Here's a couple of pics of an aftercooler (a Cummins I believe) that has not been serviced regularly.
Pretty susre it is a FL boat with year round usage.

Notice the fine collection of marine growth and impeller pieces.

Gauranteed this engine had over heating issues!!!!!

Any guesses why?

Bill D

Bill, to me that looks like the heat exchanger. Hard to believe that unit got that bad before it was checked. On top of that why did they not go get the missing impeller blades when they were changed. That is the kind of stuff that would drive me nuts.
In my last boat I went through the whole cooling system before my first offshore trip and found broken zinc pencils, impeller parts and electrical tape. Nice stuff, and the engine had been serviced on a regular basis. You just never know unless you do it yourself.

That's brutal!!

Over the years, I have asked more than a few people with impeller problems if the found the other blades when they discovered there overheating problems were related to missing blades.

Some told me I didn't know what I was talking about. :rolleyes:

that's a garbage can if I ever saw one. The cooling side of the engine is the catastrophic side. Price new engines lately?

John, in fact the pics are the aftercooler.
I'm not sure of the "sea water flow" on the CATs but on a Cummins the sea water flow is as follows.

Raw water pump to:
1. The fuel cooler (nothing really there to pick up impeller pieces) On my engines I eliminated the fuel coolers.
2. Aftercooler (that's where most impeller pieces get lodged)
3. Gear cooler (you can find small pieces of impeller here)
4. Heat exchanger (not much gets to it other than zinc gunk)
5. Exhaust mixer.

There are three pencil zins on a Cummins. Two on the aftercooler and one on the heat exchanger. Sometimes an additional two (like on my engines) on the gear cooler.

The reason an aftercooler like in the pic will cause overheating issues is a lack of raw cooling water to the heat exchanger.
No different than putting your thumb over the end of a garden hose to stop the flow of water.

I'm repowering my 35 Duffy with a Cummins. I've made a note to Never let this happen!

MBILL,

"Athens' rule of thumb" on aftercooler maintenance EVERY 4 YEARS regardless of engine hours consumed.

Other than keeping the cores clean is to make sure the cores/housing/caps where ALL touch/come together with O rings etc. are
greased preferably with Alco Metalube grease.

This procedure will prevent corrosion of "dissimilar metals" and of course allow your to "get the afterooler apart" every 4 years or so without beating the crap out of the core trying to get it out of the housing.

BTW, if your Cummins (?REMAN?) is out of the boat, used or new, now is a good time to take off the caps, remove core, grease all up and put back together. You'll appreciate the effort when you take it apart a few years down the road.

Seaboard Marine - Tony's Tips | Aftercooler Maintenance - Cummins (http://sbmar.com/main/articles/aftercooler_maintenance_-_cummins/)

Here ya go!

p.s., what Cummins engine is going into the 35 Duffy??
any pics???
Neat!

Merry Christmas, Bill D

I'm waiting for the engine to arrive. I think that I'll take your advice and grease it up prior to installation.
I'm repowering with a new "recon" Cummins QSC8.3, 550HP electronic engine. It will hook up to a ZF 1.77/1 gear. It's replacing a 450HP Cat 3208.
I'll start a new thread and post some photo's after the holdiays.

MBIll,

I like these engines and worked on a vessel that had a pair rated at 500 HP and if I do a new build want the same in either the 550 or 600 HP rating. Looking forward to your thread and by the way what hull is it going onto and what is it replacing?

Good Luck

Dave

The QSC 550 is a GREAT motor and the reman pricing (15K-18K) off "$new$" is a bargain!!!!
Keep us posted on ALL!!!!!!