Here are photos of my valve and valve seats. Showing that even thought the valve seat is below the surface of the chamber, it is by no means shrouded.












Here is a genuine Mk1 Cooper S Inlet Valve showing the seat they designed back in the early 60's, what I believe is the best flowing valve in a mini today.








Graham Russell

PS Thanks Mr Typer photo man

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"It's better to be not informed than ill-informed"

GR,
Great PicsThanks for posting.
A lot of good info in those shots

Dave

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pin holes in the seats?

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A good friend will come and bail you out of jail...but a true friend will be sitting next to you saying "Damn...that was fun!"

he uses pretty tough pins

just typical of the castings of the time & the quality of the camera used to take the pics

we`re using a CNC seat cutter these days,,, plug in the program with the profile that you want & hit the "Go" button i know it`s cheating but i`m over cutting seats for a living these days:-)

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Graham has a `Sunnen' machine for machining the head for valve seat inserts, he also uses it to machine these seat profiles dead true to the valve guides.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I thought it was always good practice to have the seat level with the chamber face?
Surely by 'sinking' it creates an interrupted flow and therefore diminished flow figures?

Mention was made of this and GR explains why he does it this way.

http://www.ausmini.com/forums/viewtopic ... c&start=45

Hi 1098
To answer your question yes it does alter the flow by making it better, by altering the top cut to different angles you can improve the flow but you may have to alter the angel before and after the 45 seat then you may have to alter the back of the valve to match the new seat then go to the dyno to see if it all works. THATS WHY WE USE A FLOWBENCH.
Now the area before and after the valve about .500 each side is the most important part of the intake track, this is about 30 to 35% of your total flow, a good petrol burning engine will use about 1.67 cubic feet of air to make 1HP so you can see every little bit you can pick up here will make a difference to the out come.
Now the NASCAR head boys use 55deg seats as these flow more the a 45 seat the down side to this is very rapid wear rate, but it only has to last 500 miles and they change the whole top end.
Graham Russell

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"It's better to be not informed than ill-informed"