No compression at all in a 1934 Jowett

[Tony Fearn]

A friend has a problem with his 1934 car.
There's no compression at all.
It won't start, even though there's a spark at the points and the plugs.
The carb bowl is full of petrol.
It ran rather roughly for about 7 miles then died, never to start again.
Any suggestions as to what to look for?
I have a few ideas, but there may be one or more other causes.
A list of suggestions, in some sort of order would be most helpful.
Tony.

[AlanBartlett]

Hi Tony,

When was it last run? Before you went on your trip.
What does it turn over like on the handle? What were the plugs like?
Without sounding the alarm for worst case scenarios. A long shot could it be a head gasket failure, running rough and blowing by? Although wouldn't have thought it would cause it to die.

Certainly something to ponder. Give me a shout if I can help.

Alan

[BarryCambs]

My money would be on exhaust valves being stuck open with carbon and gunk on the stems if it has lost compression. It should be obvious if the valve covers are taken off and the tappets have opened up. If this is the case, you'll probably be able to free them off while dowsing the whole lot with oil. It would suggest it might be due for valves and guides to be replaced though if it is the problem

Barry

[Forumadmin]

This is where I would get my €12 endoscope and have a look inside the cylinder.
But without it .....slowly turn engine over and see if you can hear where compression is leaking towards. The crankcase, exhaust pipe or the carb. Or perhaps the radiator cap where bubbles will appear.
As suggested tappets should tell you if valve is stuck.

A good habit is to charge battery every 6 weeks to stop it deteriorating and also turn engine over..not starting as this will introduce water vapour to cylinders and exhaust. Better still take it for a 10 mile journey.

[nigel jarrett]

Is there a possibility that the timing chain has snapped or jumped a few teeth

[Tony Fearn]

Thank you all for your input.
I wondered if my friend had forgotten to replace the copper rings under the spark plugs, and perhaps not even tightened them when he'd checked the gap!
A more knowledgeable Jowetteer suggested that the tappet gap had disappeared, and that the valves were all open however slightly.
My friend telephoned yesterday and said that it was indeed the tappets that had lost their 2 thou clearance.
He reset them, and is surprised how well the car runs now.
Another salutary lesson.
Nevertheless, all the suggestions are valid, and should be put into our collective memory bank.
Cheers,
Tony.

[Forumadmin]

It would be wise to check again in a 100 miles. Also to check that compression is within specifications with a meter to make sure there is still a good valve seal. You do not want rapid deterioration of the seats.