coolant in combustion chamber

[John E.B.Goode]

Had this problem with water coming out of plug holes 1 and 8.
Had heads pressure tested and told they were ok. Had them reconditioned with new valves, seals etc.Head gaskets looked okay with no apparent failings.
I thought maybe I had broken through into water jacket when helicoiling for inlet manifold but presumably this would have been picked up on the pressure test.
I replaced inlet manifold thinking maybe there was a crack in that allowing water through that way.
Just reassembled everything but water still coming out of plugholes, now numbers 6, 7 and 8.
out of ideas now, anybody have any thoughts ?

TIA

John

[Lingen]

John.
This is probably the commonest problem with a Stag engine, and as it has got worse since you took the manifold off, I think it is still not sealing properly. There has been lots of good advice posted on the Forum about getting the gaskets to seal properly, so I think you are going to have to take it off, and go through all these checks before fitting it again.
Mike.

[John E.B.Goode]

Thanks Mike
I spent quite some time with a large flat file and wet n dry as advised to flatten the IM, it took quite a while, the faces were quite distorted.
It now doesn't leak when filled, is it possible that water is still leaking across 'internally' so to speak?
John

[StagJonno]

Similarly, had water in cylinders 6 & 8 when inlet manifold gasket let go. Now, whenever it's not run for a while, I spin the engine over with plugs out (and inertia switch pulled up) with some kitchen roll laying over the plug holes to provide witness traces. Don't want to try to compress water in a cylinder as could lead to bent conrod. Has the added benefit of getting oil on bearing surfaces before they're loaded up.

[flying farmer]

You might have flattened the obvious warp, but did you check the manifold was touching the heads all the way around.
If the manifold is tight at the top but not at the bottom the gaskets will not be compressed enough to stop the leaks, this was the problem on the first Stag engine I built.
Neil

[Phil S]

plasticine is good for this, it compresses and allows you to measure the thickness as it peels off easily, there is a special putty you can get but cant think of its name right now, also used for checking valve to piston clearances when building an engine.

[wilf]

Plastiguage?

[John E.B.Goode]

I've never used it but would engineer's blue work? I understand the principal

[dasadrew]

I had quite a lot of heartache getting a good seal on mine. Some of the story is told in "The Engine Thread" with pics. I didn't bother with engineers' blue that time - just a felt tipped pen.

At the outset I foolishly assumed that the gaskets - maybe with a dab of Hylomar - would do the job. Over a longer period including refitting after the heads had to come off again (different story) I got a good seal only by being absolutely meticulous - using a glass plate with wet-or-dry to get the manifold flat and square. During one episode I even found that a slight scratch was allowing water past. This I couldn't dress out, so I deepened it a bit and used metal filler.

I used different thicknesses of plastic shims (got a shed load of Plasticard left over after my model building days) to judge the gasket thicknesses and even ended up cutting my own gaskets. Finally I used STAG Wellseal. Although they'll probably start leaking as I type this now, the manifold is now so absolutely dry that dust gathers.

Whilst I appreciate that others have had success, mine was only reached with a fastidious attention to the mating surfaces, all bolts helicoiled so that even and proper torque could be applied, bolt hole "crater edges" flattened etc., etc.

Drew

[jbuckl]

I found waving 6 sets of spare gaskets in front of each mating face in one hand, whilst holding a skeleton gun with tiger seal in the other, was a necessary war dance before before attempting to commence battle. 12 helicoils & new bolts & washers are also a helpful arsenal too!

[John E.B.Goode]

The saga continues !
Tried filing and wet and dry with not complete success, got it down to no8 cylinder leaking but that was as good as it got.
Eventually took it to machine shop to have faces flatted, also IM pressure tested, all o.k.
Just refitted and now cylinders 5,6,7 and 8 blowing out coolant.
I've used Payen thick gaskets from LD with Hylomar blue to all surfaces, new helicoils all round and new bolts.
Clamped in place with scissor jack on block of wood, braced down from garage roof ( as seen elsewhere on here ) then torqued up.
I'm now thinking perhaps I should remove IM, loosen off head bolts, re-fit IM and then re-torque head down?
Any other thoughts or ideas, I'm ruuning out of things to try.
Heads have been completely rebuilt and pressure tested, engine has been out and new head gaskets fitted, so where is coolant coming from?
I am surprised that when the engine was out I gave the block a good flush through with clean water, at this stage when I try the latest fix with clean water only, the water is coming through rusty?
Rad has been flushed and pressure tested.

HELP!!!

[Lingen]

John. I may be repeating previous advice here, but are you sure the underside of the manifold is not butting up against the water pump cover? I have come across this on numerous occasions, and it is easily rectified with a rough file. It sounds as though you are going to have to try again, so if you aren't sure, drop the manifold in to place with no gaskets, and see if it can be made to rock about, and check that all the mating surfaces are fully in contact at once.
Apologies if you have already done so.
Mike.

[John E.B.Goode]

Don't apologise Mike, all advice gratefully received, but yes I did that and had to take off some material to clear the core plug boss.

[JeffW]

Hi John

This is very perplexing.

When I look back at my problems getting my inlet manifold to seal, when it did leak it always leaked into the V and not into the bores as it was not sealing on the head faces (obviously). However, you state that it is getting into cylinders 5,6,7 & 8, which from the attached diagram stolen from Grampian Stags site (thank you!), means the rear cylinders away from the rad and the ones underneath the heads that have the long slits for the coolant flow - in the attached photo of my V, the arrow at 1.

I am therefore puzzled as to how coolant could travel up from those slits into the bores. The other water jacket ports on cylinders 1,2, 3 & 4 are above the inlet holes in the heads so I could see how water leaking down would be drawn into the cylinders (arrow 2).

When you take off the manifold is there evidence that the coolant is travelling up into the bores from there? Is there coolant in the heads where there should only be fuel (arrow 3)?

If there isn't, then by process of elimination must this be something in the block, heads or as you stated earlier something amiss internally in the inlet manifold?

Sorry I can't be of more help!

Jeff

[trunt]

Hi John



I am therefore puzzled as to how coolant could travel up from those slits into the bores. The other water jacket ports on cylinders 1,2, 3 & 4 are above the inlet holes in the heads so I could see how water leaking down would be drawn into the cylinders (arrow 2).



Jeff

The water is under pressure and can flow upwards, plus the inlet is often under a depression so it will suck water in.