Centerline double softmount for Weber carbs, any experience? - Alfa Romeo Bulletin Board & Forums

 2Likes
  • 1 Post By Gordon Raymond
  • 1 Post By gprocket
 
LinkBack Thread Tools Display Modes
post #1 of 12 (permalink) Old 12-02-2015, 12:54 PM Thread Starter
Registered User
 
Join Date: Jul 2006
Location: Pendleton, NY
Posts: 428
Centerline double softmount for Weber carbs, any experience?

Has anyone had any experience with the Centerling double softmount for dual Webers? It seems good in theory, stiffening the inner bores, tying the carbs etc, etc. The idea is to use single mounts on the outside bores and a double in the center. Any ideas out there? Is it a gimmick? Seems there might be good science behind it.
Attached Images
 
formerfiatfrank is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 12-02-2015, 01:08 PM
Registered User
 
101/105guy's Avatar
 
Join Date: Apr 2005
Posts: 6,064
The one I bought is a lot thicker than the single mounts you have to use on each side.
Pretty much unusable on a dual weber car.

'64 Guilia Spider
'67 GTV
'68 Giulia Super

Conservatives-we work hard, so you don't have to !
101/105guy is offline  
post #3 of 12 (permalink) Old 12-02-2015, 02:40 PM
Registered User
 
Alfajay's Avatar
 
Join Date: Jan 2005
Location: San Juan Capistrano
Posts: 7,970
I have used them for years with no problems.

Quote:
Originally Posted by 101/105guy
The one I bought is a lot thicker than the single mounts
I measured the relative thicknesses once and found that I needed to stack two paper gaskets on the two outer single mounts to achieve the same dimension as the siamese inner mount. I wouldn't call that "a lot thicker". Even if I hadn't used the double gaskets, I'm confident that the rubber would have expanded/contracted enough to create a tight fit at the flanges.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 12-02-2015 at 02:43 PM.
Alfajay is offline  
 
post #4 of 12 (permalink) Old 12-02-2015, 02:57 PM
Moderator
Platinum SubscriberModerator
 
Gordon Raymond's Avatar
 
Join Date: Jul 2006
Location: Northfield, Illinois
Posts: 9,625
The double mount is a preferred mounting method as it eliminates some balance link wear. It was used by Alfa on some Euro variations, but can be used with older US imported cars IF originality is not a concern. I use this center mount on all race engines using 40DCOE's. It works well.
There are some variations in lengths of the individual rubber insulators / isolators that have been available in the past. I have not checked length variation in new Pirelli insulator / isolators in either 40 or 45 mm sizes, nor have I compared the latest Pirelli offerings to old Pirelli supplied to Alfa years ago.
It is important that insulator / isolators be approximately the same length to avoid stressing Weber bodies. This would include the double center rubber. In the past, some of the individual I/I units were so poorly made that steel insert plates at either end were not even flat. One needed to remove studs and mill file the steel inserts flat, then make 4 the same length before reinstalling studs.
Many years ago, the only gaskets supplied were thin yellow gasket paper and these worked fine with original, matched length, old style Pirelli I/I units. Thicker greyish black gaskets are now commonly supplied. The thin yellow were sealed to manifold I/I, and I/I to Weber with "Gasketcinch" sealant with no issues. The thicker greyish black sandwiched between NON-FLAT I/I's will oftern burn through and leak air. A bad situation. If the I/I steel plates are flat, close to the same length, they will work fine with the thicker gaskets, but some gasket sealant should be used. I have had no problems using the double center I/I and close to the same length front and rear I/I assemblies, sometimes mixing thick and thin gaskets to get everything matched up to length, then using a sealant to be sure there are no leaks over time.
Below are pictured 4, tired 45 mm used yellow paper gaskets. The thin ones.
Attached Images
 
Alex likes this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gordon Raymond
Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT

Last edited by Gordon Raymond; 12-02-2015 at 02:59 PM. Reason: Picture?
Gordon Raymond is online now  
post #5 of 12 (permalink) Old 12-03-2015, 03:02 PM
Registered User
 
101/105guy's Avatar
 
Join Date: Apr 2005
Posts: 6,064
On my double mount, 3 or 4 thick gaskets would have to be used to make up the difference.
There has been other threads about this very problem....

'64 Guilia Spider
'67 GTV
'68 Giulia Super

Conservatives-we work hard, so you don't have to !
101/105guy is offline  
post #6 of 12 (permalink) Old 12-03-2015, 04:50 PM
Moderator
Platinum SubscriberModerator
 
Gordon Raymond's Avatar
 
Join Date: Jul 2006
Location: Northfield, Illinois
Posts: 9,625
THIN your center mount. I have used a mill to do this one or twice. Mine fit.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gordon Raymond
Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Gordon Raymond is online now  
post #7 of 12 (permalink) Old 12-03-2015, 07:46 PM
I don't know the process but I've got to believe that these should be machined square and flat after vulcanizing. There is no way that you could maintain tolerances otherwise. Actually, they should be molded, machined and sold in sets. Different molding times and temps will result in different expansion and contraction rates.

I'm sure the original Pirelli units were made right but I don't trust anything from aftermarket suppliers (speaking as an aftermarket supplier of molded rubber parts for the last 50 years).
gprocket is online now  
post #8 of 12 (permalink) Old 12-03-2015, 08:04 PM
Registered User
 
Q.V.'s Avatar
 
Join Date: Oct 2006
Location: Minneapolis, MN, US; Lausanne, Switzerland
Posts: 460
Garage
Quote:
Originally Posted by 101/105guy View Post
The one I bought is a lot thicker than the single mounts you have to use on each side.
Pretty much unusable on a dual weber car.
Quote:
Originally Posted by Gordon Raymond View Post
THIN your center mount. I have used a mill to do this one or twice. Mine fit.
Yep, same problem. Different manufacturers, different thickness.
I didn't mill the double one but made spacers for the other two.

1975 Alfetta; ex 1973 Spider; ex 1984 Alfetta Quadrifoglio Oro
Q.V. is offline  
post #9 of 12 (permalink) Old 12-03-2015, 08:09 PM
Oh heck no! If they are selling mounts from different manufacturers as a set then that's just not right... They should at least certify that the mounts have been measured and are within xxx tolerance. But they really shouldn't be selling them at all like that. Very disappointing...
code33 likes this.
gprocket is online now  
post #10 of 12 (permalink) Old 12-03-2015, 08:20 PM
Registered User
 
101/105guy's Avatar
 
Join Date: Apr 2005
Posts: 6,064
Oh, yea.....
I always have to remachine all of my replacement parts.
Centerline is one of the worst for shipping ill-made or flat out wrong parts.

'64 Guilia Spider
'67 GTV
'68 Giulia Super

Conservatives-we work hard, so you don't have to !
101/105guy is offline  
post #11 of 12 (permalink) Old 02-22-2017, 05:56 PM
Registered User
 
BlpltGTV's Avatar
 
Join Date: Sep 2006
Location: Napa Ca
Posts: 1,580
Garage
Send a message via AIM to BlpltGTV
Do other siamesed mounts work better than the Centerline ones? Perhaps ones from Alfaholics or Classic Alfa? These seem like a good way to go. I'm looking for the best mounting solution, but not finding much info on it.

Will

1959 101.02 Sprint AR1493*20198 (project) 1969 Datsun 2000 roadster
1988 BMW E30 M3
BlpltGTV is offline  
post #12 of 12 (permalink) Old 02-22-2017, 07:31 PM
Moderator
Platinum SubscriberModerator
 
Gordon Raymond's Avatar
 
Join Date: Jul 2006
Location: Northfield, Illinois
Posts: 9,625
All I've used vary a bit. A few years ago there were some 40 mm singles that were horrid. The steel was not even flat, it appeared stamped, and the rubber did not last long. I pulled studs from these, and machined the steel flat and parallel, making them all the same length, only to watch the rubber deteriorate quickly.
The double mounts I've used have good steel inserts and both steel plates are parallel. Most are dimensionally very similar, though I've no idea where they were made. Generally, if you had enough singles, you could probably find two that matched the thickness of the double mount. I do not know, but guess the double mount manufacturer(s) do not make matching singles.
One of my customers recently sent me 4, 40 mm singles that had "Pirelli" cast into the rubber like those from years ago. They were new, and all 4 were the same length. I don't know where they came from, but if they really were Pirelli made, they might hold up like the Pirelli insulator / isolators from 40 years ago. I wondered at the time if there is a Pirelli made or marked double, and if so, would it match the Pirelli singles? I do not know.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gordon Raymond
Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Gordon Raymond is online now  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome