Q-jet Choke differences
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
Q-jet Choke differences
For the mechanical chokes (bi-metal coils on the intakes) there are several different versions listed for different engines and years.
All else being equal, would an aluminum intake need a different choke than a cast iron one? (aluminum transferring heat faster, or dissipating the heat faster)
Mooser
All else being equal, would an aluminum intake need a different choke than a cast iron one? (aluminum transferring heat faster, or dissipating the heat faster)
Mooser
Drifting
Joined: Apr 2002
Posts: 1,720
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From: Manhattan Beach Ca
You can use the same mechanical coil chokes but you need the correct adaptor/rod kit for the particular intake. For instance Edlebrock intakes offer a few different choices for adaptors. The hard part is getting the rod correct after the length changes because even the adaptor kits arent always perfect. Some intakes can use direct stock setup, all depends.
Team Owner
Joined: Jan 2006
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From: Crossville TN
The bi-metallic coil only cares about temperature, not what the intake is made of. So, the correct choke coil for that particular carb will work OK on either intake manifold. If the distance from the machined pad [for that choke coil] to the mounting surface for the carb is different between the alum and iron manifolds, the choke rod will need to be a different length, accordingly.
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
I know the choke coil will still look for the certain temp but was more curious on how long it takes for an aluminum intake to reach that temp vs how long the cast one would take and if that would make any noticable difference on to the carb and the startup.
The lingages are a different story, might have to get PO Bubba in here to "adapt" them
Thanks
Mooser
The lingages are a different story, might have to get PO Bubba in here to "adapt" them
Thanks
Mooser
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
The aluminum intake will heat up quicker than cast iron, but it is heating both the carb and choke coil at the same rate. Thus, the alum intake will just allow the choke to release sooner than on the stock intake. No big deal...
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
That makes a certain amount of sense.
I guess I've known how the choke works but never put much thought into why the choke works (or what it's choking for?)
I was thinking more along the lines of it waiting until the engine warmed (combustion, oil, etc) rather than when the carb warmed.
Really the difference in how long it takes would probably be pretty insignificant anyway.
Well, hopefully I'll find out shortly
Thanks again
Mooser
I guess I've known how the choke works but never put much thought into why the choke works (or what it's choking for?)
I was thinking more along the lines of it waiting until the engine warmed (combustion, oil, etc) rather than when the carb warmed.
Really the difference in how long it takes would probably be pretty insignificant anyway.
Well, hopefully I'll find out shortly
Thanks again
Mooser
Team Owner
Joined: Jan 2006
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From: Crossville TN
Well, you are far enough north to actually need the choke. With cold fuel and cold engine, the choke just reduces the amount of air coming into the engine. That provides a 'rich' fuel situation for easier starting and running until it warms up a bit. When new, even in very cold weather, you could 'pop' the throttle and have the choke drop out after only a minute or so. If you didn't 'pop' the throttle, the choke would stay on for 3-4 minutes before dropping on its own.
Thread Starter
Race Director
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From: North of Toronto - Ontario
Nah, we've been have pretty consistent 25-30+ C (that's high 70's to mid 80's) here for the past while. I thought the choke wasn't working at all until I hit it with some freeze spray.
The primary is not closing as far as I expected but the fast Idle seems to be working now.
Once everything is warm all seems to be working very well, start-up just seems like it could be slightly better.
I think next winter the whole thing deserves a complete teardown and once over.
Thanks
Mooser
The primary is not closing as far as I expected but the fast Idle seems to be working now.
Once everything is warm all seems to be working very well, start-up just seems like it could be slightly better.
I think next winter the whole thing deserves a complete teardown and once over.
Thanks
Mooser
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Team Owner
Joined: Aug 1999
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From: Ontario
I know the choke coil will still look for the certain temp but was more curious on how long it takes for an aluminum intake to reach that temp vs how long the cast one would take and if that would make any noticable difference on to the carb and the startup.
The lingages are a different story, might have to get PO Bubba in here to "adapt" them
Thanks
Mooser
The lingages are a different story, might have to get PO Bubba in here to "adapt" them
Thanks
Mooser
Thread Starter
Race Director
Joined: Apr 2011
Posts: 11,183
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From: North of Toronto - Ontario
Most of mine were disconnected, missing and one was in backwards
Finally got them all in the right places and just re-did the Lars papers. Everything seems perfect except the choke isn't quite right
Not a big deal, just have to baby it for the first little bit until it's happy to run
Mooser
Finally got them all in the right places and just re-did the Lars papers. Everything seems perfect except the choke isn't quite right
Not a big deal, just have to baby it for the first little bit until it's happy to run
Mooser