Water Pump Break-in

[arbs_53]

I'm hoping to have a new water pump waiting for me when I get home tonight, to replace the leaking one in the 250. I seem to have read somewhere that they need to be broken in before installing to ensure the seals seat properly. Anyone know if this fact or fallacy? If fact, what's the procedure? Thanks all.

 

[CaptRoy]

There is a little paragraph in the Moss TR3 catalog, by the water pumps, that says that the pump should be run for 1 min without water for break in.

First I ever heard of this...But I'm adding a new one to the engine I'm rebuilding so I'm interested in this also...

 

[martx-5]

Years ago, I used to rebuild water pumps. I've never heard of such a break-in procedure. Some of the really older pumps used to use the machined surface of the impeller for sealing against the spring loaded phenolic, but even then, if impeller was surfaced properly, there would be no need for a procedure akin to lapping valves. Most pumps today are assembled with a ceramic or sintered iron seal face, which is generally smoother then the machined cast iron surface.

When we rebuilt water pumps, we always vacuum tested the pumps after assembly. It didn't take more then a few seconds. I'm sure the pump manufacturers are doing the same.

If it makes you feel better, you can always spin up the pump dry by spinning the pulley up against the wire brush of a bench grinder. Just be careful, and don't spin it too fast. I personally wouldn't bother. Sounds like an urban myth.

 

[Alan_Myers]

Hi all,

Actually, this procedure is noted right in some of the Triumph factory service manuals.

You can either spin the pump dry for a minute or two with an electric drill before installing it, or wait until installed and run the engine briefly (30 sec. to 1 minute) without topping up the coolant level. This was done to seat the ceramic seal used in the older pumps. If this wasn't done, the coolant were topped up completely right away, it would prevent the seal properly forming and the pump would always seep a little coolant.

HOWEVER, I don't for certain know that a pump with this type seal was ever used in the 6-cyl. engined cars (TR250/5/6) AND I would be willing to bet all new pumps today (including rebuilds) use a more modern type seal that doesn't require this sort of break-in procedure.

Ask the vendor who sold you the pump, just to be sure. The last pump I bought (for TR4, new, high performance type with 6 curved impellor blades) came from British Frame and Engine and Ken Gillanders confirmed no break-in procedure was required. Can't speak to the other vendors, but I would gamble that VB's info is seriously out of date.

/ubbthreads/images/graemlins/cheers.gif

 

[Bugeye58]

There was a thread on this subject a while ago, and the consensus was that with the modern sealing used in current pumps, a dry break in was not only not required, but could be detrimental.
If I remember correctly, one of the participants was a rebuilder, and spoke at length on the subject.
Jeff

 

[Jon80spit]

Not an expert, but from my boating days, you always want to hand turn the pump in the correct direction to allign the rubber vanes on the impeller. This curves the vanes in the right direction. Failure to do this can cause some of them to snap off on first start up.