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Weber installation question

 
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snakoil  



Joined: 09 Feb 2010
Posts: 362
Location: Montreal, Canada

PostPosted: Thu Apr 12, 2018 10:33 pm    Post subject: Weber installation question Reply with quote

Hi Guys, I'm looking forward into converting to my DCO40's in May.
For the first time ever I took a good look at the setup I had bought years ago and realised it didn't came with any linkage kit.

What linkage are some of you using?

Any picture of your setups would be really appreciated to see how I could mount this.

Also for the fuel pump, can I simply replace the second pump with a 3-4PSI pump or I should do something else with the in-tank fuel pump?
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Wed Apr 18, 2018 11:53 pm    Post subject: Reply with quote

MY '77 had only one pump and I just replaced it with a low pressure pump and Holley fuel pressure regulator. Plugging off the existing return line was a major issue, I finally found a cap (12mm I think) that I got from Vibrant performance thru Summit Racing.

For linkage my second hand Redline set had the pair of clips that connect between the throttle shafts and they work ok, tho I had to fabricate a small bracket that bolts to one carb(both would be better) to hold the throttle cable.

On my 45's that go on the track car they also have the center connection although I'll see a fellow who has been building Datsun race engines for years with Weber's or Mikuni's and I'll ask him which method is best when I see him which might be as late as early June. The center connection method I've got is also the least expensive.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
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snakoil  



Joined: 09 Feb 2010
Posts: 362
Location: Montreal, Canada

PostPosted: Wed May 02, 2018 10:31 pm    Post subject: Reply with quote

thanks for the info MikeJinCO, seems I do have those clips you are talking about. This shall be what I use for stage 1 and get it running.

Did you experienced any vapor lock with not using any return line?
I'm planning to get a holley 12-804 for the FPR and this one doesn't have a return line output.


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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Thu May 03, 2018 6:35 am    Post subject: Reply with quote

Never a vapor lock problem with no return line. I had to fabricate a new throttle cable holder that bolts on to one of the carbs. It is a slotted hole similar to the original. I'll modify it this year to attach to the other carb also to make it more stable.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
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snakoil  



Joined: 09 Feb 2010
Posts: 362
Location: Montreal, Canada

PostPosted: Thu May 10, 2018 10:02 pm    Post subject: Reply with quote

I went to the auto parts store to find a plug for the return fuel line
I thought i was wise as I had found a 1/4 NPT femeale to female adapter and a plug for it.
While the male NPT screw into my oem fuel cable, the female adapter is not big enough to connect to my hard line and thus not working.
Thought i’d share the info to anyone looking into the weber upgrade.

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rhialto  



Joined: 08 Jul 2004
Posts: 24
Location: Netherlands

PostPosted: Fri May 11, 2018 6:29 am    Post subject: Reply with quote

Use on of these (I seem to remember the 16mm are for the return line) and than use an AN6 plug, which wil be readily available in your country I guess:
https://www.holley.com/search/?q=9894DB
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snakoil  



Joined: 09 Feb 2010
Posts: 362
Location: Montreal, Canada

PostPosted: Wed Jun 06, 2018 10:31 pm    Post subject: Reply with quote

I ended up going to my local hydraulic shop as I wasn't sure of measurements.
Seems the thread on the 1979 924 is M14
They gave me a hollow nut with a ball bearing and this does the trick so far.
I ain't really nice looking in the engine bay so I might order that Holley 14mm to -6an converter.



The carbs are currently being rebuilt, will post picture once I get them back
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Wed Jun 06, 2018 11:23 pm    Post subject: Reply with quote

I looked up the Vibrant Performance catalog. They have many metric to other thread pieces. I don't recall if it was a 12 or 14 size, but I got a piece from them to convert it to an AN probably -6 thread and then just a cap for that thread. They are in Ontario so you should be able to get direct. Look under the adapters in the fluid delivery section, they have all sizes.
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'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
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procyon  



Joined: 09 Sep 2015
Posts: 70
Location: Peers Alberta Canada

PostPosted: Mon Jun 18, 2018 2:22 pm    Post subject: Reply with quote

These fuel lines seem to be 14mm. When I installed my EFI system I used 14mm to AN6 adapters for the return line.
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snakoil  



Joined: 09 Feb 2010
Posts: 362
Location: Montreal, Canada

PostPosted: Mon Sep 24, 2018 10:13 pm    Post subject: Vaccum Reply with quote

new question for my carb setup

Did you guys got rid of the vaccum booster while doing the conversion?
From my understanding the only vaccum line I'll need is for the brake booster and from my reading a simple direct line from the intake to the brake booster would provide plenty vaccum.

Is there another vaccum line I am forgetting that would require me to keep the vaccum booster?
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Mon Sep 24, 2018 11:06 pm    Post subject: Reply with quote

The vacuum line to brake booster is the only one you should have. Put caps on the distributor ports. I was worried about how the brakes were working and tested it, the vacuum did go up to about 20" which is what the booster needs. I may add a vacuum resevoir using a tank made from plastic pipe, which involves tapping the FI port plugs which are quite a tough material and hard to hold onto and small check valves in each of the input lines to see if the braking gets a better feel(I doubt it).

I marked the front pulley and set my timing at about 10BTDC and it runs pretty well. I'm at altitude(2400m,8000') and timing advance of about 1 degree per 1000' is not unusual in older cars.

I think the only way to really get the carbs right is to find one of the local race car builders who know webers and has access to a chassis dyno. The local(Denver) Datsun guru only took an hour to get a race TR4 dialed in.
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