Cummins diesel engines 480C, 2004

[BULLET]

One of my Cummins diesel engines (2004, 480C) experienced a failed valve seat. Two other boats in my marina experienced the same event! I asked Cummins in Houston, Texas about the issue with no response. Has anyone else experienced a valve seat failure on similar Cummins diesel engines?

 

[trit21]

You may want to try boatdiesel.com, I think I remember a couple of 6cta's experiencing losing #6 cylinder because of a swallowed valve. Since the block, I believe, is the same as the 480ce, might be someplace to get information.

 

[rmadaris]

What happened and how did you find this problem? I have been trouble shooting my boat not reaching max rpm's the last 5 months.

 

[vanburen]

What happened and how did you find this problem? I have been trouble shooting my boat not reaching max rpm's the last 5 months.

I went through a similar issue last year. It took almost all season to get back up to RPM. I finally cheered as I got to 2600 at WOT. I think it was a bottom issue as the RPMs would creep up on hard running but I sent a diver down and it didn't make much difference. But we moved last year and didn't put many hours on it.

This year I cleaned the Airseps (boat is 2005 - don't think that was ever done) - I was wondering if that could be a contributor. Or old fuel from the winter. I will take detailed notes this year - hopefully not an issue. What do you cruise at (RPM, knots) and what is your WOT?

 

[Ozzie-iv]

You can try something which is relatively easy and advised by a marine mechanic here in Australia..
Once your engines warm up put your boat in neutral and slowly bring the engines up to what your
maximum revs should be then drop the revs back to idle.

If they reach rpm then there is an other issue such as dirty bottom etc. If they don't then there is an
issues with the engine

A year ago I was dropping revs WOT was 3000rpm but could only get to 2600. after a bottom clean she made revs easily.
before the bottom was cleaned I tried what the mechanic suggested and the engines reach wot easily.

A year on and I am starting to get the same problem again checked engines in neutral and rev easily to WOT so probably
need a diver this time to give her a clean.

Ozzie

 

[Asureyez]

One of my Cummins diesel engines (2004, 480C) experienced a failed valve seat. Two other boats in my marina experienced the same event! I asked Cummins in Houston, Texas about the issue with no response. Has anyone else experienced a valve seat failure on similar Cummins diesel engines?

This engine fails on # 6 with high frequency. Most often due to valve lash issues. If you have never adjusted the valves on your Cummins 6CTA you are are begging for trouble.

This should be done at 200 hours when new, follow the Cummins service schedule there after, I believe it is at 600 Hr intervals there after, but check the service manual. In 90% of the time this is not a DIY job and works best with two mechanics on the work.