Water pump weep hole.

[billwill]

I did put some sealant on my 'top-hat' before I pushed it into the recess in the front casing. In my case the top-hat was slightly too big in diameter and I had to scrape the aperture until I had a good fit.

It was a Burton style module in my case and I might have bought the wrong repair kit, but that 1 or 2 thou diameter was the only significant difference.

I've done about 6 or 7 waterpumps over the years since 1969.

[billwill]

Thanks billwill

There were 2 sealing o rings fitted, it just came off during disassembley. The old pump was slightly different design and I had trouble getting it off and had to get a friend with a press to press it off, and so parts got muddled. I followed the lotus manual but for some reason put the slinger in wrongly. (Brain fade). I'll clean up and try again.
You didn't say regards the slinger and seleant, when it's pushed into timing chest, it's a snug fit, however as you can see the alloy is a bit corroded.

Kev.

Too late for you this time, but these are my guides for dismantling, which is NOT the reverse of assembly for a change.

Disassembly of a water pump.
In this case it is NOT the reverse of assembly because there is nowhere to grip the impellor to pull it off .

So:

Use a 3-arm spider-type hub puller to pull off the pulley flange, Or make one from a thick disk or bar of steel that uses the existing holes in the flange. Apply the pulling force to the centre of the shaft, not the pump housing (or timing case front of an un modified Twin-Cam).

Remove the half-moon bearing securing clip if there is one.

Press the whole shaft out from front to rear, using a tube that is fractionally tinier than the bearing hole, so that it presses on the rim of the bearing. The whole shaft assembly will push out through the back of the casing. While pressing support the casing thoroughly you probably need a steel tube with an inner diameter a bit bigger than the impelloor, so that the force is evenly spread over the back surface of the module (or pump area of the timing case). It needs to be a bit longer than the bearing.

If the bearing is already knackered but not too knackered you can try pressing the shaft out from the front by pushing on the shaft. This will kill it as a useful bearing, so you will definitely need the repair kit.

If it is too knackered and you try that, the bearing will fall to bits, the shaft will come out, but you will still need the tube or a rod of the right diameter to push out the exterior shell of the bearing.

All the bits that come out that way are in the repair kit, so you don't need to dissemble the shaft assembly, unless you want to. To get the impellor off you need to make a strong disk just bigger than the dia of the impellor, with a U notch cut in it that fits the shaft, You can then slide the seal out of the way, slip on your disk and use the spider puller to pull the impellor off.


If the toroidal adaptor ring did not come out of the housing of its own accord, you can now pull it out with your fingers. It is a ring about 3 inch dia with two O-rings in its outer edge, It just needs cleaning and the O-rings replaced if they look poorly.

And then to reassemble (for carbon read ceramic):

First the bearing is pressed into the housing from the front, pressing the rim of the bearing, NOT the shaft. If present the half-moon clip is slid in to prevent the bearing from moving, not that it ever would with that tight fit.

Then clean and fit the big adaptor ring with two o-rings in the outer edge. Being O-rings it should not need any sealant, just a touch of grease. Check that you are about to fit it the correct way around by offering up the impellor to the ring. The vanes of the impellor are designed to skim over the surface on one of the sides.

Then the cup portion of the seal, (aluminium in the above photo) fits in a recess in the module using a small amount of sealant at the edges of the cup. The recess holds it relatively close to where the impellor will be. In front of that cup there is a gap before the bearing on the shaft in a chamber which accumulates any tiny amount of coolant that gets past the seal. The chamber has a drip drain hole at the bottom, which serves as the signal to you that the seal has failed. Make sure that it is cleared on your module, as I suspect that it may have been deliberately blocked.

The carbon disk is then slipped on with the shiny side resting against the rear-facing sprung part of the seal, then a tiny ring of sealant (you definitely do not want any to leak onto the shiny surface of the carbon) is applied and the impellor is pressed on ensuring that that the other end the force is taken by the centre of the shaft, not the module casing (because that would stress the bearing). Press the impellor with a hollow tool (such as a suitable box spanner which will just surround the shaft pressing near the centre of the impellor not out near its vanes. It is tempting to use that flat rear side and mostly that will work, but you might be unlucky and crack the cast iron impellor.

Press the impellor until a feeler gauge of the designated clearance will just slip under the rear edges of the impellor vanes. Don't go too far else you are b*gg*rr*d.

Make sure it all spins freely, then press the pulley flange onto the front of the shaft, making sure that the force at the other end is taken by the centre of the shaft, not by the impellor or anthing else.

[miked]

These kits have changed over quite recent years. The last 3 I have done have been the one you show with the nice turned top hat that you can press in nicely on its own. Then follow up with the next part (half of the mechanical seal) that pushes nicely in with the fingers as it is rubber to the metal.
The ones before had a thin tin type top hat fully assembled on that part of the mechanical seal. You had to be quite careful putting it in for fear of catching the seal. Whilst it did the job it was not as nice as this latest one IMO. I also noticed that you can't mix part from the two kits as the impeller is different in depth to cope with this latest seal arrangement being a little deeper. Just thought I would mention as I had two kits side by side last year and tried to use the opposite impeller as it was cast better. With correct feeler gap the pump was too tight on the mechanical seal. I reverted to its own kit impeller and all was well. Mike

[Wevster]

Cheers Billwill

This is my first twincam water pump hopefully correct the 2nd time around, and regards 1969 that's the year I was born!!
I've cleaned up and ready for refit. pictures are a dummy dry fit. Just waiting for new o-rings.

Thanks again

Kev.

[Hawksfield]

Kev

Thanks we now have a graphic procedure for replacing the Twin Cam water pump

Anyone in doubt can now be instructed


John

[elanman999]

Kev,
In your first pic, what's that ring you're holding. That's not an official part? The rubber covered seal in the second pic should go straight in the cast housing. It looks to me as if the casting is badly eaten away.
Or, if you are going to use that metal ring how are you going to seal it into the casting?
Cheers
John

[billwill]

I think that is the bit we have been calling the "top-hat" in this discussion, but looking at the photo the part here looks much too big.

You can see it in this picture of the repair kit from Burton; with the rubber portion of the seal on top of it (possibly fixed together & why elanman99 describes it as one part).



It should fit down into the front casting making a smooth receptacle for the back of the spring loaded rubber portion of the seal

The large size may be an optical illusion because in photos 2 & 3 it seems to have fitted properly into the recess.

Because the front casting is now so rough I think you will need sealant between the casting and the "top-hat" though that chamber should be dry(ish) since any coolant that gets past the seal will drip ot of the weephole. however you do not want that "top-hat" to spin.

[Hawksfield]

Bill

Here is a kit from Paul Matty which I think is the type used by Kev, the Burton kit is similar but the spring loaded seal part looks to be a single part and the black seal does not show the white ceramic section.

Hope this helps for future pump replacements


John

[qedmotorsport]

Hi guys, just to confirm what has already been said...

The metal spacer (or top hat as some of you call it) should ALWAYS be pressed into the cover first, by itself (not assembled with the sprung gland).

Just to clear up any misinformation, we are the supplier of this kit and as with 99% of the products we supply (that aren't made in-house), they are always UK sourced (obvious exceptions apply of course - Cometic head gaskets come from the USA etc.). In fact, the metal spacer is made here, as are the 'o' ring carriers and the new front covers we sell (we have them cast for us in the UK but they are machined right here).

[billwill]

Thank You.