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Engine basics => Engine set up tips => Topic started by: David Ruff on January 26, 2018, 05:23:30 AM
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Have a nice OS engine that runs great, but bought used and the two muffler mounting screws/bolts have stripped out/boogered heads.
What is the easiest way to remove these screws?
I know you usually drill and find an easy out, but these are very (4-40?) small screws and I don't want to mess up the engine case or muffler mounting surface.
I tried to put a small needle nose on the screw head, but that is not working.
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If you have a dremel tool use the cut off wheel and cut a flat blade screw slot in the screw or what ever you need and use the screw driver to remove it..
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Hi
Personally I have never used this method, but it seems interesting especially if there is nothing left out of the hole.
https://www.youtube.com/watch?v=JCADI0YSt8M&feature=youtu.be
P.S .: If the engine is an OS is very likely that the screw is M3 or M2.5.
I do not think that OS has ever used imperial screws
Massimo
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My favorite tool is very similar to this one. For only $7 it's worth buying, especially if you're buying used engines that someone else may have damaged before you get them.
You chock up the engine so it's held tight, use the bottom side of the tool pictured. Slow speed with a good amount of pressure, spins them right out every time. Obviously the screw is trash after that, but no harm to the engine.
https://www.amazon.com/gp/aw/d/B01NGTLM40/ref=mp_s_a_1_5?ie=UTF8&qid=1516981320&sr=8-5&pi=AC_SX236_SY340_FMwebp_QL65&keywords=damaged+screw+extractor+set&dpPl=1&dpID=51REgeV2qPL&ref=plSrch
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Here's my actual set. I bought it off the snap-on truck years ago. The brand is X-out I believe.
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can we see a picture of what we are working with
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Although really small i'd be tempted to try a 2mm LEFT handed drill bit. Dremel the screw heads off and mount engine in a vice on a drill press, a bit of heat won't hurt and keep steady pressure on with drill motor in reverse of course, Surprising how they grab and just unscrew - worst case is you have an accurate 2mm hole through to re drill and tap LOL!
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If you have a dremel tool use the cut off wheel and cut a flat blade screw slot in the screw or what ever you need and use the screw driver to remove it..
Or just cut off the bolt heads & use new bolts.
It's kinda tough to mount an engine with the muffler on it.
Depending on the size engine, these should be 2.5MM or 3MM bolts.
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Use a regular drill to pop the screw heads off, remove the muffler and use whatever implement is required to remove the rest of the screws. Fingers might do it, but a little heat with ViseGrips will always get it done. y1 Steve
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In future should this arise, it is helpful to grab your phone or similar and take a photo of what you are dealing with and post it here to let others know what you are dealing with. It would help to know what OS engine you are talking about and if the muffler is still attached. Some mufflers attach with the screws entering the engine from the muffler side (they go through the muffler and into the engine. Others go through the engine and then into the muffler.
Obviously if it is the prior then one screw will be next to impossible to get at with a drill or any other implement as the muffler gets in the way. If it is the latter then a different techniques are called for. For both the path of least resistance (If the muffler is still attached) is to get rid of the screw heads. If it is the type where the screws pass through the muffler lugs and screw into the engine, Taking a file or other method to remove the screw heads, allows you to remove the muffler and you are left with about a quarter inch of screw sticking out of the engine to grab with vice grips and carefully wiggle the free.
If it is the type that pass though the engine first then screw into the muffler, knocking the head off lets you remove the muffler and you have the remainder if the screws sticking out of the muffler. As these screws are relatively small either using a drill or a file to remove the heads is the path of least resistance. Actually this is usually the best approach for getting small screws out of just about anything.
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There was a similar thread here recently, about OS carburetor screws. Here's the run-down:
- OS uses screws with JIS cross-heads, not Phillips. Using Phillips screwdrivers buggers them up
- A JIS screw head that's been buggered up by a Phillips screwdriver can look completely wallered out, and still come out with a proper JIS screwdriver
- If you can get at the screw, and you don't want to try a proper driver, I'd go with using a Dremel Dangerous Disk to cut a slot -- but in my shop, I try the right driver, first
- They're 3mm standard (for 3mm) thread. You can replace them with socket-head screws.
Best of luck!
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Kind of leaning toward cutting off the bolt heads as I can then pull off the muffler, remove the studs and find new bolts.
Photos here of the problem.
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Have a nice OS engine that runs great, but bought used and the two muffler mounting screws/bolts have stripped out/boogered heads.
What is the easiest way to remove these screws?
I know you usually drill and find an easy out, but these are very (4-40?) small screws and I don't want to mess up the engine case or muffler mounting surface.
I tried to put a small needle nose on the screw head, but that is not working.
David, this is what I use. Haven't stripped out one yet!
Good luck, Jerry
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looks like drilling them off'd be easy . 3 mm or 1/8 drill . And a clout hammer . VD~
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Kind of leaning toward cutting off the bolt heads as I can then pull off the muffler, remove the studs and find new bolts.
Photos here of the problem.
I don't trust myself enough to cut em off without damaging the case so I second cutting a slot and use a standard screwdriver to remove.
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I've used needle nosed vice grips successfully on the exact same situation you're in. Warm the engine a bit with a heat gun. Some spray PB Blaster won't hurt.
If you can file a flat on the screw head first, that won't hurt either.
Plan B is screw head removal. Phillips type screws tend to center a drill bit if you're careful.
Best of luck. You're a good builder, you'll be able to do this.
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What size is the engine, David?
The FP 20/25, FP 35/40 and the LA 40/46 all use M3 bolts.
The FP 10 uses M2.5. I can't help with the FP/LA 15 as I don't have any.
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Use a round rotary file to clean out the damage in the screw slot or you'll break the drill bit. Then drill with a left hand bit, nice and slow and many times they'll walk right out as you're drilling them.
Here's a 3mm LH bit: https://www.ebay.com/i/273018637564?chn=ps
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I would expect those to come right out with a Hozan #2 screwdriver - they are classically damaged, right at the center, but the ends of the slots seem intact (since a regular Phillips can't get to the edges).
BTW, I would suggest putting the entire thing in the freezer for an hour, and then only heating the bolts (if at all...) to take full advantage of the differential CTE of aluminum and steel.
Brett
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Well, fellas. I just ordered a set of the JIS screwdrivers. More to follow. Thanks.
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I predict the JIS will do the trick
Just had to replace my Horzon JIS set with new cuz one of my dogs is a tool thief and I am dumb enough to leave stuff where he can reach
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JIS did not work. Looks like an ez out?
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Left handed drill bit, medium pressure, should spin it out.
Regular drill bit if you don't have left handed ones, light enough pressure to just drill the head off and slide the muffler off the remaining studs. Don't worry, it's super easy.
Or send it to me and I'll take care of it for you.
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Oh, Ty replied at the same time. I'd take him up on that, mostly just to go hang out with him!
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SUCCESS!
Got an easy out set. Drilled the screw. Drilled on it with the easy out. It loosened up the screws and I took them out with screwdriver.
Now to get the new bolts.
Thanks guys.