toronado Carb

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harascho
Posts: 95
Joined: Fri Oct 19, 2012 9:04 pm
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Years Owned: 1966 Toronado Deluxe owned 1 year

toronado Carb

Postby harascho » Sun Mar 19, 2017 12:29 am

Hi folks,

I am thinking about some carb upgrade for my 1966 Toronado. Despite all actions my old carb is still leaking from the fuel bowl into the manifold. After just one day sitting it needs serious cranking to restart.
I repaired the well plugs with threaded plugs and glued them in. They withstood the soap and pressurized air test, but there was no change from the very beginning.
I am tending towards the complete aluminium casting beeing the cause of the trouble. Over the years it might become porous..

To give me something to work with I am looking for the latest electric choke Quadrajet comming of a 455 V8 to start with.
In which years of a 455 Toronado could I find something suitable? The younger the better...

Here's a more brief summary of the current situ:

The engine was overhauled, bored, mild cam, roller rockers added, still flat tappet lifters.
The pistons are + 0.040“ from Racetec and the engine now is a 434 cui instead the original 425 cui. Compression is around 9,7 :1

I overhauled the carb after a lot of research as I guessed my experience would be ok.
I cleaned, straightened the body, bushed the shafts, installed new Cam, a gasket kit, removed the idle tubes, cleaned everything and installed new ones, drilled out the well plugs, threaded the body, built threaded plugs and glued them in place….

This is what I’ve got now:

Problem 1 „Starting after sitting a while“:

Once started and driven it starts after the first turn oft he key. Sitting a day or two you have to crank it a lot until it will start. Sounds to me the carb is still leaking fuel although the well plugs were addressed. I installed a glass bowl fuel filter to see if that empties in that time.. -> NO. It stays at the same level and with the turn of the key the new fuel pump immediatly pumps fresh fuel through the filter.

Problem 2 „ Performance“
I would have expected a little more uuuumph from that new setup. I’m not able to „smoke the tires“, it still doesn’t feel like a almost 400 hp car.
It has good VAC, a nice rumbling idle, there are no VAC leaks around the carb, from the plugs color it runs a little lean. What I see at the carb that the top gasket always is a little wet with fuel.
The secondarys open, the throttle blades open to a full 90 deg.


cheers

Harald
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bcroe
Posts: 158
Joined: Thu Nov 15, 2012 12:25 pm
TOA Membership Number: 378
Years Owned: 79 Toronado or Eldorado

Toronado Carb

Postby bcroe » Sun Mar 19, 2017 5:11 pm

Check that your switch pitch trans is going to high stall when you push it hard; run the
click test. If not, you will loose performance. It will work even better by replacing the
factory control with with an electronic. Bruce Roe

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Chazzer
Posts: 120
Joined: Mon Jul 13, 2009 7:17 pm
TOA Membership Number: 146
Years Owned: 1968 Ocean Mist Metallic, purchased September 2005 in Ottawa Ontario. Car was brought up from West Virginia in the mid 90's apparently.
Location: Ontario, Canada

Re: toronado Carb

Postby Chazzer » Sat Apr 01, 2017 9:46 am

Is the carb warped? It is pretty common. I do know that hard starting and gas draining out of the card is a very common problem with the Q-jet and Olds 455 combo. One just needs to attend a GMC Motorhome rally to have an idea on how rampant the problem is.

User avatar
harascho
Posts: 95
Joined: Fri Oct 19, 2012 9:04 pm
TOA Membership Number: 0
Years Owned: 1966 Toronado Deluxe owned 1 year

Re: toronado Carb

Postby harascho » Sun Apr 02, 2017 9:37 am

The carb was wrapped.... I took care of it with a special jig and several heating / cooling cycles.

cheers

Harald
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bcroe
Posts: 158
Joined: Thu Nov 15, 2012 12:25 pm
TOA Membership Number: 378
Years Owned: 79 Toronado or Eldorado

toronado Carb

Postby bcroe » Sun Apr 02, 2017 6:31 pm

1. Some of us get fed up with wearing out the starter getting an infrequently
driven car started, so a low pressure electric pump is put in the fuel line. Push the
button for a few seconds before the first start; don't use a switch that could be
left on.

2. Did you check the switch pitch yet? Bruce Roe

MNfirefighter
Posts: 11
Joined: Sun Jun 26, 2016 1:08 pm
TOA Membership Number: 1
Years Owned: 1966 Toronado Deluxe - all original - white exterior w/ plum interior

Re: toronado Carb

Postby MNfirefighter » Tue Apr 04, 2017 5:17 pm

crow, I like the idea of putting a low pressure electric fuel pump in line - where in line would this be installed?

bcroe
Posts: 158
Joined: Thu Nov 15, 2012 12:25 pm
TOA Membership Number: 378
Years Owned: 79 Toronado or Eldorado

toronado Carb

Postby bcroe » Tue Apr 04, 2017 9:21 pm

Fuel injected 70s cars and some others had a low pressure pump built into the tank
unit. Like EFI Cads, Cosworth Vega, and perhaps some others. Otherwise cut the
line somewhere. Bruce Roe

Schurkey
Posts: 127
Joined: Fri Aug 14, 2009 8:28 am
TOA Membership Number: 67

Re: toronado Carb

Postby Schurkey » Mon Apr 17, 2017 10:03 pm

harascho wrote:my old carb is still leaking from the fuel bowl into the manifold. After just one day sitting it needs serious cranking to restart.
I repaired the well plugs with threaded plugs and glued them in. They withstood the soap and pressurized air test, but there was no change from the very beginning... ...Sitting a day or two you have to crank it a lot until it will start. Sounds to me the carb is still leaking fuel although the well plugs were addressed. I installed a glass bowl fuel filter to see if that empties in that time.. -> NO. It stays at the same level and with the turn of the key the new fuel pump immediatly pumps fresh fuel through the filter.

Leaking, or EVAPORATING? First Guess: carb gets hot enough to boil the fuel out when you shut it off.

harascho wrote:I am tending towards the complete aluminium casting beeing the cause of the trouble. Over the years it might become porous..

Q-Jet main body and air-horn castings aren't aluminum.

harascho wrote:Problem 2 „ Performance“
I would have expected a little more uuuumph from that new setup. I’m not able to „smoke the tires“, it still doesn’t feel like a almost 400 hp car.
It has good VAC, a nice rumbling idle, there are no VAC leaks around the carb, from the plugs color it runs a little lean. What I see at the carb that the top gasket always is a little wet with fuel.
The secondarys open, the throttle blades open to a full 90 deg.

1. Cranking compression psi?
2. Exhaust restricted? (includes seized heat riser valve, which could also heat the carb and boil the fuel out.)
3. Modern fuel does not color the plugs enough to tell rich mixture from lean mixture.
4. What is your fuel pressure at heavy throttle, high RPM?

As has been said, a failed torque converter or switch-pitch converter control circuit will take all the fun out of standing starts.


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