427 Impeller question:

[Sailor John]

Hello all,
Yesterday, after spring launch, the port 427 engine impeller disintegrated. That means no cooling water of course, so I shut down the engine. A friend helped me remove the old impeller and installed a new one. On restart, there was still no water. No surprize, somewhere in that cooling system are the 7 or 8 blades that broke off the old impeller.
Question #1: Where am I most likely to find the pieces, and
Question #2, what is regarded as the 'safe' life expectancy of these impellers? Should I change them every year? 2 years? 4 years? I have had the boat for 6 years and no problem until now. I love the 427's.
Thanks for sharing any advice,
Sailor John

 

[Boatsb]

2 years of use. If its removed for winters maybe a bit more but 3 tops if you want to be safe.

The impeller is probably clogging the heat exchanger or other pipes that are in need of a vacuflush if you can't get to the parts by hand.

 

[Sailor John]

Thanks Boatsb,
A member at our club suggested using a shop-vac to suck the pieces out backwards. Sound Plausible?

 

[Boatsb]

Yes if you get a good deal. I'd still hit the outlet with water to push the pieces that may be stuck harder than air will dislodge.

 

[UNIQUE_NAME]

Hello all,
Yesterday, after spring launch, the port 427 engine impeller disintegrated. That means no cooling water of course, so I shut down the engine. A friend helped me remove the old impeller and installed a new one. On restart, there was still no water. No surprize, somewhere in that cooling system are the 7 or 8 blades that broke off the old impeller.
Question #1: Where am I most likely to find the pieces, and
Question #2, what is regarded as the 'safe' life expectancy of these impellers? Should I change them every year? 2 years? 4 years? I have had the boat for 6 years and no problem until now. I love the 427's.
Thanks for sharing any advice,
Sailor John

if they are fresh water cooled CC engines like mine the next stop would be the oil cooler
followed by the tranny cooler,
heat exchanger and finally the risers.
all are easily accessible to remove the attached hoses and look inside or backflush with a hose.
the endcaps come off the exchanger for further inspection if desired.

 

[UNIQUE_NAME]

if they are fresh water cooled CC engines like mine the next stop would be the oil cooler
followed by the tranny cooler,
heat exchanger and finally the risers.
all are easily accessible to remove the attached hoses and look inside or backflush with a hose.
the endcaps come off the exchanger for further inspection if desired.

btw you might want to remove and check the new impeller you just installed. they dont like being run dry.
these 427's are quirky good marine engines but the cooling systems are marginal at best and you have to stay on top of them.
what ignition system do you have in them?

 

[Sailor John]

Thank you all for the informative insights.
I will update as I move forward on the quest for the missing impeller pieces.

Jim (Salty) you have a sister-ship to my Mad Hatter, also built in '73.
I am afraid I do not know what ignition system is on it. Probably original, it runs well enough but my
mechanic has been after me to upgrade to Pertronix.
I don't know if that's worth the money or not.

 

[UNIQUE_NAME]

Thank you all for the informative insights.
I will update as I move forward on the quest for the missing impeller pieces.

Jim (Salty) you have a sister-ship to my Mad Hatter, also built in '73.
I am afraid I do not know what ignition system is on it. Probably original, it runs well enough but my
mechanic has been after me to upgrade to Pertronix.
I don't know if that's worth the money or not.

great boats, i moved up from a 66 hatteras 34' sedan about 20 years ago.
the pertronix is a step up from original equipment in the maintenance department but the weak link
that will burn you sooner or later, sometime sooner and sooner, is really the crab cap. a number of guys with the 427's have installed a pair of DUI from performance marine.
they are not cheap but they are a dramatic improvement in reliability. if you are interested
pop over to the chris craft commander site http://www.network54.com/Forum/424840 search and read
about them. the site also has lots of good info on the 427's.

 

[Sailor John]

Good evening all,
An update, with thanks to all who responded earlier. The responses were VERY helpful!
I was able to find 5 broken impeller blades in the seawater line that exits the engine oil cooler. That means 3 more blades to go, so I will be looking into the reverse gear cooler next. (I tried to vacuum the lines backward but that was fruitless).
I am surprised there is not an in-line filter that would catch these pieces before they were sucked into the engine. Has anyone ever seen an in-line strainer?
Thanks to all,
Sailor John

 

[kelpy]

If not in the gear cooler, they could be in the lines going up to the pressure relief poppets on the sides of the exhaust elbows. Find them all - they are in there somewhere.

I replaced a Pertonix ignition on my CC 327F with a DUI ignition and the improvement was amazing. Starts immediately. Just carry a spare module available from any parts store. Crab caps are getting very hard to find.