It’s only a small leak, honest

[Saltire]

Thanks to cliff and Simon; that’s all very sound advice from folks who are much more experienced with the Elan than I am. In particular, that’s extremely useful and wise counsel on the head, because I would almost certainly have assumed it needs skimming. It’s my age showing again

I guess it’s a fine line between “if it ain’t broke, don’t fix it”, and preventive maintenance while you can. I’ll do a bit of planning a la Rambo over the weekend and take it from there.

Thanks again for the wise counsel; it’s much appreciated

[dapinky]

As far as getting the head skimmed goes, there is a tollerance for removal of material (16 thou), BUT, as Simon says, it isn't necessary as a matter of course........ it is very easy to go below the minimum deck height for the head (full measurements are in the WM, section EC, p30)...... it also shows you the ways/places to check for warp/twist and other deviations.

I tend to use a piece of plate glass which is known to be dead flat, and just place it on the workbench, and put the head on it.... by carefull observation,and a water spray, you can see if it is flat in all directions. (or at least, within tollerance).

It is very easy to remove far too much and make the head scrap, so if it needs it, just get enough taken off to get it back within tollerance, and not necessarily dead flat.

I would expect an engine of that mileage to be within tollerance, but if the head has corroded, it may need some work to renew its ability to seal to the new gasket (this is usually in the form of pitting or something more major arround the waterways). If that is the case, I would look for a specialist repairer (I know of a couple of places in Avonmouth if you don't have anyone nearer) who can clean out the 'hole', rebuild it with a lump of aluminium weld, then machine it back flat again - as such, the whole face can be repaired without any major material removal.

Hopefully none of that will be needed, and it will be a quick clean and refit.


As far as the rear mount goes, I have tried attaching the chassis end first, the engine end first, a bit of each, and have yet to find an 'easy' way (it's one of those jobs with pleanty of ways which won't work, and no obvious way that it will.... but then it just does!)

[Simon_P]

as far as getting the head skimmed goes, there is a tollerance for removal of material (16 thou),

Quite right Dave - I stand corrected!
I still wouldn't do it unless I absolutely had to.

Perhaps the rear mount is easy with a 2 post lift an d a nice workshop

[dapinky]

Simon,

I agree - always best to not do it.... but the first one I did I had no choice - it needed to be done when i bought the car, and the previous owner had been using it for a while with coolant use in the region of a litre a trip.....so he had been using water, not inhibitor/antifreeze to top up..... the aluminium was a real mess and the warp was outside of tollerance....... I only just managed to get it skimmed and it still had a slight warp, but we couldn't take any more off (machine was set to 12 thou) before it would be scrap.

Well, a nice 2-post lift and a workshop at least means you can swear at it in comfort! (but on a more realistic note, it also means that you can whip the prongeron off to get to it easier..... and the connections to altenator, starter and all the other awkward gubbins round the back).

[Saltire]

Monday's progress: I rechecked the cam timing yet again (all marks absolutely bang on), and then removed the head.

On the plus side, there's no sign of a crack in the exhaust manifold

In puzzling news, the head gasket appears OK (apart from a large lump of crud sticking to it), but three of the exhaust valves are stuck open and won't move

Head gasket

Stuck exhaust valves

The stuck valves are in cylinders 2 and 3, which would account for the lousy compression readings I got on those cylinders.

So now I'm really confused. I know how to free off the valves, although I'm mindful of Simon_P's warnings earlier, but it's something I've never seen in 50 years of tinkering with engines. What's caused those valves to stick?? I'd really like to understand what's behind the fault, rather than just reassemble and hope. It's unlikely to be something which has been developing gradually, because the engine was running as sweet as a nut after cambelt replacement and tuning.

And a final scary thought: will I be able to get replacement valves and associated parts?

I thought Isuzu engines were bulletproof . . .

[dapinky]

Jonathan,

Parts (valves) shouldn't be hard to find.

The reasons usually associated with stuck valves can be broken into 4 'common' problems (which aren't actually that common).

1) - Bent valve stem
2) - some crap stuck behind the valve head preventing closure
3) - Broken valve spring
4) - stuck (extended) hydraulic lifter

#2 can be checked with a careful inspection (but it should be obvious)

#3 may be visible, but may not

#1 & #4 will need some dismantling.

Firstly, remove the exhaust camshaft (noting the cap removal order) - as you slacken off the bearing caps, and the camlifts upwards, you may notice the valves closing..... this tends to indicate that the issue is with the lifter which is now moving upwards with the cam.

After that, with the cam out of the way, you need to feel if there is any movement in the lifters - and remove them.

You can then insect the springs for damage - and even push each valve open to see if there is any obvious sticky bits as it closes.

To check the actual valve stem you need to remove from the head, and roll it along a flat surface (kitchen worktop is good - if Mrs F isn't home!) - if it is bent, you will see the valve stem revolve in an oval plane - it should stay straight as the valve goes round in a big circle. You should be able to feel if the valve is sticking as you remove it anyway.....

It's one of those things that needs a logical approach, and there is no realistic way to guess the reason.

[Saltire]

Listen: if Pauline can plant her latest shrubs on my workbench, generously distributing potting compost around the toolbox as she goes, I reckon I’m entitled to roll my valves on her nice granite worktops

Your diagnosis is kind of what I’d figured, having sat down and though about it for a while with a glass of Montepulciano. I think 1 and 3 are probably a bit less likely in this instance, because three valves are simultaneously affected across two cylinders, which would be kind of unusual. My guess at the moment is what my aviating friends call FOD - foreign object damage. Or - as you say - crap behind the head. Bit depressing, though, after it was running so well

We’ll see tomorrow

[GeoffSmith]

Listen: if Pauline can plant her latest shrubs on my workbench, generously distributing potting compost around the toolbox as she goes, I reckon I’m entitled to roll my valves on her nice granite worktops

Would lilies be appropriate?

[Saltire]

I don’t suppose Lily would mind a bit

[dapinky]

I really hope that there is an awful lot of John Innes #3 spread around the garage......

..... because then you will be fully justified in utilising the kitchen dishwasher to give the head a really good clean.

I have to say that with 3 affected items, the FOD seems slightly less likely to be a physical block to the valve seating...... but I'd go for FOD getting into the hydraulic lifters and causing them to pump up too far and not drop back.....

.... but, as you say, we'll find out tomorrow!

[Saltire]

I tend to agree . . . Although where it could have come from is a mystery. I change oil and filter - with decent quality replacements - at least every year.

Perhaps some John Innes #3 has found its way in through the oil filler cap

[Mike Y]

I think you have been so unlucky after all the other excellent remedial work for this to happen. That's normally the sort of luck I have Better luck must be around the corner for you fingers crossed. Either that or you will have it back ready for the road in time for the second peak and lock down 2 .

[Rambo]

very bad luck. Just as the good weather is upon us

[Simon_P]

Not wishing to state the obvious , but some valves will be open while the cams are still in place. There doesn't appear to have been any contact on the valve in the photo - Could you post a picture of the whole head?

The exhaust manifold takes the whack when you ground the exhaust hence the cracks - did you spray it with water and let it dry to highlight the cracks?

All looks in good condition otherwise.

[Saltire]

Today's thrilling episode (and answering Simon's questions first):

Not wishing to state the obvious , but some valves will be open while the cams are still in place.

Correct, but I had removed the cams when the picture was taken. Also, in the case of one of the cylinders (C2, IIRC), one exhaust valve is open and one is shut

There doesn't appear to have been any contact on the valve in the photo - Could you post a picture of the whole head?

By contact, I'm assuming you mean valve to piston contact, Simon? There's none. The piston tops are in good condition with no contact marks and only very light carbon build-up. All fine

The exhaust manifold takes the whack when you ground the exhaust hence the cracks - did you spray it with water and let it dry to highlight the cracks?

Yes. Absolutely no sign of anything untoward <relief>


And in other news . . . . The head is stripped, and I now know what the problem is:

Cylinder head ready for stripping

More fun than Lego Technic!

Here's the gasket - no nasties between 2 and 3

Here's the evidence:

Valve showing rust 1

Valve showing rust 2

The three offending valves all have light rusting on the valve stem. It's not significant corrosion - you can scratch it off gently with your finger - but it was sufficient to cause the valves to be stuck pretty firmly in the head. I had to resort to a little gentle 'persuasion' to get them to slide out.

What I don't understand is why the valve stems should be rusted at all. I've not checked all of them carefully yet, but it's a puzzle.

Anyway, the good news is that the block and pistons are fine:

Top of the engine block - no damage apparent

The other ancilliaries are pretty good too:

Flywheel - not looking bad

Bellhousing looking good

BCN's short shift kit fitted and ready

So, tonight's job is to put together a parts list for the reassembly and sort out the bits to go for powder coating. While the engine is out, and everything's accessible, I'm considering getting the alternator and starter checked and refurbished. Does anyone have a recommendation as to where to send it please?

And finally . . . . thanks to everyone who has commented, emailed me, sent PM, and even phoned internationally to discuss and commiserate. While I was gutted when the fault showed up, I no longer feel I'd like to push the car off the nearest cliff, and I'm hopeful that it will be back to normal in time to enjoy some top-down motoring this year. Subject to the English weather, of course

[dapinky]

Jonathan,

I had assumed that the cam was out (otherwise the valves would be open in pairs) ........... but I still slapped myself around the head and thought "why did I not check that?"

However, my thoughts now are :-

If the head gasket has gone, coolant will be getting where it shouldn't - and if it has got into the combustion space, it may have gone up past the valve seats (whilst the engine is at rest, with valves open) - and then caused rust on the exposed valve stems.

The good news is that this indicates that the rubber valve stem seals are doing their job and not allowing oil to drip down the valve stems. (although it may have been better if they were leaking a little bit!!!!).

This isn't a definite thing, just a possible thought..... who knows where the water has come from (it can even just get in from the ambient air humidity).

Either way, it should all clean up okay....... and when the head is stripped, it is an ideal time to whack it in the dishwasher to make sure all the crud is out of the passageways

[Rambo]

However, my thoughts now are :-

If the head gasket has gone, coolant will be getting where it shouldn't - and if it has got into the combustion space, it may have gone up past the valve seats (whilst the engine is at rest, with valves open) - and then caused rust on the exposed valve stems

Those were my first thoughts too. Again, just a guess as the moisture has to have come from somewhere and I xan't think of another source.

Had the engine been standing long after the HGF Jonathan ?

[Saltire]

Had the engine been standing long after the HGF Jonathan ?

Less than two days. And I’m now inclined to think of it as “the HGF”, because none of the usual signs were apparent. I was only calling it HGF because of the poor compressions in adjacent cylinders. But we now know what caused that, and it wasn’t the gasket, which looks absolutely fine.

. . . when the head is stripped, it is an ideal time to whack it in the dishwasher to make sure all the crud is out of the passageways

Remind me to introduce you to Pauline next time we’re at Castle Combe together

[Saltire]

More good progress in the last couple of days:

Nice clean head

Valves being lapped in

Head surface checked and reassuringly flat

I was surprised to see that the valve guides are steel - I hadn’t expected that. Has anyone else found anything different on this engine?

Now awaiting parts from SJ and Kelvedon before the reassembly starts.

EDITED: Thanks to BCN for pointing out that I had written “valve seats” when I really meant “valve guides”. D’oh!

[Fredjohn]