Twin Webber Trouble

[Guest Top Cat]

To everyone who offered advice on this problem, here is the latest

 

A compression test revealed 145psi per cylinder which isnt bad so I decided an expert needed to look the carbs over as I was now convinced these were the problem.

 

Booked the car in at Bogg Brothers near Malton and handed it over to big Dave.

 

This guy is webber genious.

 

Outcome, new needle valves, reset float levels, adjust and balance carbs, reset timing, clear block breather, tune on dyno.

 

Result.......120bhp at the wheels with no more misfiring!

 

Off to Elvington tomorrow now to play.

 

I love it when a plan comes together dont you!!

[miikae]

Pleased to have got it sorted now, so now the play begins eh

 

Mike

[Guest Top Cat]

Returned from Elvington, had a better day this time with a lot more torque and acceleration. But as seems to be always with this project I now have other issues, the car now seems to be running short of fuel when getting into 4th gear on the long back straight, my initial thoughts are that the std mechanical fuel pump cant deliver enough fuel when the car is being driven hard and therefore the float chambers are emptying after going through 2nd and 3rd gears.

also it is overheating after only 2 laps even though the electric fan brings it back down to temp when left on tickover in the pits. it doesnt have an oil cooler or have the exhaust heat wrapped, would these two things make a difference?

Anyone comments welcome

[Guest trackerjack]

Perhaps more bonnet venting required as the fan is of no use at speed as the wind rush is greater, try ducting the air through the nose to make sure all of it goes through the rad.

 

I track a Dolly Sprint which most of you recognise as a "kettle" type car.

One of the mods that I have done to it is to add a modern expansion bottle with a lower hose take off which enables the car to blow out any air into the tank which is then replaced by water, so no hot pockets appear. Cosworth engines suffered a great deal and a swirl pot gets rid of the air too.

 

My S7 has not been on track with me yet but as it has an old Cortina rad and only a blow off bottle I doubt it would last long before it spat some coolant out, so I will modify it shortly.

Edited October 17, 2009 by trackerjack

[Guest mower man]

Hi exhaust wrap makes a big difference especialy combined with vented bonnet sides, I presume carb side is open allready?,is the radiator top, sides and bottom shielded to make air travel thro the core not round it?is it o/heating or just running a little warm ?just a few things to check regards mower manHTH

[Guest Top Cat]

Perhaps more bonnet venting required as the fan is of no use at speed as the wind rush is greater, try ducting the air through the nose to make sure all of it goes through the rad.

 

I track a Dolly Sprint which most of you recognise as a "kettle" type car.

One of the mods that I have done to it is to add a modern expansion bottle with a lower hose take off which enables the car to blow out any air into the tank which is then replaced by water, so no hot pockets appear. Cosworth engines suffered a great deal and a swirl pot gets rid of the air too.

 

My S7 has not been on track with me yet but as it has an old Cortina rad and only a blow off bottle I doubt it would last long before it spat some coolant out, so I will modify it shortly.

 

Sounds interesting trackerjack, I would like to see a picture or diagram of what the set up looks like as I cant really visualize what you mean by lower hose take off

[Guest Top Cat]

Hi exhaust wrap makes a big difference especialy combined with vented bonnet sides, I presume carb side is open allready?,is the radiator top, sides and bottom shielded to make air travel thro the core not round it?is it o/heating or just running a little warm ?just a few things to check regards mower manHTH

hi, no i dont have side vents in the bonnet at all. as the carb trumpets are level with the chassis rail there didnt seem much point of opening it up, but now you mention it, it would probably improve my engine performance if I somehow ducted colder air from outside the bonnet straight into the webber carbs!!!!

 

I will try and upload a picture of the carb position. though am not very good at this kinda stuff.. No cant do it, file is too big. can email it if you pm me!