So that's why ThermoQuads used open base gaskets...

[MoparKidD-4]

I finally got my TQ, Eddy Performer, and MSD-ized ELB-deleted '88 5th Ave running tonight. SO much work with the A/C compressor and emissions hardware compared to my '70 Duster, won't be doing anything like this again for a while lol. Anyway I thought it would be a better choice to run a 4-hole spacer for a spread-bore carb to keep the two plenums separated which usually gives better off-idle grunt. After getting the car started and running and initial timing set to around 12*, I noticed it was running kind of rough and smelled super rich. Even though I had modified the base gasket to open up the secondary holes to match the TQ, the secondary blades were sticking open just enough to pull fuel from the spray bars and dump it into the engine at barely above idle speed. However once I got them closed it still ran pretty rough and smelled rich; I'm familiar with ignition vs. fuel issues and this one felt like a fuel issue. So I pulled the carb off and took it apart to replace the crummy nitrophyl floats with some spare brass ones I had, thinking there was some kind of float problem. But then once the carb was back together I happened to look at the bottom of the base plate and noticed something... The ports that feed vacuum to the metering rod piston were being directly blocked by the center of the 4-hole gasket! Lesson learned: when Chrysler engineers decided to use open gaskets with ThermoQuads it was for a good reason! LOL... well that's my car-related venting for the day, I have a new Fel-Pro OEM-type gasket arriving at the parts store tomorrow afternoon so we'll see if that fixes it. I still need to finish modifying the stock 2-bbl throttle/kickdown bracket so it'll work with the TQ too, not looking forward to that since I don't have a welder uggghhhh

OH and another lesson learned, don't buy cheap "rebuilt" carbs off eBay... the top section of this carb came from one my cousin bought and ran on the 440 in his '72 Polara and it always ran like total garbage, mostly due to super worn throttle shafts. Also turns out the accelerator pump plunger had the rubber seal completely fallen off and sitting at the bottom of the well which explains why it wasn't pumping at all! Ah the joys of messing with old OEM parts... lol

 

[Aspen500]

We ran into that at work with an ebay (or similar) reman TQ for a '74 Motorhome. Leaked fuel right off the bat. There was a plug that had a threaded insert installed into the top plate near the fuel inlet, crooked. Leaked like a sieve. With that fixed, it was fine until,,,,,,,,,,the secondaries were opened and stayed open. I swear that 440 hit 8,000 rpm before the guy working on it could shut the key off. Turns out the linkage was binding. In the end it worked fine but you wonder if they even bench tested the carb before shipping it. The plastic main body on the original carb was beyond repair which is why we went with a reman in the first place.

 

[MoparKidD-4]

We ran into that at work with an ebay (or similar) reman TQ for a '74 Motorhome. Leaked fuel right off the bat. There was a plug that had a threaded insert installed into the top plate near the fuel inlet, crooked. Leaked like a sieve. With that fixed, it was fine until,,,,,,,,,,the secondaries were opened and stayed open. I swear that 440 hit 8,000 rpm before the guy working on it could shut the key off. Turns out the linkage was binding. In the end it worked fine but you wonder if they even bench tested the carb before shipping it. The plastic main body on the original carb was beyond repair which is why we went with a reman in the first place.

I'm almost certain this carb my cousin got was just quickly torn apart by some bozo and the top and bottom sections spray-painted aluminum to look "rebuilt". The irony is my cousin thought that was just the way carb'd cars were supposed to run, as in needs to idle after initial startup for 5 minutes before you can even touch the gas or it'll stall out and horrible stumbling when you open the throttle. I'm just like, "No cousin, it runs like SH** because you paid for SH**, carbs can run just as well as EFI if they're in good shape and well-tuned..." "Oh really I didn't know that!" LOL

Well I'm off to the parts store now, I'll see about posting a quick video if I can get it to run smoothly now.

 

[Aspen500]

I remember rebuilding the TQ at tech school as part of the carb class (this was in 1983 so EFI wasn't covered yet). If I recall correctly, there's 21 external adjustments that all have to be done in a specific order and be exact. Miss one adjustment and it can throw off every adjustment after that. When they're right though, they work excellent. Technically if nobody screwed with the adjustments, after a rebuild, they'd still be good as is. Kind of like the old Motorcraft VV carb. As long as everything was left alone, they worked good. It's the ones that someone messed with that would cause all sorts of headaches at work (was a Ford dealer tech from '86-'07). Anyways, enough of the rant.

 

[MoparKidD-4]

So I got the new gasket on, definitely runs better and I can see the metering tree move up and down when I work the throttle with it running. It has a bit of a stumble still though and I can't quite get it to idle as smoothly as the old stock 2-bbl ELB setup did. I think I may have set the floats too low (or high with the carb upside down), when I swapped in the brass floats I set them to 1-1/16" which is the 'highest' recommended setting, I may have to step it down to 1-1/32" or just 1". I should have the throttle and kickdown linkage set up tonight though, once I can go on a real test drive I can get a better idea of what's going on. Chances are the carb has a bit of tiny debris in some of the passages as well that need to be worked out by driving it more, I probably could have been more thorough in cleaning it out when I was putting it together.

 

[jasperjacko]

I love the TQ carbs, but I'm done looking for tuning parts and replacement fuel bowls. My carb is on it's 3rd and final fuel bowl due to cracking. When this one fails, I'm moving on to something else.

 

[8v-of-fury]

That holley dominator that looks like the TQ with a Goggle Valve-SEcondary looks damn sweeeet.

All the best designs and tricks from all the carb manufacturers from over the years.

 

[MoparKidD-4]

That holley dominator that looks like the TQ with a Goggle Valve-SEcondary looks damn sweeeet.

All the best designs and tricks from all the carb manufacturers from over the years.

You mean the Street Demon? I have the 750 cfm version actually, it won't work on this stocker 318 though since the primaries are really big. They had to limit the size of the secondaries to make it fit on a square-bore pattern so to get the increased airflow they bumped up the primary diameters. The 625 cfm version would be perfect but I'm done spending money on this project lol. If I can't get this TQ to work well (which I think I can) I'm gonna just try to find a cheap used Carter or Edelbrock carb locally on Craigslist.

The throttle and kickdown linkages are driving me INSANE though... After hours and hours messing around with it I now find the kickdown linkage hitting the grommet where the HVAC vacuum lines come through the firewall... ARGHHH

 

[8v-of-fury]

Sounds like you need a Lokar cable kit

Yes I meant the Street Demon! lol sorrrry

 

[MoparKidD-4]

OK, this thing is FINALLY working. I finagled the linkage enough to get it working right, turned out the kickdown rod was hitting the cable bracket nuts and I just popped the rubber grommet through to the passenger compartment; screw it I'll mess with that later lol.

I also adjusted the floats down/up/whatever to 1", now it runs smooooth through the throttle travel no flat spots anymore; amazing how 1/16" of fuel level can affect the carb that much. I also bought a new distributor rotor, the one I put in was used and had noticeable wear on it; now it idles perfectly smooth, with a bit more "thump" to the sound than with the 2-bbl setup before (I have homemade duals with no cats currently and a pair of Dynomax Ultra Flos). I bet the "new" timing set and chain tensioner has something to do with that based on past experiences. It also probably has more initial timing than with the stock computer, I set it at 12*.

I'm pretty satisfied now, the increase in performance and smoothness from before has made all that tedious work worth it. Mostly... LOL

Pics and hopefully a video to come...

EDIT: Oh and I didn't want to go with a Lokar cable setup because I'm not aware of any way to adapt the factory cruise control cable which I really wanted to keep. This car is a highway cruiser, it NEEDS CC lol.

 

[BudW]

The cable system works fine with Cruise.
Correction: the Mancini Racing cable works fine with Cruise and existing Throttle cable.
http://www.manciniracing.com/retobotokica.html
BudW

 

[MoparKidD-4]

The cable system works fine with Cruise.
Correction: the Mancini Racing cable works fine with Cruise and existing Throttle cable.
http://www.manciniracing.com/retobotokica.html
BudW

Thanks for the tip, I got the factory linkage to work though. I just added a small steel extension piece to the throttle cable end, I was then able to "seat" the steel sheath under the bracket instead of just the bare cable housing which kept sliding forward when I floored the gas pedal. It's all good now, the only way I made the kickdown linkage work though was by adding in adjustable rods from my old Duster setup whereas the stock ones on this car weren't adjustable. So I have adjustability at 3 places, not just one. Gave it just enough length to work right, and after some fine-tuning the shifts are when they should be and it has the right amount of travel for actual kickdown.

 

[BudW]

You did get the longer (4-bbl) throttle cable installed, didn't you?

The 2-bbl one will just barely reach without any adjustment – but just as soon as the engine twists in the engine compartment (under a load), it WILL pull the throttle cable back – leaving the throttle stuck open!

That will make your “behind” suck into the seat (pucker power) – IF it doesn't leave your britches a lot fuller than before-hand – AND IF you don't also experience a bad day from the pending solid object you are about to run into.

I have first hand experience on this matter and I'm sure others here, do as well.
Just trying to keep you from (also) having an avoidable "bad day".
BudW

 

[AJ/FormS]

IIRC, the correct float level is 1 inch with brass floats. It's been a few years........