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General Category >> Rubber Side Down! >> Re: Savage "Plug/Cap" Leak - stripped th
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Message started by ghryx on 02/13/16 at 13:14:25

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ghryx on 02/13/16 at 13:14:25

So I completed the plug repair and reassembled, everything was going as planned til I got to final tightening of the very last bolt (figures) and it stripped before I came close to torque. It's the L125 in the diagram. Makes me wonder if it was bad before i started the repair. Ordered a replacement and a spare, just in case my worst nightmare was realized. And it was. Bolt was stripped, and so is the hole. Any advice on how to fix this? I've read up on Helicoils and the like, but the deep nature of this hole has me nervous. I can get it a little better than finger-tight, but not a whole lot more than that. :-/

Title: Re: Savage "Plug/Cap" Leak
Post by Dave on 02/14/16 at 07:47:08

The aluminum is much softer than the bolt.....so the aluminum is where the threads will strip.

If you look at the side of the cylinder, you can see the place in the casting where that bolt goes - you have little chance of doing a proper Helicoil repair in that area without taking the head off. Also...most helicoil inserts are only the same length as the thread pitch - (6mm in this case), and the threaded part of the aluminum is more like 14mm. So you will need a longer than standard Helicoiil insert. The tools you get when you order the kit are not long enough to go through the length needed.

I think your best chance at a repair (without removing the head), is to buy a piece of 6mm threaded rod, insert it into the hole and thread it lightly into the hole and see where it bottoms out....then mark the rod, remove it and cut it to length. The threads on the bottom should have a slight taper on the end, and there should be some small slots cut to help the rod cut some new threads into the aluminum as you bottom it out in the hole. Then when you put it back in apply some permanent thread locker and screw the stud down into the cylinder tightly using the "double nut" method. Let the threadlocker harden for a day or two....then put the nut on top and see if you can tighten a nut onto the stud.....not sure if you should try to torque it.....I would be apt to just make it pretty snug.

Here is a repair I did to the stripped hole just behind the one you have stripped. The good news is the one you have stripped is not in the oil galley like the one I repaired. This shows the longer insert needed for the Savage head.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1448209911

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/14/16 at 13:54:32

A repair that I have done on various pieces of equipment is to tap the 6mm hole for a 1/4"-20 thread. I did this on boat engines among others. It always worked as long as the hole wasn't opened up too much.

A 6mm X1 bolt is, in my opinion, marginal in aluminium. An American 1/4-20 is far superior for alloy.
Something else that I have never tried would be to tap the hole for 7mmX 1 which at least would match the thread pitch.
One thing that might be a problem will be the bolt head size. Allen head?
I looked at my engine and it looks feasible. I don't know if 7mm bolts are available but I have a tap for that size.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/14/16 at 14:42:57

I made the 6mm stud for you.....if you want to try it send my your address and I will mail it (you pay me back postage).

Can you take photos and document the process....and let us know if it worked?

http://i63.tinypic.com/5laz6a.jpg

http://i66.tinypic.com/6rkqdk.jpg

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ghryx on 02/14/16 at 21:46:49

I just emailed you Dave - I apparently haven't posted enough to PM yet. ;-)
Both options sound reasonable. I thought the depth of the hole was going to make the Helicoil method unlikely. I'll keep you posted on the results.

Many thanks!

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by justin_o_guy2 on 02/15/16 at 04:37:22

What's the nearest but bigger SAE bolt? Daves plan sounds great.

With a cut off and dremel you can slot the bolt and make it workk kinda like a tap..The slot isn't from edge aimed at center, much more shallow. Done it several times

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/15/16 at 04:45:38

233C3A3D20271626162E3C307B490 wrote:

I already slotted it....it just doesn't show in the picture.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by justin_o_guy2 on 02/15/16 at 05:18:48

Well o course not,that slot is first in..and, it wass For the other guy. But glad you mentioned it. Gives the idea more credibity.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Art Webb on 02/15/16 at 07:35:20

53524F50040F59583D0 wrote:

If the stud doesn't work DO try this
asa Taxi fleet mechanic I couldn't count the # of times I used this trick to tighten a transmission pan bolt that was stripped, and if you weren't ham fisted it almost always worked
Heck, I didn't even use a tap, I just grabbed the 1/4 bolt and ran it in (don't do that unless you have a sensitive touch for bolts)

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/15/16 at 08:45:30

What Dave has suggested is a great idea provided sufficient original thread remains. Also, will the head cap go back on with the new stud sticking up.

Whatever you do end up doing use two quality taps. One ground off to reach the very bottom of the hole. Cylinder heads are expensive, tools are cheap. If you can figure out a method, a Helicoil is probably the best way because you will be able to use the standard bolt. Also, do you have compressed air to blow out the hole.

Good luck with it. :)

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/15/16 at 09:55:22

5859445B0F045253360 wrote:

What Dave has suggested is a great idea provided sufficient original thread remains. Also, will the head cap go back on with the new stud sticking up.

The stainless threaded rod is only slightly longer than the original bolt - it will not stick up much....I only tried to leave enough extra for whatever additional distance it might thread down into the hole. The barrel nut and bolt are only for installation of the threaded rod.

Turns out the issue is only 30 minutes from where I work.....so maybe I can go over and help.

Dave

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/15/16 at 10:24:40

Dave,
That would be very nice of you.
A repair like this is tricky at best. Especially trying to do it without removing the cylinder head.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/15/16 at 10:35:32

Dave,
By the way you need a new cloth that one has a hole in it. ;D

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/17/16 at 03:58:54

Yep.....those shop rags are "seconds" - but they were free! A friend of mine got a few bags of them from a uniform/rag business that supplies those things to shops.....the bag he gave me is a 50 gallon trash bag and it is jammed packed with them. The rags have some holes, tears or stains in them.....so I guess the company took them out of circulation. I am set for life with shop rags!

After thinking about this for a few days....I am going to take a "bottoming tap"and weld an extension on it - so that we can get as much good thread in the head as possible. This hole is not in the oil galley - so making some chips while cutting new threads won't be the problem that it would be if the stripped bolt was the 130mm one at the left rear side.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Zonablazer on 02/17/16 at 04:32:55

This problem appears to be so common. Has anyone looked into having some stainless bolt made or something? Maybe a Co-op order from a company to make them?

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/17/16 at 04:50:58

1421202F2C222F342B3C4E0 wrote:

This problem appears to be so common. Has anyone looked into having some stainless bolt made or something? Maybe a Co-op order from a company to make them?

The problem is not the bolt.....the threads that strip are the ones in the aluminum cylinder casting. Folks just seem to want to crank a lot of torque on these small bolts, and they really can't handle it. If folks are trying to torque to 6-8 ft/lbs using their 150 ft/lb torque wrench.....they stand a good chance of over torquing the bolt and stripping the threads (My 150 ft/lb torque wrench is just about useless for anything less than 30 ft/lbs....the click is so weak that you can't hear or fell it at low settings).

I do believe that anytime I have a cylinder head off in the future....I am going to just go ahead and install the helicoil insert while the engine is apart.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Art Webb on 02/17/16 at 07:26:34

On transmission pan bolts, I used to use a cordless drill / driver with clutch
mine would tighten perfectly on '5', the head mechanic's Dewalt did the job on '2' so a bit of experimentation was needed
Probably couldn't get to these with a drill / driver though
also had a 1/4 drive speed wrench for when the drill ran down, a great tool that's under appreciated IMO

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/17/16 at 07:53:13

Dave,
Would it be possible to drill the hole a bit deeper and cut new thread?

Let us know how it turns out.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/17/16 at 07:58:27

I used to have a Volvo marine engine and all the 6mm holes had some kind of S.S. insert already there.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Art Webb on 02/17/16 at 08:07:59

Actually if there's enough meat there that'd be a great option here, not a helicoil but a threadsert, if they make them in that size
I used theos to fix stripped spark plug holes a few times, and they were like 1000x better than screwing steel threads into aluminum
negated the need for never seize, too

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/17/16 at 20:23:25

The main problem is the 6mmX1 thread! The Japanese manufacturers seem to have an inexplicable affection for that anachronistic aberration.

Either use a coarser pitch or both a larger thread size and a coarser pitch.
I am sick of having to tread so carefully when working on alloy machinery using this thread.

There I said it! ;D

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 02/18/16 at 04:09:00

50514C53070C5A5B3E0 wrote:

Dave,
Would it be possible to drill the hole a bit deeper and cut new thread?

I don't believe it would be possible to drill the hole any deeper - or you will drill though the bottom of the casting. I have posted a photo below to show which hole is stripped. This hole is in a small "boss" cast in the side of the cylinder. it is a "blind" hole that does not extend out the side of the cylinder. If you tried to drill it much deeper you would make a hole in the bottom. It may be possible to use a bottoming tap and get a few more threads in the existing hole.
http://i63.tinypic.com/f7v6f.jpg

And the potential for for installing a threaded insert, helicoil or larger bolt really isn't an option when the bike is fully assembled. The bolt is 125mm long (5"), and it passes through the head cover, through the cylinder head, and into the cylinder. The insert/heli-coil is easy when the head is off - but not when the engine is assembled. The threaded portion of the hole is the bottom 14mm at the top of the cylinder....so you have 111mm of head cover and cylinder head you have to negotiate to get to where the stripped threads are located.

http://i65.tinypic.com/10dchht.jpg

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Art Webb on 02/18/16 at 07:25:16

Wow, hope that bottoming tap works, otherwise I see engine disassembly in the future
glad you're local to him Dave, this could get complexicated

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/18/16 at 09:23:23

Dave,
I completely misunderstood the situation! :-[

I thought that the female thread was in the head not the cylinder, duh.
I can see that you will have a devil of a time without removing the head.

A Helicoil or a larger thread may be your only options if your plan doesn't work out.

Be sure to let us all know the outcome.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by norm92de on 02/18/16 at 16:16:09

Dave,
Looking at my engine, and I know this is blasphemy, what would happen if you did drill through the bottom of the hole? You could put a 6mm nut on the end of your long s.s. rod and be home free

The next time, a Helicoil could be fitted with the cylinder restored to almost original.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ghryx on 05/07/16 at 17:33:36

I've been meaning to respond to this for a while. Dave not only made the part for me, but came over to my place and installed it - turns out he lives about 10 miles from me! It worked perfectly. He had to tap it gently with a hammer to get it to bite, but once it bit all was well. I took a pic of the fix, I'll post it post haste.

And BTW - THANKS DAVE!!! You're a lifesaver.

Now the irony is that it turns out the nut in the cubby next to the exhaust port was leaking and my whole cap-leak repair may have been completely unnecessary. Ah well, at least it won't need to be done again. :P

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 05/09/16 at 06:38:22

So....it is together and running again?

Great - now if we could just get the rain to stop!

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ghryx on 05/12/16 at 16:10:35

It's a bit sputter-ish. Seems like it's not very happy at low-mid throttle, almost acts like it's starving for fuel in just that spot. Seems ok everywhere else. But yeah. It works! :)

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by justin_o_guy2 on 05/12/16 at 16:42:20

You live ten miles from Dave? Your bike should act right by osmosis. Maybe ten miles is just too far..

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by Dave on 05/12/16 at 18:05:32

2F232921282B3D440 wrote:

It's a bit sputter-ish. Seems like it's not very happy at low-mid throttle, almost acts like it's starving for fuel in just that spot. Seems ok everywhere else. But yeah. It works! :)

I have ridden a couple of bikes that did that....mine included. It just needs a carb cleaning, rejetting, and a white spacer mod.

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ghryx on 05/24/16 at 15:32:16

Looks like I'll be learning about carburetors next. ;-)

Title: Re: Savage "Plug/Cap" Leak - stripped th
Post by ralfyguy on 05/27/16 at 10:46:33

I had the same problem. I ordered a 5mm longer bolt and filed three grooves on the front of the bolt to make it look like a tap. then dabbed into grease, down the hole and do a 1/4 to 1/2 turn at a time. Back out, clean the bolt, dab into grease again, repeat until the bolt is all the way in and leave it.