Just checking out my new Sprint auto and finding the usual abuse that always seems to be there.
Amongst other things, one of the holes in the inlet manifold for the thermostat housing bolts has been drilled out and tapped to take a 3/8 UNC bolt.
Would this take a 5/16 helicoil insert? I can buy them fairly cheaply but do not have a kit and would like to be sure that they fit.
If the worst comes to the worst I can put in an M8 (which I have) but it would be better to use the correct bolt.
Helicoil tap size
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Mad Mart
- TDC Member
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- Location: Winscombe, North Somerset, England
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Re: Helicoil tap size
The drill for a 5/16" helicoil is 21/64" (8.3mm.).
Sprintless for the first time in 35+ years. 
... Still Sprintless.
Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S
... Still Sprintless.Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S
Re: Helicoil tap size
Did you part company with the 1850 then Alan?AlanH wrote:Just checking out my new Sprint auto and finding the usual abuse that always seems to be there.
Amongst other things, one of the holes in the inlet manifold for the thermostat housing bolts has been drilled out and tapped to take a 3/8 UNC bolt.
Would this take a 5/16 helicoil insert? I can buy them fairly cheaply but do not have a kit and would like to be sure that they fit.
If the worst comes to the worst I can put in an M8 (which I have) but it would be better to use the correct bolt.
Cheers Rich
1981 Dolomite 1500 Auto
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AlanH
Re: Helicoil tap size
No, still got it.Did you part company with the 1850 then Alan?
Missed out on a very nice 1500 and decided to buy this. It was sort of a rebound purchase.
It drives really well but, as usual, things are crawling out of the woodwork (or dropping off the body).
As the saying goes - Marry in haste, repent at leisure.
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xvivalve
- TDC West Mids Area Organiser
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Re: Helicoil tap size
As another approach, I have several spare inlet manifolds lying around the place...