Anyone do a Whitworth helicoil in the London area?

Easy to do yourself, although I prefer a threaded insert. Try Tracey Tools if you fancy having a go?

Dan

A Helicoil is essentially a spring made of diamond shaped cross section wire rather than round . The diamond cross section matches the cross section of the threads being replaced. After boring out the the damaged threads with the proper bit the new hole is tapped for the Helicoil and the Helicoil is then wound in . A threaded insert is a piece of thick walled tubing - usually brass or bronze -threaded on the inside to match original and threaded on the outside . Inserts generally require more material to be removed from original hole

hello Paul - I have done repairs on those studs in the past. One of the spares shops used to sell a new waisted stud that was 7/16 inch BSW at one end (into the head) and 3/8 inch BSC at the other (through the barrel). The original thread in the head is 3/8 inch BSF. It would have been Taylor Matterson or Joe Francis who supplied it - both gone now sadly. They are easy enough to draw and then get made by Will Horgan at Stainless Classics or Clay Jones at Acme Bolt Maker. A 7/16 BSW tap is easily got. Good Luck , Howard

A Helicoil is inherently stronger than an insert because a minimal amount of metal is removed.  The threaded coil is also harder and more resistant to exhaust rose vibration - even when it gets loose.  The alloy casting of the heads is dubious and can be porous - not an ideal situation for a large threaded hole with a hot exhaust pipe in - especially when they work loose!  The only person I know who does Helicoils is RGM in Cumbria.

A stepped stud would be another solution, again Tracey tools can provide the taps if needed ( other suppliers are available!)

I can do that for you if you want a trip out to Essex.

The thread is 3/8 bsf in the head.

Paul

If you want to pay someone to do it, I recommend

JD Autoworx

• info@jdautoworx.co.uk
• 0208 395 2203
• Unit 8 Clyde Road Works, Clyde Road, Wallington, SM6 8PZ

Tracy Tools do "thread repair kits" (and loads of lovely taps & dies of all sizes!) but "Helicoil" is a Trade name for essentially the same thing. Whitworth threads are best into alloy - especially castings. It doesn't matter what the original was. I haven't checked for years but I though they were BSF for the nuts but Whit for the stud part.

The work can be carried out in situ, surely, to save having to remove the head?

This link confirms what I said about threads in alloy - http://atlanticgreen.com/nhth.htm

Seager Engineering in Ipswich are very good (on the web). Took a 650SS head up to them yesterday for some work. Pat or Jim will sort you out.

Previously ian_cordes wrote:

The work can be carried out in situ, surely, to save having to remove the head?

I think it would be very tricky given the limited space, and very easy to get it in on a slant. Much safer to have the head off.