Hello all, I have recently lost compression in all four cylinders of my Austin seven ruby (just went suddenly). I have changed the head gasket and the compression was back, I went to start it 2 days later and there was no compression at all just gone again all of a sudden. When I replaced the gasket the values looked good and the pistons had little movement in the cylinders ie: a lot of movement indicates broken rings, what could it be. I would not think it could be the gasket because it was fine when I drove it in and if it did blow it would not be across all four. When the old gasket came off it had not blown just a little worn across 1&2 cylinders, I am now thinking it may be a strip down.(when engine hot there is compression there when engine cold no compression).

Location: Herne bay

Hi Harry, the first thing I would check, before doing anything else, is that the tappet settings are correct.

Ian Mc.

Location: Shropshire

When I replaced my head gasket I went through a number of tightening stages over 2 days, following an experienced A7 owner's advice, to ensure it was even and tight when hot. Just wondering if you just tightened cold and in the morning it had settled 'loose'? Perhaps too obvious but strange that you have no compression at all unless there just isn't a seal.
Andy B

Have you got no compression at all or just a drop, will it start? Has it been used regularly? Just short runs? I would think that if valve clearances were to tight compression would be the issue when hot rather than cold. My feeling is that stuck rings or valves are more likely to be to blame.

Location: Auckland NZ

Hello Ian, the compression has totally gone when the starting handle is engaged I can turn it with one finger where as before it was quite a job to turn it. The car will not start and no it is not used regularly and if it is only on short run's. I know it is bad for them to be standing about but my nan struggles to drive it these day's.

Harry,
This is almost certainly a valve problem. After a long periods of inactivity it is not uncommon for valve stems,and guides to become clogged preventing them from closing.
J

Location: As far east in Kent as you can get

My first guess would be sticking rings, but it could be valves.
It might be worth putting a few cc of engine oil into each cylinder through the plug hole. Allow it to settle and then crank it round on the starter with the plugs out (might make a mess).
Then with the plugs back in test for compression with the handle.
If valves or rings are leaking the oil should seal them.
If the compression returns and the car starts it might be worth giving it a good long run to get it thoroughly warmed.
If it starts there will be a lot of smoke as the oil burns off.

Hello Jim, I tried that before I changed the head gasket, it worked in 3&4 cylinders but not 1&2. I have not yet tried it again since I have changed the gasket. When me and my friend took the head off we both gave it a very good clean including the values ( did not take them out), which did not look to worn or damaged but I suppose it may have something to do with them.

From what you have now told us it has to be the rings, when you took the head off and wiggled the pistons about it was just enough movement to temporally free them. If you can get it started a dam good run may sort things out to an extent, however I strongly suspect that the valves will also need removing, the seats ground in and the valve stems/guides cleaned. In the good old days I would have suggested a decent dose of Redex might have also helped things, but I don't know if that is still available. How often is the engine oil changed and what type/grade are you using?

Edit, it may need towing to get it started again!

Location: Auckland NZ

The oil I am using is Castrol. The oil has not been changed for along time but when I get the car going it will be new plugs and certainly a oil changed.

You could try setting the pistons mid stroke and pouring a good dose of Automatic Transmission Fluid down each bore. Leave it for a day or so then crank the engine over with the plugs out to clear as much as possible. It may be a pig to start afterwards (tow if all else fails) and will smoke heavily when it does, but it will soon clear and it might just free the rings. The trans fluid should not harm the engine but you would be wise to then immediately change the oil.

Location: Auckland NZ

Unless you have tightened the block down .010 I cannot imagine anything which would lose all compression on all 4 cyls over 2 days. Oil around the rings may have assisted initially, but is not completely magic.
Please keep us advised of the outcome

Location: Auckland, NZ

I have posted this tip before but I think it is worth repeating-coca cola down the plugholes then replace plugs turn over a few times then leave overnight.This tip was given me by an ex-F1 man.I have unstuck a valve this way.If you have ever cleaned up old coins with coke you will know how potent it can be.No,I don't know whether diet or regular is best and of course "other brands are available".Surely worth a try before dismantling.m

Location: The pits,LeicesterI have post

Bob I have to say that I agree with you entirely.
Towards the end of last year I was asked to look at an Opal engine with exactly the same symptoms. When we removed the head five of the eight valves were stuck open!
The stems and guides were coated in what looked like brown sticky varnish which prevented them from closing. Admittedly the springs were very week which didn't help.
J

Location: As far east in Kent as you can get

Hello John, I have to say all the valves are fine, when me and my friend replaced the head gasket we both check that none of the valves were stuck. One turn the handle and you could see all the valves opening and closing with ease, and we both gave them a good clean on top and around.

Location: Herne bay

Oil round the rings might get enough compression to start the engine but it is use that might free stuck rings.
It sounds as if the car has been used very little and very gently. A good run driven with enthusiasm might well free things off.
In the 70s my local garage regularly had to 'tune' a very gently driven Jaguar. This consisted of a drive to the A1 then a high speed blast of about 30-50 miles. Owner delighted with the performance improvement!

You are right Jim, the car is very hardly used at all, the last time my nan used it the car had been standing for at least 5 months before!!!

Location: Herne bay

Mmmm!
Looks like we are back to the rings, but for all four cylinders to fail together is a bit of a coincidence!
J

Location: As far east in Kent as you can get

Try the ATF and report back

Location: Auckland NZ

Does this car sometimes get started, run for a minute, then left to stand again? I remember the VW Golf I was sent to help. While the owner was away his helpful friend started the engine every day, ran it for less than a minute and switched off. After a week of this cold running, the condensation in the bores had rusted the rings to the bores - engine seized solid. Even tow-starting would not free it.

Location: Far west of New Zealand

What you said it whizzes around on the starter motor but there is no go, from all the very useful information you all have gave me I think it is most probably the ring's, I will report back on what happens.

Location: Herne bay

Hello all, I thought I would let you know that I tried putting oil in all the cylinders trick today but, that did not make a difference at all, unlike the time before although when you turn the handle round once, at first there is compression but go to turn round the second time and it disappears, I might try the cola or the auto fluid next after I blast most of the oil out.

Diesel fuel is quite a good release agent too.

You say all the valves are free - have you checked the valve tappet clearances - should all be at least 6 thou.

Tony.

Sounds like things are getting desperate here. Could try old Norfolk trick -- put tennis balls in.

Location: Norfolk

Yesterday, I put some coke in all the cylinders and left over night. I went round to my nans today, blasted the coal out and put the plugs in. At first I was not convinced it work with only very little compression but the more I turn the engine over with the starter motor the more it built up. As I turned the handle I took off the oil filer cap and could hear a squirting noise coming from it, what does that indicate (pressure leaking passed the rings)? The car did start in the end and me and my granddad took it for a run and opened it up a bit.

Hello all, just thought I would let you know that my ruby has lost all its compression again, I think it must need new rings on all four cylinders. I am quite disappointed after it went so well yesterday but, that is the way it goes unfortunately.

Harry, Try the ATF leave it at least 24hrs, maybe even crank it over and repeat, then take it for a good long run.....at least 50 miles preferably more, a jaunt round the block will achieve little or nothing.

Location: Auckland NZ