water pump blues

[mickjo]

After reading reams of reports advice etc I thought I wouldget myStag waterpump overhauled, whata complete nightmare. Aftera full day stripping the carbs and the inlet manifold off. I removed the pump casing and it seems that someone previous had overhauled it very badly. So lucky me you'd say. It could of failed at anytime. The refitting basically is where I need advice.
The two smaller threads are stripped and cannot be torqued the 20lbs ft, so where do I gohere? Can I re-tap using an 8mm tapor is there a more appropriate alternative. also the Haynes manual and workshop manual confuse me with the gasket size,am I thinking that my feeler gauge measures0.015", then add 0.025" to make 0.040" in total,which is the 0.010+0.030 gaskets. Or is it 0.015 added 0.015" to make 0.030" in total, which is just the 0.030" gasket. As both points are critical I'm not going to do anything till I'm happy.
regards mickjo

[NickA]

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Whichthreads are stripped? Normally I wouldhelicoil them so you keep your original bolt size.

Waterpump cover should be fitted and gap measured, then add 10 to 25 thou to the measurement so if it measures 10 thou you used gaskets to shim the gap to between 20 and 35 thou. The clearance is quoted in the ROM as between 10 and 25 thou

Personnally I've always tended to err on the larger clearance.

[Stevekid1]

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Having carried this out three months ago with a retired mechanic I think I can throw some light on your second point. Hopefully you will get more in depth advice in the fullness of time.

You need to fit the cover with no gaskets and do the bolts up finger tight only. Then measure the gap between the block and the cover using feeler gauge. Loosen a bolt slightly if necessary so that the gap is even all round. To whatever this measurement is you then find a gasket to fill the gap. On top of this you then need to add gaskets to provide a further 0.25-0.5mm (0.010 to 0.025inch) which then provides the correct running clearance for the pump. We added a gasket to our measured gap of 0.020inch and touch wood mine seems to be running fine.

An important point that I learnt is that you must make sure the underside of the impellor is free of corrosion and runs flat and true. I was fortunate that I had a friend who is a tool maker and he made up a shaft to fit the impellor and put it on a lathe and machined it to within 1000th of an inch tolerance.

I did all mine because the first time I used the car I spotted water on the top of the vee. As you say a day stripping down and putting back together and all new gaskets later on everything, it was great for about two weeks. Three months on and there is water on top of the vee again which this time seems to be coming from the inlet manifold so no doubt i'll be stripping it all down again once the weather gets really bad.

Good luck, hope you get the bolts sorted.

[Sheepdip]

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Stevekid1 wrote:

An important point that I learnt is that you must make sure the underside of the impeller is free of corrosion and runs flat and true. I was fortunate that I had a friend who is a tool maker and he made up a shaft to fit the impeller and put it on a lathe and machined it to within 1000th of an inch tolerance.

Absolutely agree to skim impeller anyway.

Another thread suggested putting blue tack on top of impeller bolt then using a couple of larger gaskets, torque it down, undo then measure the thickness of blue tack - I like this idea as find it difficult to confidently measure the gap using feelers.

I've only tried removing manifold (instead of heads) once and found it adoddle, only thing is make sure the difficult bolts at front are put in first, I found the RH one very tricky.

NB - the bigger the clearance the better - a colleague disagrees, firmly believing pump efficiency and better cooling is down to close running between impeller and cover. I've kept to the book clearance, he goes 10 thou less. :shock:

[mickjo]

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Nick A. There are three bolts that hold the pump casing down, and its the two smaller bolts that have stripped the thread. I've used helicoils many years ago with limited success. I havent looked at UNF/UNC helicoils yet.Will lookonline today. Stevekid1, Another valid point you raise with the impellor which I will look at, makes me wonder about the state of the corrosion inside the casing itself. Its fairlybad. half of the lug is missing. I think I'll invest in a good replacement casing. Sheepdip. Its a good tip about the blue tack Ill try that and see how it goes.

Thanks chaps. mickjo

[mickjo]

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Well thanks for the advice and I manged to retap the holes with a 5/16th UNF helicoil which was painless and all seems well however I cant start the the ruddy car.I origionaly thought the fuel pump was not working properlybut, Iheard a rushing of liquid from the left handcarb with fuel spilling all over the top of the engine. I stopped and thought I might have re-piped it wrong. I've looked at rimmer bros web site and cannot find a good drawing to show where I've gone wrong here, is there a site where there is a drawing to show which hose goes where andmaybe tips on restarting after strip down.

[Sheepdip]

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You'll probably find its one of the carb float valves thats stuck open, they always cause trouble at some time. Best to fit two new items. Take the carb pedastal assy off, invert carbs, undo the float chambers (might need new gaskets) and the needle valves are in the corner, operated by float. Just change for new.

This wouldn't have stopped it starting tho unless totally flooded so need to look elsewhere

[mickjo]

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Hello, well finally got it going, traced the problem to the fuel, i.e. not enough of in the tank. Had put 10 litres in first, but had to put another 10 in to get it to go. Started eventually spluttering away. Lots of water leaks but sorted them out, the thermostat housing was the worst couldn't get a seal at first. Eventually took the thermostatout and sealed ok.(will try to refit it again later) Next job was the seized clutch, took three attempts but finally tried being a bit vicious with it and eventually it broke away. Sounds a bit rattley which is a bit disturbing.Will be fitting a oil pressure gauge as I'm not happy with the rattles. Lots of jobs to do so hopefully will bit a easier on the fingers than the water pump. Thanks for the advice.

[Sheepdip]

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Excellent - will never have too much fuel ina Stag......keep going before the snow sets in up there! Be careful with thermostat bolts as easy to strip those as well, but easier to get at.

Is the rattling coming from the clutch or engine? Does it go when clutch depressed clutch/gearbox)? Suggest treat this as a priority - it could be simple or a problem.

There are several places the engine can rattle from, the most notorious is worn camchain. If its a knock at startup probably the crank but if a tinny rattle that equally goes when oil light goes out could be worn timing chains and speaking from experience need looking at promptly.

Glad its going anyway.