PMO install and throttle linkage

[mgatepi]

Hello All,

I am installing PMO's on my 3.0 (83 sc) and have run out of adjustment in my throttle linkage. It appears that the throttle rod running thru the tunnel and connecting on the tranny is the problem. Anyone else experience this? Somehow I need to shorten this, but how? I have taken up all the available adjustment on the turnbuckles.....

Why am I having this problem?

Thanks
mg

[jpnovak]

I am assuming that you have adjusted the linkage on both the pedal and tranny ends.

I had the same problem adapting a 3.0 with webers to an early car.

The early carburetor bell crank on the transmission has a different angle between the two ball-joint connection arms.

At this point you have three choices.

1. shorten the throttle linkage rod in the tunnel. (cut off and thread down the end with a die)
2. shorten the throttle linkage from the bell crank on the tranny to the carb
3. replace the bell crank with the early style. This is the best choice as it offers better off-idle tip-in and low speed modulation.

[R_Builder]

You are having this problem because the throttle linkage in your '83SC was designed to properly manipulate a CIS throttle body, not a dual manifold carb setup .

Another option is to get the older style link that goes from the tranny bellcrank up to the bellcank on the LHS carb manifold. Plenty of used ones out there, but you can still get them new for about $100 as of this time last year. I need to look in my notes to see if I changed out the bellcrank on the tranny to the earlier carb style one. I think I did...

Those two changes created the needed throw without having to mod anything but the pass through hole in the engine sheetmetal. Make sure you get the accelerator to stop at the pedal stop and not the carb stop(s) when doing your final adjustments.

FYI, this was all on an '83SC motor w/PMO's installed in a '73T.

Hope that helps,

[mgatepi]

Great advice!!

I will take a new look at this tonight.

Thanks!
mg

[mgatepi]

R_builder,
What year Link should I look for ?
Thanks again!
mg

[R_Builder]

The part number is 901-423-026-02. Should be '65-'68 as there is a different p/n for the MFI cars. It looks like this:



Overall, it is shorter than the straight CIS link you have now. And don't try to make the CIS link look like the one above... it is not stiff enough to do the job when working against all those PMO return springs!

[mgatepi]

Thanks R_builder!!!

[larrym]

at least 2 separate issues here

If you are using PMO tall manifiolds, the "old stock" bellcrank setup still will not have full throttle opening - you'll also have to slightly relocate the ball-stud on the bellcrank at the manifolds

[The Watson]

Can someone tell me which year bell crank to use per option #3 below. There is a version used from 1965-69 and another used from 1969-71. Thanks!

Originally Posted by jpnovak

I am assuming that you have adjusted the linkage on both the pedal and tranny ends.

I had the same problem adapting a 3.0 with webers to an early car.

The early carburetor bell crank on the transmission has a different angle between the two ball-joint connection arms.

At this point you have three choices.

1. shorten the throttle linkage rod in the tunnel. (cut off and thread down the end with a die)
2. shorten the throttle linkage from the bell crank on the tranny to the carb
3. replace the bell crank with the early style. This is the best choice as it offers better off-idle tip-in and low speed modulation.

[juanbenae]

I was not getting full throw on my set up at one point on my spec 911 car. fortunately I was able to get a handful of differing length rods on a race weekend from jerry woods' trailer and tried one after the other till I found the right one. as I recall it was a fine line between too long and a tad too short....

[GG Allin]

So the throttle rod I just paid $100 for plus tax plus shipping is not going to work with my PMO's?

[Kemo]

i know this is an older thread...but...im using the search function here, trying to be a good pelicanite

in any event, im going down the PMO route on my 3.0 SC and came across this thread. I found this linkage rod: https://www.pelicanparts.com/More_Info/90142302602.htm?pn=901-423-026-02-OEM&fc=Y but was not so lucky on the bell crank at the transmission. from this thread, https://www.early911sregistry.org/forums/showthread.php?127437-Transmission-throttle-rod-bell-crank I was able to find part number 901.423.027.03 as quoted from the thread:

"according to my Spare Parts Catalogue for 1969/70, the bell cranks for 912, 911T, E, S, RHD and Sportomatics were the same: 901.423.027.03
The pages are dated 8/70."

here on pelican i found https://www.pelicanparts.com/More_Info/90142302703.htm?pn=901-423-027-03-OEM&bc=c&SVSVSI=0686 which appears to be the right part number but doesnt have a picture.

I just wanted to double check here before committing the $250

[The Watson]

I thought I would have to go through that on my 1977, 911. But it turned out all the stock linkages worked without any issues whatsoever. I would try it with your current linkages before I invest any money. It’s not too hard to swap out things later if you need to.