Morris Minor Owners Club

Well I removed all the valves in the end to inspect, they seem fine. All valves put back in their original places (minus the dead one!) with new O-ring seals and a drop of oil for good measure. Of course all valves lapped in again.

I have been noticing a reluctance under load when cold. Mixture checked and spot on. Ignition timing I've left well alone, as I spent ages slowly retarding it a tiny bit at a time until the pinking dissapeared, and it seems to run well. I may invest in a new strobe light in the near future though, my brother drove over my last one!

Just given the car a run, thought I'd change the oil after so any crud would be in suspension instead of ready for the new oil!

New valve, shape of combustion chamber is more obvious here, very difficult to see on the other pic I agree!

The offending valve!

I wonder where the missing lump ended up - maybe it's rattling around inside your silencer?

bmcecosse wrote:chicken - This is 'supposed' to be a no doubt very expensive 'unleaded' head - which should take everything thrown at it!! No point buying such a head - and then taking it gently. -snip-.

true, but unless you re-build the head yourself and know what's gone into it, ye canny be sure if they put new valves in or just the old valves into unleaded hardened seats to save a few quid.

I still think with an old car its worth being a little mindful of its age.

While you were working on the head you could have radiased the point
of the 'Heart' shape to help flow.

If I paid good money for an 'unleaded' head - I would expect new valves. But if the history of the head is uncertain - wellll !
Willie - it takes a 'bit' more than that to increase the flow !!
My car is well over the 100k miles - it gets hammered everywhere it goes - can't be letting them modern cars give us a showing up!

Willie, I just wanted the car back on the road, the MOT ends tomorrow and I need to sort out some welding.

ChickenJohn, the car is always carefully warmed up and meticulously looked after (oil never gets far from max at all!) But i expect it to perform as my daily transport, I just hope I'm not asking too much.

I've adjusted the tappets twice, Once after the head was torqued down (just before midnight last night!!) and this morning thinking I must have missed one. There is a constant tappety clack thats worrying me. Do new valves do this? Or should I have changed all the old valves? All the pushrods, springs and valves were kept in order, I made sure of that. I find it a little worrying as it hasn't settled down after 20 or so miles.

Just think of it as the 'clickety whirr' of a well oiled machine !

Turns out I'd missed No.6 rocker! Teach me to check tappets at just gone midnight *slaps wrist*

Are you SURE that's an UNleaded head ? I don't see any sign of exhaust valve seats in there ?

Well before it was mine the car was my Father's and he payed for an unleaded head to be fitted. Whether it was a rip off I don't know! I'm not particularly bothered as a mate of mine has given me first refusal on a 12g940 (unleaded) from a metro hes breaking.

Oh yes - go for the 940 - it works very well. Spend some time on the valve throats - especially the exhaust - it's very restrictive and easily sorted! And just get the exhaust valves sunk into the head by 40 thou to get clearance from the block.

Also been offered an ital 1275! Complete with moggy front and rear engine plates and flywheel. The snag being its low compression and way up north.

Maybe BMC is interested?

His 'way up north' is probably no-where near far enough north in BRITAIN to be anywhere near me !

But then asking doesn't hurt

Unless I get a 1275 engine for about £5 - I will be sticking to my trusty and well modified 1098 for this year now! With redundancy threat hanging over me i'm in selling mode now - not buying mode!!

Unless I get a 1275 engine for about £5

Well that explains why you cant find one.

Another 'unleaded' head failure !!

the valve failed - not the seat, so hardly a failure due to VSR!
Judging by the burn shape of the valve, it has failed due to a material defect. Valves that burn from the edge creating a 'pie slice' void almost always have void that meets the edge of the valve smoother than your one. To me it looks more like a piece of the valve cracked out or it had an inclusion/hole in there to start with.

And just get the exhaust valves sunk into the head by 40 thou to get clearance from the block.

If you do that on an original 940 unleaded head you are going to end up with a non-unleaded head. Austin didn't use hard metal inserts - they just hardened the surface, so removing the surface is going back a step. Then you're back to using additive or waiting for the valves/seats to burn.
If it's a post-production unleaded head (ie one that has had hardened inserts) then you stand a chance with removing the 40thou.