head bolt, or head stud

Skarrd

Skarrd

Member
just a thought i've been having (didn't notice if it's been discussed before)

since we all know the head studs are crappy, i've been considering replacing them.

but also at the same time, debating if our motors really need studs. or if using long enough bolts would work out just fine.

bolt:
pro: Easier to take the jug on and off
con: no studs to align it

stud:
pro: Easier to align and hold jug and head in place
con: can make it more difficult to remove jug with motor still in place.


what do you all think?
 
Depending what threads you find in the case, you might have problems finding a bolt long enough. It's been my experience that the case threads in most engines, 2 stroke Chinese, is a 1 thread. You'll need a bolt nearly 6 inches long with a fine thread. Most of what you'll find at fastener suppliers will be a 1.25 or a course thread when the bolts get that long. I searched at speciality/metric suppliers here in Denver and their catalogs didn't show a 6" length bolt with a fine thread. That'll be the rub.

Retapping the case might be an alternative but not advisable. There isn't a lot of 'meat' down there to work with.

There have been discussions here before about stud threads. From what has been reported there are studs with a fine thread on both ends and there's some with a course thread, both ends. Every engine I've worked with/owned has had a fine thread, 1.0 thread in the case and a 1.25 on the top, cylinder head end. Others will argue this but I can only report on my experience so far. My engines have come from three different suppliers and one unknown source.

Tom
 
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