Santa (technically, my sister’s boyfriend) brought me a lovely gift this Christmas: a carb rebuild kit for my spare Thermoquad including all of the gasketry, springs, and other small parts needed to overhaul the mechanical bits. Introduced by Chrysler in 1969, the Thermoquad is a four-barrel carburetor designed with two small primary and two large secondary bores. At idle or cruise, the primary bores supply fuel to the engine in small amounts for efficiency, and under load or acceleration the secondary bores open up to dump fuel into the engine, adding power. It’s built around a phenolic resin chamber sandwiched with two aluminum plates, which was supposed to keep the temperature of the upper bowl 20˚ lower than standard metal carburetors of its day–because vapor lock was standard equipment on a 440 big block. So I’m going to have to study up on this Malaise-era marvel of engineering.
My engine, near as I can figure, is a 1979. As the 70’s wore on and emissions standards got stricter, engine displacement decreased and smog equipment strangled engines. IH trucks weren’t as strictly governed as passenger vehicles of the era (trucks over a certain weight and load limit were exempt from CAFE regulations, hence IHC advertising the Scout as the XLC in 1975 onwards) but smog equipment was still added to pass emissions tests, and the carbs got more complicated as the decade drew to a close. The Thermoquad sprouted all sorts of ports and valves and complicated linkages to govern choke, temperature, airflow and throttle, and the result is a lump of metal that looks like C-3PO screwed a pinball machine.
I’ve got three Thermoquads in my collection. The first is the one that came on Peer Pressure, which I had overhauled by my friend Rodney a few months after I got the truck. Tracing the serial number (9128S), it was originally made for a ’79 IHC 345ci engine with an automatic transmission. Rodney is a gearhead of the first order (he has a slingshot dragster parked in his driveway) and no stranger to carburetors. He made it sing, but that was eight years ago.
The second is a spare I picked up from a fellow north of Baltimore. This too is a 9128S. It’s the spitting image of the one on Peer Pressure, minus the funky extra linkage on the throttle arm to the left. It’s also the rebuild candidate and the one I’ll be working with here.
The third is a spare I picked up from my friend Jason, who converted his Traveler over to fuel injection two years ago. Tracing the serial number (9203S), it was originally made for a ’79-80 IHC 345ci California smogged engine with an automatic transmission. The top of the air horn at the fuel inlet is different, and there is one vent tube where my other carbs have two. It’s also super crispy and in need of a major wash. It will be my bench reference and possibly a source of spare parts.
The first order of business is to arm myself with knowledge. I downloaded a series of getting-to-know-you videos from YouTube where a gentleman steps through the features of the TQ, and another where he goes through the steps of rebuilding one. I’ve got the original ’72 Chrysler TQ service manual, an updated ’82 Federal Mogul manual, and the Dave Emanuel bible.
The first order of business is to clean them both, which will require a bucket of Simple Green and a couple cans of carb cleaner, which I’ll pick up this weekend. Then it’s on to the teardown.
I got impatient this afternoon. I had about 1/2 hour of free time, so I looked around the basement for some scrap metal I could use to build a temporary repair for the throttle bracket. Spying a used IKEA drawer rail from Finn’s dresser (a couple of years ago she leaned on the open drawer with enough force to bend the rollers off the rail, so I had to get replacements from the store and fix it), I measured it in place, then took a hacksaw and lopped off about 4″ at the end. After drilling a hole in the middle, I mounted it to the bracket and then mounted the cable bracket to the end–giving me another 2″ of slack in the throttle cable. I fired it up and the clutch acceleration problem is gone. To celebrate, Finn and I loaded it up and drove to the pool, where we swam until darkness, and then we drove home under a sky full of stars.
Later this summer, I’m going to fabricate a cleaner, more permanent solution. But we’re back on the road, and that’s all I care about.
I got the accelerator cable in on Friday, and after breakfast on Saturday morning I went outside to put it in. It’s fairly straightforward and went in without too much hassle, once I realized the loop molded into the cable wasn’t supposed to hook over the top of the bracket, but used to screw in (and provide room for adjustment) on the bracket itself. The cable hooked right up, and in about 10 minutes I was ready to fire it up and go for a test drive. But when I put the clutch in, the engine revved.
It turns out this isn’t an uncommon problem; what happens is that the cable is too tight on the carb, and the clutch linkage at the pedals travels up the firewall right next to the accelerator. When I push the clutch in, it forces the throttle linkage backwards, revving the engine. Problem is, I’ve got no play at all on the bracket. The cable is pushed as far forward (towards the carburetor) as possible; there’s nothing else. The arms on the carb aren’t adjustable, and there’s no other allowance for adjustment in the cable itself.
I looked in the fittings and bracketry that came with my second engine, but there’s no spare there. So I’m going to fabricate a U-shaped piece of metal with two holes. One side will go on the bracket and the other will hold the cable, and I’ll build in room for forward adjustment.
In other news, Finn and I drove to White Marsh to visit a guy who had an original IH Service Manual for sale on Craigslist. I have the new reprints from Super Scout Specialists, and they’re great, but I couldn’t pass this up. It’s softbound but 3-hole punched, so now I’ve got to keep my eye out for a 1 1/2″ red binder to put it in.
In doing the preliminary research on my carburetor, I stumbled upon a 16-part video series detailing the process of rebuilding a Thermoquad, which I downloaded for future reference.
Driving back from a yard sale on Saturday morning, the accelerator pedal dropped to the floor, again. Since I’ve owned Peer Pressure, I’ve had intermittent problems with the throttle cable, which was originally jury-rigged to the engine block with an automatic cable bracket. My friend Alan swapped me that for a manual bracket, but the cable itself was held to the bracket with a rubber-grommeted clip. When the engine heats up, the grommet gets slippery and the cable slips out of it. Usually this is a 5-minute fix, but on Saturday the grommet disintegrated in my hand as I was refastening it. With Finn waiting in the back seat, I jury-rigged the cable with some zip ties and we made it home under our own power.
On the phone with Super Scout Specialists, I learned that I have the wrong cable completely. The one I’m supposed to have is manufactured with a loop that goes around the bracket and held in place by the clip, so I ordered the correct part last night after investigating. I’ll have to carve out time to install it, based on when it gets here.
And I was thrilled last week when Bill Caswell started following me on Instagram!
Here are some crappy cellphone shots of my kick panels. The driver’s side was patched crudely before I got the truck, but the passenger’s side has always been swiss cheesy. I think I’ll wait for warm weather, take the angle grinder to both sides, and hit them with some rust encapsulator. One of my goals for this year is to get a decent welding rig and start practicing again so that I can take some smaller repair projects on; this would be a good one.
In other news, a printing vendor I use at work had a special on circle-cut stickers last week. I’ve been noodling with a design for our ad-hoc Maryland IH group, called Old Line State Binders, but I was having a hard time nailing down a design incorporating the Maryland flag. It’s a great flag but very visually busy, and in the last year there’s been a glut of shape-plus-flag stickers out there: a crab, deer, dogs, mustaches, etc.
My original idea was to use something ubiquitous to vintage 4-wheel-drive trucks: the locking hub. That part was pretty easy to nail down, and I took away some of the visual clutter to clean up the image. Integrating the flag and the name was the hard part. In order to keep the design circular (and get my cheap stickers before the deal expired), I left out the name and went with the following design:
Eventually I’ll figure out how the rest of the design should look. If you’d like a couple, drop me a line and I’ll send you one when I get them.
I’ve been really quiet on the Scout front for the last year or so due to work and family commitments. I haven’t visited the Binder Planet in ages. I’m hoping to get some time in the spring to organize a meeting and get back in touch with people.
Until today, whenever I had a passenger ride with me, I (usually) had to get out and lift their door from the outside in order to get it to close. This was annoying. Recently, the latch on the inside disengaged from the linkage, meaning I’d have to get out to let my passenger out.
The girls took a trip up to Philly today, so I was on my own. I made a quick dinner and pulled the Scout out of the garage, pulled the panel off the door, and took a look. The plastic retainer clip broke in my hand as I took it off, so I raided my stash to find a spare. The two doors I’ve got and my spare linkage are from a later year, so the clip is a grommet/steel combination that fits into a larger hole. I drilled out the hole and fit the clip, and that was that. Then I figured I’d look at the door itself.
I put some bracing under the door and loosened the six hinge bolts on the door itself. Then I tightened the middle bolt on the bottom, pivoted the door upwards, and readjusted the bracing. Then I cinched the middle top bolt, loosened the bottom, and pushed it in 1/8″. After tightening everything down, I tested it, and I got lucky: it closed as well as the day it rolled out of the factory.
A question for the ages. I’ve got an entire truck that needs rust prevention, so what best to use? I watched a friend use Eastwood products on his Sprite (English sportscars of the 60’s rival US vehicles of the 70’s for their ability to spontaneously dissolve), and thought they worked pretty well. After some basic research, my original thought was to use Encapsulator in an aerosol can, but as I dug into the online materials a little more, I came to understand that Converter was better suited to my needs. Converter is a two-part acidic paint that converts rust to an inert oxide, while Encapsulator seals rust off and keeps it from spreading. Yes, I need to seal it off, but Eastwood says Converter is better for heavy rust, which is what I’ve got. Then, as I hovered over the Add To Cart button, I saw that they offer a quart bottle for only $6 more than a 12oz. aerosol can. Such a bargain!
I bought a cheap Harbor Freight dremel last weekend and cut down the outside housing of the LED lights I got from Amazon; they are about 3/4″ deep shipped, and about 1/8″ too wide all the way around the outer perimeter. Once I’d cut and sanded down the edges, the light fit flush into the outer bezel. It’s not perfect, and not pretty, but it works. Pulling the originals out of the buckets, though, it appears the quick connect at the end of the wire is actually inside the inner fender, so in order to swap these out I’d need to (probably) pull the headlight out of its bucket to access the inner fender.
Given all the work this took, I may take Mike’s advice and just buy LED bulbs to replace the rest of the incandescents.
Having finally brought wired power to the garage, I thought it would be a good idea to add a battery conditioner to help the Scout make it through the winter. I generally get out and start her up every weekend during the snowy months to keep systems lubed and working (three of the saddest words in the English language are ran when parked) and there have been some days when I’ve needed to pull one of the Hondas up to jump the battery. I found an inexpensive battery conditioner on Amazon and got it delivered a few weeks ago. It’s meant to keep the battery topped off, which is just what I need.
I heard from our friend Mike in Colorado after a long quiet spell, who has been driving his shiny Scout daily after rebuilding it from the ground up. He offered me a spare set of traveltop window seals he’s got sitting in his garage, which is fantastic timing. I’ve been eyeballing my traveltop in the garage, thinking it would be wise to get it back on the truck before things get really cold. I’ve got experience putting a traveltop on in December in a chicken barn as the sun was setting, and as the last three or four bolts went in my fingers went numb.
My top has solid side windows but I’ve got a set of sliders from the crappy top I chopped up in the backyard, and the seals they came with are OK but not new. One of my goals before it goes on is to knock down and shoot the rust inside along the bed rails with some Eastwood encapsulator and then cover them with etching primer. It’s in great shape overall but there are a bunch of inexplicable screw holes on the roof that need to be welded shut–something I’d like to test out a new welding rig on.
I had a little time to fool around with the Scout this weekend after taking her camping; I tackled a few smaller issues that I knew I could wrap up quickly (with a bored daughter rolling around in the back seat). First up was the passenger door handle, which has been loose since I got the truck. I pulled the inner panel off, took the handle off, and fitted a couple of lockwashers to the mounting screws, then tightened it up snug to the body. Next I took the shitty pot-metal rearview mirror mount off the passenger door (the mirror was gone when I got the truck).
Then I fitted a replacement glove box door to the dashboard. See the clip held in with two screws in the photo above? That’s an early-style clip, from what I can gather. Later clips were actually a hoop of metal the latch hooks onto. My dash is old so the metal lip the hoop mounts to is smaller. I’ve got to figure out some kind of temporary fix for this so I can actually use my glove box.
I also have to get up under the dashboard and POR-15 the seam at the firewall; I noticed some water leaking down inside when the truck was sitting at the campsite. I may actually use some Eastwood rust inhibitor this time to see how well it works, and I can get it at the Advance when I pick up some new door jamb switches.