Head failure - Valve stretch?

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the bus driver
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Head failure - Valve stretch?

Post by the bus driver » Thu Jul 12, 2018 4:22 pm

Is it possible that my inlet valve is going through the seat or has the seat extensively worn in a short space of time?

The nut is completely wound out and I have previously added some shims below the rocker arm (I'm aware this is a bodge job but it has given given a couple of great weekends) to create more clearance but it seems every time when I check the clearance (approx 60 miles) the valve has come further out.
There's also a 40% combustion leak!

I'm going to pull the engine in the next few weeks but I'm curious about what's going on.. they were brand-new heads fitted in August LY

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vwJim
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Re: Head failure - Valve stretch?

Post by vwJim » Thu Jul 12, 2018 7:50 pm

If the head gets too hot the valve seat can fail. I've had the seats mushroom into the head before. Engine still ran. Got poor MPG but still drove okay.
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BJ1
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Re: Head failure - Valve stretch?

Post by BJ1 » Sun Jul 15, 2018 8:15 am

Hi Stephan! Pull the engine now mate and take the head off. Something is seriously wrong with either the valve or the seat. The valve will almost certainly fail very soon and trash the piston. 5 hours work would save the motor.
Brian
1966 Westy in Velvet Green - being restored
1967 Devon from Devon still in Devon
1967 Sundial from Idaho
1971 Westfalia from LA
1971 patina Delux from Montana now living in Germany
1972 Devon now owned by No 1 son!

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