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10-18-2017, 02:59 PM | #1 |
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Join Date: Jul 2016
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Modern Valves - cutting?
I’m beginning to assemble my A engine with the guidance from Les Andrews handbooks, and I have a question: when installing the modern valves, he instructs to cut the valve so there is only a 1/16 reveal below the keeper. What is the best way to cut the valve stem? Is this something I should have a machine shop do? Any advice is appreciated. Thanks!
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10-18-2017, 05:30 PM | #2 | |
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Re: Modern Valves - cutting?
Quote:
Take it to a machine shop and have them grind it to your specific dimension. |
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10-18-2017, 05:40 PM | #3 |
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Re: Modern Valves - cutting?
Consider when that book was published. I believe a lot has changed since then regarding modern valves. I have installed modern valves and all were different. Never had a reason to cut any of them.
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10-18-2017, 05:49 PM | #4 |
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Re: Modern Valves - cutting?
Don't do it! At least until you have demonstrated the need to do so. With your cam in place, determine if the recommended valve lash can be achieved by lifter adjustment. Then you can proceed either by lifter adjustment, valve stem grinding, or maybe a combination of both. The out come as to which path, is dictated by the choice of components.
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10-18-2017, 07:25 PM | #5 |
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Re: Modern Valves - cutting?
Have a machine shop do it.
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10-19-2017, 01:58 PM | #6 |
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Re: Modern Valves - cutting?
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Russ/40 has good advice here. However, if you do have valve stem 'cut', have you considered whether that same stem needs to be hardened, against wear, again ? |
10-19-2017, 03:52 PM | #7 |
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Re: Modern Valves - cutting?
1. magnaflux for cracks
2. replace guides 3. install seat rings as needed, then grind or cut seats 4. install camshaft and lifters, then valves At this point you can figure assembled spring height and see if but end works as is or if it needs to be shortened on the valve grinder. |
10-19-2017, 10:26 PM | #8 |
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Re: Modern Valves - cutting?
Thanks for all the good info, Gents. You all gave this rookie things to consider... I’m sure I’ll be back with more questions.
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10-20-2017, 07:47 AM | #9 | |
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Re: Modern Valves - cutting?
Quote:
Agree! (Only if necessary and then by a machine shop.) Good Day! |
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10-20-2017, 11:23 AM | #10 |
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Re: Modern Valves - cutting?
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10-21-2017, 01:38 AM | #11 |
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Re: Modern Valves - cutting?
Do not rely on Andrews' 1/16" number as the final measurement. That is .0625 as a reveal and is quite a bit to take up. Presumably you are using adjustable lifters. The proper clearance depends first on which "modern" valve is used and its length. Most important is to measure the deck height, ie, that is the distance from the pan rails to the top of the block. That will affect the clearance of the valve stem to the lifters. 1/16" from the keeper may or may not be right depending on whether some one in the past has shaved the deck, installed hard seats, how deep the seats are, etc. It is probable that the deck has been shaved--you need to know by how much. As noted, adjustable lifters leave some room for variations. Measure, measure, measure.
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