Rave valve snapped screw

[MEDOO]

So I was rebuilding the Rave valves on my motors for the first time since I've had it and I got to the last one and was backing out the 2 retaining screws that hold it on the head, and snap! Got one half way out and it snapped off flush. It looks like some thread locker seized it up some how.

I do not want to pull the head so I was going to try to drill it out, and retap.

Does anyone have a trick to repair this before I get started?

 

[kicker]

drill and retap is where you have to start. Us some duct tape to cover the opening.
Good luck.

No thread locker required on those bolts.

Sent using Tapatalk

 

[racerxxx]

This is a little open ended really. Which screw will determine what else you need to remove. You only have access to the very back PTO screw, if not the exhaust mani is in the way of a drill, even a right angle drill. I would buy a set of transfer punches from Harbor freight, bolt the RAVE housing back on and use a 1/4" transfer punch to mark the center. Then you know you're damn close to center of the screw, then drill VERY carefully. Use a piece of tape to mark the depth of the hole(use another hole to find the depth) then drill through. Then very slowly step up in drill bit size until you have all the material removed. If my memory is correct a 3/16 (.187) drill bit will get you to the minor thread diameter of an M6 screw. From there you could pick the remaining material out. I don't like easy outs, if you break one in there now you're in a deeper problem. And if you need to remove the exhaust mani, that is another can of worms if you break one of those screws.

You could also lay a 6mm nut on there and TIG weld the screw to the nut and fill the nut with filler rod. You're basically making a bolt. A TIG will concentrate the heat to the screw and should not do any damage to anything around it and hopefully loosen the bolt a bit to back it out. I have used this in other situations and it works like a champ. Remember, disconnect your battery and I would pull the plug from the front of the mag housing just to be safe. This step would require you to either have a TIG welder or go to someone who does but would save you from having to mess with the exhaust mani.


http://www.harborfreight.com/28-piece-transfer-punch-set-3577.html#.Uyw6qahdVbw

 

[TheMachin0]

you will have all kinds off trouble drilling it stainless bolt in an alum jug I would try drilling a small hole in the bolt and use an easy out tool stainless is harder than most bits your going to need to get some fancy drill bits. "BEST OF LUCK I HOPE IT WORKS OUT FOR YOU"

 

[MEDOO]

I'm thinking my only option is drilling it. I got the screw about half way out before it seized and snapped. I'm affraid a little nut welded on there wont hold well enough and too seized for an easy out. I have snapped off an easy out in a screw, it was all over but the cursing then...

I will try the punches and some bas azz drill bits.
Can someone recommend some bad azz drill bits? There is a Northern Tool and Harbor Freight not far from me.

And yes it is the front valve on the front screw... *&%$#%!! But I have to pull the exhaust anyway, there is some sort of water leak down there that I can just barely see. It only leaks when its running.

 

[racerxxx]

You can get a decent High Speed Steel bit from MSC or Mcmaster Carr, not sure I'd put the 3rd stringers (HF, Lowes or HD) into the final minutes of the playoffs if you know what I mean. Start small and work up to the finish size. Most guys guy start with the "finish size" drill bit which is completely wrong and will walk on them drilling off center. Maybe start with a (wire size)#47 drill bit then to a #36 then a #28 drill and finish with a #16 drill(.177") which is .010 under size--just in case. 135 deg point on the drill bit is better for drilling hard material. Run the drill SLOOOOOOOOW like 200 to 300 rpm and use plenty of oil, you want to keep the heat out of the drill bit and the material, that is why drilling stainless is a bitch. These screws are 316 stainless and that will work harden kinda easily, once it's work hardened you're basically hosed. Keep the bit chucked up so the flutes are just outside the drill chuck and not like a 1/2" away, lose your balance and you'll snap a bit--ask me how I know. Plenty of oil and go slow and steady, let the drill bit do the work--no hard pushing. Once done you could probably and carefully run a tap in the hole. M6 X 1 so you probably want to order one of those too. Sounds like a fun project you got yourself into.

http://www.mcmaster.com/#standard-drill-bits/=r6v5g8

You would at least want Black Oxied or TiNcoated. Not cheap when your dropping up to $6 per bit.

Drill down the list on the left.
http://www.mscdirect.com/browse/tn/...-Bits/Jobber-Length-Drill-Bits?navid=12106186


http://www.mcmaster.com/#standard-drill-bits/=r6va19
select heavy duty chip clearing HSS jobber drill bits

 

[MEDOO]

Thanks, I'm not worried about price when it comes to something like this, too much at steak..

Yeah, I fixed the one that wasn't working well, and was just going to rebuild the other one and snap. I love this boat, but it's wearing me out.

 

[MEDOO]

I grabbed a set of the transfer punches and the drill bits came in from McMaster.
I went to storage and looked at the broken screw again. It is sticking out of the head about 1/4", so I could get some vise grips on it.
Does anyone have a trick to get the seized screw loose and back it out? Would heat do it?

 

[racerxxx]

Post #3, second paragraph. Thread a nut on there THEN tig it on, a 1/4" is just over the height of a 6mm nut. A guy should be able to get a nice weld on that. I also would not try and drill that screw out sticking up as far as it is, tape the ports off and cut it off as close as you can--less distance to drill. If the TIG doesn't work out you can fall back on drilling it out. Once you put vice grips on it you lose any chance of threading a nut on it, this would be my last ditch effort as vice grips usually don't grab round items the correct way.

 

[MEDOO]

Thanks, I'll be working on this next week.

 

[MEDOO]

Update- welded a nut to the protruding screw and it snapped off again, so I cut the screw off flush with the top of the head and went to drilling. About 1/2" in or a little less using the smallest of the bits, it snapped off. So I guess I'm screwed. I will be looking at pulling the top of the motor off and take it somewhere to to get the screw removed. I can't think of anything else to do.

Will the head come off without removing the exhaust manifold?

 

[MEDOO]

Nevermind, the head is off now.

 

[MEDOO]

All back together and runs like a champ! Thanks guys!