Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> Dual Carb Installation, Success - She Screams
Mblizzard
post Apr 5 2013, 07:36 PM
Post #1


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
Working through the less than stellar instructions for the installation of my dual Webers. Beside having obvious errors in them it is not entirely clear which direction the cross bar should be pointed. To the front or the rear. I have not started placing the carbs on the car yet so the moment I move from the bench it may become clear but I think the front is correct. The directions seem to indicate that but if you install the linkage as shown one side of the crossbar link to the carb ends up at the front and the other at the back?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
5 Pages V  1 2 3 > »   
 Reply to this topicStart new topic
Replies(1 - 19)
Bob L.
post Apr 5 2013, 07:48 PM
Post #2


Senior Member
***

Group: Members
Posts: 851
Joined: 7-August 11
From: Austin TX
Member No.: 13,411
Region Association: Southwest Region
Once installed on the engine the carbs will be staggered a little bit, front to rear. Could that account for what you're seeing?

Pic's are always helpful.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ConeDodger
post Apr 5 2013, 08:03 PM
Post #3


Apex killer!
***************

Group: Members
Posts: 24,461
Joined: 31-December 04
From: Tahoe Area
Member No.: 3,380
Region Association: Northern California
The crossbar linkage should be installed in the nearest garbage can.

Call McMark for some good linkage... (IMG:style_emoticons/default/laugh.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 5 2013, 08:05 PM
Post #4


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
May not be apparent but if you do the bench install as indicated, the connection on the throttle plate for the cross bar link winds up on the wrong side. Meaning the cross bar is to the rear and the connection point is in the front. Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Apr 5 2013, 08:06 PM
Post #5


Custom Member
***************

Group: Members
Posts: 24,705
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
Towards the rear of the car.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
jmill
post Apr 5 2013, 08:20 PM
Post #6


Green Hornet
****

Group: Members
Posts: 2,449
Joined: 9-May 08
From: Racine, Wisconsin
Member No.: 9,038
Region Association: Upper MidWest
QUOTE(r_towle @ Apr 5 2013, 09:06 PM) *

Towards the rear of the car.


(IMG:style_emoticons/default/agree.gif)

But what really matters is what direction the throttle cable pulls. Most have it pull from the front and have the bar to the rear.

On a side note - that setup is one of the poorest ones. Get cast baseplates and the hex bar if you go with the crossbar. If your bar is round throw it in the trash. The arms will slip and it'll flex. You'll be constantly tweaking to get it right. BTDT.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 5 2013, 08:24 PM
Post #7


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
I will be pulling from the front so looks like a flip is in the works.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 6 2013, 05:54 AM
Post #8


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
So if I "Call McMark for some good linkage" where do I call and what is good linkage?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Apr 6 2013, 06:02 AM
Post #9


Custom Member
***************

Group: Members
Posts: 24,705
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
Original customs in Napa ca, or nearby.
Mcmark here.

He has a center pivot bell crank linkage that may work better.

For the ultimate setup, call Chris Foley at tangerine racing about his cable driven pulley system.

I have tried every cross bar setup I can find, and three bell crank setup.
The cable driven pulley system is just so simple ans so right.

All other systems can and do get out of adjustment over the full curve of the motor running up and down the rpm range.
Cable system is the closest to perfectly matching...


Rich
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rhodyguy
post Apr 6 2013, 06:24 AM
Post #10


Chimp Sanctuary NW. Check it out.
***************

Group: Members
Posts: 22,252
Joined: 2-March 03
From: Orion's Bell. The BELL!
Member No.: 378
Region Association: Galt's Gulch
mike, i prefer the bar on the front. space is tight enough as it is. with it on the rear, dealing the drop link adjs, and access to the throttle stop screws you be working a little blind and all bent over leaning. imho. plus you'll be making the throttle cable working distance that much longer. did a cable holder come with the package? personally i'd go with the cbtall intakes, not the shortys. if you don't have the cb weber book GET ONE! save yourself a bunch of bs and do the pre-install proceedure. it's clearly written to the point even a caveman can do it. buy the synco tool as well you're going to need one. did you purchase 40s or 44s? while you have them in hand confirm the current jetting. idle, and the components in the main stack. again, easier now than later. be methodical in your approach and don't get frustrated. double check your valve adj NOW! before you fire it up. if the old carb is still on confirm your timing too. not later when your chasing your tail dialing them in. good luck...enjoy the ride.

k
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 6 2013, 06:57 AM
Post #11


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
Kevin - You went through my check list. Timing dead on. Valves already set. New plugs. Completed spread sheet with all jet sizes. Cleaned carbs. Doing complete bench assembly before moving to car. Will disassemble all components and clean again before moving to car.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rhodyguy
post Apr 6 2013, 07:18 AM
Post #12


Chimp Sanctuary NW. Check it out.
***************

Group: Members
Posts: 22,252
Joined: 2-March 03
From: Orion's Bell. The BELL!
Member No.: 378
Region Association: Galt's Gulch
as ed china would say. "here's a top tip"...take the engine lid off! you can thank me later for that one. (IMG:style_emoticons/default/wink.gif)

k
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ConeDodger
post Apr 6 2013, 07:54 AM
Post #13


Apex killer!
***************

Group: Members
Posts: 24,461
Joined: 31-December 04
From: Tahoe Area
Member No.: 3,380
Region Association: Northern California
QUOTE(Mblizzard @ Apr 6 2013, 03:54 AM) *

So if I "Call McMark for some good linkage" where do I call and what is good linkage?


Mark DeBernardi is McMark here. He owns Original Customs and you may see the banner ad at the top or bottom of the page. The hex bar linkage is a bitch to work with. It is hard to synch and once it is synched will wear and go out of synch fairly soon. I even had one 'arm' break off and had to have my car towed because it was only running on one carb... Mark recommends an imported linkage setup that I have found to be very accurate, easy to synch, and stays tuned... Pic below...


Attached image(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
audio_file
post Apr 6 2013, 08:03 AM
Post #14


Member
**

Group: Members
Posts: 295
Joined: 6-August 11
From: Everett, Wa
Member No.: 13,409
Region Association: Pacific Northwest
QUOTE(r_towle @ Apr 6 2013, 05:02 AM) *



For the ultimate setup, call Chris Foley at tangerine racing about his cable driven pulley system.

I have tried every cross bar setup I can find, and three bell crank setup.
The cable driven pulley system is just so simple ans so right.

All other systems can and do get out of adjustment over the full curve of the motor running up and down the rpm range.
Cable system is the closest to perfectly matching...


Rich


+1 to this ^ being a great option. I had the hex cross-bar setup and removed it just because I thought it was UGLY (IMG:style_emoticons/default/barf.gif) After installing the tangerine setup, I was blown away by how much more smoothly the carbs/pedal operated. Easy to sync up, no bushings to wear out like the X-Bar too. (And, it looks better (IMG:style_emoticons/default/happy11.gif) )
Chris
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
vw505
post Apr 6 2013, 02:39 PM
Post #15


Member
**

Group: Members
Posts: 228
Joined: 17-April 03
From: San Antonio, TX , Navy retired
Member No.: 579
Region Association: None
I looked on McMarks web site and didnt see it listed
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 6 2013, 06:55 PM
Post #16


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
Installation looks pretty good. Some set up still to come. Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 7 2013, 07:43 PM
Post #17


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
Beaten! Tried everything possible to get these to run. They seem to do fine and run well for a minute or 2 when first starting the car. Engine revved well ans it sounded great. Then it almost seems like a choke or something kicks in and the car will barely idle and the dies. When I could keep it running none of the adjustment procedures seemed to have any impact on the smoothness. I will post some additional details tomorrow. (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ConeDodger
post Apr 7 2013, 07:51 PM
Post #18


Apex killer!
***************

Group: Members
Posts: 24,461
Joined: 31-December 04
From: Tahoe Area
Member No.: 3,380
Region Association: Northern California
I repeat: Install in nearest garbage can... (IMG:style_emoticons/default/biggrin.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
jmill
post Apr 7 2013, 07:56 PM
Post #19


Green Hornet
****

Group: Members
Posts: 2,449
Joined: 9-May 08
From: Racine, Wisconsin
Member No.: 9,038
Region Association: Upper MidWest
Are they new or did you rebuild them? Also you need to use the thick spacer and good gaskets on the base of your manifolds. Cheap manifolds and thin gaskets give you vacuum leaks and needle valve adjustments have little to no effect.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Apr 7 2013, 08:21 PM
Post #20


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States
I used the ones that came with the new carbs. I have some of the thicker ones but I checked well for vacuum leaks and found none. If I had vacuum leaks it would seem like the idle would be high. But Tim seems like once it gets done running right after starting it just seems to run slower and slower until it backfires and dies. When you first start it it revs great and then just seems to shut down. It will do that every time you restart it.

Recheck everything for 6 hours. Verified fuel pressure. Timing good. Valves set. New fuel filter. I need a drink!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

5 Pages V  1 2 3 > » 
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Switch to: Standard · Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 9th June 2026 - 01:17 AM
Invision Power Board v9.1.4 © 2026  IPS, Inc.
...
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...