Changing a a cylinder head on a 420a?

[gotdunn]

I have recently started having problems with my cylinder head. it seems that it has been blowing spark plugs out. since it has done it twice...i have had to put two heli-coils in.

All i know is that soon enough, hopefully over the summer, i would like to put the cylinder head in myself. Just wondering what could i do, what would be the easist way? would 4g cylidner head fit on it? im plannin on getting doin more motor work on it eventually?!

Just watd to know from the people that might know?

 

[tqmx1]

Has it popped a plug after you helicoiled the holes? If yes change the head, If no helicoil the other two and be happy.

 

[vernvision]

Is the piston striking the spark plug or is it because your valves are burnt? Yeah you are not going to get the greatest seal with heli coils. If you could post a picture of the spark plugs it might help us out to see what is happening. Did you cros thread the plugs by accident maybe and they popped out because of that perhaps.

 

[Rex2342]

Your main concern right now should to find out why this is happening before going any further. If the head was damaged to begin with and the threads were gone then I can see the spark plugs blowing out. If nothing was damaged before the first time then you have a problem elsewhere with either excessive blow by caused by bad valves or rings or your pistons are contacting with the plugs.