Wildguzzi.com
General Category => General Discussion => Topic started by: canuck750 on July 30, 2016, 10:57:02 PM
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Stripped the head 12 O'clock head stud plug, I found the correct helicoil on Ebay, nice kit with drill bit, helicolis, and insert winder
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/IMG_0678_zpszxmjfnca.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/IMG_0678_zpszxmjfnca.jpg.html)
The original Eldorado / V7 Sport style threaded plugs use an aluminum crush washer and take some torque to seal, it doesn't take much to strip the aluminum head threads.
I bought the newer style hex plug with the O ring seal, much better
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/IMG_0679_zpsxey37zs9.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/IMG_0679_zpsxey37zs9.jpg.html)
This is the size of helicoils if anyone needs to do this repair
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/IMG_0680_zpsad9ptsxn.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/IMG_0680_zpsad9ptsxn.jpg.html)
This 20mm was a surprisingly easy helicoil to fit, I also fitted some of the small rocker cover 6mm helicolis, I find these helicoils difficult to seat and often have to tap and retap the hole to get the helicoil to thread all the way down.
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Did you consider a Timesert? I'll never use a Helicoil in my life.
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Did you consider a Timesert? I'll never use a Helicoil in my life.
Ditto, far superior to helicoils.
Ciao
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Well done. A helicoil in that application,sealing with a captured-in-groove "o" ring is a fine repair...as you always do. :thumb:
Terry
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Well done. A helicoil in that application,sealing with a captured-in-groove "o" ring is a fine repair...as you always do. :thumb:
Terry
Absolutely.
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Did you consider a Timesert? I'll never use a Helicoil in my life.
I have never used a TimeSert (or seen a kit for sale for that matter), but now that I have googled the product it sure looks like a better choice for any fastener that requires significant torque.
The 6mm rocker cover bolts and drain plugs only take 7 foot lbs torque, I don't think I have to be concerned about a helicoil being puled out by that force, but for many other applications it looks like the way to go.
Next time I go shopping for 8mm and larger I will get a hold of the TimeSert kit,
thanks for the tip
cheers
Jim
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You're good on that application but now that know about TIMESERT you're good to go.
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I prefer the helicoil for that application. I looked up the specs for a M20X1.5 time sert, and it calls for a tap drill of .797" and a minimum c'bore of .950". That would eat a *lot* of stock out of that boss.
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I prefer the helicoil for that application. I looked up the specs for a M20X1.5 time sert, and it calls for a tap drill of .797" and a minimum c'bore of .950". That would eat a *lot* of stock out of that boss.
Good call.
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I have never used a TimeSert (or seen a kit for sale for that matter), but now that I have googled the product it sure looks like a better choice for any fastener that requires significant torque.
Exhaust studs with a Timesert are the only way to go. After a couple of Helicoil failures on my CX, I installed a TS and that was 15+ years ago.
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Hi Jim, I ordered two new style plugs for my V7 Sport after reading this topic.
Do you have the part number of the o-ring? or even better, if you can tell me the dimensions of the o-ring so that I can buy them from the local o-rings shop.
Thanks.
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Machine shop I worked at built a lot of stuff for the military. It was common to install helicoils in all the threaded holes at manufacture. A properly specified and correctly installed helicoil is stronger than the original part would be with just a tapped hole.
Stronger than original is good enough for me.
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Machine shop I worked at built a lot of stuff for the military. It was common to install helicoils in all the threaded holes at manufacture. A properly specified and correctly installed helicoil is stronger than the original part would be with just a tapped hole.
Stronger than original is good enough for me.
There is nothing specifically wrong with the canucks original helicoil repair in the application he posted due mainly to the fact that its simpler and the plug is just a plug but a timesert is way better in my opinion.
The issue with helicoils is not strength but the fact that they come out when you remove the bolt more often than I am happy with. This used to happen with the fuel filter cover retaining ( helicoils fitted std from factory)bolts on GE jet engines and was a real PITA on an overnight service. Also painfull when you do a simple plug change and the helicoil comes out with the plug and you dont have to hand the tooling to reinstall it.
Ciao
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Hi Jim, I ordered two new style plugs for my V7 Sport after reading this topic.
Do you have the part number of the o-ring? or even better, if you can tell me the dimensions of the o-ring so that I can buy them from the local o-rings shop.
Thanks.
In my opinion, switching to the plug with o-ring is a step backwards. If you're going that route, buy lots of extra o-rings and change them often (every valve adjustment?) as they tend to harden and leak. Never has a leak with the aluminum crush washer type and have never stripped the threads of that hole. <shrug>
Guzzi part no. 90706203. "UNI Standard size": OR 3081 (2.62 mm wide x 20.3 mm ID)
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Hi Jim, I ordered two new style plugs for my V7 Sport after reading this topic.
Do you have the part number of the o-ring? or even better, if you can tell me the dimensions of the o-ring so that I can buy them from the local o-rings shop.
Thanks.
Here you go
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/DSC05598_zpsid6ezxje.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/DSC05598_zpsid6ezxje.jpg.html)
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/DSC05599_zpsr76l4pkk.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/DSC05599_zpsr76l4pkk.jpg.html)
(http://i249.photobucket.com/albums/gg217/canuck750/1974%20Guzzi%20750S/DSC05600_zpsquudlw6a.jpg) (http://s249.photobucket.com/user/canuck750/media/1974%20Guzzi%20750S/DSC05600_zpsquudlw6a.jpg.html)
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In my opinion, switching to the plug with o-ring is a step backwards. If you're going that route, buy lots of extra o-rings and change them often (every valve adjustment?) as they tend to harden and leak. Never has a leak with the aluminum crush washer type and have never stripped the threads of that hole. <shrug>
Guzzi part no. 90706203. "UNI Standard size": OR 3081 (2.62 mm wide x 20.3 mm ID)
I have to admit, in that location, the oring is a problem. They get hard as a rock and occasionally just leak. If you touch that plug, it will probably leak unless you have a new o-ring.
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I have never used a TimeSert (or seen a kit for sale for that matter), but now that I have googled the product it sure looks like a better choice for any fastener that requires significant torque.
The 6mm rocker cover bolts and drain plugs only take 7 foot lbs torque, I don't think I have to be concerned about a helicoil being puled out by that force, but for many other applications it looks like the way to go.
Next time I go shopping for 8mm and larger I will get a hold of the TimeSert kit,
thanks for the tip
cheers
Jim
I buy them here;
http://www.mechanicstoolsandbits.com/time-sert-c-21.html?gclid=CjwKEAjww_a8BRDB-O-OqZb_vRASJAA9yrc5eZDOx-WqckdkiJ4IWHXlZ24SZ4Fee6byI0zFrwwptxoCiZ7w_wcB (http://www.mechanicstoolsandbits.com/time-sert-c-21.html?gclid=CjwKEAjww_a8BRDB-O-OqZb_vRASJAA9yrc5eZDOx-WqckdkiJ4IWHXlZ24SZ4Fee6byI0zFrwwptxoCiZ7w_wcB)
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Probably choosing the wrong material for your O ring.
http://www.marcorubber.com/materialguide.htm
These folks will sell you O rings good to 650F.
A lot of standard ones fail at 250F.
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I prefer the helicoil for that application. I looked up the specs for a M20X1.5 time sert, and it calls for a tap drill of .797" and a minimum c'bore of .950". That would eat a *lot* of stock out of that boss.
Helicoil vs Timesert.
I have used both and both are effective repair.
If you have the stock available around the effected hole and can afford the extra cost the timesert is the way to go.
If on the otherhand like many holes on a Guzzi engine there isn't a lot of stock around them helicoil are the way to go.
Yes I have had a few helicoil come out and eventually you will come to the point where a helicoil won't work and more difficult repairs are required, with modification or welding to build up the area a timesert would be preferred over a helicoil.
So what do you do when the thread in your timesert fails? Bearing in mind the difficulty of removing the damaged one, you helicoil it...
Horses for courses.
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Thanks Charlie and Jim, those are very helpful information.
The original plugs on my V7 Sport have many chisel marks around the recess/grove where the aluminium washer sits. I think someone tried to dig out the over flatten washers somewhere between 1973 and 2013. Having said that, they didn't leak.
I'll keep the o-ring plugs as spares and see how it goes.
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Heli-coils, time serts, and ez lok inserts all have their place. Time serts can be had with a heavy wall, (big sert) for oversized holes, ez loks can be had with a very thin wall. Ez loks can also be had with sae outer threads and metric inner threads and I think maybe vice-versa. Inserts can also be hand made which is what I'll be doing for the drain plug on the convert transmission that I already screwed up with a crooked heli coil installation. We're, my machinist friend and I, making an insert that's 1/2x20 outside by 10x1.5 inside, there isn't much material to work with in the transmission cover and we hope to accomplish the repair in the frame. I got the heli coil crooked by not paying enough attention and being over confident, would have been fine otherwise.
Brian
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Helicoil vs Timesert.
I have used both and both are effective repair.
If you have the stock available around the effected hole and can afford the extra cost the timesert is the way to go.
If on the otherhand like many holes on a Guzzi engine there isn't a lot of stock around them helicoil are the way to go.
Yes I have had a few helicoil come out and eventually you will come to the point where a helicoil won't work and more difficult repairs are required, with modification or welding to build up the area a timesert would be preferred over a helicoil.
So what do you do when the thread in your timesert fails? Bearing in mind the difficulty of removing the damaged one, you helicoil it...
Horses for courses.
Has a Timesert ever failed?
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Has a Timesert ever failed?
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I have only seen a timesert come out unintentionally due to extreme circumstances (corrosion) that would have destroyed the aluminum anyway. And in that case it simply unscrewed from the case and a new one went back in its place. Properly installed a timesert is as permanent a repair as you can get without welding it up and starting over.
Canuck called it right on his repair, a coil is best there due to the size but I always timesert those pesky valve cover and oilpan screws if they get haggard.
As a side note I have noticed that people who are well versed in thread repair are often the least likely to need it. Hmmm....
Hunter
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Has a Timesert ever failed?
We used to timesert VW case studs and spark plug bores. Those aircooled engines seemed to like 'pulling' the long head studs and stripping out seized spark plugs (AC and Champions seem to gall the worst). The 'failure' of the timeserts was never pulling threads. The common failure was them binding to the spark plug and coming out when you changed them. In the head area, no amount of antiseize or spiking the t-sert shoulder would stop this on some specific units. We had customers in for tune-ups who'd bring us points, condenser, valve cover gaskets, spark plugs and a t-sert for #3 hole because that one was going to come out and we were so tired of supplying them for free that we had our problem children buy their own.
But in a thick aluminum casting, especially if you have to install in situ, the t-sert is the right fix.