Carburettor jet issue

[davewhitefoot]

I have had a serious misfire issue with my TR3a. After very lengthy searches for the problem  and changing all ignition parts and fitted a new fuel pump (see my previous query regarding petrol in the sump) I have now found that the jet of the front carburettor has a hole abut 5mm across suggesting that the top of the jet has disappeared somewhere. How can this have happened? More to the point is there some small brass item in the engine or is it too small to cause serious damage?

[RogerH]

Hi David,

there should be a few components attached to that.

In the SU reference cat it shows it as an assembly  P/N0. WZX1539 That your tube goes into.

Are there any threads inside your  tube for anything  to screw  into.

 

Roger

[RobH]

It can't have gone into the engine during running because the carb needle doesn't come fully out of the jet, so would have held it like a threaded bead.  

[Ralph Whitaker]

At least you found the problem, that would have been dumping neat fuel into the engine.

Ralph

[davewhitefoot]

Thanks for your responses gents.

My real concern is that I did not solve the engines failure to run until I lifted out the carb piston and did not notice a small brass bit on the needle and must assume it fell inot he carb. Having found an old jet in the "it might come in handy one day box" it put that in and the car fired up imediately - such a sweet noise after so long trying to find the problem. But if the detached top of the jet fell into the carb it might have been sucked into the engine.

I have asked Burlen for more info on what might have gone wrong and a guess at the size of the detached bit and how it might cause damage.

I'll post any response I might get.

I have run sidescreen TR's since about v1966 and have never seen this sort of problem and people I have asked have not seen it either!!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Nigel C]

indeed worrying, I would have thought it would have ingested it by now but for piece of mind it might be worth the hassle of lifting the manifold off and checking whats in there and the port?

I've been thinking of buying an endoscope that you can plug into your mobile phone (about £20), you could look in the bores to see any damage to the top of the piston(s)

 

 

[RogerH]

Indeed, taking the plugs out and looking inside - a boroscope would be handy

 

Roger

[BlueTR3A-5EKT]

Couple of options really 

in and straight out

in and jam valve

in and embed in piston crown 

pull the plugs and check the gaps. The one that has closed may have been whacked by a bit of brass.  

[Ralph Whitaker]

19 hours ago, davewhitefoot said:

Thanks for your responses gents.

My real concern is that I did not solve the engines failure to run until I lifted out the carb piston and did not notice a small brass bit on the needle and must assume it fell inot he carb. Having found an old jet in the "it might come in handy one day box" it put that in and the car fired up imediately - such a sweet noise after so long trying to find the problem. But if the detached top of the jet fell into the carb it might have been sucked into the engine.

I have asked Burlen for more info on what might have gone wrong and a guess at the size of the detached bit and how it might cause damage.

I'll post any response I might get.

I have run sidescreen TR's since about v1966 and have never seen this sort of problem and people I have asked have not seen it either!!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.

 

 

If your engine now runs and sounds sweet I would not bother trying to look in the engine for further problems. Might open another can of worms.  The small bit of brass, if it did indeed get into the engine is long gone by now. Unless the throttle butterfly was being held open when the offending part dropped off the needle it couldn`t have got through, although it could have rested there until the engine was next started.

Ralph