crack in cylinder head

[rayofleamington]

I expect the gas flow would suffer if the car was tuned to any extent

very true, but this effect on a 940 head would be minimal if it's used to replace a standard Minor head - the ports are better, compression higher and valves MUCH bigger to start with.

[bmcecosse]

In fact - one of the Mini tuners (not sure of name - not that well respected - Calver I think) did a trail about a year or so ago on this - and he claimed the power INCREASED when sinking the valves - he thought it might be something to do with shorter run into/out of the head - he did both inlet and exhaust, can't see why - only need to do exhaust. Personally - not convinced. When I have done this I always flushed off the chamber ceiling so the valves were not pocketed in any way and made sure the walls were slightly ground back to allow good flow around the valve head. Always worked well on my engines!

[Dru]

Thanks, all who have advised and helped . The replacement head (thank you, WPR678B) is now installed...

<a href="http://www.flickr.com/photos/belvedere/2909739933/" title="nearly there by Dru Marland, on Flickr"><img src="http://farm4.static.flickr.com/3157/290 ... b17b81.jpg" width="500" height="388" alt="nearly there" /></a>

...and the Trav is running like a sewing machine.

Well, actually, it's running like a Trav with a healthy engine. You know.

[WPR678B]

Excellent! Well done
A healthy Minor is a happy Minor

[bmcecosse]

Well done! Keep a weather eye on the exhaust valve clearances - I set at 15 thou to make SURE they won't close.

[Dru]

A useful idea. The outgoing exhaust valves were beyond redemption. Like, yurk

[bmcecosse]

Indeed - tighten the head down again after a good run (44 ft lbf) - and then reset the valve gaps - 12 thou is fine for inlets but exhausts should be 15 thou to allow for any expansion of the valve when it gets hot!