degrees and 60 percent humidity. Charge was based on 80 percent of the 5.25 lb R12 charge called for by the sticker on the blower box. No real pressure fluctuations so the compressor seems OK and the tech did not think the orifice was clogged.

So, ?
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,622
Reaction score
28,872
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Approx 95 degrees and 60 percent humidity. Charge was based on 80 percent of the 5.25 lb R12 charge called for by the sticker on the blower box. No real pressure fluctuations so the compressor seems OK and the tech did not think the orifice was clogged.

So, ?

Does it cool better while going down the road? My initial hunch is that it's either overcharged, or there's not enough airflow through the condenser.

70 is way too high for the low side, which is why it doesn't cool very well.
 

Goldie Driver

Full Access Member
Joined
Mar 19, 2018
Posts
4,054
Reaction score
6,685
Location
Houston, Texas
First Name
Britt
Truck Year
1980
Truck Model
GMC K1500 Suburban
Engine Size
350
Does it cool better while going down the road? My initial hunch is that it's either overcharged, or there's not enough airflow through the condenser.

70 is way too high for the low side, which is why it doesn't cool very well.
Yeah, but it has always since I have owned it blown colder while moving. I wonder if there is some restriction in the lines but really don't know. We just did an evac and recharge and the machine will only let you program a fixed amount. So, topping off after that would need to be with a can.

Bleeding off is manual as well unless you run through another evac, vacuum, and charge cycle.
 
Last edited:

bluex

Full Access Member
Joined
May 9, 2013
Posts
1,987
Reaction score
2,637
Location
Spartanburg SC
First Name
Paul
Truck Year
1978
Truck Model
C15
Engine Size
350
LOL- whatever OE for 1980 was. :Big Laugh:

I keep reading that parallel flow is the way to go but no idea how you would pick a replacement part number.

Most replacement condensers are parallel flow type now, since it's almost impossible to find r12. It should look more like a radiator with small fins than the OE one with a larger tube appearance. GPD 3612C is listed for an 80 an says it's a parallel flow. All the available options on rock auto right now say parallel flow, with the exception of an out of stock UAC part which doesn't really say. Picture looks like a parallel one but it says tube an fin in the description.

If you put a R12 style condenser in with 134 it definitely won't cool as well. 134 doesn't get as cold as 12 anyway an the larger tube's in the 12 condenser don't help it shed heat as well.

I agree the pressures are a bit high side. General rule of thumb is low side should be half ambient temp an high side double ambient plus 50. So at 95* ambient you should have been 50 and 240 on your pressures.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,464
Reaction score
5,630
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Yeah, but it has always since I have owned it blown colder while moving. I wonder if there is some restriction in the lines but really don't know. We just did an evac and recharge and the machine will only let you program a fixed amount. So, topping off after that would need to be with a can.

Bleeding off is manual as well unless you run through another evac, vacuum, and charge cycle.
My 1980 K25 pickup has the original everything in it including the compressor, condenser, and evaporator and it is ice cold almost all the time. I do have the low speed on the electric fans set to come on when the compressor is engaged though. The only things I changed when I converted to R134 is the pressure switch and the orifice tube. I went to a blue tube and I get about the pressures that @bluex stated. Mines a pickup, so probably less total charge than yours but it took exactly three 12oz cans of R134.. which is 2.25lbs.
 

Radiohead

That guy on the Columbia
Joined
Mar 17, 2022
Posts
2,488
Reaction score
8,119
Location
Low Earth Orbit where it's safer
First Name
Eric
Truck Year
MCMLXXIX
Truck Model
C-20 Silverado Camper Special
Engine Size
454 crazy cubes, or 7.4 luscious litres
When I bought this truck it had a bit of a stinkbug stance. Over the winter it got new rear leaf springs which didn't help the situation.
Tonight I finished putting some longer shackles to help reduce the gap in the rear wheel wells and level the truck out.
The shackles on the truck were 3-1/2 inches which I question if they were the correct length. The new shackles are 6-5/8" centre to centre.
This resulted in a 1-1/4" drop at the wheel wells and 1-7/8" drop at the trailer hitch.
Not a huge difference in measurement but that little change really looks better to me.
I have a set of the heavier 454 front coils sitting on the shelf that I need to get on at some point. I figure it will be pretty level at that point.
Before and after pics.
If you toggle between the pictures fast enough it looks like the truck is twerking. Lol
 

Latest posts

Forum statistics

Threads
44,418
Posts
957,172
Members
36,755
Latest member
square-up
Top