Servo problem with new Weber ict 34’s

[Huyrob]

So…just had new twin Webers ICT 34’s fitted. Engine runs perfectly, really pleased. Only problem is whilst oomph has increased by perhaps 30% my brake efficiency has decreased by about the same %. So now great up hills but panic going down them
The carbs have a balance pipe fitted T’d off to the original servo. The garage didn’t check the non return valve so possibly/coincidentally this has become faulty. I am told that the take off from the manifolds is 8mm I/d but with the Barb may be as small as 6mm.
Im due to take the van back in next week to have the valve checked but thought I’d see whether anybody has encountered this problem and any remedies if it’s not a faulty valve.
Thanks in advance
Dave

 

[67panel]

Had to make my own fittings when I added a servo, just used brass screw in fuel barbs with 8mm pipe to a home made 8mm T piece and that works. 8 to 10 mm adaptor onto valve with pattern servo metal pipe to front, it works.

 

[Huyrob]

So similar to what has been done on mine?…perhaps it is the valve

 

[ozziedog]

I don’t think it’s anything to do with the valve at all. I think that now you have unlimited performance, you are now driving like a lunatic and racing about thinking you’re gods gift to formulae numptyness.

Ozziedog,,,,,,, no idea actually,,,, in case you hadn’t guessed

 

[Huyrob]

Funny you should say that…That was exxxxactly how I felt going up the first hill, began to question my godly gift as I approached the roundabout at the bottom at speeds I hadn’t reached since my R4 GTL.

 

[Graham L]

So similar to what has been done on mine?…perhaps it is the valve

Are you sure they've connected the servo pipe, servo pipes are usually a minimum of 10mm ID and it's important the one way valve is in place, who installed the carbs?

 

[Huyrob]

I’m pretty sure that all was connected up and hopefully the valve is in incorrectly and / or not working.
Id rather not say who installed, the reason being that they have done a great job ( the servo notwithstanding) and it would be unfair to appear to criticise when it may be a simple human error ( or failed part). They are very keen to sort the issue out.

 

[Huyrob]

All sorted. “ T” from balance pipe removed with pipe left serving carbs only. New servo feed taken off front of L/H carb and …Hey Presto ! As Ozziedog put it I can now drive like a lunatic……and stop.

 

[ozziedog]

All sorted. “ T” from balance pipe removed with pipe left serving carbs only. New servo feed taken off front of L/H carb and …Hey Presto ! As Ozziedog put it I can now drive like a lunatic……and stop.

You are just showing off now because you know I still can’t stop and the brakes on mine seem to be winning the battle of wills at present.

Ozziedog,,,,,,,,,,,, glad it was simple

 

[Huyrob]

Ye Oz but you know …knew at one time what you were doing

 

[ozziedog]

I’m off today, so I’m going down to wrestle with the other side. Both drums are cleaned out , all the bearings are out. I’m just gonna
(famous last words)
I'm just gonna whiz the other back plate off and the flexi and rebuild from there, then it’s just squeeze them bearings back in, pop the drums on, adjust the brakes , bleed the brakes, check out the push rod length. Maybe fiddle and adjust again then rock and roll

Ozziedog,,,,,,,,,,,,apart from freezing to the concrete, what could possibly go wrong ?

 

[67panel]

Fan heater blowing up the left trouser leg will fix that!! To cold to go down my unit and work on the Austin, also waiting for this cold to shift (reaches for tissue)

 

[neilswheels]

All sorted. “ T” from balance pipe removed with pipe left serving carbs only. New servo feed taken off front of L/H carb and …Hey Presto ! As Ozziedog put it I can now drive like a lunatic……and stop.

I'll be fitting the same carbs to my bus, so just to clarify, there is now one balance pipe between both carbs, and a separate take off for the vacuum on the left carb, is that into the manifold? Any chance of a pic?

 

[Huyrob]

Yes, the photo was taken before the servo pipe was attached.It located onto a barb that was inserted into the blankedoff point shown on the front of the manifold ( to the left of the spark plug cable with 4 white lines . I‘ll try to get an “after fitting “ photo later.

 

[Huyrob]

Update. My engine is S/P and somebody on late bay suggested this may have given rise to the problem with a “T” off the balance pipe?

 

[67panel]

You should have been able to T of the balance pipe but that should be fitted between manifolds , where does your balance pipe go? Mine is a SP with TP heads and I had to drill manifolds for the balance pipe fittings on the raised lugs.

 

[Huyrob]

You should have been able to T of the balance pipe but that should be fitted between manifolds , where does your balance pipe go? Mine is a SP with TP heads and I had to drill manifolds for the balance pipe fittings on the raised lugs.

It was T’d off the balance pipe. The pipe went between the carburettors as advised per spec. There was no need for any drilling .The set up was not bought as a cheap off the shelf kit. Balance pipe worked well for balancing the carbs but the T produced way too little “ suck” to activate the servo.

 

[pierrox]

The balance pipe should go between the manifolds, not the carbs. The vacuum port on the carb is for the ignition advance. If you have CBPerf manifolds, they have a port for this. If you have the short Empis, they need drilling.
I run the servo on mine off a T between the manifolds and 0 problem. And one carb vacuum goes to the distributor, though I have a 123Ignition so I could adjust it. On a regular dizzy, you probably need to use the vacuum from both carbs (therefore with a T) to get more succion as the short manifold create way less vacuum than long manifold to a central carb.

 

[matty74]

I think he did mean between the manifold risers, I’ve seen Dave’s set up, balance pipe going from rear of manifold risers. I’m sure he’ll reply to confirm this

 

[Huyrob]

Yes, my error …meant manifolds not carbs I also have the 123+ distributor. All I can confirm is that it didn’t work with the T but worked fine with the single take off, why I don’t know.