Water pump leaking..help its driving me nuts..

[staginhiding]

I need some advice before I go mad..

I bought a so say fully reconditioned engine a few months back from a man who tells me he has built lots of Stag engines to a good standard.

Fitted the engine into the car,plumbed it up and filled with water to test for leaks..havent even started it at this point..
Water(lots of) ran down the Vee not even under pressure..It appeared to be coming from the pump overflow.
Took off the manifold, 12 vane pump,6 vane cover also bolts for cover too long.
Ok Ive changed a few of these pumps over the years albeit 20 years ago so fairly competent(I think)
Pump looked pretty new so put it back together,changed the cover and guess what it leaked..

Out again renewed top seal,refitted again and still leaking although not as much..but this is still without any pressure or the engine started..

Can water leak out of the overflow only if the seal that sits under the impeller is the problem.The underside of the impeller is flat and clean and looks newish.
Ive not heard of this but if I run the engine are things likely to settle down (wishful thinking on my part)

I have built Stag engines before although only using new pumps and not dismantling old ones,so am I missing something..is the only way out an LD parts mod..

Help would be appreciated Guys..

[StagnJag]

There is a core plug that often gets overlooked on the bottom of the inlet manifold, could it be that?

Rgds Dave

[elvimto]

This was my first pump rebuild, I removed all the bits and checked them also checked the shaft for straight and made sure that the area where the seal sits has no pitting or cuts, I did take a clean up cut on the back of the impeller then assembled. Did you remove the brass cage and replace the o rings on that.? I used a standard seal replacement kit no problems. I am not sure but can you mix covers i.e. 6 vane impeller to 12 cover and vice versa? Since you are dealing with an unknown it would be best to start from scratch and double check everything i.e pump clearance etc

good luck Stuart

[jakesmig]

Buy a replacement thats fitted to an RV8, they don't leak, often.

[new to this]

staginhiding

you can not mix 12 vane pumps with 6 vane covers, may be thats why it leaks

dave

[staginhiding]

Thanks Dave I did know that and have changed the cover,might not have explained that very well..QUOTE=new to this;181572]staginhiding

you can not mix 12 vane pumps with 6 vane covers, may be thats why it leaks

dave[/QUOTE]

[staginhiding]

Tried that Dave its definately coming from the pump overflow area,thanks

There is a core plug that often gets overlooked on the bottom of the inlet manifold, could it be that?

Rgds Dave

[elvimto]

Staginhiding

Did you remove the brass cage and replace the o rings on that.? or if you did you may have cut or nicked one going back in. worth a second look.

[staginhiding]

Yep,did all that,dont think I nicked one on the way back in but I guess its all going to have to come out again so will check..thanks

Staginhiding

Did you remove the brass cage and replace the o rings on that.? or if you did you may have cut or nicked one going back in. worth a second look.

[flying farmer]

The last pump I rebuilt leaked but only when running, and it is getting better with mileage.
However a pump that leaks when not running is a different matter. The only thing I can think of other than the O rings being damaged is that the impeller has been skimmed too much, and there is not enough travel left in the graphite seal to make contact with the impeller
Neil

[staginhiding]

Thanks Neil,all good advice..will check but the impeller looked fine to me..will take it all out again and check the rings..

The last pump I rebuilt leaked but only when running, and it is getting better with mileage.
However a pump that leaks when not running is a different matter. The only thing I can think of other than the O rings being damaged is that the impeller has been skimmed too much, and there is not enough travel left in the graphite seal to make contact with the impeller
Neil

[Motorcycle mad]

Hi
I recently rebuilt my stag engine, in so doing I overhauled the water pump and experienced the same problem that you are, I did exactly the same as you remove the pump etc but was unable to find the cause. I then looked at the problem again, and found that it was thermostat housing that was leaking, I had not correctly fitted the thermostat, it had dropped out of its location in the housing, and holding the cover off allowing a bad water leak, I correctly refitted thermostat and housing problem solved.

Ken

[staginhiding]

Thanks Ken,I had the same thought with that and the hoses,but have checked them and they all are dry..

Hi
I recently rebuilt my stag engine, in so doing I overhauled the water pump and experienced the same problem that you are, I did exactly the same as you remove the pump etc but was unable to find the cause. I then looked at the problem again, and found that it was thermostat housing that was leaking, I had not correctly fitted the thermostat, it had dropped out of its location in the housing, and holding the cover off allowing a bad water leak, I correctly refitted thermostat and housing problem solved.

Ken

[jbuckl]

Most potential items have been mentioned.

Brass cage orings can/should be fitted with rubber grease or vaseline (mineral grease not recommended)

A standard pump will seal of course, but Peter LD parts mod is worthwhile.

After I did his mod, I had water in the vee which was coming from hoses not sealed 100%

It didnt look like it was the hoses.

On another occasion the stat housing was the culprit as already posted by others.

Never had the manifold core plug leak yet.

Hope this helps.

Another 'pair of eyes' might help? (local)

Julian

P.S. LD parts also sell a leak detection kit....no connection etc

[staginhiding]

Thanks Julian,good tips.
I do have another pair of eyes in Julian near me and we are both scratching our heads..