Water Pump Impeller Trick

tidester · 11-22-2004, 08:02 PM

I had the fun job of dropping the foot from a 1987 Mercruiser Alpha 1 this evening to check the water pump.* The impeller was totally chewed...

After cleaning it out and putting in the new gasket, base plate and cover gasket I needed to place the impeller in the new housing.

I tried soap and water, but it wouldn't go so I got out my secret weapon...* A tube of Krytox Grease.* This stuff doesn't harm rubber and is slick as greased snot.

Well, I rubbed a bit inside the pump housing and on the tips and end seals of the impeller.* My workbench attempts of trying to put the impeller in the housing looked sort of like a kid trying to put a cat in the toilet!* It just would keep popping out around the edges.* After a few frustrating minutes, I got a brainstorm of how to solve this little mechanical riddle.* I got out a 3/8" wide zip tie and used it on the impeller like a piston ring compressor.* I was able to easily fold the vane tips in the right direction and slide it into the housing.

I just thought it was a slick trick that I'd pass along to other do it yourselfers.

gd · 11-23-2004, 06:28 AM

Krytox grease huh, I know you didnt get that stuff at your local ace hardware, and I know how much it costs too. You wouldnt happen to work in the semiconductor buisness would you?

Sequoiha · 11-23-2004, 06:35 AM

You know if you would just put the impeller on the drive shaft, set the housing on the impeller and with light pressure push down on the housing and twist the drive shaft clockwise at the same time it will slide right on very easy, and now you know, and like GI Joe says Knowing is half the battle....

tidester · 11-23-2004, 11:04 AM

Not the semiconductor business, but I do work with oxygen and other high pressure / highly reactive gasses.

I tried sliding the pump housing over the shaft and impeller, but it kept cocking and binding.* I was very concerned about damaging new parts using that method.

modunlavy · 11-23-2004, 11:15 AM

Jeff,
I have seen where engines have overheated before because people used grease based lubes to install the water pump impellers...the grease can effect the ability of the pump to create adequate water flow....

Michael

paxfish · 11-23-2004, 12:12 PM

Interesting - Shipshape TV did one at the Mercury factory the other day, and they just used regular grease.

Also - did you find all the pieces of your old impeller?

Megabyte · 11-23-2004, 01:56 PM

Neat tip. If I remember correctly, Krytox is also used to lube the glass stoppers in labware so that they won't stick (and break).

Man... that was a long time ago!

WB2101 · 11-23-2004, 02:05 PM

I use Silicone Spray, on the impeller rubber and inside of the water pump housing. I also use waterproof grease on the drive shaft and key. Have not had a problem using my finger tips to fold the vanes in the correct direction, while putting on the pump housing.

tidester · 11-23-2004, 02:52 PM

I got at least 90% of the old pieces out...* The pieces were small, so before I fire the engine, I'll drain the coolant and see what's in the heat exchanger.

Mike,

Unless the impeller is made of fluorocarbon, the perfluorether based oil in the grease shouldn't hurt it.* The total amount I used was about the size of a pea.* We use this stuff on o-rings all the time, and after 15 years of service, the o-rings still look great.

By the way, how's the new career and home going?* Ballsy moves you have made in the last year.* I don't have the stones for that radical a change in my life anymore.

All,

Krytox is available in small amounts from Miller Stephenson chemicals.* A sample syringe (about 30 mL) can be had for a couple bucks.

Nauti Buoy · 11-23-2004, 05:39 PM

Have you ever tried a hose clamp?

scubadown · 11-23-2004, 06:13 PM

I work for NASA at the Kennedy Space Center and we use Krytox for oxygen and propellant systems. It is quite expensive but works great.

modunlavy · 11-23-2004, 06:37 PM

Jeff,
I have questioned my sanity moving 650 miles and back in a matter of 6 monthes....so has my wife!!

The new job is going great and I really love it. I miss Charleston too though and part of me wishes we could have lived there at least a few years. LCE was a really good company but they didn't seem too interested in what I did (and I had no interest in switching over to Reliability Engineering) so when the oppurtunity came up to get into the yacht business I just had to give it a shot! The yacht business has definately been a career change from manufacturing process controls and automation design.

Michael