Author Topic: Valve guide reamer size?  (Read 779 times)

Offline sprint

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Valve guide reamer size?
« on: 18.06. 2014 12:55 »
What size reamer is required to do the phosphor bronze guides on a SR head, 63 RGS.

Exhaust valves are Hepolite V128's, don't know what inlets are but I assume that they are reamed to the same size?


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Offline wardleybob

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Re: Valve guide reamer size?
« Reply #1 on: 18.06. 2014 16:52 »
I'm sure there different sizes ? You need 2-3tho Clarence .
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Online muskrat

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Re: Valve guide reamer size?
« Reply #2 on: 18.06. 2014 21:44 »
I think your right Bob. In the book it says 0.310" for both but the new ex valve is 0.3095" to give a tad more clearance. 2 thou clearance max on the inlet will give 2 1/2 thou on the ex.
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Offline sprint

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Re: Valve guide reamer size?
« Reply #3 on: 18.06. 2014 23:04 »
Thanks for the replies.

A 5/16" reamer is 0.3125 which should give the right clearance of 2.5" to 3.0" thou? Assuming that you are referring to valve stem dia's of 0.3095 to 0.3100?
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Offline Briz

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Re: Valve guide reamer size?
« Reply #4 on: 18.06. 2014 23:21 »
Yep; 5/16" reamer works great. Which I'm pretty sure is what the factory intended.

Offline trevinoz

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Re: Valve guide reamer size?
« Reply #5 on: 19.06. 2014 00:35 »
Just for the record, bronze guides were only used in the alloy heads until some time during 1957. Iron guides were used thereafter and were also fitted to the early A50/65.
Whether it was to save money by using the same guides in all heads or some other reason, I guess we will never know.
I have iron guides in my alloy heads with no issues, except for the '54 head which needs new guides.
According to the parts book, the change was from CA7SS 4025 & CA10R 5603.


Trev.
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