Water Pump failure

[alan_thomas]

We have all heard of the saga of waper pump shaft gears failing due to 'soft' gear teeth. Some of you will recall I had the same problem recently. I have a selection of waterpumps from different TR7, Sprint and Stag engines and I compared the shafts. All but one had the spiral grooves continuing up past the gear teeth with the groove finishing in a rounded end. Just one had the grooves continuing past the teeth and then gradually shallowing to nothing.

Myfailed shaft was the odd one out. Doing some trawling thru the stagdigest.net archive I came across this posting

Re: water thrower for water pump
Posted by: kenhockey (IP Logged)
Date: May 07, 2007 09:39AM

I don't know if this helps, but the water pump shafts I have had trouble with seem to be the ones where that grooving above the drive gear tapers off - the ones where the grooves are the same depth all the way I have used with no drama, but no guarantee I suppose - I guess they were hardened in batches and that may be where the problems lie.

Interesting to see Ken reached the same conclusion.

So if you have to fit a new pumpshaft it would seem a good idea not to fit the shaft with the 'tapered grooves'

- Alan

[Sheepdip]

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Alan, had me really hopeful, had a look at my pumps tonight, unfortunately doesn't look like the logic applied. The failed one is on the left, the hopeful replacement on the right. That said I also fitted a new jackshaft and still undecided which chewed what.

[alan_thomas]

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Damm! another theory blown out of the water! I notice that the failed one is steel colour but all the shafts I have are like your one on the right they are 'blued'

- Alan

[StagnJag]

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Is this issue on SOCTFL's radar?

I think they should be thinking towards getting hold of samples of pumps and jackshafts and checking dimensional accuracy and metalurgical properties compared to the originals and reporting back to the club and the component manufacturers to find out where the faults lie. Or is it a design issue? Has there ben any advances in gear teeth technology in the last 30 years that might be able to help? These things wreck engines and cost us owners 000's from what I have read. (I haven't had this problem myself - yet:shock.

Just my penny's worth!

Rgds

Dave

[stustag]

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alan_thomas wrote:

Damm! another theory blown out of the water! I notice that the failed one is steel colour but all the shafts I have are like your one on the right they are 'blued'

- Alan

The one on the left hasn't been nitrided as far as I can see and therefore is softer than the one on the right!

It would be interesting to get the 2 shafts hardness checked to see what the differance is?

To me the one on the left has had a process (vital one)missed!

Stuart

[Ian B]

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Dave,

I agree with you, this is what we pay our membership fees for; in my opinion more money should be diverted in the direction of SOCTFL, as you point out parts such as the poor manufacture of water pumps / jack shafts etc etc can cost members thousands. the accounts show the club is running at a loss so the sooner more money is put towards parts such as above the better rather than continuing with the exorbitant cost of the Mag.

[Sheepdip]

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Interesting comments guys. I was really hoping Alan had a link here. Can't comment on the shaft hardness (I put the colour down to the use, the one on the left did 1700 miles, right 70k and I hope many more to come......).

I've bored the pants of many people hawking my bits around, I'm not looking for revenge, I just want to know what happened to make sure it doesn't happen again. One supplier thought the jackshaft teeth angle was incorrect, another said the hardness stamp (the numbers on the LH shaft) proved it had been tested and conformed - I hada certificate somewhere.

Re SOCTFL - I had a chat with Mike Allem and Kingpin on this a few months ago, suggesting the club should be interested asthere seemed to be quite a fewfailures costing us a lot of money.There wasn't any interest.......the only suggestion was to use proven parts.

[StagnJag]

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seems odd to me. Following the forum, I get the impression that the Jackshaft/waterpump issue is the single biggest concern for Stag Owners at the moment. Since I have been looking at the forum it has come up many times.

[stustag]

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Sheepdip wrote:

Interesting comments guys. I was really hoping Alan had a link here. Can't comment on the shaft hardness (I put the colour down to the use, the one on the left did 1700 miles, right 70k and I hope many more to come......).

I've bored the pants of many people hawking my bits around, I'm not looking for revenge, I just want to know what happened to make sure it doesn't happen again. One supplier thought the jackshaft teeth angle was incorrect, another said the hardness stamp (the numbers on the LH shaft) proved it had been tested and conformed - I hada certificate somewhere.

Re SOCTFL - I had a chat with Mike Allem and Kingpin on this a few months ago, suggesting the club should be interested asthere seemed to be quite a fewfailures costing us a lot of money.There wasn't any interest.......the only suggestion was to use proven parts.

Sheepdip if that stamp was to prove it had been hardness tested their having a laugh as you wouldn't be able to stamp it if it had been hardened!!!:shock:

Stuart

[DJT]

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Sheepdip wrote:

.......the only suggestion was to use proven parts.

Problem is, there are going to be fewer and fewer 'proven' parts around unless something is done :X:X

Dave

[Sheepdip]

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I can only believe what I'm told.....I don't like stating names as I don't think our suppliers are knowingly selling dodgy bits, but I do think our club should be acknowledging and investigating the problem.

Tell me if I'm wrong but this problem with the gears mangling seems to have occurred in 2 phases; 20 or so years ago and more recently, while I'd heard of it I thought it had been overcome. So why does it seem to be happening again now and whats the common factor?

New 12 vane Water pump and jackshaft purchased from one of the forum top suppliers, picked up at National day, Wales (4 years ago?). I only wanted a pump kit but let it go @ £60. The jackshaft was 'cause old one had chipped disi drive. Pump had a hardness certificate. Unfortunately I've mislaid it.

Perhaps naively I fitted new jackshaft and water pump with confidence.

I showed the mangled bits to one of our club top people. He noted the pump stamping and stated that after the problem a few years back, every new pump was hardness tested and certificated - his opinion the fault was elsewhere - and reckoned the jackshaft.

I've got over the seething stage, and just want to make sure it doesn't happen again - to myself or others.Its not just the cost, its the loss of confidence.

The problem is I still don't know what caused it.

[Andy Rundell]

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Sheepdip wrote:

Re SOCTFL - I had a chat with Mike Allem and Kingpin on this a few months ago, suggesting the club should be interested asthere seemed to be quite a fewfailures costing us a lot of money.There wasn't any interest.......the only suggestion was to use proven parts.

I thought that Water Pump Shaft manufacturehad already had SOCTFL support :?, it is even listed on the SOCTFL web page

[Sheepdip]

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You're right, just hada look andit does. I'll drop them a line and see what its about, it maybe the hardness testing carried out that I mentioned.

I must add tho that we keep talking about "the" club and "the SOCTFL", its not another organisation, its unpaid members who are doing the best for us - and need our support and participation. If the water pump saga really is becoming a problem and not just aselect few, we need to make our voices heard!

[x deputy coord Suffolk area & area writer& thus responsible for reducing new club mag by 10 pages :P]

[mad cyclist]

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Sheepdip wrote:

You're right, just hada look andit does. I'll drop them a line and see what its about, it maybe the hardness testing carried out that I mentioned.

I must add tho that we keep talking about "the" club and "the SOCTFL", its not another organisation, its unpaid members who are doing the best for us - and need our support and participation. If the water pump saga really is becoming a problem and not just aselect few, we need to make our voices heard!

[x deputy coord Suffolk area & area writer& thus responsible for reducing new club mag by 10 pages :P]

please see my thread about wter pumps and jackshafts and vote on the poll.

its part of getting heard i think

[Bob Heritage]

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I believe Tony Hart was involved with the pump shafts, probably worth trying to get hold of him and find out the whole story - we would all like to know.

Bob