DCOEs and removing starter circuit

[zigzag240]

My winter project this year is to install a set of new 40 DCOEs on my L28 240. Rather than buy the whole assembly prebuilt, I decided to buy the carbs seperately as well as the manifold and linkage.

The manifold I have is made by TWM but its design doesn't take into account the starter circuit and lever on the rear of the DCOE for some reason...the linkage standoff gets in the way.

 

A workaround is to remove the starter circuit cover and lever and put a block off plate on it since I don't plan on using the starter circuit anyway. But after years of Z mods I'm pretty much a Weber newbie....my questions:

 

- When I remove the starter lever is a matter of simply blocking off the opening with a plate? Do I need to remove any jets or block anything else off internally?

- Does Weber make a block off plate or should I get out my dremel tool and a piece of sheet aluminum and fabricate one?

 

See the photos below:

http://datsunzgarage.com/index2.htm

 

Bryan Little

New Haven, Connecticut

[Tony D]

"The manifold I have is made by TWM but its design doesn't take into account the starter circuit and lever on the rear of the DCOE for some reason...the linkage standoff gets in the way. "

 

That would be because TWM is a fuel injection outfit, and their manifold was designed to use their ITB's which merely are the universal Solex/Dellorto/Weber bolt pattern. They don't have the protruberances out back like the carbies do!

 

Weber does make a stamped-steel cad plated block-off plate for people eliminating that function. Most of this is covered in the various Weber Tech Manuals out there. Redline Weber online may be able to supply the pieces. It's pretty straightforward to eliminate it's function... lock the plungers down however you choose (there may be an 'elimination kit' available) and block (or not block) the area at the back where the lever and mounting casting formerly were.

[cygnusx1]

Hmm, New Haven, CT.  It gets cold there.  You might want to find a work around if you like easy starts in the colder months.  Maybe a set of anti-vibration mount spacers to set the carbs further back off the manifold.  I don't have a picture in my head but maybe that would work?  Yes, now I see your photos.  It should work well.  Besides, you probably SHOULD run the anti-vibe spacers with the o-rings and thackery washers.

 

BTW, Hi Bryan!

 

 

Edited November 5, 2010 by cygnusx1

[josh817]

Like Cygnus said, use anti vibration mounts. They're like... 1/2" thick. Then I'd say why not just do some grinding on the manifold without breaking into the threaded hole?

 

Don't worry about cold starts. DCOE's have accelerator pumps. Just work the throttle a little with the fuel pump on. Here in Texas, coldest weather we've had maybe in the teens. I've never, ever, EVER had a problem starting, so long as you pump the pedal a couple of times first. My problem is actually in the heat of summer when I've been driving for maybe 30 minutes. Stop for gas and then I have to wrestle it to get started again.

 

I don't know if its a big deal for Datsun's but one problem I see you may have is the fact that there is no balance pipe on your manifold, like Cygnus has on his Cannon. Balances the vacuum from all the runners so your brake booster and dizzy vacuum advance will work rather than pulling from one cylinder. I could only see a problem if you run a stupendous cam...

[zigzag240]

Appreciate all the tips.

 

Thinking I had would rather have a version with balance tube, I just called Top End Performance who I bought the carbs from. The guy who answered went out and checked one of their Cannons and said the brace wasn't a balance tube and could see no openings in the runners...oh well.

 

So I just doubled up the anti-vibration spacers on each carb throat so there were two on each...perfect clearance. No need for a block off plate now. Thanks guys..you put me on the right track.

 

This is gonna work...heh-heh. Scroll to the bottom for the photo of the fix: http://datsunzgarage.com/index2.htm

 

 

 

-Bryan

Edited November 5, 2010 by zigzag240

[josh817]

I'm running the same ones that Cygnus is using. I could have sworn when I was grinding on the intake that it had a balance pipe... The thought of "I hope metal shavings don't get stuck in there and get sucked into the motor" kept going through my head... I'll check my pictures.

 

Damnit not enough angle!

Edited November 5, 2010 by josh817

[zigzag240]

Maybe they were just telling me what I wanted to hear, see if you can see any opening in the runners.

Edited November 5, 2010 by zigzag240

[cygnusx1]

 I remember looking inside my Canon manifold to see if the runners were connected for vacuum.  Unfortunately, I don't remember what I saw (sucks getting old).  I do know that I have plenty of brake boost and a dead smooth idle with the factory L28 cam.   Bryan, here are the spacers with the proper spring washers.  Email them to confirm thickness but I think they are all standard.

 

http://compare.ebay....4=263602_304662

 

 

 

 

EDIT: Once again I am late to supper....glad you got a fix for it!

 

 

Edited November 5, 2010 by cygnusx1

[rejracer]

My recollection of the cannon manifold ( I have one with 40 DCOE-18's ) is that the bar that runs between the manifolds is hollow. I was still concerned about this not being enough for the brake booster, so I thought running a vacuum manifold with 6 vacuume lines to each runner would be a good idea. I never implemented it, and went back to SU's. I'll deshelve that project when the turbo conversion is done.