Bell Housing Accellerator lever

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gregg hake
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Bell Housing Accellerator lever

#1 Post by gregg hake »

Hi

I'm trying to adjust my gas pedal to carb linkage and cant get it to fully open the throttle body.

1. Looking at the bell crank, it looks different that the few I see in diagrams in that the arm the throttle rod connects to is shorter than the one the looped wire connects to on mine. Significantly shorter...50 mm for the throttle rod arm and 80 mm for the looped wire end. Is that correct?

2. In the attached picture, my arm with the throttle rod is at 6:00 o'clock at rest. Is that correct? It seems to not be able to pull the crank far enough to open the throttle body all the way.
IMG_4698.jpg
IMG_4698.jpg (669 KiB) Viewed 972 times

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Paul Ahnell
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Re: Bell Housing Accellerator lever

#2 Post by Paul Ahnell »

Throttle Linkage Adjustment.pdf
(3.69 MiB) Downloaded 58 times
Greg: Looks like you have a late B or C. if you have a 741 twin mount tranny, the short answers are : #1 - yes; #2- no.

See attached Workshop Manual Fig. 9 on page SF 26. Note that "...the distance from the rotation center to the ball joint center is 20 - 21 mm...." It appears that you have to extend the length of the link from the pedal (the one with the rubber vibration dampener) so that the inner bell crank arm is at ~4:00 - 5:00. not 6:00.

FYI: There are several different lengths of the looped rod depending on your tranny. See Stoddard for those available.

Also, See the attached procedure by Ab Tiedemann. Step by step, don't start in the middle. Pete Zimmermann had a good writeup on servicing the accelerator linkage in the Jan/Feb '02 issue of the Registry Rag. 6 pages. I'll e-mail if you wish. Good luck.

Paul
Paul Ahnell
'60 Normal Coupe

gregg hake
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Re: Bell Housing Accellerator lever

#3 Post by gregg hake »

Interesting. I adjusted the angles and distances on the Bell Crank on the fan housing so that part is correct. The ability to connect the pull rod from gas pedal to tranny bell crank and have the crank at 4:00 o'clock...I'll have to look at that because it appears I am 3/4 of an inch short on rod length. I already have all the pull rod-associated ball sockets at maximum length.
All of these components were operational when I put the car on blocks and started the rebuild (decades ago), but I never checked to see if it was adjusted correctly back then.

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Paul Ahnell
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Re: Bell Housing Accellerator lever

#4 Post by Paul Ahnell »

Greg: It sounds like you have the wrong loop rod; too short. I have a '60 coupe w/741 dual mount. I just went through this and had a similar situation. I found that my loop rod was 516 mm long (installed by some PO) where the correct length should be 545 mm for a 741 dual mount. I used Ab's instructions to adjust and was barely able to use the 516 mm by extending everything in the train to just about the last thread but it gave me a poor pedal configuration. I got a 545 mm from Stoddard. I haven't yet installed it but it should put everything in the correct position with some wiggle room left on the threads and a better pedal position.

Make sure you have the proper loop rod and measure/adjust tranny bell crank position to 21 or 22 mm per the spec.

Paul
Paul Ahnell
'60 Normal Coupe

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Dave Wildrick
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Re: Bell Housing Accellerator lever

#5 Post by Dave Wildrick »

Another trick for adjusting the accelerator linkage was suggested year ago by guru Mike Robbins (sadly now deceased):

Subject: Re: Throttle linkage--"coat hanger" and end-end adjustment
From: mike robbins <robbinsroost@worldnet.att.net>
Date: Mon, 19 Aug 2002 22:27:05

It isn't unusual for the "coat hanger" link to have to be readjusted after
putting the engine back in. And if you also had the trans out, there's all
the more chance of losing the adjustment. This is one of those things that
theoretically shouldn't change but somehow does. It sounds like yours is
too loose...that your initial pedal travel is taking slop out of what you
call the "flattened loop".
In order to gain more adjustment on the link I cut it in two and splice it
back together with about a 4" length of wire or rod the same, or nearly,
diameter. Use the copper electrical splicing connectors that resemble very
small U-bolts. Your friendly hardware store should know what I'm talking
about. By altering the length of the splice, you change the overall length
of the link...you can adjust the bejesus out of it....2 or 3 inches.
Mike Robbins
Dave Wildrick
Houston, TX
#10230
64C coupe
65C coupe

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Ron LaDow
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Re: Bell Housing Accellerator lever

#6 Post by Ron LaDow »

Also: download/file.php?id=57178&mode=view
And someone deserves credit for that; anyone know who did it?
Ron LaDow
www.precisionmatters.biz

gregg hake
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Re: Bell Housing Accellerator lever

#7 Post by gregg hake »

Hi

Is everyones bell crank lever starting at 400?

My most obvious shortage that I see is the pull rod that goes from gas pedal to tranny bell crank. If the bell crank arm is supposed to be at about 4:00 o'clock, as Mr. Ahnell says, then my Gas pedal ->Bell crank lever pull rod is way short.

This makes sense to me since (currently, with lever at 6:00) the depressing of the gas pedal cant pull the lever far enough to pull the looped wire/rod far enough to open the throttle to max.

Currently, depressing the gas pedal moves the lever from 600 to 800 and the throttle isn't open all the way. You cant pull the lever any farther because the arm is pointing at the gas pedal pull rod. If I can somehow lengthen my gas pedal pull rod and start at 400, then depressing the gas pedal has a MUCH longer throw possibility...from 400 to 800 (where it cant pull any more).

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Dave Wildrick
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Re: Bell Housing Accellerator lever

#8 Post by Dave Wildrick »

Ron LaDow wrote: Tue Jul 23, 2019 11:31 am Also: download/file.php?id=57178&mode=view
And someone deserves credit for that; anyone know who did it?
Ron,
I have this same drawing connected to a post on the throttle linkage by Sterling Vaden in Aug 01, 2009.
Dave Wildrick
Houston, TX
#10230
64C coupe
65C coupe

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Paul Ahnell
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Re: Bell Housing Accellerator lever

#9 Post by Paul Ahnell »

Gregg: Yes, but....Let's look at it this way: instead of starting at 6 you start at 4 (more or less, by adhering to the 20-21 mm dim.) and pull to 8 or 9 you'll be pulling a greater arc, thereby pulling the loop rod farther forward, and thereby opening the carb to a greater degree.

Follow Ab's procedure from the start and set the tranny bell crank to the 20-21 mm dim.

It looks like you have a few threads to play with on both ends of the rod forward of the tranny bell crank, and don't forget you have some more linkage threads available under the driver's side floor board. Use them all to get that 20-21 dim. If some Turkey in the past cut your forward rod short and rethreaded it (doubtful) get a new one.
Paul Ahnell
'60 Normal Coupe

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Tom Keating
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Re: Bell Housing Accellerator lever

#10 Post by Tom Keating »

Hi Gregg,
While you are doing the linkage,replace the rubber coupler with newer metal style. The rubber tends to fail at worst time.
Tom
Tom Keating
1964 356C Sunroof

gregg hake
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Re: Bell Housing Accellerator lever

#11 Post by gregg hake »

Hi

"While you are doing the linkage, replace the rubber coupler with newer metal style. The rubber tends to fail at worst time"

Yeah, I am getting a new one. Am I the only guy to notice that on the Stoddard site, it costs 123.93 and on the NLA site it costs 12.98 dollars !! That Stoddard version must be some high quality rubber !!

gregg hake
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Re: Bell Housing Accellerator lever

#12 Post by gregg hake »

Hi
1. As Mr. Ahnell suggested, I lengthened the pull rod by unscrewing everything as much as possible and found the coupler on the gas pedal end has a ton of threads compared to the other sections, so I may be OK on length. Thank you for the suggestion. I didn't think there was any leeway on that as I saw a lot of thread showing.
As far as my comment on prices, I spoke with Stoddard today and they say the 123 dollar price is correct on the coupler, but that is a genuine Porsche part. Then he said they have an aftermarket version that is functionally identical (not shown on the website) and it is 12 dollars. I opted for the aftermarket version !!
Once it comes in, I should have everything I need to get the linkage adjusted.

Thanks All.

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