snap ring on water pump shaft

[Ken Heyman]

While it is preferable to have the snap ring on the end of the shaft(after changing the impeller), I have not done this as it has been impossible to get enough shaft to attach it without sliding the shaft out a bit. I've read previous posts on this subject and the suggestions include lubricating the shaft with dish washing soap and gingerly slide it out a bit. I am concerned that I may disengage the shaft which I have done B4 but would prefer not to repeat. How critical is the snap ring? Does the shaft slide forward and hit the cove plate. I haven't noticed any problem in three seasons.

Thanks,

Ken

[SteveLyle]

I don't see any practical need for it.  After messing around with the ring in my first year I haven't used it since (4 years).  Looks like a classic case of overengineering to me, or the manufacterer REALLY wanted to keep the impeller on the shaft prior to installing in the pump body.

Anyway, if it is critically important to snap ring the impeller on the shaft, you're not alone in running the risk.

Steve

[Ron Hill]

Ken : I ASSUME that you're talking about an Oberdoffer raw water cooling pump!?!?
If you are the shaft is 3.43 inches long and the male stud end that mates with the female inside the engine is .25 inches long.

I've always put the "C" clip on and install the shaft and impeller as a unit.  I do that as it's easier to get the impeller and the shaft out of the pump for inspection.  I look for cracks at the base of each impeller blade and lip seal wear on the shaft.
I gently take a long nose pliers and grab a blade near the center and pull the unit out.  Guess that it doesn't make any difference if the clip is on as I've never heard of the shaft moving forward and disengaging from the engine (in my 19 years of experience)!  

I ALWAYS lube the shaft and the pump face with waterproof grease (Bill Nuttall's Aqua Lube) to cut down the wear on the faceplate and the lip seal on the shaft.  The unit slides out easily.  I've written a number of Mainsheet Articles on this very topic.  

[Ken Heyman]

Thanks, I have a Sherwood Pump so perhaps therein lies the difference. I'll lubricate the unit before use. I have been using Vaseline but I will probably get longer life out of the components if I add some aqua lube as suggested. A petroleum based product probably is not ideal for the impeller.

appreciate the advice,

Ken

[Ron Hill]

Guys : Ken's question is the CLASSIC example of why you need to give all of the particulars, when you ask a question!! 

Ken : Here's what I'd do.  Take the shaft with out the impeller on and slide it in and engage the female slot in the engine, as far as it will go.  Then slide the impeller on to the shaft and see what kind of distance that you're talking about for "C" clip engagement.  Then you have to be the judge, but it shouldn't be too much if Sherwood has their s__t together!!
You still have to inspect the shaft for the 2 lip seal wear marks, blade cracks on the impeller and face wear on the inside of the  cover plate.  Then you have to decide if you want to use the "C" clip on the shaft or not.  Sherwood did have a problem on the M25XPB and M35B engines of the shaft being alittle short and needing a sleeve. 

BTW, all of the Oberdoffer parts are bronze/brass/stainless and do not rust.  In any case you may want to get a Globe impeller (from Defender) for your Sherwood.  That way you don't have to worry about petroleum based grease attaching your impeller.  I look at it this way, better a new impeller than wear on the inside face plate and loss of suction.  OUT!!