1985 phazer exhaust port

[85phaznut]

i just bought a 1985 phazer with 5000 kms on it. it was rebuilt because the ring clipped the exhaust port and the piston chipped away a little bit. i dont why that would happen all of a sudden with only 5000 k on it but any way i pulled the heads off just to see what kind of damage there was. the head was dented inside a little but other then that no skoars or anything in the cylinder. also this sled has a psi pipe and is apperantly jetted for it. at the top corners of the exhaust ports in both cylinders there is small wear marks. is this normal? is it factory like that? is it somthing to worry about?

 

[YooperWoods]

How long ago was it rebuilt, has it been run yet? Top of the piston looks brand new but doesn't look like they honed the cylinder for new rings. Almost looks like gouging on the top corners of the exhaust port, no that's not normal. It should at least be honed and if that doesn't clean it up well enough for new rings then bored oversize.

 

[85phaznut]

it was rebuilt at the end of last year and no kms since rebuild. i just think its weird how that happens with such low kms. im pretty much taking a chance riding it this winter.

 

[jimmy99]

Damage was likely caused by detonation. There was another thread here somewhere that had the pistons coming apart at the ring lands after installing an aftermarket pipe. That could definitely cause the rings to "catch" on the exhaust port and create the damage in your pic.
Check the jetting in the carbs, should be at least a couple of sizes larger than stock for the PSI pipe. Might have to run a higher octane fuel.

 

[85phaznut]

i think the previous owner used a small grinder of some sort the shave the corners of the port to prevent the same thing from happening again. also the pistons have some play inside the cylinders. but anyway i bought some new cylinders and want to try them and see if the pistons have play inside the new cylinder i got. anyone have any tips on setting the pistons in the cylinders? is the a ring compressor tool or do i do by hand? should i take the piston off the rod and set it in that way?

 

[YooperWoods]

You don't need a ring compressor, just pinch the rings with your fingers on each side and carefully slide the cylinder down. Make sure the rings are lined up with the locating pins. You can also just measure the pistons and the bore to see if they are in spec and calculate clearance. Will be hard to tell for sure by installing the jugs on the pistons what kind of clearance you have. Could pull a ring off each piston and slide it down into the cylinder(nice and square) to measure ring end gap. Being new rings and pistons that will also give you an idea of the condition of the cylinder.