Machining the choke off a Holley
- Thread starter Malcolm
- Start date
Basicall you machine it down level with the top of the air cleaner retaining ring and blend it in smoothly with a sanding roll. Dont forget to plug the hole that the choke linkage goes thru with epoxy. If you check out a few drag race sites you will get a better idea.
I've just used a hack-saw to cut them off.
You're done!
Now - Why do you need to do this? I typically only do it when I have a low clearance / scoop issue.
- Completely disassemble the carb.
- Leave the accelerator pump nozzles in place.
- Masking tape over the front rear and bottom of the throttle body itself to keep shavings and specs from getting into the carb.
- Put a dob of chassis grease over the air-bleed orifices.
- Cut away the air-horn (leave the center part that holds the air cleaner stud)
- Radius the edges with a die-grinder or files.
- Remove tape
- Carefully pick the grease globs out of the orfices.
- Wash thoroughly with Lacquer thinner, warm water and liquid soap.
- Blow clean with compressed air making sure to have air coming through all the orifices.
You're done!
Now - Why do you need to do this? I typically only do it when I have a low clearance / scoop issue.
I have never used the choke in 19 years for starters. Then if you look at the air flow when inside an air filter, the choke walls reduce the access into the carb. As I am about to have the car on a rolling road, now is as good as time as any to finally do what I thought about doing for all these years. Have own mill and hack saw so no costs involved (unless I screw up!). You do see this mod on a lot of Holley based race cars so there must be something in it. Once I have milled and cut it up, I will be sending it off to a specialist to re build it as it hasn't been touched for 10 plus years and then to rolling road and on to Spa!
Thanks for the tips guys, much appreciated.
Thanks for the tips guys, much appreciated.
Malcom,
Jegs or Summit;
PROFORM replacement main bodies
Some guy's say they have had machining tolerance issue's with them, I've had nothing but good luck with though.
Holley also sells them a-la-carte, I think.
S
Jegs or Summit;
PROFORM replacement main bodies
Some guy's say they have had machining tolerance issue's with them, I've had nothing but good luck with though.
Holley also sells them a-la-carte, I think.
S
Well I machined it all off this afternoon. Spent most of the time prepping the carb. Took a different approach to that described above in that I kept the carb built up. Used cling film and tape to secure any orifices from swarf. I think machining is better than hack sawing as the swarf is good and chunky so less likley to go where it is not wanted. Tidying up with a little file after was the most risky bit for swarf invasion. Test starting the engine hopefully tomorrow when I refit the normal exhaust system (cos it is quieter!).
Ron Earp
Admin
Hey Malcolm,
I shudder to think what a specialist in England is going to charge you to rebuild your stone age simple Holley. Buy the $10 book from Amazon, a $15 carb rebuild kit, and do it yourself. You've got the skillz, put them to use. We had to learn how to rebuild a Holley or Carter by third grade here in the Southeast, part of our redneck heritage!
Which reminds me, I need to rebuild the one on the Torino so it'll stop mosquito fogging the neighborhood with fuel.
R
Howard Jones
Supporter
Malcom. You gotta post pics with a project like this, buddy. That's half the fun of GT40s.com. Checking out other people's ideas.
RichardH
AKA The Mad Hat Man
$15? - the kit that I got was about £65 - the exchange rate isnt that bad is it?
Ron Earp
Admin
No, it is just that you guys get hosed on prices for anything having to do with American engines. I imagine the Holley rebuild book will be twice as much too!
Ha! Took some this afternoon! But none of the carb in clingfilm! Sorry to the PVC lovers out there. Have been made an offer on carb rebuild books so will be using the $15 wisely, or was it £15?
Car is running well post op and even starts better than before so maybe I don't need to rebuild it and can leave it another 15 years. I mean it is a Holley not a namby pamby set of Webbers that need fettling each time you start the car now! Honest, not trying to stir it up between webber and holley sides.....Have been thinking of a heat shield under the carb and maybe a home built air filter casing. I am not keen on the Ford Motorsport round chrome look even with my K&N element. Anyone made a plenum/air filter for a Holley? Now that would be worth a picture or two. I will try and post my pics tomorrow. Getting close to test running Mick Sollis's work at Southern GT on the chassis surgery, someting I am very much looking forward to doing.
Here are the pictures of the carb post machining. It is running well so overall a worthwhile job. Thanks to Anthony for help with some rebuild books. And also to the others who have sent PMs with other web places to visit for more ideas and tips. My prime aim now is to get the car ready and reliable for Spa at the end of the month which even though is a decent time away is not much time due to a busy schedule, including crewing for Glenn at Le Mans for the Friday parades in his Southern GT. Never been to Le Mans before so first visit includes being IN the parade is pretty cool for me. Those exhausts really do need coating again!
Attachments
Howard Jones
Supporter
Nicely done. Thanks for the pictures.
Here is a 650 that has got the "Full Monte" done to it, drop leg boosters, thin throttle plates, Choke tower removed, all edges radiused and flowed, removable air bleeds, 4 corner idle, different linkage and resized idle feed restrictor, 650 DP is very fat at idle.
http://i725.photobucket.com/albums/ww256/Rick289/Picture181.jpg
http://i725.photobucket.com/albums/ww256/Rick289/Picture181.jpg
Hi Rick,
My 650 could never look like that with the choke tower removed as it does not have the meat in it to radius the corners like that. Clearly that is a better result than what I have acheived but it looks like it was cast differently from day one. When my air filter is on actually the flow of air is not too broken up by the top of the holley post machining, so I think I have acheived about 90% of the air flow improvements possible. You definately look to have about 100% of the air flow improvememt achievable. And with the other mods, that is a proper carb. What do you mean by fat at idle? Lumpy? Rich? That is a new term to me.
My 650 could never look like that with the choke tower removed as it does not have the meat in it to radius the corners like that. Clearly that is a better result than what I have acheived but it looks like it was cast differently from day one. When my air filter is on actually the flow of air is not too broken up by the top of the holley post machining, so I think I have acheived about 90% of the air flow improvements possible. You definately look to have about 100% of the air flow improvememt achievable. And with the other mods, that is a proper carb. What do you mean by fat at idle? Lumpy? Rich? That is a new term to me.
Yes, Rich.
Malcom it is the exact same casting. Look at it closely. The cutter in the mill was taken all the way down the the flat surface outside the choke horn. I left 4 small sections of the air filter housing rgister at 90 degree intervals to locate the air cleaner. Then radius the edges evenly.
Malcom it is the exact same casting. Look at it closely. The cutter in the mill was taken all the way down the the flat surface outside the choke horn. I left 4 small sections of the air filter housing rgister at 90 degree intervals to locate the air cleaner. Then radius the edges evenly.
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