Please help me figure out my throttle linkage on PMO

Tidybuoy · 08-18-2016, 01:19 AM

I'm in the final stages of my PMO conversion and I think the throttle linkage at the transmission-to-engine section is too long and needs shortening.

I've followed the directions provided by Clewett Engineering and checked and double checked for proper setup. The throttle works correctly and smooth when activated by hand in the engine compartment.

I've adjusted the throttle cable/rod (the one in the tunnel) and have turned the ends so that it is the shortest it can possibly be.

1) Can you look at my photos of my throttle setup and let me know if anything looks wrong.
2) Has anyone shortened the throttle rod from the trans to the engine (looks like a coat hanger) and if so, could I cut the end off and rethread the end. I feel that an inch needs to come off.

Sorry for the sideways photos. My new Windows 10 computer posts everything sideways and I don't know how to fix it.

T77911S · 08-18-2016, 02:49 AM

it looks like there is more adjustment on the end in the top pic.

cam the "gold" part on the manifolds that the rod ends attach to be flipped.
you would have to also flip the ball ends that the rods attach to.
it also looks like there are multiple holes in the gold part that would compensate for rod length.

tobluforu · tobluforu's Garage

Turn that puppy in (coat hanger) and see if it helps enough.

zedsn · 08-18-2016, 03:11 AM

There is an adjustment up front in the pedal box as well on the far right. You could try there to take up the rod slack before you go any further.

toddu · 08-18-2016, 03:35 AM

The holes in the bellcrank on the manifold are different for tall and "short" manifolds. Is the rod from the transmission to engine the stock one?

I ended up getting an earlier rod (has a bend in it) as well as getting an earlier bell crank for the transmission. I still have some adjustment to do, but very close to WOT now. I also turned the rod in the tunnel as short as possible. I have heard others have actually shortened it about an inch. Sorta looks like that is what you need.

Todd

prschmn · 08-18-2016, 03:59 AM

Does look like a stock link to me-that need shortening-not a surprise.

Gordo2 · Gordo2's Garage

Same experience and solution here - Gordo's PMO Carb Tuning

Good luck, Gordo

kent olsen · kent olsen's Garage

The most important issue is, do you get full throttle. Take a broom, put the handle on the gas pedal and the broom part against your seat, push down to full throttle. Go back and look in the throttle bores and see if the butterflies are full open, both throttles. Now adjust the linkage from the carbs back towards the transmission as necessary.

Tidybuoy · 08-18-2016, 07:38 AM

Quote:

Originally Posted by Gordo2

Same experience and solution here - Gordo's PMO Carb Tuning

Good luck, Gordo

The reason I post a lot on this forum is because I always get good answers and solve my little problems.

THANKS Gordo!

I checked out your link and saw how easy it is to shorten that rod. I was worried that I was going to have to cut, re-thread, possibly not getting the threading correct to fit the end piece....

After reading your link, I went out to the garage, found my portable map-gas torch, heated the end and it came right off. I cut off one inch and cleaned it all up and it is now ready for brazing. I tried solder by my solder wouldn't stick so I will bring this to work today and have our shop do this for me. I'm sure they have brazing rod but I'm going to pick up some on the way, just in case.

Thanks again, I think I will have this running tonight!

Tidybuoy · 08-18-2016, 07:45 AM

Quote:

Originally Posted by T77911S

it looks like there is more adjustment on the end in the top pic.

Thanks! I didn't even see that adjustment until you mentioned it. I just adjust it to it's shortest position and that gave me 1/2 of adjustment. I still need more and shortening that rod should solve it. I already adjusted both ends of the tunnel rod and that was not enough either.

Fleming · 08-18-2016, 12:24 PM

on a 1967 911 transmission I have found two different bell cranks, giving different linkage lengths.
The long arms allowed the desired fit and the short arms were... well, too short.

Also the wide stance between the arms would move the throttle shaft to rub on the side of the engine tin rather than flow in the middle of the tins opening.

The model or year for this part variation is unknown. Just for your review and the Pelican files.

Tidybuoy · 08-18-2016, 02:04 PM

ALL DONE!

I took Gordo2's advice. I heated the linkage rod with a portable map gas torch. it got red hot and the end fitting came right off (using pliars).

Cleaned up the end with steel wool and cut 1.5 inch off the end (I figured 1.5 inch would give me enough space so that I can use the turning ends for fine tuning. Next, I headed out to a welding supply store and bought brazing rod. I can't remember what the guy told me but he stated it was very high quality with high silver content - it was a whopping couple bucks.

Then I remembered, I work at a factory and we have guys that can be bribed

one 12 pack of Bud Light later, it's all done. Probably worth less than a 12 pack but these guys do things for me all the time and I want to keep that access handy.

End piece after heating with a torch for about a minute - end pulled right off.

After cutting of 1.5" an brazing back together: