SU Carb Overflows

[Steve Priest]

Hi all,

 

Hopefully this is a simple one to answer. The SU carb breather/overflows on my TR4 are not connected to anything. A recent problem with dodgy needle valve resulted in petrol spilling out a little too close to the exhaust for my liking so I think it's time to sort it out. I assume each overflow should have a pipe that leads out the bottom of the engine bay, but can someone please tell me where and how they are routed. A picture would be very useful.

 

Cheers,

Steve

[trevor]

Hi Steve,

The overflow pipes on my TR4 are as you describe, just stubby little 90'0 bends close to the carbs.

Trevor

[TorontoTim]

Hi Steve,

 

Mine lead down inside the inner wing and have their outlets fairly low down. They also both locate in a single kind of "clip" which is a tag welded to the inner wing. (Looks a bit like those holding the wiring loom to the body - infact, maybe it IS one...)

 

If no-one's posted a photo by tomorrow morning Toronto time, I'll take one for you.

 

Tim

[TR 2100]

Hi Steve,

The overflow pipes on my TR4 are as you describe, just stubby little

90'0 bends close to the carbs.

 

That's the way they left the factory, although the bend was turned

so the outlet was against the air filter, supposedly sucking any

overflow back into the carbs.

 

AlanR

[4Mal]

Many years ago and pre the restoration, I had fuel dripping from the overflows.

I've made my own set of pipes and fitted them to come out low down and towards the front.

If you want photos, just pm me your email address.

[littlejim]

Overflows??? Vas ist das 'overflows'?

Although I've recently spent hours gazing at my HS6s(tr4A) I haven't spotted that part yet.

Thank god rewiring the ammeter is keeping me busy so I don't have to worry about it yet. (I'm determined to get some use out of the "+" side of the meter not just the "-".)

[Dazzer]

Hi All

 

Interestingly I've just had to modify the overflows on a pair of Strombergs on the 2000 rally car as the brass pipes breather/overflow did originally as AlanR points out for the SUs as well, go back into the air filter/carbs.

 

This might look a safer option, however in autotests and under extreme stop/starts, a small amount of fuel surge sometimes spilled out of the overflows momentarily choking the engine.

 

I've therefore re routed the pipes down onto the inner wing of the 2000 AKA as some of the TR4s which has cured the problem.

 

Cheers

 

Darren

[Steve Priest]

Overflows??? Vas ist das 'overflows'?

Although I've recently spent hours gazing at my HS6s(tr4A) I haven't spotted that part yet.

Thank god rewiring the ammeter is keeping me busy so I don't have to worry about it yet. (I'm determined to get some use out of the "+" side of the meter not just the "-".)

 

 

On my H6 carbs the overflow outlet is on top of the float chamber (across from the fuel inlet/outlet). It may be different on your HS6 carbs - sure someone with a bit more experience can give you a definitive answer.

[stuart]

For H6 type you could use the longer overflow pipes like these.Overflow pipes.

Stuart.

[Badfrog]

Hi all,

I assume each overflow should have a pipe that leads out the bottom of the engine bay, but can someone please tell me where and how they are routed. A picture would be very useful.

Steve

 

 

Hi Steve,

 

I use a hard black plastic pipe about 1 ft long, going down the inner wing, aiming at the frame rail. However, the secret is not overflowing. Good fuel pressure (2.5 psi), good bowls innards ....

 

Badfrog

[Steve Priest]

Hi Steve,

 

I use a hard black plastic pipe about 1 ft long, going down the inner wing, aiming at the frame rail. However, the secret is not overflowing. Good fuel pressure (2.5 psi), good bowls innards ....

 

Badfrog

 

 

Understood. The original problem is now fixed and a regulator fitted for good measure.

 

Thanks for your help chaps - it's given me some good ideas.

[D Murton]

Overflows??? Vas ist das 'overflows'?

Although I've recently spent hours gazing at my HS6s(tr4A) I haven't spotted that part yet.

Thank god rewiring the ammeter is keeping me busy so I don't have to worry about it yet. (I'm determined to get some use out of the "+" side of the meter not just the "-".)

 

On my HS6 carbs (AUD209) on the 4a there are no stub pipes. The overflows are on the floatbowl covers behind a little plated steel cover.

 

It wasnt very obvious what these were for till a float needle stuck & fuel p***ed out from behind one of them

 

Dave

[littlejim]

On my HS6 carbs (AUD209) on the 4a there are no stub pipes. The overflows are on the floatbowl covers behind a little plated steel cover.

 

It wasnt very obvious what these were for till a float needle stuck & fuel p***ed out from behind one of them

 

Dave

 

Thanks Dave I'll have a shoofty later. I'd prefer them not overflowing, like now, so will worry about more pressing problems.