Knackered rocker gear, and a tiny spring...

I'm running a '92 Fiesta with a 1.1 HCS engine, and was a bit late (by ~1500 miles) adjusting the valve clearances when I got round to it yesterday.

I think the car was telling me I was late: in the last week or two it has seemed to pull even less well than usual - it won't hit 70mph as early as normal on well-known roads, and doesn't seem to want to accelerate from 60mph on even the tiniest inclines. Also, when checking the oil a week or two ago the level had dropped to just below min, when it had been above 3/4 the previous week. I topped it up and it's been fine since - and I haven't found oil spots anywhere. On the plus side, the awful top-end rattle stayed the same as ever...

I had the lid off yesterday, and the first thing I noticed while turning the crank was that the no. 4 inlet valve spring was only being compressed about half as much as the others. I checked its clearance, and could have stuck my little finger in the gap, never mind the feeler gauge. I tightened it up (it took at least a full turn on the adjuster) and turned the crank twice and re-checked it, and again it needed re-tightening, but seemed okay on the third check. None of the others needed anything like that kind of adjustment, but while doing it I split one of the adjuster bolts.

While checking that there weren't bits of bolt left in the rocker box I found a tiny spring (the gf tells me I can keep her tweezers in the toolbox now...) - about 1mm in diameter and 3cm long (though it'd obviously snapped), and it tapered to a point at one end (not the snapped end) - any idea what that is? Does it explain the one valve clearance that'd gone mental?

I bolted it all back together (leaving only 7.5 adjuster bolts in there) and took it out for a couple of roundabouts on the dual carriageway. It was as noisy as ever (I can usually fool myself it's a little quieter after I've done the tappets), and seemed as gutless as in recent weeks. I'm coming to accept that it isn't going to last much longer, but does anyone have an idea what's going on?

Oh, and if someone can check their crystal ball and tell me whether it's going to give out with a bang on the motorway, or fizzle out in a more convenient way, that'd be great....

Reply to
Mick Brooks
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Knackered camshaft? Try checking the cam lobes for lift.

If the problem is due to cam wear, the engine is unlikely to expire suddenly. Mike.

Reply to
Mike G

I'm trying to think where I've seen a spiral spring like you've described and I'm buggered if I can! ISTR it looked like a small piston ring but made of spring material. Perhaps someone else will know what I'm talking about.

It might have been on some valve seals or something similar.

I think you should get the compression checked.

Si

Reply to
Mungo "two sheds" Toadfoot

In message , Mick Brooks writes

The camshafts are prone to wear on these engines. It sounds like yours is knackered. Its an engine out job to replace it so you'd better start putting a value on the car and figure out if its worth replacing. I can't think what the spring is. Could it be a piece of swarf which has fashioned itself into a coil or perhaps a helicoil insert?

Reply to
Paul Giverin

Hi Mike,

Thanks, but breaking rocker gear has been the peak of my DIY career, and I've no idea about how to do that. Could you give me some guidance?

That's good to know - I can take my time finding a new banger. And it will take a long time, especially if there are any hills between me and the seller...

Reply to
Michael Brooks

Hi Paul,

Worth replacing: The camshaft? No. The car? Yes. :-)

I don't think it was swarf, it really was a very fine spring - with something like 50 turns per inch, and tapered very nicely. It's natural state is fully closed, i.e. it can only be extended, not compressed, because each turn touches the next.

I've never seen a helicoil (only heard about them here) and imagined they were much bigger than this thing.

Reply to
Michael Brooks

Hi Si,

Thanks, I'll try this - if only for interest and the experience, but it'll have to wait till next weekend.

Are there any reasons why I shouldn't just pick up the the cheapest tester I can find?

Reply to
Michael Brooks

No, any one will do.

Have a look at this:

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..and this:

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I *think* the bands around the top of the valve seals might be springs like the one you have found. If they are, and I'm really guessing here, perhaps one of your seals has disintegrated causing the valve to flop about? An even bigger guess...if one of your valves is flopping about perhaps it's been hit on one side by the rocker and it's been bent a little? It sounds unlikely but I can't think of any other reason why you'd suddenly have a big gap appear unless the top of the valve has broken down.

Si

Reply to
Mungo "two sheds" Toadfoot

It does sound very much like the spring on an oil seal as Two Sheds suggested. Off the cam shaft seal?

Reply to
Taz

Are these engines OHC or OHV?

Si

Reply to
Mungo "two sheds" Toadfoot

OHV.

Reply to
SteveH

Fort so. In that case it's unlikely to be a bit of camshaft oil seal.

Si

Reply to
Mungo "two sheds" Toadfoot

Heathen.

It the holy sign should _never_ be abbreviated.

Reply to
SteveH

Heheheheh. Last time I saw push rods was in my Triumph 250, and I had to make them. Got to be part of the valve oil seal then.

Reply to
Taz

Ah, yes, clearer in the second picture - that looks like it could be it.

In fact, it reminds me of something I forgot to mention - there was something free to move up and down the valve stem on the exhaust of no.

  1. What's the diameter of the seals in your first picture? They look familiar. Heh - I didn't realise that was important.

I think this explains the spring, but can the exhaust valve seal disintegrating lead to a huge gap on the input valve?

Reply to
Michael Brooks

Offers the Trembling "Just ridden thirty miles on a C90" Handshake as appeasement.

Si

Reply to
Mungo "two sheds" Toadfoot

Yep. Valve stem seals.

They normally have (the ones I've seen anyway!) a tiny double coiled spring around the upper end of the valve stem.

If one of them broke, you'd end up with a spring about 30mm by 1mm long.

Pete.

Reply to
Pete Smith

They're valve stem size :) About 6mm internally.

No, but if one's gone then it's a fair bet that some of others have too. I don't know if valves can be bent in this situation, it's just a guess (you have to say stuff like that in newsgroups because there's always someone waiting to jump on you for saying something that might be wrong), but I suppose it's quite likely that it won't do them any good.

If you're feeling adventurous it's not a difficult job to replace the seals and/or valves, in fact I rather like doing them. No, I don't know why either.

Si

Reply to
Mungo "two sheds" Toadfoot

I'd love to try, but don't really have the tools or someone who knows what they're doing to stop me rounding every bolt in sight. I think I'll just start looking for something else.

It feels good to get to the bottom of it though, so thanks to all for your help.

Reply to
Michael Brooks

It is indeed the partial remains of a broken valve stem oil seal tension spring. The springs are close coiled extension springs with one end wound down in a spiral to a point. This male end then screws into the opposite non tapered female end of the spring to create a closed circle. This resulting circular spring fits over the top of the nitrile rubber stem seal to tension it against the valve stem and prevent oil leakage down the valve guide. What you have found is a few mm broken off the male end of the spring. The rest will be somewhere else in the engine. With broken and/or missing stem seals the oil consumption will be very high.

The valve clearance is due to extreme wear in the cam follower (tappet) which itself is the result of wear on the cam lobe. Strictly speaking it is not the cam lobe wear that creates the extra valve clearance because the cam lobes wear over the nose of the lobe and the valve clearance is set on the base circle of the lobe which does not wear as it is not actually in conctact with anything else. However extreme wear on the nose of the lobe wears out the follower too and this then does create extra valve clearance. The only cure is a new cam and all followers and a good engine flush and oil change. However the rest of the engine is likely to be in poor condition by this stage anyway and not worth fixing in an old vehicle.

-- Dave Baker - Puma Race Engines

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Reply to
Dave Baker

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