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TwinCamJohn

Carb air filters TR3A

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I couldn't find any discussion on this subject. If there is a link maybe someone can point me to it ?

Anyway, when I bought the car it came with the original air filters although the engine was fitted with short trumpets and foam filters.

The overflow pipes (plastic) from the bowls are led down to chassis level.

I believe the originals were a right angle pipe (copper?) into the air filter? However there doesn't appear to be any hole to accept that in the filter, only the mesh.

So how did it work?

 

At the same time what is the opinion on leaving my system as it is or going back to original.

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I would leave as is, or if you want to put on the original filters leave the overflow piped going to chassis level.

Originally the short brass overflow pipes just poked into the edge og the mesh.

 

Bob.

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Maybe there were different arrangements but I have only seen short steel drain tubes that just exited the top of the carb and allowed fuel to drain to the ground.

 

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Do not mess with what is working.

The vents are just that - they will vent excess fuel and balance air above the fuel level in the float bowl to atmosphere. - therefore not hampering the rise and fall of fuel level as the engine functions.

Moderns (TR6 etc with carbs) will have miles of plastic pipe to a carbon canister to catch any over spill or fumes to prevent escape to a************** (censored in accordance with  impending resolution 9.9 activation)

Cheers

Peter W

Vote NO on resolution 9.9

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1 hour ago, TwinCamJohn said:

Errrr ??

Protesting the proposal to neuter this forum at the upcoming AGM.

 

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57 minutes ago, TwinCamJohn said:

Neuter? In what way?

TR Reg members should read the full set of issues being voted on at the upcoming AGM but the proposal that is causing the most indigestion is the one that would ban all criticism of the club, club officers and companies that advertise in TR Action like the company that has been systematically swindling TR Register members for the last year.

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Thanks for the pic. Are those pipes just touching the mesh, or pushed inside?

 I have been trying to find the thread on this subject on the FrenchTR forum. It was suggested that performance was better with the pipes going into the mesh as opposed to led down to the chassis.

I can't see what difference it would make. Any thoughts?

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They just touch the mesh and no it wont make any difference to performance if they go down to the chassis but it is a bit safer.

Stuart.

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On 11/15/2018 at 7:31 AM, billy l said:

Hi John, here is a picture of mine which I think is original.  Cheers, Bill.

P1020681_1242a.jpg

Beautiful!! Just wondered if the wiper motor isn't a 3A one?

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If the pipes are run down to the chassis make sure that the ends are not so low that they act as a draft tube, this will put a vacuum above the fuel in the float chambers and draw fuel away from the jets. I know that the air filters also can cause a draft but this is far less then travelling at say 70mph

George

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I have overflow pipes running down to level with chassis bottom. Had no problems up to **mph !  HS6 carbs fitted.

Bob

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34 minutes ago, Lebro said:

I have overflow pipes running down to level with chassis bottom. Had no problems up to **mph !  HS6 carbs fitted.

Bob

Shouldn’t that be     * * * mph bob. 
:ph34r:

 

 

on track days obviously !

Edited by Hamish

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I could not possibly comment

Bob

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It 

3 hours ago, Lebro said:

I have overflow pipes running down to level with chassis bottom. Had no problems up to **mph !  HS6 carbs fitted.

Bob

It was something that was happening on my MG TD (so obviously at slower speeds than a TR but I am surprised only 2 stars Bob) and in a way it's how the anti run-on works on a US TR6 admitted using manifold vacuum.

George

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On 11/15/2018 at 1:51 PM, TwinCamJohn said:

Thanks for the pic. Are those pipes just touching the mesh, or pushed inside?

 I have been trying to find the thread on this subject on the FrenchTR forum. It was suggested that performance was better with the pipes going into the mesh as opposed to led down to the chassis.

I can't see what difference it would make. Any thoughts?

I know its an old post, but on this point I was thinking that if the ends of the pipes were longer and pushed into the mesh to the point where they were affected by the vacuum of the carbs, would this cause the level in the float bowls to rise, causing a richer mixture, especially at higher speeds, or is it impossible for the level to rise as it is governed by the float and needle valve?.  Just thinking aloud.

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Ralph 

The float and needle valve will stop additional fuel entering the float chamber and any vacuum on the breather pipe will try to draw fuel away from the jet, this will make the mixture weaker 

George 

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5 hours ago, Ralph Whitaker said:

Maybe that particular French owner had overflowing carbs that were dumping fuel into the airfilters.:D

I was always convinced Standard-Triumph knew best and that the overflow pipe was best placed facing into the filter mesh.

But now it seems an unnecessary hazard. So two fingers to originality. It makes perfect sense to fit long pipes of modern material taking any excess fuel as far away from the engine bay as possible.

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FWIW Healeys used to have their tubes running down to the chassis as standard. Available from Burlens.

Stuart.

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8 minutes ago, stuart said:

FWIW Healeys used to have their tubes running down to the chassis as standard. Available from Burlens.

Stuart.

Problem only arises with H4s and H6s, right? Not relevant to DCOE Webers?

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Just now, DavidBee said:

Problem only arises with H4s and H6s, right? Not relevant to DCOE Webers?

No they dont have overflows, if fuel overwhelms the floats it either makes the engine run very rich or runs back out the throats!

Stuart.

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7 minutes ago, stuart said:

No they dont have overflows, if fuel overwhelms the floats it either makes the engine run very rich or runs back out the throats!

Stuart.

So, not an idle question, as I feared. It means, in practice, one less hazard to worry about. Leaving old rubber fuel lines, or braided hoses splitting, or loose olives (?) as the potential risks to be aware of, I guess.

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