1.7 inch intake valves

A

acenewman

Member
Sending my block off to the machine shop. Considering increasing the intake valve size to 1.7 inches. Can anyone comment, do I need to fly cut the head for valve clearnce with the 1.7 intake valves? Thanks, Chris
 
For others that may read this:

I had a 1950's original Thomas 8.25 to 1 head it required extra room so that the edges of the 1.7 valves would clear the head.

Also the Lionhead III needs machine work according to what I read on Charlie Yapp's webpage.

The site talks about the newer Lionhead IV as already being machined for 1.7 valves. That was sometime ago so it might be good to check about the Lion Head IV.
 
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General info, per Benson, Wieand 7:1 head also needs to be opened up a bit for the 1.7 intakes. Plenty of material to do it.
 
acenewman said:
Sending my block off to the machine shop. Considering increasing the intake valve size to 1.7 inches. Can anyone comment, do I need to fly cut the head for valve clearnce with the 1.7 intake valves? Thanks, Chris
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If you are going to use the stock intake and carb, I think you are wasting your money, although it wont hurt. You might think about boring out the intake and running a B carb.
 
Couple comments:
Another advantage to using the 1.7" valves that has not been mentioned is that you are cutting the seat into new metal allowing the valve to rest higher in the combustion chamber. Depending on the valve set and cam you are using, it may eliminate shortening the valve stems.
I have used a few Snyder heads with the 1.7" valves and .330 and .340 lift cams and have not had any issues with valve clearance to the head.

The nicest working valve package I have used is supplied by AER (Antique Engine Rebuilding). The one piece guides allow for lengthened stem support and a truer centering valve in machining and operation over the two piece guides. I have found the solid guides from AER to be truer than the one piece slip fit and two piece split guides held in place by the valve springs. (My comments are based on results of performing compression checks and cylinder leak-down tests on all engines going out of my shop.)
Good Day!
 
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Dave in MN said:
Couple comments:
Another advantage to using the 1.7" valves that has not been mentioned is that you are cutting the seat into new metal allowing the valve to rest higher in the combustion chamber. Depending on the valve set and cam you are using, it may eliminate shortening the valve stems.
I have used a few Snyder heads with the 1.7" valves and .330 and .340 lift cams and have not had any issues with valve clearance to the head.

The nicest working valve package I have used is supplied by AER (Antique Engine Rebuilding). The one piece guides allow for lengthened stem support and a truer centering valve in machining and operation over the two piece guides. I have found the solid guides from AER to be truer than the one piece slip fit guides held in place by the valve springs. (My comments are based on results of performing compression checks and cylinder leak-down tests on all engines going out of my shop.)
Good Day!
Click to expand...

I agree!
 
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