Carb with stripped threads

[bgthomas@earthlink.net]

Hello everyone,

I've sure got a problem this time. I was finally ready to try to fire up the TC with its' new XPEG 1500 engine. When I turned the key, the fuel pump started and the rear bowl connection started to leak. When I went to tighten the connection holding the float bowl to the carb body, I stripped the threads in the body. DAMN!!!

Now what?? I guess I can try to find a replacement 1.5" carb, but I've got new throttle shafts and such in this one. Is there anything I can do to repair / replace the old threads??

After almost a year of work and waiting, it has been a long day. Any help or suggestions would REALLY be appreciated.

Bob
TC EXU 7388

[Keith and Maggie Black]

Bob
Have it taped, thats what I would do first.........wishing you well, Keith

[Dwyer]

Bob

Tapping the hole to a larger size is a last resort, 'cos then you'll need to make a special large diameter screw, etc.

First try to find a "Helicoil" (thread insert) to repair the carb body. I don't know what the thread is - my guess is BSP - but I can measure one tomorrow if you need me to.

If you can't find a Helicoil, #maybe# there is enough metal in the boss on the body to allow you to screw in a thin sleeve, threaded outside with (say) UNC and inside with BSP or whatever the union uses. Use Loctite to the body and it won't move again. However this may be more trouble than finding another carb: it depends on what equipment you have.

Regards
Dave Dwyer

[ROGER FURNEAUX]

The trouble with either a helicoil or a sleeve threaded inside & out is that a lot of metal will be removed from the carb. Almost as good is a sleeve smooth on the outside, made to be a press fit in the hole you bore in the body (but use a drop of Loctite as well).

When I last re-bushed some carbs for a friend, using the new Teflon split bushes, I found they had already been re-bushed, but in aluminium, so it was not obvious until I had started to machine them out. It is best not to use brass in ali. although helicoils would be OK as they are stainless steel, but IF they are available, they would be an expensive option 'cos the special taps required are not cheap!

ocTagonally
TCROGER

[Skip Kelsey]

Bob:

I know he is not up to speed yet, but Phil Marino does a nice repair on this type of problem. He has done it for me in the past. I am sure someone else has also done this.

Skip Kelsey.........................

[Jennifer and Hugh Pite]

Hi Bob, I recently dismantled a 1 1/4" carb that had the float bowl threads stripped. The PO had made a neat and functional repair. He blind drilled and tapped the center of the threaded hole on the carb body to fit 1/4 - 20 thread, he also threaded the internal of the bolt holding the float bowl onto the body with the same 1/4 - 20 thread. He then made a stud of appropriate length (threaded rod would do) and thread size to go into the newly threaded hole of the carb body. He had previously drilled the stud with a 3/64" drill down its axis and another hole of the same size in a radial direction on the portion of the stud which would not be threaded into the bolt or the body. The purpose of these holes was to allow gas (petrol) to flow between the float bowl and the carb body. This was on old repair on the carb and was in service for a number of years after it was done.

This is one way to repair the damage and I am sure that there are others.

Good Luck, Hugh Pite
'48 TC '33 J-2

[Viv James TraX Interconnect (Pty.) Ltd]

Bob,

Stripping these threads is a standard problem. Here in Cape Town, "Helicoil" wire inserts with the correct thread (BSF?) are fitted by Link Engineering, a local machining shop. I get them to do do all my carbs before refitting them. I'm sure you'll be able to find some these locally. There is no need to scrap the carb. body.

Rgds
Viv James