Engine Trouble Engine stud hole stripped

[BWB]

That is a good price on the heli coil kit. And since you stripped one the others are most likely weak. The heli coils will make them stronger than brand new ones.

 

[HeadSmess]

just follow the instructions when using helicoils... if you arent confident, experiment on something else instead. i have seen so many multi-cylinder banks destroyed by the amateur use of a helicoil kit... yep, they are cheap compared to a $1000+ cylinder block...until the moron strips them out, retaps to the next size, strips them, helicoils them, plus takes out the cam bearing locating dowels, then ends up drilling right through the thing and wacks a bolt with a nut on the end through the hole... whereas if the same person had used g-clamps, or simply gradually gave each and every bolt a half turn, rather than try tightening each one individually... would have been no issue for us when we went to work on it after my friend bought it!


sorry, i digress....

could always just drill side on into the case with a 3-4mm drill, so you go through the stud itself, then hammer in a small piece of steel bar... pin it in place

 

[dotcom]

I got the kit in the mail today and will likely try and fix it tomorrow but I was wondering if since I also have a 6mm stud hole stripped would I need the 6mm x 1 kit or the 6mm x 1.25 kit ? Noticed for the 8mm kit that I got today, it was 8mm x 1.25 so im wondering if the 6mm needs to also be 6mm x 1.25 or just 6mm x 1 ?

 

[HeadSmess]

standard M6 is 1mm pitch.

never heard of a M6x1.25 . doesnt mean it doesnt exist, but usually "special" threads are finer, rather than coarser than the standard...

keep the helicoil kit together! do not mix the tap up with any other taps you happen to collect! its a special size.

 

[dotcom]

A drill bit did not come with my kit or a size specified.
anyone know the size of the drill bit that I need for the 8mm head bolt stud holes.?

 

[bakaneko]

Okay, I am back. I actually had the same problem as you again with all my bolts because I really use my engine. This is for others that will eventually have the problem of a stripped bolt hole and might stumble upon this thread.

Here are solutions to this problem and some are remarkably cheap. Video starts at 0:45



I went with aluminium foil and bought 4 new 8mm 1.25 hex bolts. I put a good long toothpick size piece all the way into the holes to do this. I didn't use the acorn nut because even that was stripped and you have a higher risk of shearing off the bolt if you tighten too hard. The results is that the bolts are in there really tight and I feel with more pound pressure than I was able to do before with the acorn nuts.

 

[dotcom]

I actually did find the size

 

[HeadSmess]

and what was it?

normally, you subtract the pitch from the diameter to get the tapping size(80% depth thread... 100% thread is a nightmare to tap, and only 10% stronger), but obviously helicoils need a larger tap, hence drill...

just for future reference... the size would be a nice thing to mention

 

[dotcom]

8.3mm = 21/64 is what was on the packaging. Just a bit hard to find. Mission complete too and stud hole is fixed with the helicoil. A bit crooked but I am lucky to be able to keep using the motor. Crooked because I did not have the proper tools necessary to drive the tap down properly but not so bad so I can bend it with force to fit in the cylinder.
So the 8mm tap and helicoil kit total cost me about $20 with 12 extra helicoils. Now just ordered a 6mm helicoil kit for $12 dlvd which comes with 25 helicoils. Onward and upward

 

[butre]

I don't bother reading the size, I just grab whatever drill from my index is recently sharpened and about the right size. say for a half inch threaded hole I'll grab my easy to find and always sharp 13/32 bit, or for a quarter inch I'll usually grab a 7/32 bit if I can find the damn thing (I make a lot of quarter inch threaded holes and have a bad habit of not putting things away).

it's not that much harder to tap 100% thread if you don't try to monkey it all in one go, just peck tap it with a spiral flute tap.