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vortec upgrade, what about the choke

G

Gary_D

New member
Any suggestions? I have quadrajets and the new aluminum intakes have no provision for a choke rod/heater. What have others done? run without it?
 
The Vortec engine in a car or truck was either TBI or MPI. The exhaust heat crossover ports were eliminated.
I would go with the electric pull-off choke units.

The helix is what is what closes the choke plate, and the electric element is what heats the Helix and causes it to open the choke plate.
I'd do a search for Quadrajet electric choke conversions.
However, I'm thinking that not all Q-jets lend themselves to this conversion.
Give it a search and see what you find.

Gary, not that you asked, but if your engines are raw water cooled, you will eventually have issues with the aluminum intake manifolds. Not necessarily soon, but perhaps eventually.
If these are closed cooling systems, no issues.


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J C WHitney used to sell a choke kit that used a temp sensor you bolted to a hot surface. Worked very well.

Jeff
 
They make kits for the divorced style of chokes...depending upon the specific manifold you are using, you have to do some minor fabricating. Just remember, it is usually easier to shorten the link than it is to 'extend' it.
 
makomark said:
They make kits for the divorced style of chokes...depending upon the specific manifold you are using, you have to do some minor fabricating. Just remember, it is usually easier to shorten the link than it is to 'extend' it.
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Mark, point well taken, but I think there's a problem.
The Vortec cylinder heads no longer offer the exhaust cross-over ports, and neither do the Vortec intake manifolds accommodate for any exhaust cross over.
So even if a Helix pull-off unit could be adapted, there may not be enough heat to sense for full helix operation.

IMO, his best bet would be to find and adapt the electrically heated helix pull-off unit. But like said, I'm not sure that all Q-jets lend themselves to this conversion.

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RicardoMarine said:
Mark, point well taken, but I think there's a problem.
The Vortec cylinder heads no longer offer the exhaust cross-over ports, and neither do the Vortec intake manifolds accommodate for any exhaust cross over.
So even if a Helix pull-off unit could be adapted, there may not be enough heat to sense for full helix operation.

IMO, his best bet would be to find and adapt the electrically heated helix pull-off unit. But like said, I'm not sure that all Q-jets lend themselves to this conversion.

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Click to expand...

This appears to be my situaion. I could maybe find a pair q-jet cores somewhere with the itegral choke that can accept an electric heater - big hassle though since the part that I need is the main body of the carb - total rebuild in order. I could buy the appropriate carbs new or rebuilt - big expense. I could jury rig a manual choke - I don't really want a rigged up choke. I'm learning a lot about these vortecs - they look just like a plain old sbc until you look closer - expensive roller cams, expensive lifters, expensive down thrust capable distributor, expensive pistons, rings. I sure hope those couple extra ponies are worth it. BTW rick , I do have closed cooling so the alum corrosion is not an issue.
 
Gary, earlier I assumed that you installed Vortec cylinder heads on your existing blocks. I now read that you went with the Vortec engines. You mentioned expensive pistons. Can you explain this?
Expensive pistons may mean a LC Quench style, of which would be excellent, if that's the case. Otherwise, the GM Vortec engine is typically fitted with the full dished pistons. If so, carefully watch your ignition TA.


As for the chokes, somewhere and somehow, you may need to just bite the bullet! Either replace the Q-jet$, or rig up a cable choke system. You did mention being in Florida. You may get by without the chokes.

Q-jets are somewhat prone to fuel evaporation. The Vortec engines should have electric fuel pumps on them. If you install a momentary helm switch to activate the fuel pumps, you can prime these, and you'll start out with accelerator pumps that will squirt fuel right out of the gate.
This may help in the warm Florida climate if you forgo the chokes.

BTW, to my knowledge, there are no new Q-jets. Any that you find today will be re-manufactured. There is a Holley spread bore that makes for a decent replacement, and these would have the electric helix heating element.


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The J C Whitney kit I mentioned does the job you need done. It has a sensor to determine engine heat, which opens the electric choke on schedule. Works great. Had one on my old RV.

Jeff
 
RicardoMarine said:
Gary, earlier I assumed that you installed Vortec cylinder heads on your existing blocks. I now read that you went with the Vortec engines. You mentioned expensive pistons. Can you explain this?
Expensive pistons may mean a LC Quench style, of which would be excellent, if that's the case. Otherwise, the GM Vortec engine is typically fitted with the full dished pistons. If so, carefully watch your ignition TA.


As for the chokes, somewhere and somehow, you may need to just bite the bullet! Either replace the Q-jet$, or rig up a cable choke system. You did mention being in Florida. You may get by without the chokes.

Q-jets are somewhat prone to fuel evaporation. The Vortec engines should have electric fuel pumps on them. If you install a momentary helm switch to activate the fuel pumps, you can prime these, and you'll start out with accelerator pumps that will squirt fuel right out of the gate.
This may help in the warm Florida climate if you forgo the chokes.

BTW, to my knowledge, there are no new Q-jets. Any that you find today will be re-manufactured. There is a Holley spread bore that makes for a decent replacement, and these would have the electric helix heating element.


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Well, Expensive is a relative term. plus I may be a little tight with a buck. I went with factory style full dish ( I know, I know) I was afraid of balancing issues using different parts. They were around $250 for each set.
that compares to about 80 bucks for plain old sbc's

I'm looking forward to the electric fuel pumps , no more crank crank crank crank after a few days of not running the motors. Hopefully with the full full bowls at get go she'll fire right up sans choke with just a few pumps of the accelerator . I really dont want to buy two new carbs. Mo money, mo money mo money.
 
Gary_D said:
I was afraid of balancing issues using different parts. They were around $250 for each set.
that compares to about 80 bucks for plain old sbc's
Click to expand...
Gary, you'll do just fine the way they are. Just watch your TA.

But should you ever do this again, build yourself a quench effect into the combustion chamber and take full advantage of the Vortec chambers.
Nothing else needs to be modified with exception to the compressed head gasket thickness.
The benefits will be noticed. :D


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