Wvtroutbum81 186 #1 Posted October 5 Engine experts, M12 with 2,201hrs. Oil has always been changed twice a year. Does not smoke or use oil, the head gasket was leaking on exhaust side. This is post cleaning Share this post Link to post Share on other sites
Wvtroutbum81 186 #2 Posted October 5 17 minutes ago, Wvtroutbum81 said: Engine experts, M12 with 2,201hrs. Oil has always been changed twice a year. Does not smoke or use oil, the head gasket was leaking on exhaust side. This is post cleaning Is there anything i should inspect while apart Share this post Link to post Share on other sites
adsm08 2,050 #3 Posted October 5 The mating decks of the block and head should be inspected for any deformation. The correct way to do it is with a machinist's straight edge and some feeler gauges. I usually just pass the straight edge over the surface with a flash light behind it. If I can't see light under the bar I don't bother with the feelers. If the head needs any straightening you can deck it yourself by coloring in the entire surface and sanding it with a piece of sand paper wrapped around a piece of glass. There are others who are more familiar with that process than I am. 1 Share this post Link to post Share on other sites
kpinnc 12,017 #4 Posted October 6 (edited) It looks clean, but of course impossible to tell if the bore is still within spec. As @adsm08 said, it’s a good time to check the head. @ebinmaine has some posts on here doing it the right way. If the engine still made good power and didn’t smoke, I say true the head and run it. Edited October 6 by kpinnc Share this post Link to post Share on other sites
leabassett@sbcglobal.net 149 #5 Posted October 6 New head gasket and head bolts. Than let her rip. Share this post Link to post Share on other sites
Wvtroutbum81 186 #6 Posted October 6 20 minutes ago, leabassett@sbcglobal.net said: New head gasket and head bolts. Than let her rip. Where is a good source for the bolts? do they have to be replaced Share this post Link to post Share on other sites
ebinmaine 67,472 #7 Posted October 6 39 minutes ago, kpinnc said: true the head and run it. 18 minutes ago, leabassett@sbcglobal.net said: New head gasket and head bolts. Than let her rip. Gotta true the head. It's almost certainly warped even if only a small amount. I do NOT install a cylinder head without trueing it. Ever. We use a piece of known flat steel. Tape a piece of sandpaper to the steel. There should be a thread on here describing the procedure. 3 minutes ago, Wvtroutbum81 said: Where is a good source for the bolts? do they have to be replaced If the engine has NEVER been apart the head bolts MIGHT be reusable. Older K series use normal Grade 8 bolts. Not sure about a Magnum. Share this post Link to post Share on other sites
Bill D 1,920 #8 Posted October 6 The Magnum is basically a K series with electronic ignition. Grade 8 bolts should be fine. 2 Share this post Link to post Share on other sites
oliver2-44 9,743 #9 Posted October 6 Now would be a good time to pull the carb so you can clean the breather and adjust the valve clearance. If the head checks out to be flat with a feeler gage go with it. But do check it’s 1 Share this post Link to post Share on other sites
953 nut 55,218 #10 Posted October 6 Once the head has been installed with the new head gasket and has run long enough to come up to operating temperature allow it to cool down and then re-torque the head bolts using the same sequence. 1 Share this post Link to post Share on other sites
WHX?? 48,815 #11 Posted October 6 ... all of the above these guys know what they are talking about. If possible use a head gasket of the fire ring design... I know OEM and Stens have this feature. they generally never fail if head trued and torqued proper. 1 Share this post Link to post Share on other sites
Wvtroutbum81 186 #12 Posted October 6 Thanks, I ordered a new Kohler gasket, Going to adjust valves and replace the breather. Also got copper spray! 1 Share this post Link to post Share on other sites
Wvtroutbum81 186 #14 Posted October 6 Is a dab of blue loctite ok 1 Share this post Link to post Share on other sites
ebinmaine 67,472 #15 Posted October 6 Just now, Wvtroutbum81 said: Is a dab of blue loctite ok All I've ever used on cylinder head bolts is clean engine oil. 1 Share this post Link to post Share on other sites
WHX?? 48,815 #16 Posted October 6 (edited) No no locktite... some guys use a dab of antisieze tho. Never hurts to chase the threads either... 3/8-16 tap. Edited October 6 by WHX?? 1 Share this post Link to post Share on other sites
adsm08 2,050 #17 Posted October 6 24 minutes ago, Wvtroutbum81 said: Is a dab of blue loctite ok Never. Chase the threads in the block, then dip the first 3-4 threads of the bolt in clean oil, and dab a bit under the shoulder of the head. You want the bolt lubricated and to go in as easy as possible to make sure your torque is accurate and you get the correct clamping force. The reason head bolts (or any torque-to-yield) bolt needs replaced after use is because when you tighten a bolt it stretches, that's what makes it tight. A reusable bolt will go back to its original length after it is loosened again. A TTY bolt is tightened until the metal permanently deforms, this is the yield point, and will not provide the same clamping force afterward if reused again. In this scenario that results in repeated head gasket failures. Any torque sequence that goes Ft.lb, then angle is a TTY sequence and those bolts should not be reused. 2 Share this post Link to post Share on other sites
8ntruck 6,999 #18 Posted October 6 TTY = Tighten To Yield. Share this post Link to post Share on other sites
