I have stripped threads on the head in my car it is the distributor hold down screw I did not think i overtightened it but it will pull when you tighten the jam nut. I know about heli-coil but do not like that idea as much as using a thread-sert, so it will be steel and epoxied in place looks like a good solution have not checked yet but I believe the thread is 3/8". Ideas and tips appreciated. thanks
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Oversize [ 1/2X13] studs are available. -
I think this is the dizzy hold-down screw., the one with the jam nut.
Over the years ppl have jacked the crap out of the jam nut, that is how this happens.
If the head is off, a helicoil is easy to install, but not so much on the car.
3/8" is .375, 10mm is .3937
I have successfully carefully used a 10 mm tap as a fix while the head is in the car, then blue loctite the 10 mm bolt in place, and forget a jam nut.
There are 3 different pitches to metric bolts, I forget which pitch I used, but it was the one that most closely matched the SAE pitch that was already there. Just hold a 3/8 fine thread bolt up to each of the three metric sizes and you will immediately see which is the best choice.
Of course be careful of the chips!
BTW what is the diff between a helicoil and a thread sert? Not familiar with that. Got a link?
I find helicoils easy to use and in this case I would red loctite it inLast edited by tbirdtbird; 09-24-2017, 10:44 AM.Comment
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http://www.wurthusa.com/web/en/websi.../time_sert.php I think this is better than a heli-coil T-bird your thoughts?Comment
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This is what I am thinking of doing. 3/8 fine thread do you know what pitch i will figure it out this seems to be best on an open hole repair in stainless steel. The threads already were jacked in my head and are only gonna get worse. -
not sure how that is different from a helicoil....what comparison do have with each? i am always looking for new tricks..... -
Fine thread is not a good idea with cast iron. You should use a coarse thread.
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Chief,
the metric size u want is 10mm x 1.0 mm
pitch is almost an exact match to 3/8-24
the first 3 threads will be the same, just cut deeper, the last 3 threads will be a new cut, (the hole is not very deep), and you'll be surprised at how well this works.
I may have even left the manifolds on, can't recall. Just go slow, and back out every half turn as with any tap you use
Stuff a rag in the dizzy hole, when done tapping, let'er rip with the blow tip, then remove rag
The dizzy really isn't going anywhere, i don't understand why people jack the hell out of the jam nut, snug is all that is neededComment
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Once the coil is installed my small jewelers needle nose would grab the tang, they twist right off
Or just block the inside of the hole for the dist shaft and knock the tab off with a little screw rodger.png "smile")
then retrieve it
3~ Tudor's & 1~ Coupe
Henry Ford said,
"It's all nuts and bolts"
"Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible."
Mitch's Auto Service ctrComment
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When I am making a hole that I don't want to contaminate the area with chips, I simply place a magnet around the drill, or at the hole and let IT do the de-chipping. Blowing it out most often gets chips where you really don't want them, specially in the dizzy hold down screw. If you are drilling that out it will drop chips down past the head gasket hole and we know what is down there.
MY 2¢You wana look waaay far up da road and plan yer route because the brakes are far more of a suggestion than a command!Comment
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if you are gonna pull the manifolds then you can do a helicoil, you'll have room to drill.
After you drill and tap the hole for the proper helicoil or timesert size, (of course with a rag down the dizzy hole), then blow the chips, remove rag, insert a broom handle or other pipe or metal the same diam. as the dizzy hole to act as a stop for the helicoil or timesert, and let'er rip.
A hemostat will snap off the tang nicely, and you can get those at hardware stores nowComment
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I used heli-coils to repair the spark plug threads in the aluminum heads on my BMW R-60, and they work fine. The mirror on the same bike screws into the aluminum clutch handle housing, and it was stripped. I repaired it with a Permatex product where you dip the threaded part (mirror post) in a wax, then mix the solution and put it in the hole, then inset the mirror stem. It held up fine.
You can also use a shop vac on top of the hole to suck up the grit as you drill and tap.Comment
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Thanks for all the input I thought the thread-sert might be a little better repair in the place it is going in. of course length can be an issue with it not sure if you can get different lengths, T-birds idea on the metric bolt would work quite nicely but I would like to make it stock, however this is a "B" police head on this car. The previous owner had the B milled off of this head and he also put some kind of epoxy paint on this engine was real pretty but would not let it dissipate heat block was all pitted around 2-3 valve seats. I could not get the head off so I let my engine builder do it He was the one who told me the head was a B and showed me why and the differences. The engine was also balanced and someone forgot to adjust up the clutch fingers as well.Comment
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Tom here is what we use for spark plugs. It's a product called Perma Plug.. There is no tab to break off and the insert has it's own built in tapered seat for the plug to seal against. Many times the seat is screwed when the plug blows out or when you go to tap it...The tool is a combo tap and installer, once the insert is in place the other tool makes the seat.
We loctite these in as wellYou do not have permission to view this gallery.
This gallery has 1 photos.3~ Tudor's & 1~ Coupe
Henry Ford said,
"It's all nuts and bolts"
"Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible."
Mitch's Auto Service ctrComment
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"I repaired it with a Permatex product where you dip the threaded part (mirror post) in a wax, then mix the solution and put it in the hole, then inset the mirror stem. It held up fine."
Tom, I would love to know a PN for this product, it is something I could have used quite a few times over the years, DaveComment
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That was back in the mid 80's, so I don't know the number, but would ask the auto parts stores.Originally posted by tbirdtbird View Post
The wax was just to keep the repair from sticking to the threads while it set up.
Maybe a Google search for "Permatex Thread Repair" would turn up something.Comment
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T bird it was a permatex product if you do not come up with something let me know.Comment
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It could have been what bob posted been a long time but the description sounds the same.Comment
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Thanks Bob for mentioning Loctite, as it might have been that product. It was just over 30 years ago, so now I'm not sure which brand it was. I couldn't open the pdf, but will see if I can find it using Google.Comment
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I never used this product before
This is what Bob posted
You do not have permission to view this gallery.
This gallery has 1 photos.3~ Tudor's & 1~ Coupe
Henry Ford said,
"It's all nuts and bolts"
"Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible."
Mitch's Auto Service ctrComment
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Well, I've been around the block a few times but this thread repair epoxy is news to me, and will hold up to 128 ft-lbs of torque.
Turns out Permatex has their own brand, which I just ordered,
This has been a GREAT thread!Comment
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Yep. that's what I used, and the price is still about the same. I let it set up for 24 hours before using the bike.Originally posted by tbirdtbird View PostWell, I've been around the block a few times but this thread repair epoxy is news to me, and will hold up to 128 ft-lbs of torque.
Turns out Permatex has their own brand, which I just ordered,
This has been a GREAT thread!Comment
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