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Hi all,
I am just getting the parts together to rebuild the top end of my 27 J. I plan on using new valves, guides and valve springs for intake and exhaust - among a long list of other new parts.
I am uncertain about though about re using the intake valve housing. First the two housings look very slightly different - see the posted pictures.
One is flat across the top, the other seems to be a made up of three levels. When measured from the valve seat aperture they are, however, both the same height.
One looks to be lighter overall construction but again the essential dimensions are identical and both fit into the cylinders I plan on using. The guide threads and valve seats look in very good condition in both to my eye.
All of the other housings I have seen in pictures seem to be of the flat topped variety and I wondered whether this was a later or earlier factory variation?
I cannot think of any reason why the cylinders would have been fitted with these different types as standard when the motor was new but one or other may well have been replaced during its working life.
I'm just intrigued to know whether anybody else has come across this different type and knows when or why it was introduced?
And also whether there is any reason why I should not use them in my motor. I'd like to keep as many of the original parts as possible but not at the expense of compromising the engines performance
Thank
Martin
I am just getting the parts together to rebuild the top end of my 27 J. I plan on using new valves, guides and valve springs for intake and exhaust - among a long list of other new parts.
I am uncertain about though about re using the intake valve housing. First the two housings look very slightly different - see the posted pictures.
One is flat across the top, the other seems to be a made up of three levels. When measured from the valve seat aperture they are, however, both the same height.
One looks to be lighter overall construction but again the essential dimensions are identical and both fit into the cylinders I plan on using. The guide threads and valve seats look in very good condition in both to my eye.
All of the other housings I have seen in pictures seem to be of the flat topped variety and I wondered whether this was a later or earlier factory variation?
I cannot think of any reason why the cylinders would have been fitted with these different types as standard when the motor was new but one or other may well have been replaced during its working life.
I'm just intrigued to know whether anybody else has come across this different type and knows when or why it was introduced?
And also whether there is any reason why I should not use them in my motor. I'd like to keep as many of the original parts as possible but not at the expense of compromising the engines performance
Thank
Martin
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