not a cannondale but i need some help?

[440speedrider]

i have a buddy that has a 400 ex, he sent the motor to a the local napa machine shop to have a 440 kit put in it, he got a brand new head, new titanum vales and springs, when he got it back it ran fine for about 45 min and then it blew a head gasket, and if it runs for about 10 min it will blow a head gasket or the spark plug, any ideas what wrong with this p.o.s honda? thanks for the help also someone posted earlyer that the sleve may have moved up and they will have to mill it flush with the top of the cylinder would this fix it for sure or could their be many other posibilites?

[kdeal]

QUOTE

Originally posted by 440speedrider
i have a buddy that has a 400 ex, he sent the motor to a the local napa machine shop to have a 440 kit put in it, he got a brand new head, new titanum vales and springs, when he got it back it ran fine for about 45 min and then it blew a head gasket, and if it runs for about 10 min it will blow a head gasket or the spark plug, any ideas what wrong with this p.o.s honda? thanks for the help also someone posted earlyer that the sleve may have moved up and they will have to mill it flush with the top of the cylinder would this fix it for sure or could their be many other posibilites?

Actually just the opposite is possible. Try running your fingernail where the sleeve and new liner meet. If you can feel any difference in height (the liner would be lower). Then what happen is they didn't press the liner down deep enough and the liner has dropped.

Think about it, when you install a cylinder sleeve you press it in and then you mill the top of the sleeve down to the head surface. There would be no way the liner would be higher!! What ends up happening is they press it down while the liner is cool and the cylinder is hot and while it cools the liner comes up a little in the block. They then machine the top of the liner down even with the block. When you start the motor up it runs fine until the block heats up and the liner then sinks to it's normal postion. I just saw this the other day on a Raptor. It took about 10 minutes to blow the head gasket.

[440speedrider]

so what do i do if i pull the jug out and its low?
i know that i mill the sleve off if i pull it out and its to high, what what do i do if its to low when i pull the jug?

[kdeal]

You mill the block down to match the new level of the sleeve OR you make them buy you a new sleeve and install it.

[440speedrider]

some retard put the piston and sleve in i tryed to tell him not to let this guy put those in but he done it for free and no one can fix it, so the cannondale guy is ganna step up and do it, with alittle help from kdeal

[kdeal]

Have a good machinist measure the drop and see how bad it is. If not too bad, just mill the block down to the sleeve level. Make sure someon presses the sleeve down to make sure it is all the way down first!!! It should be, the compression from the motor when it got hot did the job for you most likely. I'll bet it was blown bad when it went too.

[440speedrider]

im have a couple years experiance as a machinest so ill take the ol dial calipers and check it out, what is to much to mill off the block?

[kdeal]

The raptor I saw last week, they just milled the blockk down to the sleeve height. But measure and see what your difference is. You don't want to take off too much, as this throws everything else off (cam timing,etc).

[cdrookie]

i've been told thats it's pretty common for big bore ex's to blow head gaskets. is it a high compression piston? the cure is to drill and tap a hole for another head bolt, if the liner isn't the problem.

[claas900]

..I know Sparks offeres over sized studs,i always thought thats why they blew head gaskets. Iv been told big bores will start to pull the stock studs..I dunno i ran a 440ex for almost 2 years,stock studs no issues.Tho its was only 11.1 piston..Im with kdeal on this one,something wasnt done right with that sleeve.