DownDraft Weber carb linkage issues, any Ideas?

[KlassicMotion]

1971 510 with an L20B, new engine mounts, and Weber 38/38 downdraft.  I pulled the linkage off the L16 Hitachi carb.  Everything lines up, but the carb sits an inch higher than the throttle rod from the fire wall.  The linkage binds and wont reach when I try to connect the two. 

 

Has anyone else experienced this?  Are there kits to get rid of the stock throttle linkage?  Any suggestions on a fix?

 

Thanks in advance.

 

[Stoffregen Motorsports]

Space the bracket away from the fire wall and use timing tensioner or valve cover bolts (which are longer) to hold the bracket in place.

[KlassicMotion]

At the moment this is what I'm going to try:  I'm looking for another linkage rod and firewall mount for the 510.  I'm going to weld on an 18 guage piece of sheet metal to the firewall side of the mount.  This piece will be one inch longer (towards the bottom of the mount).  Then I will cut the top side of the mount off, allowing me to raise the mount one inch.  Then I will re-drill new holes in the mount, to match the factory holes in the firewall.  Then I will carefully remove the welds from the spring/ball rod plate on the linkage rod.  Redrill the spring/ball rod plate so the rod will slide in closer to the spring side of the plate and reweld.  This hopefully will give enough offset so the ballrod will reach and not bind.  Worse case, I have to make a new spring/ball rod plate with proper offset. 

 

We'll see what happens, hopefully I can find another linkage set this weekend.  (I need to keep my current set intact because I have a set of dual SU's being rebuilt and I want to compare the performance between the two carb setups.

[Stoffregen Motorsports]

Sounds like you have a good plan. We used to do it the way I described on our ITC race cars and there was never any binding, so that shouldn't be a concern.

[racerx]

Wuz wondering why you went with 38/38 and not 32/36 weber.

[KlassicMotion]

Wuz wondering why you went with 38/38 and not 32/36 weber.

 

First let me start by saying that when I bought it months back I did hours and hours of research on all the different setups, and for the money, I chose it.  I've had 32/36's on other cars, and they just felt...ehh...lacking I guess is the word to describe it, compared to SU's or Sidedraft Weber's.  My SU's are with Dana Britton at sucarbs.com.  He has had them for 8 months (pathetic), but insult to injury, he made me pay $325 up front for the rebuild!  That's why I bought a weber in the first place, inexpensive temporary carb.  The SU's are 38's and synchronomos, so those and the Weber 38 DGES synchronomos should be roughly the same cfm.  My primary use is street, but I do autocross when time permits.  Plus, I intend to build a hotter engine later down the line.  If/when that happens I will have the engine dynoed with as many different setups as I can get a hold of. 

 

Side note:  When I had my Ford 347 Stroker built and dynoed, we first used a Holley 670 that I had on the engine before hand.  Next we put on a 600 Edelbrock out of the box no mods and it made 10 hp more.  Which helps prove that bigger carb doesn't necessarily get you more power, and it's a fact that most street engines are over carbureted. 

 

So, short answer:  It should be similar cfm's to the SU's, and, I just felt like trying it over the 32/36. 

[KlassicMotion]

Sounds like you have a good plan. We used to do it the way I described on our ITC race cars and there was never any binding, so that shouldn't be a concern.

 

Well I suppose if you've had good luck running it that way, then I will try it until I can get a second setup for my car.  Thanks

[racerx]

Could jetting on edelbrock have been bigger? Yes, 38/38 weber is meant for hottet engine. Im not an expert but had 75 celica and was a 2.2 engine and that only needed 32/36. Good luck with getting it to work.

[KlassicMotion]

Could jetting on edelbrock have been bigger? Yes, 38/38 weber is meant for hottet engine. Im not an expert but had 75 celica and was a 2.2 engine and that only needed 32/36. Good luck with getting it to work.

 

 

The 347 stroker dynoed at 408hp and 439 torque was only pulling 540cfm.  You can dump as much fuel down an engine as you want, but that won't make more power.  Getting the perfect fuel/air mix will make the best power. 

 

Like I said, I haven't been too impressed with 32/36, so I thought I'd try the 38.  We'll see what happens. "If you don't try it, how do you know you don't like it?"

[racerx]

Thought you wrote when u put edelbrock carb, it made 10 more hp, thats what i base my response on. The 32/36 is not really a perpormance carb its more of a replacement from stock. If you do, howver, put a thicker spacer, you can feel the torque more, did this on 2 ol skool capris back the dayz. I dont think its possible w our datsuns cuz of hood clearance issue.

[KlassicMotion]

Sorry, I miss understood.  I did a quick search on the jetting for the Holley 670 and Edelbrock 600... I didn't find anything.  I will have to dig deeper for the answer.   I'm curious now what the difference is. 

 

But right now, I'm going to get a can of fuel and see if I can't resurrect my 510 after 12 years of sitting!!!

[racerx]

yeh that's the fun part..lazarus..12 years oh yeh..is your gas still fresh and gas tank,  BTW 347 stroker, what car? 

[KlassicMotion]

Tank was empty.  Fresh gas today.  Fired right up.  I need to flush the heater core so I can attach the coolant lines and really warm the engine up to tune the carb.  I'm also having issues with the right front brake not pulling any fluid through.  May get to drive it in a couple days.

 

I had a '65 Mustang Fastback for the last 11 years.  TKO 5spd. The car was setup for street, but had all the suspension goodies for autocross fun. The '76 Bronco and the '71 510 have taken it's place.  "If you don't sell, you can experience others".

[racerx]

dang it..I, too, have a 65 Mustang fastback.,.had a feeling when you said 347 strocker.  Still have my stang after 17 years.

[KlassicMotion]

Yeah I loved it, and I will have another, but when we get back from Alaska in 3 years or so, I will pick up a Lotus Elise.

[racerx]

maybe sometin like this will work:

 

http://www.carburetion.com/Products/ProductDetails.aspx?Part=99007.551

[KlassicMotion]

Interesting...  I might look further into that after Wednesday.  I should have my new "adapter plate" cut out tomorrow, then on Wednesday I will get access to a MIG and we shall see how my design works.  I will post pictures if it's a success!!

[racerx]

fairly sure this has been done before..have you tried getting a of weber direct or pierce manifold and see what other people have done.  Had to do something similar to my 75 Celica, somehow the linkages just did not line up. HAd to install a metal plate maybe 1/2 thick agains firewall and had holes then was able to install linkage.  good luck.

[KlassicMotion]

I'm going to weld this up tomorrow, but here is what I'm going to try first.  This design bolts into the factory holes, no new holes needed.  It also raises the throttle rod so it's near level, and it centers the linkage from left to right with the center of the carb linkage.  Test fit looks promising, and there does not seem to be any binding in the system.  My welder is broken so I have to wait and borrow one tomorrow, otherwise I'd be driving tonight.

 

[KlassicMotion]

Here's the quick and dirty end result.  I tried it on the car today and everything worked great.  The throttle rod is level with the carb and all the linkage seems to be functioning well, with no binding at all.  And I didn't have to modify the throttle rod like I originally thought I would.

 

[racerx]

good to hear that..I think there's another noob that is going through the same thing as you but yours is running. Rapakhatui under General discussion trying to hook up 38/38 also, maybe good idea to give him pointers...just a thought.

[KlassicMotion]

I looked for Rapakhatui under General discussion on this forum and the realm.  No luck finding them...

[racerx]

http://community.ratsun.net/topic/53570-weber-hookup-with-all-the-wrong-parts/

 

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