Carburetors.

You might have noticed that things are slowing down a bit and that posts are less... focused... than when we began a few weeks ago. Things are still moving forward, but given that I only have one or two days a week to put into the car (and I'm working alone right now), the project isn't exactly moving blindingly ahead.

 

Also, sometimes things don't go very well and I end up burning up a whole day on a task that I really thought would take a couple hours. Today was such a day. One of the days last week was, too.

 

Anyway, here's a refresher of what things under the hood used to look like. Of note is one pair of SUHS6 carburetors, which are [if I may say so] one of the most elegantly designed and highly functional carburetors in the history of engines. Presto:

 

 

Those carbs are now sitting on the shelf in the garage, where they'll wait for some other project, or maybe I'll hear from someone interested in buying a professionally rebushed set with proper needles for a B20 and K&N elements tucked into the original filter housings.

 

SUs like that are just dandy for engines that produce up to something around 140hp, and for engines that produce more than something around 140hp, larger carbs are warranted. And as terrific as SUs are, they're British, and British things are considered kind of stodgy (which, of course, is absurd). Italian things, on the other hand, are considered really sexy and also functional, though perhaps a little finicky. My wife is Italian, so she's probably an expert but I haven't decided to ask her about the finicky part.

 

My friend with the Fiat summed it up nicely, "It's Italian. If I can start it, it will WIN!"

 

Enter the legendary Weber 45 DCOE.

 

A guy I used to work with told me that DCOE stands for "Double Carburetors On End." That's not quite right, but it's close enough for us Americans. Doppio Corpo Orizzontale something something. I'd run a pair of 42 DCOEs on this car when I first put it together, which I later sold, but managed to come up with a pair of 45s more recently which were, sadly, not being used. Neglect is a real problem for DCOEs. Horrible waste.

 

The first thing to do was to test fit the forward carburetor. The intake manifolds that are being used are much longer than the old Warnerford piece that I'd used before, so I anticipated cutting a hole in the inner fender.

 

With the inner fender removed:

 

Yep. Gonna cut.

If we'd stuck with the old manifold, cutting wouldn't be necessary. But that intake has a couple fairly sharp bends that the fuel mix would have to navigate on its way into the engine, which doesn't help fuel atomization and can lead to an increase in turbulence (which is a good thing in some places but not in the intake charge. At least not to this degree. Er.. it works pretty well, it's just not ideal, and we want ideal).

The other thing that's preferable about a longer intake manifold is that there's a whole science behind optimizing the fuel mixture beyond just 'reducing turbulence.' Smart people have measured how well a Volvo engine will run with different length intake manifolds as the variable, with carbs and engines as constants. In short, there's an ideal distance between the carburetor and the intake valve, and those short manifolds come up... uhm... short.

There are a few long manifolds on the market that are functionally excellent - TWM and MISAB come to mind - but the Holy Grail (far as I'm concerned, anyway) are the VCS [Volvo Competition Service] intake manifolds. Back before Volvo came up with the R-Sport line, they offered factory made race car parts through their VCS Catalog, which hardly anyone knew about and dealers did little to promote (thus, the rarity of all the bits they offered). No other intake manifold is as appropriate as these. Functionally excellent, and genuine Volvo.

I'd owned a pair of such manifolds [NOS, no less] some years ago (actually, two pairs) but had sold them when finances were dire. As this project was coming together, I contacted the fellow who'd bought one of the sets and he very graciously agreed to sell me another NOS pair he had on hand.

They're only NOS until someone installs or alters them, after which their market value decreases. They become "used." I happily committed this travesty and stuck 'em on the car.

Once the manifolds are fitted with the carbs, the carbs have to connect to the gas pedal. Most of the racers I've seen use a really sweet dual cable assembly that does an excellent job, but I wanted the old school rods and levers setup.

One real benefit to the cable setup is that the effective throttle input doesn't change if or when the engine rocks. Even so, we're going with rods and levers. Sexy billet aluminum levers fitted to industrial strength stainless steel rod. It looks like this:

One nice thing is that the setup is really adjustable, as all the little arms cinch down on the shaft that runs back to front. As long as you line everything up super carefully, it works very well.

Rod and levers and a support and a lockring:

Another view, from a different angle. The excess rod has been cut from the forward end (see the black line? Right there):

... and from the front. The inner fender is now in place, with a big honker of a hole in it. The splash shield isn't in place (actually, it hasn't even been made yet). Also please ignore the crap that's laying across the top of the carbs:

  

 

These last two pics illustrate the difference in length between the VCS manifolds (top photo) and the Warnerford (lower pic). Sorry the scale is so completely off:

 

 

 

The benefit of the Warnerford is that you don't have to cut away your inner fender. No big deal on a PV, as these are replaceable pieces, but if you have a 122 or an 1800, you might think twice about it. I'm told that the Warnerford is the only option for a right hand drive Volvo, so if you're in Australia, that's probably the one you'll want.

 

The other benefit to the shorter manifolds is that the carbs aren't hanging way off in space away from the engine. We'll devise some kind of support. Probably.

 

And that's about it. We're nearly caught up with the car's current state, which is kind of cool. I'd hoped to take a test drive later this week but it's not looking promising with recent setbacks. We'll see how tomorrow goes.

 

Cheers -