The Stovebolt Site Forums The Shop Area Engine Shop Offenhauser-Fenton Carb Linkage?

I know a lot of you have the Offenhauser-Fenton manifold setups on your inline sixes with a pair of Rochester B's. The question is what did you do to fabricate the carb linkage. I just tried to use my stock linkage rod, which used to run from the engine pivot-bracket to the carb and I found that it is not going to work for my new set up. I do have the duel carb linkage assembly installed already. I would appreciate any diagrams and pictures you might have as well.
Thanks.

If you have the Offy linkage that is used for the twim Rochesters then I don't know why it doesn't work. What exactly are you have the problem with?

I found that I had to make a new rod from the bellcrank to the linkage tying the two carbs together. I used an aluminum rod and hand bent it to configure it to get through the passage way which the Offy - Fenton set up creates.

The rod from the engine block pivot up to the carburator when connected to the offenhauser linkage hits the rear fenton header, the rear carb flange, and does not sit squarely where it attaches to the offy linkage. I think the rear carb flange is also limiting the travel of the throttle link rod. Here's a photo: http://community.webshots.com/photo/109150147/124279908BKHefk

I will probably be able to bend this rod to make it work properly, but I do not want to do it right now. Once I get my newly rebuilt engine back in the truck, I going to use the original intake, exhaust, and carburator set up that I know was running well prior to the rebuild. I will have enough to worry about with the rebuilt engine, trany, front-end, brakes, generator, starter, and new wiring harness. As the guy from the show Tremors says "The possibilities for disaster boggles the mind."

cujo8, you will have to make a new rod. I again suggest a 1/4" or 5/16" aluminum rod, probably 1/4", and bend it to fit. It'll take a little messin with, but you can do it. I have never seen the stock rod work. The path through the new intake and exhaust headers is different with Offy and Fenton!

Cujo,
I know how you feel with all you have to do however consider this. Hooking up the dual carbs on the engine with linkage and getting the engine test run out out the truck will work out better in the long run than trying to get the linkage working when the engine is in the truck. Except of course you have the fenders off. I found that hooking all this up or redoing after in the truck difficult at best.

OK, now I understand what your problem is and it's the very same one we all have with custom set-ups. I'm currently making the bellcrank rod too but am using the dual Carter Webers. Very same problem in snaking through the two manifolds and getting to the lever on the pivit shaft. I bought some 1/4" steel rod and and will thread the ends to accept ball joint connectors. Like you and everyone else it is a matter of trial and error.

I am a little surprised on your choice of material for the heat plate however. It seems to me that the copper tubing will vibrate and cause leakage problems at one end or the other. I've decided on braided stainless hose between the gooseneck and the plate so there will be no worry of leaks or heat burning rubber hose. You may want to consider something like this yourself.
Take a look at my linkage.
http://www.picturetrail.com/birdhtr

cujo8,

Looks like you would have a much better (straight) setup if you fab a new lever arm and have it welded to the cross shaft directly above the bellcrank. Easier to do now rather than later when you're standing on your head over the fender to see things.

That big "J" bend in the rod doesn't look like it can be made to work very well.

PRW

I made my own rod for my 261 out of threaded ready rod and ball joint ends from the hardware store. I just have a single carb but here is a pic:
[img]http://photo.starblvd.net/guitarzan/1-1-3.jpg[/img]

Paul, I agree with your idea about the straight shot up from the pivot assembly. I think I should be able to grind off the existing weld holding the Offy linkage rod connection and move it directly over top of the pivot bracket assembly and reweld it.

53moneypit, I actually bought this entire manifold setup off of ebay in one auction that included the Offy Intake, Fenton Headers, 2 rochester-B's, Air cleaners, and water hookups. The water lines are actually steel and should work fine. The fuel line from the fuel pump to carb have been plumbed out of this type of material for many years on all types of vehicles. I do agree from an aesthetics point of view that the braided stainless steel would look better. Where did you get the braided stainless steel lines for your truck?

I believe many of you have called the pivot bracket assembly I referred to above as a "bellcrank" is this truely what they call this bracket? The reason I ask is I replaced the two bellcranks on my 84 Winnebago, which are part of the steering linkage on a Chevy P30 Chassis and they do not look anything like this bracket.

http://community.webshots.com/photo/124532337/124532774CUFeei

52PU, I do want to have the linkage figured out before I put the engine in the truck, but I also want to drive the truck with the original single carburator and single exhaust system to see how that feels before I switch to the other manifold setups. I only drove this truck once down an old back road in Upstate NY when I bought it 1-1/2 years ago, so I really do not have a good feel for how the truck will behave with the stock set up and a fresh rebuild. After I get a feel for it in the stock set up (except for the Howard's M4F cam) I will then install the dual carb Offy setup and see what that does for the performance. Then I will finally install the dual exhaust system and then see how things are with this upgrade. I feel I can really learn what factors make the biggest difference this way. Will the Offy intake bolt up with the stock exhaust mainfold?

CUJO, I think I may still have the original linkage arm for mine and no use for it. If I fnd it you are welcome to it. No Charge. Not sure it will work with the Offy pivot arm however. I have a new unopened Offy kit available too if you need more parts.

As for the braided line it can be had at nearly any speed shop or implement supplier. Also online from dozens of outfits like Summit Racing, etc.

Hang in there man.

When on my 235 the rod went straight down. Did you get a bellcrank with the set up? I modified the bell crank and rod from the pedal to the bellcrank only, the verticle rod was stock with the return spring tab. Seems the arms went forward from the bellcrank, several ways to install. Zeke

Cujo8,

I wouldn't call that thing in the picture a bellcrank...idler maybe.

That little two-lever dohickey that pivots and changes the direction of push on the rod....is what I call a bellcrank.

PRW

Cujo, the thing you are calling "throttle linkage bracket" in your photo Linkage 2 is what the rest of us are calling the bellcrank.

So how is it coming along?

I have not done anything further on this linkage problem yet, since I last posted. I have actually been using my woodshop as it was originally designed for and built a couple of cabinents for my buddies garage in trade for a couple of brand new Craiger wheels for my 71 LeMans project. Hopefully I will be able to get back on this project over this weekend. I have so many things to be done on my 54 GMC restoration project that I never know exactly what I will be working on when I head out to the shop. I am also in the process of rebuilding my generator and starter and I have many front end parts being painted at this time. When these get completed I have the Trany, Steering box, and many more parts waiting to be stripped, primed and painted. I am hoping to get my truck back together and on the road this summer, but there is much to do yet. I will feel alot better once I start putting things back on the truck and stop taking things off. When I first got this truck 1-1/2 years ago, I thought I would just clean up the engine bay and put some new gaskets/paint on the engine, but before I knew it I had the engine out to be rebuilt, entire front clip removed, cab gutted and I am now considering removing the cab from the frame as well. It's funny how these projects seem to get bigger and bigger, but when I get back on the road I will have the satisfaction of knowing that it done right and I will then feel comfortable taking it on some long road trips as well.