CAPPED PISTONS

[BEARKILLER]

I was watching a special on the ALCO 628 CENTURY locomotive.

During the show, the narator stated that the first several units released suffered from piston burn-through, due to the turbo and other variables.

ALCO took them back in and installed CAST-IRON capped pistons that could withstand the excessive heat levels, without melting.

Could/has this been done in our engines??

If so, what was the outcome??

Thanks.

[CAJUN 93]

i don't know about the capped idea but there are several companies that offer coatings to protect the pistons. i'll dig around and see if i can find some info.

daryl

[KTA]

Many large diesels use a steel topped 2 piece piston. The crown is steel and the skirt is aluminum. Current trends are to do away with the aluminum skirt and use a solid forged 1 piece piston with very narrow skirts. The steel pistons are very heavy and therefore aren't good for high rpms like the cummins turns, yes 3500rpm is alot for a big diesel, most steel top applications are 2500rpm and down because of the weight.

[BEARKILLER]

Maximum RPM on the big ALCOs is 900 RPM.

Idle is 300 RPM.

I guess that would explain their ability to run the heavy pistons.