Remove Vacuum Advance?

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
huskerjeep
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Re: Remove Vacuum Advance?

Post by huskerjeep » Fri Oct 07, 2011 6:45 am

Hopefully these pics can clarify what i have. Sean's description sounds the closest. Looks to me like the distrib gets twisted slightly by the "can" .
V_Advance 001.jpg
Here is where it comes out of the intake.
V_Advance 001.jpg (94.38 KiB) Viewed 2627 times
V_Advance 002.jpg
Here is the distrib. and vac advance.
V_Advance 002.jpg (88.17 KiB) Viewed 2627 times
How the vac advance "can" is attached.
V_Advance 006.jpg
V_Advance 006.jpg (128.65 KiB) Viewed 2627 times
My carb is a Carter so I'm not too confident it has a port to attach the line to..thus the port on the intake manifold.
Early March 1944 MB 313xxx


huskerjeep
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Re: Remove Vacuum Advance?

Post by huskerjeep » Fri Oct 07, 2011 6:47 am

An inside view of the distributor guts. Not sure if it's possible to tell that there is a mechanical advance or not from this view.
V_Advance 007.jpg
V_Advance 007.jpg (143.66 KiB) Viewed 2626 times
Early March 1944 MB 313xxx

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Sean Collins
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Re: Remove Vacuum Advance?

Post by Sean Collins » Fri Oct 07, 2011 7:28 am

huskerjeep wrote:Hopefully these pics can clarify what i have. Sean's description sounds the closest. Looks to me like the distrib gets twisted slightly by the "can"
Yep, that's a narrow-body IGW series distributor (IGW-4129 or 4189), used on '46 thru '51 station wagons, Jeepsters, pickup trucks.

You can remove it entirely (you'll need a standard hold-down clamp to replace it), but it's still not "correct" for an MB :wink:

The mechanical advance weights are under the breaker plate.
My carb is a Carter so I'm not too confident it has a port to attach the line to..thus the port on the intake manifold.
Looks like you have the vacuum port on the throttle body, plugged w/a pipe plug.

Sean

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Re: Remove Vacuum Advance?

Post by Marty, SoCal » Sat Oct 08, 2011 6:17 am

If you have the Vacuum advance connected to manifold vacuum, it will be adding advance at idle, and under light loads. This can be an advantage. You can have the initial advance set to normal setting of 5*, or even at retarded a bit at 0* TDC, this will allow easy starting. Then once the engine starts the vacuum advance will kick in adding (usually) about 10* timing. The modern gas will allow this advanced timing, compared to the original 68 Octane fuel. To maintain the normal idle speed, the throttle idle stop screw may need adjusting. Under part throttle, the engine will be making around 15" vacuum, which will add vacuum advance, too. At full throttle, the vacuum advance will come off, which would help prevent detonation from over advanced timing. The added advance under light loads will add to your fuel economy and part throttle power.

It would take a little bit of trial and error or dyno time to see what your best combo of initial timing, vacuum advance setting and mechanical advance curve to get the most out of the system. Some speed shops still have a distributor tuning machine where they can test and adjust the mechanical advance curve to your specs.
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Re: Remove Vacuum Advance?

Post by Wolfman » Sun Oct 09, 2011 6:17 am

Interesting ideas, Marty.
First thing that comes to mind though is the disclaimer read at the beginning of extreme TV shows.
" What you are about to see is being performed by trained professionals and shouldn't be tried at home."
You, myself and a few others know what you are talking about.
A lot of others don't, but will try it anyway.
In the best interest of happy jeeping, I would hook things up the way the were designed.
To those that decide to try alternate systems or settings, but not sure what you are doing.
Get a little help from someone who understands what your up to.
And have fun with the experience. :D
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Re: Remove Vacuum Advance?

Post by Marty, SoCal » Sun Oct 09, 2011 11:44 am

I've been looking for a vacuum advance distributor to play with on my GPW, I read one of the Willys sites where the poster stated in one of the pics that they had used a modified Nissan distributor on the "Racing" flathead willys. I might hit the bone yards and pick one up to play with. (I have a lathe and a milling machine)

http://clubs.hemmings.com/clubsites/woc ... 12.htm#top" onclick="window.open(this.href);return false;

Some of the older Nissan/Datsun distributors have the proper counterclockwise rotation, with a vacuum advance.
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Re: Remove Vacuum Advance?

Post by Wolfman » Mon Oct 10, 2011 4:46 am

I'm thinking the Nissan dist. would have really been modified.
Beside fitting the hole, the RPM range between a 134 Go Devil and a Nissan is a pretty wide spread.
I would think a collection of distributor springs, modified orginal weights for an original willys dist. and the distributor machine you brought up earlier might be an easier route.
Change the dist. gear on a later Dist. from gear to chain drive would solve the direction of rotatation problem.
Don't know what to do about the vacuum can spring to change that rate. Don't think the can is easily disassembled.
Also thinking you have a lot more time than I do. :roll:
Sounds like fun. After I retire. Make that if ! :D
Mike Wolford
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Re: Remove Vacuum Advance?

Post by Joe Gopan » Mon Oct 10, 2011 4:53 am

And a well tuned CJ, or Military 4 Cyl Jeep will give a Jeep with a vacuum advance a run for its' money. The postwar 4 cyl Jeep vehicles having Vacuum advance also had higher speed diffs. :wink:
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Re: Remove Vacuum Advance?

Post by Marty, SoCal » Mon Oct 10, 2011 7:01 am

I've got the 8-1 aluminum head, and an overdrive on my GPW, cruises nice at high speeds on the freeway! Mainly hoping that a vacuum advance will pick up the gas mileage a little bit.

Wolfman, Can't change the rotation of the gear on the oil pump, it wouldn't mesh with the cam properly. Many engines like max mechanical advance all in by 3600 rpm or so. Well within the range of the L134.

I've also been kicking around modifying a CCW rotation Pontiac V8 HEI distributor. Have to see if a Chevy Vega HEI 4 cylinder cap will fit the V8 base. The housing would have to have the base turned down to match the opening in the block, and the shaft would need to be extended, and of course, the large housing would need to clear the block. A points type Pontiac Distributor may also be an option, since it's smaller. The GM/Delco distributor is very easy to tune and parts are cheap.

Going further off the deep end....A buddy of mine wants me to add Megasquirt EFI and turbo it. :shock: (He's an Import/Honda tuner) With Megasquirt EFI You can eliminate the distributor functions all together, and run a coil pack by fabricating a tone ring and sensor for the crank pulley, the computer sets the timing curve through laptop programming. TBI or Multi point injection replaces the carb. A small Turbo with around 5psi boost would really boost the power. Would probably start fresh using a CJ gear drive block. Not sure I'm going to do that unless I hit the lottery! I don't know if you guys have seen this Turbo CJ-5, sounds pretty cool!
http://www.youtube.com/user/acme663ryo# ... WEPxpDq49A" onclick="window.open(this.href);return false;
43 Ford GPW 92098
53 Dunbar Kapple M100
Sold: 61 CJ-5, 41 T207 WC-1 Dodge closed cab pickup
MVPA #8266
USMC Tanker (1811, 1812), 85-93
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Re: Remove Vacuum Advance?

Post by Wolfman » Tue Oct 11, 2011 4:30 am

Brain Fart ! :oops:
You can't just change the dist. gear. Got me !! :lol:
Now I know you have more time than I do. If you get this Turbo, Fuel injected Go Devil built, Send me a picture.
I would sure like to see it.
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Re: Remove Vacuum Advance?

Post by Chuck Lutz » Tue Jul 25, 2017 10:03 am

BTT
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