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Helicoiling timing cover/alloy block in-car


Mj17

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Hi,
Does anyone know if it's OK/possible to Helicoil the bottom timing cover threads, the ones in the alloy block with the engine in the car or does it require a partial strip-down?

My concern would be that the threads go right through the alloy block so any swarf is going to end up in the sump.  If the hole isn't right through then seems it should be possible...?

Thanks,

Mark

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Mj17,
I'm fairly sure the holes are blind holes not through to the sump. The hole for the Helicoil may be larger than the hole in the timing cover though.
                                                                        Cheers,  
                                                                        Paul

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Yes in the car is possible ,  taking the radiator out gives a better access , just drill and tap out to a larger size .
they strip when the  setscrew thats been used is too long and it bottoms  out in the blind holes ,

in alloy its a   just clamped and a light nip is all thats required .  
you may reclaim with an 8mm x1.25 tap and metric  setscrew, or you could go to 3/8"unf



Pete

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peterhlewis wrote:
...they strip when the  setscrew thats been used is too long and it bottoms  out in the blind holes...


Seems to have the correct, short bolt in there and needed a little effort to unscrew (i.e. needed a spanner, not just fingers rather than meaning 14' breaker bar) but not sure it would take 1 lb/ft screwing it back in, let alone the book's 10 lb/ft (from memory).

I doubt the combination of a UNF thread (come on chaps, UNC in aluminium) and the action of two dissimilar metals help much either.


I have to say the fact that the thread in to the (steel) engine front plate, the one under the alternator mounting was stripped was more impressive!

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or you could bond a stud in there with some 'chemical metal' it is harder than the alloy block itself,will need to thoroughly degrease the hole and any remnants of thread in the hole will aid grip of the compound. :)

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there's a few Triumph alloy fitting with unf threads I think they did it on purpose to give us a hard time in the after life of these little cars , why was is alloy and not a cast billet . who knows.. goes with the wooden block fillers ,, a  common  principle in its day   cork ,wood,asbestos, cord  .   sealant...whats that
at least  steel replacement bridges  are available now.  

may be the design team for the front end didnt speak to the back end team    

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There is a company , albeit not hard to do oneself, that is making steel replacements. Of which Id have to look up and advise
There is also another problem that came to light ,recently, relating oil leaks. That the domed screw that holds this block into place in the case , is sitting proud  in the countersunk hole, then the sump pan cannot sit flat . Hence a leak at the front
I took mine up to 3/8ths using a ratchet tap holder......no need to remove anything. However sense prevails and it would be better to strip down and do properly

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