Why oh why did it happen to me

[pittss1c]

piston

port damage

port2

dome

 

I have had some overheating issues, but I don't want to jump to any conclusions.

I am actually a little concerned that the ports weren't done quite right.

I probably obly have 10 or 15 good rides since the topend was redone.

 

Any input is appreciated.

[rubberneck]

piston

port damage

port2

dome

 

I have had some overheating issues, but I don't want to jump to any conclusions.

I am actually a little concerned that the ports weren't done quite right.

I probably obly have 10 or 15 good rides since the topend was redone.

 

Any input is appreciated.

for some reason i cant bring up the pic of the piston, and its hard to tell from the pics of the ports, but did it catch a ring in the exhaust port? Maybe the ports weren't chamfered enough?

[Duneman101]

def not a heat issue... looks like the ring just got out enough to catch the port. that sucks. when you rebuilt the top end did you have it bored or just a hone?

[pittss1c]

Don't know. I bought it freshly rebuilt.

The pistons have 1.50 stamped on them... time to start figuring out where to get them reworked if they can be.

[blowit]

Port chamfering is your culprit. Good news is the damage on the bore will not affect running so you can smooth that area, chamfer your ports, and go. We take a lot of time chamfering ports here because it makes a huge difference in motor life. Make sure you get someone experienced to do this. radius, finish, blend, all makes a difference. I would suspect if you measure the ring land width on the exh side of the that piston, it will be deformed from pulling on the ring.

 

woops, I did not see your piston pic. Question answered.....

 

 

 

B

Edited September 30, 2009 by blowit

[JMADD]

I have rebuilt several stock motors by just honing them. I did not know about chamfering the ports then, but I never had a problem with them. I guess I got lucky. Will definitely have someone chamfer them in the future. It doesn't sound like a DIY process for me.

[blowit]

I have rebuilt several stock motors by just honing them. I did not know about chamfering the ports then, but I never had a problem with them. I guess I got lucky. Will definitely have someone chamfer them in the future. It doesn't sound like a DIY process for me.

 

Honing a cylinder should not need port chamfering because you should remove less than .001 of material more or less to add cross hatching. I have, however, seen many virgin Banshee engines that had little to no chamfer. Boring should always be followed up with a proper chamfer. We do a 3 step process. The smoother than transition is, the long the rings and pistons will last.

 

 

 

B

[jayzx10r]

My vote is the ring caught on the port lip.

[pittss1c]

There seems to agreement that the ring caught the port.

I assume this happens only because of a poor job in the port chamfering.

Now I will be trying to find the right person to take the cylinders to.