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I use BP6HS. However, in this link http://www.britishcarforum.com/bcf/showthread.php?74698-Spark-Plug-Recommendation-for-a-TR3it is suggested that BP5HS helps with undue carbon build-up in the plugs.

 

I have been trying to tune the car and came to a point where leaning the fuel any more with make the car complain, while at present, despite, high consumption, the car is running very well. However, the plugs continue to be black, even if I am cleaning them every day to check on mixture.

 

Any comments on BP5HS?

 

Thanks

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I'm working on the carbs and waiting for delivery of carb cleaner before I have another go. What I can't ubderstand is why one carb hisses (as it should) when I test it by increasing the acceleration but the other one does not seem to do any hissing at all. However, as I said the car runs (very) well.

 

Any ideas?

 

Camilo

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I'm working on the carbs and waiting for delivery of carb cleaner before I have another go. What I can't ubderstand is why one carb hisses (as it should) when I test it by increasing the acceleration but the other one does not seem to do any hissing at all. However, as I said the car runs (very) well.

 

Any ideas?

 

Camilo

 

Difference in the tone/volume of the airflow into the carb will vary with air velocity. If one carb is pulling in more air it will be louder than the other one. What are you using to balance the carbs ?

 

Stan

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I used a carb air flow meter

 

http://sucarb.co.uk/air-flow-meter.html

 

and left the carbs absolutely balanced. However, after refitting the filters I listened to the carbs. The fron carb hisses as normal; but the rear does not. I can only assume that maybe the jet needs centering (I also suspect that the front carb is not making the metallic sound when the pistion is lifted and allowed to fall); the carbs got dirty while they were in the workshop for a couple of months without the filters; or that the filters themselves are dirty (how do you clean them?).

 

But, as I said, the car is running well.

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Are the filter gaskets allowing atmospheric air under the piston?

see slides 13 and 12

https://supertrarged.files.wordpress.com/2017/07/final-pdf-how-does-an-su-carburettor-work-iwe-2017.pdf

 

If a piston is sticking its a waste of time trying anyhting else. A sticking piston compeletely messes up the 'constant depression'

 

Peter

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Are the filter gaskets allowing atmospheric air under the piston?

see slides 13 and 12

https://supertrarged.files.wordpress.com/2017/07/final-pdf-how-does-an-su-carburettor-work-iwe-2017.pdf

 

If a piston is sticking its a waste of time trying anyhting else. A sticking piston compeletely messes up the 'constant depression'

 

Peter

 

 

That is another job I have in mind. I bought a can of Starting Fluid and after cleaning the carbs/checking the jet centering want to see if there are any leaks.The mechanic who disassembled the car when it went for the sand-blasting/painting had some difficulty putting the manifold back on (so he told me) possibly because it was sandblasted and maybe some bits were no longer there...

 

Do you think that could account for high consumption, and a carb not hissing, even if the car runs well and sounds OK?

 

 

PS -

 

When I mention high consumption (and I mean anything up to double what it should be), that was before I closed off the jets by 4/5 flats. Does that make a very big difference? if I added another flat, the car no longer behaved nicely,

 

I haven't checked consumption since then, so maybe it is better.

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I used a carb air flow meter

 

http://sucarb.co.uk/air-flow-meter.html

 

and left the carbs absolutely balanced. However, after refitting the filters I listened to the carbs. The fron carb hisses as normal; but the rear does not. I can only assume that maybe the jet needs centering (I also suspect that the front carb is not making the metallic sound when the pistion is lifted and allowed to fall); the carbs got dirty while they were in the workshop for a couple of months without the filters; or that the filters themselves are dirty (how do you clean them?).

 

But, as I said, the car is running well.

In my experience, if one carb is working "hissing" more than the other particularly at idle, it's usually cured by a simple linkage adjustment. However, that adjustment must be made before further tuning or balancing.

Tom

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Hi Camillo

 

did you not break/undo the linkage connection between the two carbs to balance them with your balancer?

The carbs must be independent of one another for this to work properly. Both carbs must be adjusted so the HISS is the same, better still measure with your carb balancer tool.

 

If you follow the SU guide sent to you will see why this is necessary. Follow the guide step by step, no short cuts, and all will be resolved.

 

Iain

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Hi Iain

 

No, I did not undo the linkage. I followed youtube videos and the instructions of the balancer...

 

So, what linkage in the image below do I have to undo? You mention the SU guide; are you referring to a past post?

 

Sorry, but my memory and ability...

post-14128-0-63815700-1502697238_thumb.jpg

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Hi Ian



Yes! I got the email; I printed the attachment; I read it all; I forgot all about it!



I do have a memory problem.Alzheimer's? I'm afraid to find out...



I am very sorry. i will have another good read and go from there.



Regards and many thanks for your patience.



Camilo

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qim ~

 

The shaft nearest the manifold has two clamps fitted. Undo one lock nut which will disconnect the carbs.

Adjust each butterfly until you get an even reading then re-tighten the clamp.

 

Recheck your readings again.

 

Tom.

 

 

Tom, forgive my ignorance but..

 

If the carbs are already balanced, when I undo the lock nut they are going to continue balanced. So what is the point of undoing it? I am missing something, obviously!

 

Unless by butterfly you don't mean adjusting the tickover.

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Qim

You have to balance each carb separately not when their linked.

 

What you need to do is slacken off one or more of the small nuts that hold the linked throttle spindles together between the carbs, so that each carb. is then independent of the other (i.e when the throttle is operated it only operates on the front carb.). Then use your carb. balancer on each carb. in turn to get the same reading by adjusting the throttle screw on each carb. Re-tighten the nuts and re-test the balance of each carb.

 

Job done!

Rob

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Last time, I promise
I was down in the garage looking at the car and getting abit confused with what I read:
Whenever the throttle adjusting screws (3) are fitted they, and not the slow-running valves, must be used to adjust the idling speed. Screw down the slow-running valves (which must remain closed) and set the throttle adjusting screws (3) 1.5 turns open. In items 2 and 3, adjust the idling speed with the throttle adjusting screws.

 

 

Am I to understand that what I marked in red in the photos of my carbs are the "throttle adjusting screws" and that what is in gree is the "slow running valves"?
In any case, what I used up until now to control the idling is the screw in red.
Could you clarify, please?
Thank you
PS - It was dark in the garage.I am being an idiot and forgetting the three screws that hold down the piston chamber, the one in the green circle being one of them!!!... in which case where is the slow running valve?

post-14128-0-36645700-1502734903_thumb.jpg

post-14128-0-78497900-1502734945_thumb.jpg

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Your SU carbs do not have a slow running mixture control valve, only idle speed adjusting screws.

The only mixture control you have is winding the jet up or down, & that affects mixture over the whole rev range.

 

Bob.

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Last time, I promise
I was down in the garage looking at the car and getting abit confused with what I read:

 

Am I to understand that what I marked in red in the photos of my carbs are the "throttle adjusting screws" and that what is in gree is the "slow running valves"?
In any case, what I used up until now to control the idling is the screw in red.
Could you clarify, please?
Thank you
PS - It was dark in the garage.I am being an idiot and forgetting the three screws that hold down the piston chamber, the one in the green circle being one of them!!!... in which case where is the slow running valve?

Here's how I do it and this is probably not by the book: Loosen the bolt to the left of the screw in red on your picture. That will disconnect that carb from the linkage and the other carb. I loosen the one on the other side too. Then adjust the idle and mixture (lifting the piston method) on each carb separately. Hiss or air flow gauge should then be equal. Then make sure the actuating tab is just touching the slot on the carbs and tighten the loose bolts. Check that the throttles move in unison. Works for me.

Tom

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What is that line running across the suction chamber in your first photo, Camilo? It looks like a crack in the metal dome. If there's a vacuum leak there's no way the carburettor will ever work right.

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Hi Don


Thank you for spotting that apparent crack. I have just gone down to the car and not only there is a line suggesting a crack, but it is very shiny all the way up and around it meaning that some sort of attempt was made at repairing it. Now, I have had the car for 40 years and not only I never noticed that, but the shiny repair is obviously recent.


The car was left for a couple of months with the mechanic who dismantled it. He was supposed to change the needles. He is very experienced (ex-Triumph Portugal man)and has looked after my car for several years). He would have pointed out that situation to me had it been there before. At the time he dismantled my car, he had another TR3A recently imported from the States in his workshop...


Unfortunately, there is no way I can prove that parts were "mistakenly" taken from my car.


Now, what can I do? In about an hour or so, I will take the car out to warm it up and then spray Starting Fluid on the outside of the piston chamber to see if there is a leak. I understand that if the car revs up, it is a sign of a leakage. Is that right?


Next, I have to find out how to replace the piston chamber. I read somewhere that the TWO domes are calibrated together and maybe to replace one, I must replace both. I saw a video where the air entries are blocked and holding the domes by hand with the pistons inside they must fall at the same rate.


Are these domes still available? Can they be repaired? Should I commit suicide?...
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