cham-ed 0 #1 Posted June 27, 2008 :whistle: Just a little gloating. I'm rebuilding my k241. Well I started about two weeks ago. The flywheel didn't want to come up. I tried the PB Blaster and pressure from a puller. No luck, but I'm blest with a machinist friend and his shop has an oxy-hydrogen torch. Well we heated that flywheel and kept going for a what seemed like a long long time. But all of a sudden the puller worked easily and off came the wheel! I know this is what a lot of people have done, but I sure felt glad when that flywheel loosened. Cham-Ed Share this post Link to post Share on other sites
HorseFixer 2,012 #2 Posted June 27, 2008 Next time when you do that take a dead blow hammer and use an impact socket to get between the fins and hit it with the hammer on the outside edge of the flywheel inwards in like a star pattern. Then screw a nut on the crank to protect your threads. Then take a prybar and put it behind the flywheel next to the engine casing and pry outwards with pressure. Rap the shaft dead center on the nut with the dead blow hammer and off it will come, and will be held on by the nut so it wont fall off on the floor. Applying that much heat to that cast iron Flywheel or Crankshaft is not a good thing! But glad you gut it off... hope that tip helps! Duke Share this post Link to post Share on other sites
TT-(Moderator) 1,131 #3 Posted June 27, 2008 I'm prepared to take a lickin' for this reply, but I really have to comment. 5 things I was taught a long time ago about flywheels - whether they are aluminum or cast-iron is: 1 - NEVER hit them with any kind of hammer. 2 - NEVER pry on them with anything. 3 - DO NOT heat them. 4 - NEVER use them if fins are broken or missing. 5- NEVER use an impact wrench to tighten the bolt/nut holding the flywheel. *1&2 ~ Hitting or prying on a flywheel can crack them. The center web of most flywheels is very thin and can crack easily. If the engine is reassembled with a cracked flywheel, centrifugal force can cause the flywheel to EXPLODE. On a front-engined WH, you might lose part of your leg..... but on a mid-engined WH you know exactly what you have to lose! The OEM K series/Magnum Kohler flywheels are only safe to 4000 rpm to start with. That is why the pullers use a steel (or billet aluminum) flywheel on engines exceeding that speed. Most tracks/clubs even require a safety "scatter shield" to be installed on the engine for operator and spectator protection. (look at drag race cars too) *3 ~ Heating metal changes the metallurgical structure. Heating of gray iron causes it to become brittle - unless the cool-down period is carefully controlled. Heating of aluminum isn't nearly as bad because less heat is needed for expansion, but I still would never do it to a flywheel. *4 ~ A flywheel is a precision balanced rotating mass. If a fin is chipped or missing, it is no longer balanced. If a replacement flywheel isn't available, the flywheel can probably be rebalanced by companies specializing in engine balancing. *5 ~ Over-torquing of the nut/bolt that retains the flywheel can split the flywheel at the mounting hole/keyway. You won't realize this until the engine is running at full throttle and pieces of the flywheel end up in the side of the garage - or the neighbor's car! A taper is a brillant mechanical engineering accomplishment. The tighter it is assembled, the harder it is to get apart. Separation can normally be acheived by a "shock" from the opposite direction of assembly. Flywheel keys have nothing to do with holding the flywheel tight - they are merely there for alignment (timing) or driving. (starters) Some of the old engines don't even have flywheel keys! These tapered surfaces should be clean, dry, and rust-free when assembled, with all nicks and burrs removed where possible. Make sure the key is straight and clean and completely seated in the keyway. (Install the aluminum keys in Briggs engines after the flywheel is placed on the crankshaft.) I can't recommend what YOU should do if a flywheel is being stubborn, but I haven't encountered one yet that I couldn't remove. I use a draw puller on the larger flywheels with puller holes, and a "knocker" on the smaller or undrilled ones. A draw puller is nothing more than a block of steel (about 1" square X 5" long) with several hole patterns drilled through it. (A 3 hole flywheel requires a steel "disc" drilled to match the bolt pattern) Appropriate bolts (preferably with flat washers under the heads) are installed through the holes and threaded in to the tapped holes in the flywheel. (chase the threads with a tap and lubricate!) Make sure the bolts are long enough to get a good "bite" in the tapped holes when applying torque to loosen the flywheel - it's not hard to pull the threads out of the holes! The block is drawn against the end of the crankshaft by alternately tightening the bolts. (I insert a flat piece of brass between the puller block and the crank to protect the threads when applicable) Some of the time, tightening the bolts will "pop" the flywheel free from the taper, but on most occasions, a sharp "rap" with a hammer to the center of the puller block is needed. I have also removed many flywheels from engines by using a "knocker". This is actually a tool designed and sold by B&S for removing the flywheels from their smaller aluminum engines, but the principal is the same for many manufacturers. (I've even done it on "big block" Kohlers.) The B&S tool is a hollowed-out piece of steel with a brass "button" at the top of of the hole. It is simply placed over the end of the crankshaft and hit sharply on the end with a hammer. The sudden "shock" in the opposite direction of the taper will pop the flywheel loose. I use this same method on K-90/91/141/161/181/M-8 Kohlers and many Tecumseh engines too. A chunk of brass held squarely against the end of the crankshaft and hit sharply with a hammer does the exact same job as the Briggs knocker, but is very universal. Make sure the crankshaft is pushed firmly to the flywheel side before hitting the brass so the full "shock" will go to the taper. (support the flywheel with wooden wedges or blocks) (Once again: not responsible for typos or boredom incurred in this post) Share this post Link to post Share on other sites
bambooheels 0 #4 Posted June 27, 2008 sorry guys i dont ever heat my fywheels, and ive never pryed on one either. ive dealt with stubburn ones before, but never on taht requires heat like that or a big hammer. I USE AN IMPACT HAMMER ON THE CRANK SHAFT, with a nut on the end so as to not damage anything, this is what kohler taught us in school and it works everytime, with no damage or headaches. :whistle: Share this post Link to post Share on other sites
HorseFixer 2,012 #5 Posted June 28, 2008 I'm prepared to take a lickin' for this reply, but I really have to comment. Yeah thats one way, Nice story! <_< But I haven't had a problem on my flywheels, and the main thing is you have to use common sense, And not a 5lb hammer If cast iron is that flimsy by removing the way I suggested then it is defective and would fail anyways. Many K-90's don't have tapped holes for pullers either. When your down and out and on a mission like we all get then, Im not gonna fart around and order a specialty tool! The fly wheel is comming off! Right Then Right Now. 100's later and still going strong!!! Duke Share this post Link to post Share on other sites
TT-(Moderator) 1,131 #6 Posted June 28, 2008 Gee, Duke..... the last time I checked, a hunk of brass and a hammer were't considered "specialty tools", and pounding "into" a taper surely won't loosen it either. And...... Here's a nice little excerpt from Brian Miller's website: Share this post Link to post Share on other sites
cham-ed 0 #7 Posted June 28, 2008 This is Cham-Ed who started this string. I just wanted to say after seeing TT's post, I wanted to say I did try a puller just like in the drawing + PB blaster and no luck. Another thing, not to be confused with a 8lb sledge, I did tap the flywheel with an 8 oz hammer after applying the Blaster. I didn't even swing it more than an inch. this is just to provide a little vibration to help the Blaster get in. The BIG thing is very gentle and just to help the Blaster and NOT to break the thing loose. I'm afraid too many people think if a little tap is good a giant smack is better. No, NO, NO. Thanks again for all the advice. Cham-Ed Share this post Link to post Share on other sites
HorseFixer 2,012 #8 Posted July 2, 2008 This is Cham-Ed who started this string. I just wanted to say after seeing TT's post, I wanted to say I did try a puller just like in the drawing + PB blaster and no luck. Another thing, not to be confused with a 8lb sledge, I did tap the flywheel with an 8 oz hammer after applying the Blaster. I didn't even swing it more than an inch. this is just to provide a little vibration to help the Blaster get in. The BIG thing is very gentle and just to help the Blaster and NOT to break the thing loose. I'm afraid too many people think if a little tap is good a giant smack is better. No, NO, NO. Thanks again for all the advice. Cham-Ed Thats correct a small hit isnt going to break anything! The guy who told me this in the first place has been working on kohlers for 45 years hasnt hurt himself yet nor busted a flywheel. As I said, its all about common sence. Duke TT I seen that same drawing and have read it all and I agree Using pullers wont work on a K90 no holes to grab on! And yes I use a small hammer for this not sluggo! Duke Share this post Link to post Share on other sites