Tell me about Cat C7s please

[Adopo]

I am looking at a boat with these, and I have read that these were prone to failure. They appeared to be the 454 hp model, with only 640 hours or so on them since 2011. The broker explained to me today that the engines where put in the 2009 boat in 2011, because the original C7s where not epa compliant, that somehow they slipped by and got installed. That’s the story, so the owner said replace them.

Anyway, the only real question I have about this boat is the engines. Anyone with personal experience please chime in. Thanks!

http://www.yachtforums.com/review/cheoy-lee-68-long-range-cruiser.11331/

https://www.yachtworld.com/boats/2009/cheoy-lee-serenity-68-3723567/

 

[BrisHamish]

Have replied in more detail to your other message regarding the same boat.

In summary, the two known issues with C7s are (1) the original salt water aftercoolers fitted to higher hp models and (b) the HEUI pumps.

If - and its a big 'IF' - you can keep on top of those two issues, then the motors are otherwise very good for their vintage, in my experience.

Hamish.

 

[fgarriso]

The CAT C7s are mechanically good engines. The electronics are not. The sea water cooled after coolers are not. and the HEUI pumps are not.

If you can live with those issues then go for them.

 

[Adopo]

Thanks fo the replies, so other than replace the engines, are there i upgrades that can fix this?

 

[BrisHamish]

How to address the C7 issues? I think it is mostly a case of very deliberate and careful regular maintenance, as follows:

For the aftercoolers - assuming there hasnt already been a failure and assuming salt water hasnt already gotten into the engine core - first purchase and install the modified CAT design (post 2011), and then every year flush the seawater circuit with Rydlyme or barnacle buster, actually pull the cores from the aftercoolers and inspect them physically and clean them every 2 years, and replace the aftercooler cores every 6 years. Keep that cycle of maintenance up, without exception, and I expect you will be problem free in the aftercooler department.

For the HEUI pumps, just buy and install new ones before the current ones give out (because when they give out, they can damage the injectors), and then replace them on a regular basis say every 6 years or when you are feeling overly wealthy...

Hope this helps.

H.

 

[Adopo]

Thank you for taking time to answer, this is helpful.

 

[Arc]

That is a proper boat. Beautiful lines

 

[Lepke]

You can buy a C7 HEUI pump rebuilt for about $1200. In a truck, they're usually guaranteed for a million miles. There are places that sell a new "Cat" pump for the same money. I assume Chinese. The core charge on a rebuild is about $800 to $1200. You can buy a used pump, probably needs a rebuild, for about $500.
Road engine and marine engine pumps are different internally. Marine pump produces more hp. But most rebuild shops can rebuild a road pump into a marine.
Take care of the aftercooler. It can last many years but needs regular inspection and cleaning. There were places in the US that made an after market drop in replacement.