2 stroke 115hp thermostat housing bolt snapped

[davehank]

With stuck bolts and stuck "Easy Outs", you have to know when to stop LEANING on it and go to plan "B"..

For bolts, maybe heat, penetrating oil, etc.

For drilling the broke bolt (too late now I know), but if you can't get a good center (with a punch), I'd grind it flat so you can find/keep center and punch/drill..

If there's any stud sticking out, I'd simply plug weld a nut to the stud. Between the heat and now you have something to grab onto, it usually zips right out..

A machinist has tools that can fix with what you have now..

BTW, you won't need a new head. Even if threads got buggered up some, a Heli Coil installed (which requires drilling the old hole slightly larger) works great and is stronger than the original aluminum threads.

There was a stud sticking out. I should have welded a nut to it but I don't have a welder and my friend who does have one is out of town. Could have used the cylinder head cover to get a good centre and drill straight but didn't think about it until after I started. The easy out was a lot weaker than the bolt, didn't take much to break it. Tried heat and penetrating oil but I guess I wasn't patient enough. Definitely learned a couple things.

[TownsendsFJR1300]

Well, live and learn.. The bolt is pretty soft. The seizure apparently was bad.

Perhaps the Easy Out was a cheapo. It's rare I use them but have never broke one. Broke drill bits inside an object thou! (got too hot, seized and broke)..

[panasonic]

That went well. I started drilling off center so the bigger drill size started cutting into the head. That didn't look good, so I decided to ignore everyone's advice and try an easy out. After 30 minutes messing around with that... I broke it off in the bolt! Live and learn I guess. I'll check with a machine shop if they can do anything, otherwise I guess it'll be a new head.

Machine shop job now. Take the head off and bring it to a good machine shop. They will mount the head on a milling machine and use a CARBIDE end mill and cut the bolt and easy out from the hole. Chase the threads with a tap. They may have too oversize the hole and put in a helicoil to bring the hole back to size.

If you would like to see a video on this...

https://youtu.be/WeLYDf_NwY0

He is the "Getter out" guy in Perth Australia.

I have removed many, many broken off easy outs. They much harder then a drill bit and that makes them brittle and easy to break off. Only thing that will cut an easy out is a carbide end mill or carbide drill bit.

[99yam40]

those small ones do not have much meat to them and are brittle.
they can burn them out without hurting the metal around it, but with you drilling hole off center not sure what they will do.
Just have to ask

[panasonic]

those small ones do not have much meat to them and are brittle.
they can burn them out without hurting the metal around it, but with you drilling hole off center not sure what they will do.
Just have to ask

They will clamp the head to a milling machine and use a carbide end mill and cut it out. No matter if is the hole is off center, the end mill will cut straight down and not follow the off center hole like a drill bit will. Or use an EDM machine and burn it out. Most shops don't have a EDM machine though.

[fairdeal]

If you would like to see a video on this...

https://youtu.be/WeLYDf_NwY0

He is the "Getter out" guy in Perth Australia.

enjoyable vid.
My favorite part was letting the camera run while he tuned up the drill bit-
took him all of 10 seconds...

[panasonic]

As for getting out the remaining bolts, I would use a good heat gun and get the bolts good and hot. Tap the head of the bolts with a hammer to shock them, let cool and heat again. Do this several times for each bolt, the heating and cooling cycles will help break the hold on threads.

Then try and break them free. Hope and pray you don't break off any of the head bolts in the block, world of hurt then.

Hopefully they will come out without to much trouble. Rodbolt probably know best method on Outboard cylinder head bolts.

[rodbolt17]

long before I paid fore a machinest I would buy a good used head.
however it is why bullit point bits were mentioned.

[oldmako69]

I'm confused. If a machinist (or me with an easy out, or over boring and re-tapping) can do the job for 30 bucks and leave the head in place, why go through all the effort to find a head (and hope that it's decent) and then replace the one currently on my engine? Seems like a hell of a lot of extra work and risk. How many head bolts are you going to shear off, etc??

I had a spark plug blast its way out of an aluminum head once (on a very expensive head) and simply drilled it out and replaced it with a helicoil. I then ran that car another 100,000 miles. Of course the dealer told me I was flat out insane. They wanted 15-1800 bucks to do the job and would not stick to the price because "we don't know what else we'll bust on the way in." I figured that removing and replacing the head was such a hassle, that I'd try this first and see if it worked. It did. Cost me about 30 bucks. Took an hour, max.

Not trying to be a ****, just wonder what I'm missing.

[pstephens46]

I'm confused. If a machinist (or me with an easy out, or over boring and re-tapping) can do the job for 30 bucks and leave the head in place, why go through all the effort to find a head (and hope that it's decent) and then replace the one currently on my engine? Seems like a hell of a lot of extra work and risk. How many head bolts are you going to shear off, etc??

I had a spark plug blast its way out of an aluminum head once (on a very expensive head) and simply drilled it out and replaced it with a helicoil. I then ran that car another 100,000 miles. Of course the dealer told me I was flat out insane. They wanted 15-1800 bucks to do the job and would not stick to the price because "we don't know what else we'll bust on the way in." I figured that removing and replacing the head was such a hassle, that I'd try this first and see if it worked. It did. Cost me about 30 bucks. Took an hour, max.

Not trying to be a ****, just wonder what I'm missing.

Let's be reasonable. He hasn't tried Drano yet.

[99yam40]

I think it not as simple as drilling it out when a tool is broke off in the hole as his is right now.
I never heard of a shop drilling a broken tool out of an aluminum surface, but it does not mean is not possible.
I am not sure of they can get the whole motor positioned in the machine to do it either

[rodbolt17]

as that easy out is tool steel and rather hard you cannot drill it.
you can try to weld to it.
burn it out with a tap burner or try a carbide endmill.
all will most likely require head removal except the welding.

if I am predrilling a hole in a piece of wood most any old bit will do.
if I am trying to drill out a 6mm bolt it is with a NEW BULLIT POINT bit.
start it straight and it wont walk.

drilling a steel bolt in an AL casting with a standard 135* bit is touchy.
did it for years until I found bullit points.

typically it is not the threads that grab it is the hole around the bolt.

but oxy/acetylyne is my best buddy.

most shops have a labor rate that starts at about 100/hr.
I bill 1 hour min for each bolt.
this covers my drill,it wears out, my bits, I typically wont reuse them for drill outs again.
and my time and my knowledge.

sometimes you simply pay for what I know.

bullit points from Dewalt are pricey.

normally I can work it out with heat and patience.

[boscoe99]

It never ceased to amaze me how easy it was to snap off a Yamaha 6mm bolt. Even brand new ones. That is some strange steel IMO.

Woe be unto him that uses a 3/8th drive wrench and who is heavy handed.

[rodbolt17]

never ceased to amaze me how easy it was to snap 1/4x20 on the mercs,jonny-rudes and chyslers.
even the 3/8ths lower unit bolts snap off.

means the maint was not done.

it is rare I use anything bigger than 1/4 drive on them little buggers.

[TownsendsFJR1300]

IMO, bring it to a machine shop as is and let the machinist see what HE can do. Perhaps another shop as well. You have NOTHING to loose..

Depends on the equipment they have and his expertise. It won't cost you but the time to trailer it down there, nothing else..

Your not the first person to bust off a Easy Out or drill bit..

As a side note, I have, maybe 50% of the time, been able to smack / shock the broken bit out of the hole. Once that's out, piece of cake..


.