Tuesday, March 3, 2015

side draught

One of the first things I did, after installing new gauges was to swap the dual SU's out for a single 45DCOE. I've always loved Webers. The sound and look. Ease of running and love that once tuned, always tuned. Oh I hear those groans and moans but I'm gonna say, I have run a Weber DCOE on my street Spitfire for over twenty years and NEVER had to readjust it and those who know Ruby, know she get up and goes "like her A$$ was on fire"!!!

Twin SU's
I put this same single 45DCOE on Ruby's motor when I rebuilt it back around 1988 or 89 when I was going to photo school in Daytona Beach. I re-jetted it and it ran great right up till the time when Bob Kramer gave me a set of dual 40 DCOEs with a SAH manifold. These "free" carbs cost me somewhere around... well, my wife is going to be reading this so let's just leave it at FREE!

Ruby's dual Weber 40 DCOE carbs
Anyway, the dual 40's have been on Ruby now for around ten years now and again, I have yet to have to retune then. The DCOE really is a work of art. They do take some understanding in order to get them tuned right but once dialed in, you'll NEVER forget them because of that induction roar!

So back to the carb swap. As my 45 DCOE had been sitting on a shelf for the last ten years and seeing as I did need to "pinch" a few parts off it for one of the 40's a parts order was in order.
Along with a rebuild kit I ordered a new "Mickey Mouse" hat for it as well as new idle jets. Those had been missing on one of the 40 DCOE's.

DCOE parts laid out for cleaning

ready for rebuilding

Rebuilding a DCOE is really pretty straightforward. Not much to it but a few gaskets and a bunch of brass jets. I "boiled" out he carb overnight with some carb cleaner as well as all the brass jets. The next morning I made sure all the passageways were clear by spraying more carb cleaner thru them as well as all the jets. Then just reassemble and "Bob's your uncle".

As for fitting the carb to the block, I did need to grind away some of the intake manifold mounting plate to make it fit with the STAHL header flange. Not really too difficult of a job, just grind, fit grinds some more, fit some more grind some more. Small steps is best as it is VERY difficult to grind the metal back on!

Ready to rock and ROAR!

The linkage was a bit to figure out. My manifold was for a cable linkage and this car has the bell crank linkage. I need to figure out how could I make the throttle plates open while pushing them up from below. Luckily, Wide open throttle is not past twelve o'clock on the throttle shaft so all I had to do was drill a hole on the current stock linkage, install a bell crank rod and it now pushes the throttle up from about seven o'clock at idle to about eleven o'clock at WOT.

fuel line
The fuel line need sorting out next as the SU's had a hose clamp to tighten down the fuel line but the Weber has a banjo fitting. I purchased a AN banjo fitting and made up a length of steel braided hose.
I ran this over to the fuel pressure gauge that is mounted on the firewall. next was an in-line EARL'S fuel filter followed by a new Holly low pressure fuel regulator. The Weber like around 2.5 PSI. Also, I've always run a minimum of three fuel filters with my DCOE's. They are very fussy and any "swarf" getting into a jet. So, one filter in the trunk, one in-line on the firewall and the built-in filter in the carb.

air cleaner
Next, I had to figure out an air cleaner. I went with a RAM AIR box type filter. I like the idea of a "filter box" type cleaner instead of individual socks or screens on the airhorns. While the socks and screens look way cooler, my thoughts are if one sock clogs more than another, then you are no longer balanced. With the "air box" type filter, it's one common air chamber the airhorns are drawing from. Even on my street car with dual 40's I have one air filter for both carbs. All four velocity stacks are inside the same chamber.

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