Are my 3.2 p+c s no good?
 

Hi all,

I have taken a few pics of my 3.2 (spun a big end) pistons and cylinders.

They have scratches on them. The cylinders have still got the cross hatch pattern on them but there are also the scratches.

Are they shot?

Am I now looking at a crank (which is cracked) as well as a new set of PC's.

I would greatly appreciate feedback from those who are in the know. This is the first set of PC's that I've seen.

Thanks in advance
Jakes

http://forums.pelicanparts.com/uploa...1114723639.jpg
http://forums.pelicanparts.com/uploa...1114723760.jpg
http://forums.pelicanparts.com/uploa...1114723881.jpg
http://forums.pelicanparts.com/uploa...1114723983.jpg
http://forums.pelicanparts.com/uploa...1114724102.jpg
http://forums.pelicanparts.com/uploa...1114724203.jpg

looks like it got way to hot. Pistons almost siezed up from the looks. Why?? Oiling or cooling problem?

Yep I think it got too hot.

Funnily enough the temp gauge was only a couple of mm higher up the scale than normal? If things got this hot I would expect the temp to have gone a lot higher, maybe somewhere up near the red???

Still not too sure what caused it, but will continue to look into it.

Thanks for the reply
Jakes

You say you spun a big end. Have any pictures of it? They would help determine why things went south. I am thinking a lack of oil and or oil pressure, almost had to be the source of this problem. Why? Because you spun the rod bearing. Just overheating may cause the pistons to sieze up but should not cause a problem with the lower end until a piston actually siezes up, which it aparently didn't. Only a general lack of oil should cause everything to go south. If the rod bearing was bad for a significant period of time it could have lowered the oil pressure to the point where the squirters were no longer efffective, causing the piston damage. Not real likely but a possibility. Are the cams and cam followers showing any signs of damage?

Thanks for the replies guys.

I think there was a lack of oil pressure which could have caused this. The oil levels were regularly checked etc, but am working an the premise that there was a blockage of some sorts. But to be safe I am replacing my oil pump with a new one.

But to just check with you guys, would you use those pistons and cylinders again or should they be replaced?

Regards,
Jakes

You need to measure them = and depends on the scoring of the cylinders.

Tough to tell from the pictures

Measure everything, its the most important step you can take to see if you can still use your pistons and cylinders. The photos of the scratches in the cylinders are not good enough to determine the actual extent of the damage, if any, to them. Depending on the finish in the cylinders, they may be able to be reconditioned.

Sorry to hear of this if its any consolation my 3.2 did this to me 2 weeks after buying it. I did alot of homework and if the cranks cracked it should not be re-used (mine was and it took me weeks to find one which wasnt!) A crack never get's better........

The piston looks saveable. The most important dimension on pistons is ring-land to ring clearance. The skirt may clean up.

The cylinder is the big question. If you can catch a fingernail in any of the grooves, or even feel any of the grooves with your fingernail, then they won't hone out.

And as stated above, check for taper and ovality of the cylinder.