“Like a Hole in the Head”

There is a thread, (cant find it), that had 2 or 3 valve adjuster thread marks on the inside of the head where the adjuster had been floating around and getting pounded into the head.
Jus' sayin'... :sneaky:
 
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No damage to the cylinder, piston, etc. I took this apart with the engine in the frame. Took all the motor mounts out except the bottom bolt. It let me pivot enough to remove valve cover and head. I got lucky for such an unfortunate series of events. Now the question remains, countermeasure? How to avoid this from happening again.
 
I honestly think it came out all at once during that short ride. I woulda/shoulda noticed and heard the shatter. I had a lot of shatter at first start up after I built it. Come to find the cam chain tensioner assembly was missing a shim/cushion. Fortunate I have plenty of parts. Already have an extra head ready to put on.
 
Thinking out loud here
Guessing that the adjuster came lose and got wedged between the cam and surface where it slammed through.
Depending on how much resistance that gave there can have been a Yank in the cam chain / Cam adjuster and /
those parts / lower sprocket
Engine running and cam stopped. Not necessarily dimensioned for that
If the hole punch was low force nothing have happened at the other places
But if that resistance was high .. Other parts can have taken a hit.dynamic forces.
There can be shrapnel from the breakage going somewhere.
On the picture the cam looks fine but that is a hardened piece.
I would check the cam bearings ..I would do that every time open it up Since I have had those
gone bad . And if doubt and / or some miles on them replace.
I think I would put in a new cam chain if some miles on it.
The cylinder head is gone .. There can be cracks ..Welding it can make it warp and is difficult to do if I got that right.
So this will be a cylinder head job .. And the cylinders come off
Inspection of the crank rotation. Small end play.
Hoping for the best ..
 
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To my knowledge I have 76’-77’ BS38’s. Shouldn’t these air mixture screws have rubber orings? I took a quick cruise thru the forum and found an oring size chart. Got these from Mikes and no orings were included. Oring or not?
 
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If it ain’t one thing it’s another. I was going to heli coil this…”Snap goes the tap” I wasn’t white knuckling this either. It didn’t bottom out. Damn shit. Haha Gave it a slight tap on the side to straighten her out…I thought it was slight.
 
View attachment 200467 If it ain’t one thing it’s another. I was going to heli coil this…”Snap goes the tap” I wasn’t white knuckling this either. It didn’t bottom out. Damn shit. Haha Gave it a slight tap on the side to straighten her out…I thought it was slight.

A43AAC3A-2478-4458-A923-90416721F1CE.jpeg I feel your pain brother!
 
View attachment 200467 If it ain’t one thing it’s another. I was going to heli coil this…”Snap goes the tap” I wasn’t white knuckling this either. It didn’t bottom out. Damn shit. Haha Gave it a slight tap on the side to straighten her out…I thought it was slight.
Vacuum out as many chips as you can and grab the tap with a pair of fine tipped needle nose pliers, the grab the end of the needle nose at a 90 with a pair of vise grips. That should allow you to back out the remainder of the tap.
 
Oh man! JRay this kinda stuff has to happen to somebody! I'm starting to feel pretty safe with it all happening to you. This kind of stuff really sux!
There is the new type of low melting point aluminum rod that would probably weld the hole up. It was a surprise to me to find the patched 2X2 inch hole in mine. Boy was I stupid for leaving it that way building the engine back up. It worked fine but the patch seeped oil.
Makes me want to pull the tappet covers off next oil change and check the nuts!
 
Taps, they're brittle. Old rule of thumb when I was an apprentice was if you dropped a tap on the concrete floor, pitch it as it would likely break next time you used it.
As for removal, as Rusty commented use compressed air, vacuum, small picks, whatever you can find to fish most of the chips out. Then see if needle nose will turn or wiggle it. If the thing is loose enough to move then half your battle is won.
If not it's been my experience that there are three ways to remove a tap.
1) Brute force involving hammers and punches to break it out and pick out the pieces. Works better with through holes and in steel.
2) Acid, used to be a kit you could by called "Tap Out", came with putty to make a damn to contain the acid though with aluminum and stainless it wasn't much necessary. Basically dissolves the tap, works great in aluminum and stainless which are not affected by the acid but not carbon steel. Takes sometimes several cleanings and repeat applications because as the acid works it becomes depleted in effectiveness.
3) Plunge EDM, often called a Tap Burner. Call around to machine shops to see if they have one, pretty specialized piece of equipment so not all shops will have one. Uses a tubular electrode through which coolant is run while the machine uses electric current and packs at the tap core disintegrating it and flushing out the bits. Works really well but may cost a few bucks depending on what they want for shop time, shouldn't take more than an hour set up and everything.
Best of luck how ever you choose to go. The floor of the cam cavity in the head can be repaired by a decent welder but it may be easier and cheaper to replace it and have it repaired later as a back up.
 
Taps, they're brittle. Old rule of thumb when I was an apprentice was if you dropped a tap on the concrete floor, pitch it as it would likely break next time you used it.
As for removal, as Rusty commented use compressed air, vacuum, small picks, whatever you can find to fish most of the chips out. Then see if needle nose will turn or wiggle it. If the thing is loose enough to move then half your battle is won.
If not it's been my experience that there are three ways to remove a tap.
1) Brute force involving hammers and punches to break it out and pick out the pieces. Works better with through holes and in steel.
2) Acid, used to be a kit you could by called "Tap Out", came with putty to make a damn to contain the acid though with aluminum and stainless it wasn't much necessary. Basically dissolves the tap, works great in aluminum and stainless which are not affected by the acid but not carbon steel. Takes sometimes several cleanings and repeat applications because as the acid works it becomes depleted in effectiveness.
3) Plunge EDM, often called a Tap Burner. Call around to machine shops to see if they have one, pretty specialized piece of equipment so not all shops will have one. Uses a tubular electrode through which coolant is run while the machine uses electric current and packs at the tap core disintegrating it and flushing out the bits. Works really well but may cost a few bucks depending on what they want for shop time, shouldn't take more than an hour set up and everything.
Best of luck how ever you choose to go. The floor of the cam cavity in the head can be repaired by a decent welder but it may be easier and cheaper to replace it and have it repaired later as a back up.
We have a EDM type of machine at work to remove taps. BIG transformers inside it. It’s been called an elox if that sounds right? Now figuring out how to use it when no one is around. Haha
 
Lets hope it's loose. But with the chips out as much as possible, using Rustie's idea, you could also heat the area around the hole. The Al will expand more then the tap and might it turn easier?
 
If it is not loose I believe it will come loose with a drift tapping counter clockwise in the visible grooves at the fracture surface
And then the pliers as in RP # 29

??? Making an own fork with a cutting disk or file fitting into the grooves ( 2 of them ) and then a wrench on the outer end ???
 
Excellent idea Jan_P! I thought about two pins spaced right in a piece of stock and the outsides ground for clearance but too much trouble for a one-off.
 
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I replaced the valve cover with another. Took out the rockers and assemblies. Cleaned all the oil pathways. I chased the oil tube banjo treads before install this time. I peenwd over the valve adjustment screws a few threads so they won’t back all the way out. What sucks: Now a guy has to remove valve cover to remove adjustment screws. Up a few posts, anyone have an idea about that air mixture screw on the carbs? Should take an o ring? I found a chart on here with the o ring size….
 
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