Richard I would clarify that a little bit. The top of the piston and plug deposists are dead givaways for DETONATION!!!! Usually timming, but could be a lean deto. A temp related sieze you would see the tell tale "4 Corner" stick meaning the piston expanded evenly all the way around. Lack of lube, will generally give a score on both skirts, along with blue'd wrist pin bearing. A lean sieze is usually a melt on the top of the piston closest to the exhuast port. Warning!!!! A bunch of that aluminum that used to be a piston, is now in the crankcase. I would not even think of just cleaning up the jug and stuffing a piston in it unless I had a race that day, otherwise flush the crankcase best you can. CR PS I have a stack of 125 pistons with every type sieze you could imagine!!!
Richard Schmidt <[EMAIL PROTECTED]> wrote: Ken, I doubt that your piston melt down has to do with high water temp. Aluminum deposits on the spark plug is a sign of a melted piston. Most likely caused by too lean a fuel mixture to that cylinder. Lack of proper lubrication could also cause a piston to seize, but this would not cause the top of the piston to melt. A lean running engine will run hotter and put more energy into the coolant, but this an effect, not the cause. Do not attempt to rotate your engine any more than you have. This could cause more damage. The fix is to disassemble the top end of the engine and remove the affected cylinder and piston. Carefully inspect the other cylinder walls and piston for damage. It may not be necessary to remove the other cylinder if no damage can be seen to the piston and cylinder walls. You can easily remove the aluminum welded to the cylinder wall using common hydrochloric acid used for pool maintenance. Be sure to do this outdoors and wear a good pair of rubber gloves. Make sure you are up-wind from the cylinder and just pore a little at a time in the cylinder. You will get a lot of bubbling action. Carefully rinse the cylinder with water and examine it. Use a steel bristle brush to remove any oxidation. If some aluminum still remains, repeat. The acid will not harm the steel liner. Be careful not to get the acid on the other aluminum parts of the cylinder. When all the aluminum is gone, inspect the cylinder for scoring. If you broke a ring, you may have scoring. Depending on how bad it is, you may just be able to use a hone on the cylinder to remove some of the scoring and get a cross hatch pattern again. Get a new piston and rings and reassemble. Piece of cake ! As for the fastest way to get going again, replace the engine, most likely no more that two hours of work. Of course you have to have a standby engine. If possible, never go to the track without a backup engine. It may seem like an extra expense, but if you add up all the expenses of just getting to the track and entry fees, you will soon realize that you will actually save money if you have a back up engine to run on Sunday rather than go home. Richard ----- Original Message ----- From: "Kenneth Kirkland" To: Sent: Saturday, August 26, 2006 10:32 PM Subject: [F500] Melted 494 piston question > Hello all!!! > > I'm an F5 newbie running my first season of regionals > in the Midwest Division. I've been lurking on the list > for a while but haven't had a question to pose yet. My > first is a doozy. > > Apparently, a piston in my 494 melted down due to high > water temps during a regional at Hallett on 8/6/06. > There are some wonderfully shiny metallic deposits on > the spark plug in the left cylinder. The crank will > only turn about 45 degrees, with some metal on metal > sounds accompanying what little rotation there is. > > I had hoped to run one more regional before the end of > the year to get a national license when I renew my > license in early '07. What's the best approach to > remedy this situation? Redo the top end? Bolt in an > entire rebuilt engine? What symptoms would dictate the > need to work on the bottom end? > > > Thanks for any and all assistance, > Kenneth Kirkland > MiDiv #18 > www.kirklandracing.com ________________________________ FormulaCar Magazine - A Proud Supporter of Formula 500 The Official Publication of Junior Formula Car Racing Subscribe Today! www.formulacarmag.com or 519-624-2003 _________________________________ _______________________________________________ F500 mailing list - [email protected] To unsubscribe or change options please visit: http://f500.org/mailman/listinfo/f500 *** Please, DO NOT send unsubscribe requests to the mailing list! ***
