Cylinder head plug

[czakky]

My poor v11 has been neglected lately and I got around to doing some maintenance on the old girl. One of my ongoing issues has been low compression on the left cylinder. So I recently got a leak down tester and I figured I’d take look see.

Right side was darn near perfect! Left side was right around 20% loss. Not surprising, but not good. Sure enough a nice hissing sound could be heard coming from the exhaust. Rubber mallet in hand I bumped pressure up to 100psi and gave it a couple of whacks, then the loss side dropped even further. I check the pushrods and notice no play in the exhaust side... Savvy mechanics probably no what happened by now. I was wondering if I wasn’t on compression stroke?? Turn engine over a few times and verified I was. Was my valve so burned? I made adjustments until I got some play, but it was a lot. Finally I realize a valve keeper made it half way out..... Well I might as well make lemonade out of this. So I get to tearing down the top end to take it to a machine shop.

 

I’ve had Guzzi top ends apart a few times and run into issues on this plug that gets access to the top nut before but this one is a major pain!

Does anybody have any tricks to removing this stubborn POS? This one is completely screwed now and getting heat on it is a bit dicey considering all the petrol in between the cylinders.

 Thanks for any input

[Pressureangle]

I don't even play with those plugs anymore. I have Snap-On 1/2" drive socket keys and a 24" breaker bar. Scary but it's as good as it can get. 

[czakky]

Yeah, my electric impact gun made the key nice and round.... 

These things are funny, during the break in/re-torque of the heads on my T3 I purposely didn’t snug these plugs up tight. Sure enough when it came time to remove them they were next to impossible....

[Chuck]

23 minutes ago, czakky said:

Yeah, my electric impact gun made the key nice and round.... 

These things are funny, during the break in/re-torque of the heads on my T3 I purposely didn’t snug these plugs up tight. Sure enough when it came time to remove them they were next to impossible....

Yeah. Austin just put the left cylinder on his G5 together last week. Did the usual 5 heat cycles and retorque. That sucker came loose with a pop! After the Ohio rally, I'll have him retorque again and put anti seize on it.

So, now what are you going to do Czakky? Drill it out and big hunker eze out?

[czakky]

I’m going to try and get some purchase with a punch. 

My 7.5a impact gun didn’t touch it. That thing will take a counter shaft sprocket off in neutral! 350ft/lbs or something... I’m not hopeful.

[68C]

Can you weld a 17mm nut to it then heave on the nut.  Usually work as the heat from the weld loosens things.  And of course that spilt fuel will help.

[czakky]

No 5 spiral bolt extractor gave up after I put an old fork leg on it for 3/4 of a turn... ground a nice flat on the plug to give some good smacks, then the plug split. Now I’m getting nervous

[gstallons]

What is that ? The Weather Channel reporting on this stuff off Florida ?

[footgoose]

wish I could see it better. Is that the plug with a hole drilled in and a broken easyout protruding? In different circumstances of course, I've then removed the easyout and continued drilling with larger bits till I almost reach the female threads... then pick away at whats left till I can get a clean-up tap in. I learned that technique once while having a wisdom tooth removed at the dental school.

[czakky]

Sorry, Docc will tell you I’m no photographer. Yes you are right that’s a broken no5 easy out and the outer rim of the plug is breaking away. These don’t have loc-tite on them?

[footgoose]

hopefully the easyout comes out easy. then if enlarging the hole VERY carefully won't work, use a die grinder or dremmel tool with grinder bit to hollow it out. just don't get into the female threads.

[gstallons]

The cylinder head comes off very easy . Don't be afraid to take it off and do it right . If things get too f'd up .Time-Sert is the ultimate repair .

[68C]

Again, weld a nut to the sheared off easy-out and remove it. I cannot see which type you are using, I do not like the left hand thread tapered type, as you screw them in they squeeze the nut/bolt out making it even tighter in the casting. Go too far and you will crack the casting. There are parallel easy outs that work well with the correct drill but once they slip you have to go up a size.

I feel attempting to drill, grind and then picking out the remaining thread should be you last idea as you will find it very difficult to drill central and square. You could well end up using a thread insert but that opens up difficulties with making it oil tight as you may encroach on the o'ring.

Of course removing the head allows you to get to a machine shop for a professional repair, at a cost.

Please try the welding a steel nut on first, it really does work and is cheap.

 

[czakky]

I guess I need to get a welder out here....  Do you worry about warping the head?

[68C]

You are only doing a five second weld at the most so should not warp the head. 

Disconnect any electronic items, voltage regulator, battery, possibly the tacho and any Power Commander etc.  May be worth disconnecting any LED lights, you just need to unplug them.

The best method would be with a TIG welder, next MIG and lastly an Arc welder.  You could even use Oxy Acetylene although that would require heating for a little longer.

I don't have a TIG so use a MIG or an Arc.   Weld through the centre of the nut to avoid any damage to the casting.  

If you are still trying to remove the easy-out remember to turn it clockwise to remove it.

Stuff some wet rag down the oil drain channels.

Good luck.