Engine Trouble The sound of 4 stroking?

[Carl Walichnowski]

Try not using the trademarked word Helicoil when you do your eBay search if you are. It could be that some listings are avoiding using the name and are just calling it thread repair kit. It just seems strange that you're not finding the very same red handled kit like the one I bought. But $15 is still better than $25 I guess.

And thanks for the extra advice on the eBay search. I found a 23 pcs. kit for $10.27, a good deal.

 

[crassius]

when you do this, stuff the motor with a lot of rags and smear a heavy coat of grease all around the area - you don't want a single piece of metal scrap falling in there or that motor will be dead

 

[Carl Walichnowski]

Ok so I bought myself helicoil set from advance auto. Now the set I got did not come with a drill bit. It states a 21/64 bit is needed. Now I have a brill bit with my 8mm 1.25 tap and die set but the bit doesn't state a size, only a letter "H". Would you know if that's the same as a 21/64 by any chance?

 

[gary55]

Use the size directed by the tap that came with the helicoil set. The bit with the 8 x 1.25 tap will be to small. Just put the two taps next to one another and you will see the helicoil tap is larger than the Irwin 8 x 1.25 tap. 21/64" is a must.

 

[Frankenstein]

8.5mm Straight Shank 8.5mm Bit Dia HSS Twist Drill Bit Black

http://www.walmart.com/ip/8-5mm-Straight-Shank-8-5mm-Bit-Dia-HSS-Twist-Drill-Bit-Black/133970527

This will do the job, it's .07 mm larger than the recommended size but I don't think 7 hundredths is something you'll have to worry about, free shipping too.

 

[gary55]

8.5mm Straight Shank 8.5mm Bit Dia HSS Twist Drill Bit Black

http://www.walmart.com/ip/8-5mm-Straight-Shank-8-5mm-Bit-Dia-HSS-Twist-Drill-Bit-Black/133970527

This will do the job, it's .07 mm larger than the recommended size but I don't think 7 hundredths is something you'll have to worry about, free shipping too.

Just out of curiosity, If you are going to buy a bit why on earth would you not buy the size recommended by the manufacturer as optimum for the job. Making a connection even negligibly weaker for no reason makes no sense to me at all. Is this the ol get a smaller sprocket to make up for the bigger wheel ploy?

 

[gary55]

The helicoil has a bearing point of .75mm. remove .07 and you lose just under 10%, but it is probably more than 10 % lose of strength as the bearing surface is removed from the thickest portion of the coil.

 

[Frankenstein]

The helicoil has a bearing point of .75mm. remove .07 and you lose just under 10%, but it is probably more than 10 % lose of strength as the bearing surface is removed from the thickest portion of the coil.

You mean you lose only .035 off the radius, and that's just tips of the thread most inward/towards the center of the hole, which is the thinnest part of the thread and most likely to get stripped off by funky bolts anyway, unless it's going to physically expand and let the helicoil threads rip out I honestly can't see the 10% of strength reduction, mind you that's 10% of the maximum theoretical torque of the aluminum threads, which after tapping for a helicoil are technically stronger because thats just the nature of a larger threaded hole.

Done and done I wouldn't be worried. And by the way is that bearing surface the surface on just the width of the thread that makes contact? Again the diameter is reduced by .07 but since threads are on each side of the hole that's only .035 of that thread missing so only 5% loss on the theoretical max... Shouldn't dip into our 12-15 ft/lbs that we use on the head bolts anyway.

 

[Frankenstein]

Or maybe it is 10% but something tells me it just isn't.

 

[Frankenstein]

Well I didn't buy what I believed to be an incorrect size, I purchased what I thought could very well be the correct size based only on the fact that the drill bit came in the package with the 8mm 1.25 tap, I wasn't sure of the size cause the package only lists the letter "H" as the size. I figured I'd buy it while I was there, ask you guys if it was the right one & if so I wouldn't have to go back and buy the right bit. If I'm wrong then I have the receipt and can simply return it asap.

It's not right as he said, that drill bit is going to be under 8mm so that the tips of the cutters will make threads 8mm wide, of you took that much off in the hole an 8mm bolt would drop right in. The helicoil is even larger (it's a nut that wraps around an 8mm bolt, so it has to have something big enough but only so much that the tap has something to actually bite. A 21/64 bit is available at the home depot just up the road from my house, so you shouldn't have trouble finding it near you either.

I picked an 8.5 just for the hell of it, I could have easily recommended a 21/64 but really hate the ridiculousness of the standard measurements (it just sucks) and I really prefer metrics, so I'd rather have my 8 8.5 9 and 10mms instead of my 1/4th 17/64 6/32 something/other-just-as bad-number etc...