tr7triumph.com

Hi all,
Just refurbishing a 12 vane water pump and unfortunately cracked the impeller while trying to ease it off the shaft despite being as gentle as possible.
I have a spare used impeller which has a damaged blade and I am considering whether or not to use it. I am fairly sure that it will still flow sufficient water, but my concern relates to any potential imbalance that might manifest at higher revs due to the damaged blade.
Any advice would be greatly appreciated.
Thanks,
Rich.

Bin it, new ones can’t be all that hard to come by.

Hi Cobber, thanks for your reply. I can’t seem to find a source of new impellers anywhere over here, only new pumps at over £300 from all the usual Triumph part suppliers; hence my hope to use the spare used one.

They were readily available last time I looked, mind you that would’ve been a fair while ago.
The same part was used in Stags and Dolomites and someone may well correct me here but I think some of the old Saab99s too.
There were both 6 and 12 vane versions, I do seem to remember that there was bugger all difference in overall performance between the designs.
But maybe the supplies have dried up, it maybe time to bin that bloody awful design and go to an electric water pump, a bit of buggerising about but it will solve the problem once and for all.
If you were to look back and do a search though the old treads and posts here there was a bit about this.

Yeah, they went from 6 vane to 12 vane to increase water flow. Whether it did or not is a matter of speculation as engines still overheated most probably because older rads became more plugged up from sediment and owners not taking the step of power cleaning or recoring their radiators but blaming coolant flow instead. I remember Hasbeen saying his TR7 never overheating, I know mine never did, even in hot stop and go driving not moving the needle more than a needles width. Mind you it's a FI model, always giving the 14:1 intake ratio. The old rad leaked so got a recored one to replace it.

There has to be used impellors out there some where. Especially in the UK where they were in other models not found in N/A.

Be careful which water pump you purchase. There are some aftermarket ones with improperly hardened gears which will quickly ruin you jackshaft.

The pump cover is different for a 6 or 12 vane pump as well so you must change both parts if you upgrade you pump.

Edward Hamer
Petaluma CA

Thanks Cobber, FI Spyder, and HDRider for your thoughts.
Sources of impellers do seem to have dried up unfortunately. Both 6 and 12 vane complete pumps are readily available from specialist suppliers but the prices are ridiculously high.

If a decent pump impeller can be found then in might be a good candidate for 3D scanning, then that leaves open the possibility of 3D printing.

I like that idea.

I’ve often thought that a library of 3D scans of obsolete parts should be compiled

That would be good. Not sure if anyone on this forum has the required skills and kit.
Might have to resort to epoxy repair putty to get my pump up and running.

Repaired the impeller with epoxy repair putty and have reassembled the pump and housing with new bearing and seals etc. Will be refitting to the engine tomorrow.

Someone was selling new N/C machined aluminium impellers but I can't remember where I saw it.
It was one of the Dolomite Sprint engine specialists.

Might’ve been Sprintparts in Sydney, I don’t think that they’re still trading anymore

Cobber wrote:Might’ve been Sprintparts in Sydney, I don’t think that they’re still trading anymore

Think you are right Cobber, might well have been them.