Bent valve following hibernation

(wardell) #1

I’d just like a bit of confirmation before I start pulling things apart.
Following a 6 month winter hibernation during which my MK9 wasn’t started up, I squirted a couple of teaspoons of oil down the bores, left it a week an then turned the motor a few times by hand. The following week I spun the engine on the starter, but didn’t fire it up. Whilst it was spinning I heard a dozen or so loud clacks, rather like a loud spark discharge. It then went off. The words valve contact them sprang to mind.
I have done a compression check and find that one cylinder is down to only 100psi, all the rest are 150. The exhaust valve clearance on that cylinder is also exceptionally wide at 15 thou.
It looks like a head off job to me. As the head hasn’t been off for 30 years it may put up a bit of a fight, so I intend to drop the whole engine and gearbox out from underneath, and jack the body up do I can pull it clear, in order to make working on it easier. I also intend to clean up the engine bay, fit new power steering hoses and renew the clutch at the same time. Plus other unexpected jobs that will inevitably crop up.
I will post updates and photographs as and when.

(Paul Breen pay palled it) #2

Had same on my XJ6 but after 24 years “parked up” following “oily turnover” maintenance. I didn’t check the valve clearances but compresion was down on two cylinders. Tipping some petrol into the removed and upturned head (after cams removed) had it quickly leaking out of two exhaust valves onto the bench. Couldn’t expect much better after 24 years I expect - a long time for things to dry and stickt! Paul

1 Like
(wardell) #3

Yes valve bent, not much but bent. Also valve seats pitted and guides worn particularly the exhaust ones.

Need to find a machine shop that knows what they are doing
Got the head off with the engine in the car but I intend to drop the rest down to renew the clutch, gearbox oil seals, and clean up the engine bay.

(69 FHC ) #4

I’d suggest Coventry West. They did my engine, transmission and differential. The work is first class and the prices are reasonable.

(Paul M. Novak) #5

Wardell,
Where in the world are you located? Recommendations for a machine shop to do this cylinder head work will depend on what country and city you are in.

Paul

(wardell) #6

Hi Paul. I’m in York UK.

(wardell) #7

Thanks John. I like to do everything myself particularly when you hear other people’s horror stories.

(Geoff Allam) #8

I am guessing that you are planning to have a local machine shop do any required machining and then do all the reassembly yourself? If so it would be very informative if you started a thread describing your procedure and experiences. I for one would be very interested.