How to deal with stripped threads on cylinder?

mthomps

mthomps

Location
Cleveland
Can you guys point in me in the direction of the right way to do this?

I bought a sweet cylinder used it to build a motor. During leak down test I noticed an exhaust bolt kept turning. I'm not sure if I did it or not. Either way I need to fix this before I run my new motor.

Helicoil or timecert or? I've never had to repair a thread before. I'm not sure if a local autopart store kit even hast he right thread pitch or what to keep all the bolts the same.
 
augustaf

augustaf

Location
central florida
That means the screw diameter is 8mm and it has 1.25 treads per mm. You drill the stripped hole larger with the (hopefully) supplied drill bit- deeply enough so that the expanded coil does not bottom out (use cutting oil for a smoother hole) , then thread it with the special Helicoil tap (again cutting oil), then install insert so that the last (the one facing you) thread is recessed about at 1/2 -3/4 thread. This will be stronger then before. If you cant source cutting oil suitable for aluminum, at least use something like penetrating oil on the drill bit and tap. Keeps the alu from smearing and makes for decent threads.
 
Norass411

Norass411

Hoarder
Location
NC
Ok. I've got plenty of taps, bits and collars; just didn't know if there was some weird proprietary thing in there.

Sent from my SM-G900V using Tapatalk
 
mthomps

mthomps

Location
Cleveland
Norass411 said:
Is that whole kit really necessary? At $70, you'd be better off buying a cylinder.
Click to expand...

If it were a stock cylinder sure. This is a jetworks freeride ported x cylinder with a fresh bore and hone from jetworks with a carb and pump mods all designed specifically for it...(as soon as I get this problem figured out). I can't just give up! lol
 
mthomps

mthomps

Location
Cleveland
Lumpy said:
What size are you looking for? I have some laying around. I could help you out for the cost of postage.
Click to expand...

Thanks Lumpy that would be killer. I'd use them and send it back. Maniac says M8 x 1.25 so I'll say that's what I need, lol. It's the threads for the exhaust manifold
 
Magnum Mike

Magnum Mike

Site Supporter
I would do a heli-coil. Clean the hole with compressed air, a q-tip and some acetone, then use red/permanent loctite on the helicoil. After the helicoil is in clean any red loctite that made it to the inside of the threads using more q-tips. If you have time, assemble the exhaust 24 hours later so you know the red loctite is dry. The red loctite prevents the helicoil from coming out at your next disassembly.
 
Frosty

Frosty

New York Crew
Location
Western New York
The time sert is tapered so that when you use the installation driver tool it will expand the lower part of the threaded insert. That bites into the existing hole so it will never come out.

So the installation tool is unique to time sert... you also need the counter bore bit to allow the top of the time sert to set flush with the surface.

personal preference - I know the time sert kit is more, but they will never come out. I don't like helicoils.
 
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