Carburettor overhaul

[XTREME KARTS XF 1,212]

Hey fella's

 

I have 2 carbys that i want to rebuiild

 

I want to overhaul the Carter Thermoquad that i got off a mate of mine, now i know some people dont like them and they can be a bit of a pain to tune but i want to give it a crack myself. How hard is it to rebuild one?

 

And the 600 Holley that came with the wagon (parts car) works ok but i would like to put a kit through it at some stage.

Again how hard is it to rebuild a 600 Holley? its got vacuum secondaries.

 

 

 

[FORD_MAN 1,026]

Holley's are easy as, it probably take under an hour depending on how anal you are with cleaning it.

thats why it takes me 4 hours to kit & port a weber.

Thermoquads aren't to bad, just lots of linkages and crap. my first carby I rebuilt was a thermoquad.

 

[SPArKy_Dave 8,895]

I'd really like to get an ultrasonic cleaner one day, for all the small parts such as in carbies.

 

I also have future plans to get a small zinc plating setup too,

to re-plate all the small parts like linkages, small screws and so-on.

 

Makes a carby rebuild/ engine bay freshen up look so much nicer.

[gerg 10,871]

I threw a kit in a ThermoQuad maybe 20 years ago, from memory the main dramas were the plastic acc pump transfer tube kinking when trying to fit it, the leaky main jet wells that are held in place by epoxy glue, and the metering rod piston not sealing, due to the main body being worn (not repairable). Also the plastic body is famous for warping and not sealing.

 

Holleys are straightforward if you apply common sense and as with any carby, treat them like the precision device that they are. I found a couple of areas a bit tricky:

 

the vac diaphragm needs to be pulled into the housing by the actuating rod a tad so that you don't get it bunching up/twisting as you tighten the top cover.

 

Also if it's a single fuel feed, the transfer tube to the rear bowl can be a bitch to line up while installing the front bowl and at the same time lining up the acc pump arm. You'll eventually get the knack after changing jets twenty times. Use a bit of Vaseline on the o-rings too.

 

Run a fine file over all flat surfaces like meter block faces and body to base. Never file off the ridges around the outside of the meter block. They're there to grip the gasket and seal properly.

 

Tighten jets only slightly more than finger-tight otherwise they can seize in there, especially on alloy-bodied carbs.

 

The base gaskets go one way only; the idle circuits are different front to back.

 

The rear idle circuit has tiny little ports below the throttle that may block up. Use a guitar string-sized wire to clean them.

 

Set up your throttle to show 0.020" of transfer slot from underneath the carby. This is the correct initial idle setting for all Holleys.

 

Make sure all of your air bleeds are clean too, they're just as important as jets.

 

Power valve number should be 1/2 your idle vacuum reading.

 

On vac Holleys there's a linkage from primary to secondary that needs adjusting so that the primaries fully shut off the secondaries. If it doesn't, your throttle might hang up slightly from the secondaries not closing after getting on it.

 

Oh and get yourself the nastiest carby cleaner you can find. Dip the whole lot in vinegar overnight to clean it all up

 

That's all I got

[bear351c 10,273]

Thermoquad. Good fuel economy.

 

Holley. Stops paperwork flying off bench.

[PRO250 1,506]

give this bloke a call

shane walker
54613613

this blokes a gun and cheap as hell ive been using him for a while does good work and the carbys mostley turn out like new

he is in Maryborough but you can stick it in a freight bag he will do and return

[deankxf 20,329]

thermoquads crack/break when you get a backfire on lpg(dual fuel) then set fire to the engine bay if you switch over to petrol. for dual fuel you should definitely run a holley, but in that case its hardly worth putting a kit through it as it will dry out and get a flat spot before long anyway(accelerator pump mostly)

[XTREME KARTS XF 1,212]

Thought i'd bring this thread back from the dead.

 

The 600 Holley is in desperate need of an overhaull, i've noticed that theres a Quickfuel gasket kit as well as the Genuine Holley kit.

What brand of gasket kit should i get? Of course i wanna re-kit it myself

[hendrixhc 10,921]

Thermoquad. Good for holding the shed door open.

 

Holley. Makes falcons fly down the road.

 

fixed

[FORD_MAN 1,026]

I'd just grab the holley kit, if it's a vac sec don't forget to check the vac diaphragm and are sold separately,

another tip is run a seal pick around the fuel rail O ring to make sure its not twisted as they like leaking.

[gerg 10,871]

I found the Quickfuel one to be ok, some bits lacking in quality, like replacement idle screws with dodgy threads. They come with all kinds of base gaskets for all sizes of carby but you need to specify spread or square bore.

 

Holley kits are model-specific i believe.

 

Vac diaphragms come in 3 types (length of pushrods varies).

 

Hume performance sells every nut, bolt, gasket, washer you can think of for Holley carbies as well as some Rochester bits. They do online order and delivery too.