Rebuilding a Thermoquad

[Paul_G]

The 78 440 motor home engine I picked up has a Thermoquad on it. I ran the engine before tear down and everything worked. So I decide to try the TQ on my 49 Plymouth with a 318. It has an EDDY intake that will accept a spread bore carb. It started and idled well actually, then the accelerator pump died. So I decide to rebuild the TQ and try again.

I have the TQ tore down and all cleaned up. A kit should arrive here during the week.

Any rebuild tips or tricks that would be helpful?

I would need a spread bore to square bore adapter plate to put the TQ on my other car. I am just doing that for shits and giggles anyway. Do the adapter plates work well?

 

[rumblefish360]

Yes the adapter plates are fine. Add in 1 more inch of height. It is an over estimated amount but not by much. Normally around 3/4 of an inch thick though it will vary by maker, then add the gasket thickness on top and bottom. Measure. They vary as well. Normally seen @ 1/16.

 

[Gold Rush]

This will come in handy. The instructions that come with the kits are not all that good usually.

http://imperialclub.org/~imperialclub/Articles/ThermoQuad/index.htm

 

[T2R9]

Since its going to be apart I recommend re-epoxying the jet wells on. They dry out over the years and can leak. I like to use Marine-Tex epoxy, works well. Clean all the old epoxy off real well and scrape the edges with a fresh razor blade so the epoxy has something to bite on.

 

[mopar 3 B]

Since its going to be apart I recommend re-epoxying the jet wells on. They dry out over the years and can leak. I like to use Marine-Tex epoxy, works well. Clean all the old epoxy off real well and scrape the edges with a fresh razor blade so the epoxy has something to bite on.

I used "the last glue" last time 5 years ago and still holding up.

 

[mopar 3 B]

Follow all ajustment instructions to the tee. Getting them out of order will totally mess up every thing.

 

[mopar 3 B]

Yes the adapter plates are fine. Add in 1 more inch of height. It is an over estimated amount but not by much. Normally around 3/4 of an inch thick though it will vary by maker, then add the gasket thickness on top and bottom. Measure. They vary as well. Normally seen @ 1/16.

Using the original thermo type gaskets will add all most 1/2" plus the adapter.

 

[Paul_G]

Thanks for all the tips. The kit I got was from Walker. Went together very well. I had to trim the bowl gasket just a bit to get it to lay flat. The instruction sheet wirh the kit was very good.

I am really surprised at how well the car runs with the Thermoquad. Crisp throttle response, wot feels stronger then the Holley 600 vacuum secondary does. Overall I am impressed.

I am going to drain the Holley and run the TQ for a while.

 

[rumblefish360]

The Thermo quad is the best dual purpose street strip carburetor. I do think you’ll like it.