Weber DCOE project in the "Blogs" section

[RazorbackNOR]

hmm thats solid works right and not ProE ?

will there be a cold airduct for fresh air to that filterbox?

Sry Oskar, none of the above... 

Used Inventor 2009(the best IMO), but I also have SolidWorks2009 if I ever need it. Have also installed Autodesk Alias Studio for schetching, and Autodesk Showcase for digital prototyping.


Anders, can you mail me the drawings and I'll see what I can make of them.

[RazorbackNOR]

Just fiddled a little around today with your drawings and pics Anders....

[Anders Dinsen]

Just fiddled a little around today with your drawings and pics Anders....

That's easy to recognise as a genuine Weber 40DCOE - with a few parts missing! Well done!

[RazorbackNOR]

Modeled some more....

[Anders Dinsen]

It's great to have friends!

My car decided to give up tonight. I don't know why yet. The first sign of problems was friday afternoon when it stalled on the way back from work. It's a very short drive, only 2 km, so it was cold and I thought it was just the cold running problems I had experienced before. Friday evening, I switched the fuel pump to one that's supplying the correct pressure. That shouldn't have any effect (the carbs coped with the higher pressure), and now, Sunday evening, I was to drive out to Frederik Moes to give him the final drawings of the airbox so he can weld it up for me.

To make a long story short, I stranded completely about 2 km from home. One hour later, Frederik had towed me back and the car is now sitting in its usual location.

I'm very close to scratch it all and refit the good old Solex carb, but I'll withstand the urge an find out what's wrong. I think I'll have to take the carbs off and inspect everything. It could be almost anything: Dirt, broken manifold gasket, starting system leaking...

Symptoms are starting problems, idle mixture jets seems to have little or no effect, it can idle, but dies after being rev'ed up a little, and the popup headlights almost didn't work - or worked only very slowly.

I'm puzzled. And a bit annoyed.

Thanks for helping me, Frederik

[Waldo]

Get a diesel

Well seriously I'm sorry to hear about your problems... I don't have any thing clever to suggest.

[Anders Dinsen]

Get a diesel

You behave yourself, now young man! Last time I saw your car, it didn't even have an engine inside!    

I think I'll know later today...

[Anders Dinsen]

My suspicion about air leak was correct. I have to admit, that I cut a corner when I assembled the carbs over summer:
One of the O-rings to fit in the spacers between the carbs and manifold were missing. I sealed it with silicone instead  With the carbs and manifold off the car, I could see that a bit of it had been sucked in. Depending on temperature, it was probably allowing quite a bit of air to pass through all around. This was on the same cylinder where the vacuum takeoff for the headlight system, which explains why I coulnd't raise the headlights last night - it was simply not producing enough vacuum.

Fortunately I ordered a set of new O-rings with my last order from Fastroadcars - and I can see now that I should have replaced them from the beginning. The new O-rings give better spring function, which is essential to prevent fuel frothing in the float chamber.

I actually noticed last night, that fuel in the right hand carb was indeed frothing. This was visible when I took the inspection lid off. The other one was fine.

Now that I had the carbs off the engine anyway, I thought I could just as well move the linkage to the underside as I had planned. It took a bit of fiddeling to get it right, but finally it worked. I thought! Because when I had the whole assembly fitted on the engine, I wanted to give it a last check by one complete push on the pedal - BUT IT COULD ONLY MOVE HALFWAY!

It turns out that the connecting rod on the linkage hits the manifold, so the throttle can't open fully It looks good to have the linkage on the underside, but there's not much fun if I can ever only run 2/3's of full throttle!!

I got quite pi.... off when I realised this, but I'm better now I "only" need to take the manifold and carbs off ONCE MORE  and move the linkage... "only" two hours of work or so fiddeling with the nuts on the underside of the manifold 

By the way: I managed to get the carbs aligned better this time, so I think the syncronisation problem will be fixed

- Anders

[krede]

Get a diesel

Thats what I did!!... and it uses exactly HALF ( Fact!) as much fuel as the Murena....
.. However I must admit that it also takes TWICE (not a fact) as long to get anywhere 

[Waldo]

So now you only need to combine your two cars 

Get a diesel

Thats what I did!!... and it uses exactly HALF ( Fact!) as much fuel as the Murena....
.. However I must admit that it also takes TWICE (not a fact) as long to get anywhere 

[Anders Dinsen]

I've posted an update on the blog:
http://www.matrasport.dk/forum/index.php?action=blog;blog=25

Here's how the system currently looks:



Yes, it looks good... but runs like hxll Read the blog for details

[JL]

Hi Anders

Having raced a number of cars running twin 40 Weber and Dellorto set ups including rear engined Simca derivatives, I would strongly recommend having the carburettors set up on a rolling road; not only will this you the optimum mixture across the rev range but will also check the mechanical advance/retard mechanism in the distributor and also the timing can be tweaked if required. They would also check the ignition system in general.

When using a standard single throttle cable you could remove one of the return springs, this will reduce the load required to open the throttle and prolong the throttle cable life. To counteract the extra load on the rear engine race car where I had to use both return springs, I used to make a throttle cable using motor cycle brake cable which was more than capable of taking the load

Regards
John

PS. Sorry if this has already been suggested.

[Anders Dinsen]

Hi John

Thanks for sharing your experience! It's much appreciated

I ran with only one return spring for some time, but last time I refitted the carbs, the single spring didn't return the spindle to the idle stop, so I fitted the other one too. Thinking about it again now, it shouldn't be necessary as the engine vacuum will make sure that the throttle remains closed when the engine is running. The pedal is quite stiff, but it actually does not feel much different with one or two springs.

The idea of using motorcycle brake cable is very good!

We don't have that many engine tuners with rolling roads and knowledge of carbs here in Denmark. I think the situation is much better in England. The guy who tested Lennart's Murena back in 2004 (?) has been recommended by a few people, but lives some 80 km from me, so in any case, I would either have to refit the old carb before going, or make sure the new carbs are well enough to do the jurney.

Fortunately I think I may have solved my problem: I replaced the ignition coil yesterday evening (it was the only component I hadn't attended to), and much to my delight, the car sprung to life very easily!

Checking the old coil, it turned out to have a secondary resistance of 6000 Ohm, which indicates that it has been burnt inside. It's only two years old, and it has never run "open ended", so why it has failed remains a mystery. It was probably the wrong coil, though, since it had "ballast" written on it, but with a primary resistance of 1.2 Ohm and electronic (current limited) ignition to drive it, it should have been able to take the load anyway. It didn't, however, and it has now been replaced with an old Bosch coil which I salvaged from Waldo's car in July, and which I had lying around.

I sweared a lot over the engineer who decided on the location of the coil on the 2.2: It's hopelessly inaccessible! And the right side of the engine room is probably the wettest place in the engine room with the alternator's fan throwing water around just next to it 

- Anders

[krede]

engine room is probably the wettest place in the engine room with the alternator's fan throwing water around just next to it

I concur... that part of the engine bay gets completely soaked in the wet... hopeless place to fit the electrics.. but  hey... it's French ..

[Anders Dinsen]

Problem is indeed solved, and never has the configuration run this well. Hot, cold - it just pulls nicely from 2000 rpm and up and fires up easily. I have a flat spot around 1500 rpm, but nothing bad, so this might be the right time to go on the rolling road. Still, I have to gain some confidence in the setup, but the running problems are history now! and I'm very happy

- Anders