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I have a E31 head that I am considering haveing modified to put the larger 280 valves in. I have heard that if I do this and place the head on my L24 that I will have to have the block notched to accomadate the larger intake valve. Is this correct? Any other sugestions?
 

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RE: E31 head & 280 valves - Notched block?<

It's a DIY project. I found the block on my L24 "nicked" by the valves after the head was installed by the previous owner. Some grease in the cylinder bore, and a die grinder/stone and it was done! Didn't pull the engine or nuthin'! Valves were still straight in my case, but I assume it could cause real problems. "An ounce of prevention is worth a pound of cure!" Good luck!
 

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go to zhome.com. i think carl beck just put up an article on heads that says the valves will only hit if the cylinders are stock. if you have any kind of overbore you're ok.
 

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What would overbore have to do with it? The height of the piston top at TDC would be the same unless you used dished pistons or shorter conn rods.
 

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my understanding is that the valves actually touch the block with this modification and not the pistons. once the block is overbored, the diameter of the opening is increased, and the valve no longer touches the block when it opens. touching a piston would seem to me to occur only when timing is way off or if your using a monster cam.
 

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Legal Z got it!

YES!!! The valves in my example BARELY nicked the top of stock cylinders, and if it was overbored .060", I don't think they would've hit. I relieved out to the gasket fire ring, and down to .030" above the top ring's upper limit of travel. (Unshrouding the valve to the max, EH?)
 
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