almost finished the rebuild, then found a stripped thread on final assembly- the worst one, timing case inner cover - next to the oil pump.
I started with 1\4 unc helicoil, turning the drill bit slowly by hand, stopping when the drill bit snagged on something. The `something` looks to be the outer edge of one of the oil galleries which run from the oil pump either side of this threaded hole.
It gets worse - I tapped it and put the insert in, only to find I have wandered off square, and the screw won`t go in properly, it binds (obvs).
My plan is to extract the insert (stud extractor?) and, as I have only drilled in about 10mm, start again, (using a cordless drill, and metal tee square this time).
Has anyone else done this repair?
I am slightly concerned I will take some metal off the oilway, but looking into the hole, it wont be by much, maybe 1mm.
If you have broken into the oil way odds are the oil under pressure will make an escape bid up the threads in the helicoil..
I think I would use a solid insert here (fitted with loctite to seal it) rather than a helicoil which as idie says would allow oil past it.
I like that solution, are they called tineserts or timeserts?, and if I can find 1/4 cei, it will keep it the same all round.
thanks chaps
1/4 BSF will do as a substitute, but that will be hard enough to find. BSCy all but impossible, I'd say.
true - I have only managed to find 1/4 unc, the price for a kit is about £200 with 5 inserts!!
found this insert on fleabay- needs shortening, but looks a tad more affordable!- plus, I have metric taps in stock, the timesert tools are about £120 :( These have a simple screwdriver slot to insert
Use the correct tool to remove the insert to minimise damage. Its just like an arrowhead.
do you mean the tool for the helicoil? I was wondering what to use. As the coil is still flush, I was thinking, could I grab it and pull it out like uncoiling a spring?
If you're lucky, that works. They just pull out by unwinding.
I still don't see how a heli-coil is going to give an oil-tight seal though.
A helicoil had come loose on my Norton Electra crankcase. I made an insert in the lathe using a 5/16" BSF setscrew drilled and tapped 1/4" Cycle. It worked very well. It is a daft design as the weight of the primary chaincase plus hefty starter motor are supported only by 4 1/4" setscrews.
The helicoil:
(https://www.iansoady.org.uk/Norton%20Electra/images/helicoil.jpg)
Making the insert:
(https://www.iansoady.org.uk/Norton%20Electra/images/thread%20repair%202.jpg)
Insert in place:
(https://www.iansoady.org.uk/Norton%20Electra/images/thread%20repair%203.jpg)
yep - definitely using an insert
Helicoil - the remover (arrowhead) tool bits into the first coil then as you unscrew it winds the helicoil reducing its dia so it unwinds from the thread. You may be able to pick the first coil free then get some pin nosed pliers on it but don't pull, unwind.
thanks - helicoil removed, my buddy has a timesert kit, and after several beer bribes in t`pub, gonna install it for me, fingers crossed, what could possibly go wrong?
has anyone successfully filled the hole with jb weld and re-tapped?
Good idea, but risk of the JD weld going into oil way.
roger that, hopefully timesert works!