Are Heli Coils safe in a Flywheel???

The clutch is just a glued together conglomeration, how they don't always fly apart amazes me.
The only issue of the fly wheel bolts is if they loose the torque that holds them on.
Jim

 

I have brand new billet aluminum flywheels for the early Olds in stock

Tony

 

Chy, it takes all of about 2 minutes to pull one and check his threads on install. EVERY racer, sandrail, boat, bike builder, ANYONE involved has used them. They test at a higer strength more often than not. Many racers will put them in BEFORE first time use, just for that reason.

The cluth failure you keep mentioning, comes from a shearing of the bolt as I asked on my first post on this thread. Have you ever seen a flywheel or clutch explode? I have several times. Go look, 99% of the time, the THREADS of the bolt are still in the bolt hole, because the bolt was simply sheared off. That shearing has NOTHING to do with the threads.

So, yea, I'll stand by what I've said.

 

Is there a reason you couldn't take it to a machine shop and have all of the holes drilled and tapped to a larger bolt? I could see where one may not work because of balance but if all of them were done what's the big woop?

 

No that would be a flex plate!
A real man needs something to do with the left foot thats why we drive a stick. And the more gears the better.
Jim

 

only seen the after the loud scary noise ,,a neighbor of ours brother got killed when we were kids fro such a thing,,so yeah seen it,,Perhaps thats why I feel as I do

 

We have run Heli Coils in our Aluminum race flywheel for a long time now. I check them each time we are down. No problems. But we only run up to 5000 RPM though.--TV

 

I have a main cap thread that had to be repaired. Heli Coil did the trick. We don't have any problems---only solutions!

 

Did you go investigate the REASONS OF FAILURE? Sorry that happened, but find that flywheel, and the THREADS of those bolts will still be in it. The bolts snap ABOVE the thread line.

Seems to me that your reason "might" be a good reason to not run clutches at all, but really not much in the way of answering the original helicoil question.

 

ok hows about this,,since we can't see it ,,take it to a shop and have them look it over and let you know if its safe to run,,thats the best answer

it is a piece that could be a safety issue and not being able to actually look at it,,best to take to an expert

 

On a similar line to the flywheel - would a Helicoil be safe in the back of the crank too?

I have a stripped thread in one of the flywheel bolts, and was wanting to put a helicoil in it to ****on up the flywheel.

 

http://www.helicoil.com/pdf/HC1018 REV_2.pdf

If they are good enough for the Space Shuttle,
and Boeing 747, they are good enough for me.

As long as they will hold the torque, nobody will ever know.

 

Helicoil is realy just a spacer,in some areospace parts we build its put in to have steel threads in aluminum parts.Im sure these see alot more abuse than the fly wheel we are talking about.Wouldnt the flywheel be bolted in between and would have to shear the bolts off to fail?If they looked like they werent installed correctly,not square, i would be concerned.Burl.

 

Sounds like some people don't know what a Helicoil is, or why they are used.

http://www.helicoil.com/media/win/helicoil.wmv

http://www.helicoil.com/products/helicoil.asp

 

Is it a Helicoil or a threaded insert? I prefer to use Time-Serts. And I have trusted them on race bikes to 12,000+ RPM. I really wouldn't have a problem with a Helicoil if it is in fact installed correctly. And I have inserted brand new threads before ever even running an engine.

 

That is how Helicoils are installed, the hole is drilled and tapped
SLIGHTLY larger, then the insert is installed. The trick is they use
special,oddball taps, that are smaller then the next size bolt.

Drilling and tapping for larger bolts would weaken the part
more than installing Helicoils.

 

If they're good enough for a 747-400, i guess they'll work in a flywheel. I'd be curious to see what else might be wrong with said flywheel, if anything.

 

Flywheels are typically cast or Forged. Very substantial pieces.

 

I would not rotate the pattern. When you do that you reduce the amount of metal between bolts that take the strain of the centrifigal force. If its one place I dont skimp it is the flywheel. Just my two cents worth, and you might get change back.

Josh

 

would you have to rebalanced if you heli coiled or moved the bolt pattern ?

 

Helicoils are also designed to have a higher thread to thread contact percentage on the bolt side, than just drilling and tapping. THATS why they test higher than the original thread. Most drilled and tapped holes are done so at a 65%-80% depth. The hole side of the helicoil is the same, but at a bigger hole. The bolt side is actually a higher percentage because of the way it is designed.

 

Wouldn't on the helicoil, but might on the rotation, depends on if its a nuetral ballance or has weights.

 

Don't sweat it put that F-er together...
I love the fact everyone a engineer, in my past experiences I've used Helicoils in various applications , numerous head bolts , aviation engine cases , industrial equipment ect.... if you don't feel safe with it have a machine shop redo them for you. just my .02

 

way back when we were racing 4 speeds in B/A , we would heli coil all of our clutch bolts in "new alum wheels" it made them stronger and no issue when replacing pressure plates
over and over and over..................

 

"helicoils I've messed with put the threads right back to the original size, not bigger."
Yes...the original fastener (which is far stronger in the threads than the aluminum) is kept, but the OUTSIDE of the heli is in effect a LARGER thread going into the casting.
This is why helicoils are oft put into NEW aluminum parts for hard use and why they are stronger. In racecar stuff that gets frequent wrenching, they also prett well elininate thread wear and galling from steel bolts into aluminum. The bolt gets steel-to-steel threads, the aluminum gets threads that have bigger holding area and which are never moved during repairs. That's why people put them into undaged parts.

 

where did aluminum come from ?? I'm lead to believe he's talking 303-324 flywheel..os steel on steel,,but again he needs to take it to a Professional and have it looked over to see it was done right and safe

 

Stock would be iron, but any hotrod one would be aluminum in this time period.

 

Seems like most consensus is turning towards not only not likely a problem, but maybe even better if done properly.

But, seems like everyone is still ***uming he is trying to put together an 9 sec. car or something. Maybe this is just a normal hot rod and he isn't planning to try to break any speed records just get the car running and driving properly. Some of the extreme concern maybe is only a factor if he is planning some extreme driving.

Frankly, I would be more worried that some odd flywheel bought off ebay has other wear and balance problems that need to be looked over by a machine shop regardless.

 

On an early Olds...flywheels for hotrods tended to be aluminum aftermarket because Olds and Cad stick parts were getting rare...the Hydro was well accepted by '49-53, and Olds stickparts were ALWAYS a bit scarce!

 

I'm guessing this is the one he got.

http://cgi.ebay.com/ebaymotors/OLDS...ryZ33732QQssPageNameZWDVWQQrdZ1QQcmdZViewItem