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Valve guide knurling #766062 02/21/19 7:33 pm
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tomoil Offline OP
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Hi All
The AMCA Las Vegas chapter has an Arial Square four we're restoring, and I have the heads.
I looking at the valve guides, I see they have a spiral cut in them. would this be a form of knurling to tighten up the guides, or a stock item in particular to Arial's?
Cheers
Mike Head

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Re: Valve guide knurling [Re: tomoil] #766111 02/22/19 2:54 pm
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Adam M. Offline
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It's knurling and it doesn't last in the bike engine longer than 500 miles.
Somebody who didn't know did this misservice to the bike's engine.
You have to replace the guides or use guide inserts.

Re: Valve guide knurling [Re: tomoil] #766649 02/27/19 5:46 pm
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bodine031 Offline
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I must have done something wrong. I did a lite touchup on my valves and hit the seats with a nu-way cutter, then ran a .312 knurler through the guides. That was in 1996 on my 69 B-44s and its gone way more than 500 miles and runs great and does not smoke.

Re: Valve guide knurling [Re: tomoil] #766787 02/28/19 10:46 pm
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chaterlea25 Offline
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Hi All,
I think there is some confusion going on with the term "knurling" ????

Knurling a part usually done in a lathe presses a serrated wheel or wheels into the outer surface
The effect of this is to enlarge the outer diameter to a degree, or to put a pattern onto the likes of a screw on cap
Its sometimes used as a dodge or bodge to restore an interference fit between parts
(as in a loose valve guide) It is not a good engineering practice to repair a head / guide though

If you can see a spiral groove on the inside of a valve guide it can be the result of a spiral guide liner having being fitted
Those liners are sized by pressing accurately sized ball ended rods though them
I have not heard of the term "knurl" being used for those tools

The usual tools used to size valve guide bores are reamers (some USA people use the word "ream" instead of reamer) ???
or hones which have an abrasive stone to enlarge the bore to size and provide a good internal surface finish

Lost in translation or what???????

John


Re: Valve guide knurling [Re: tomoil] #766987 03/03/19 1:37 am
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tomoil Offline OP
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Hi all
Thanks for your reply's
I'm going to guess that it is knurling, or by whatever name.
Just by looking at what was done, I can only imagine the amount of oil allowed to weep through, and indeed even the intake side was coked and crusted with burnt oil.
Apparently it was a common practice back in the day, and no doubt there were a lot of smoking cars bikes running around.
So it's going to be new guides and perhaps seals as well.
Tom Oil

Re: Valve guide knurling [Re: tomoil] #767111 03/04/19 3:58 am
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Bigtwin Offline
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Hi, Tom!
While reading all of this, I would have to say that the observations are, by and large correct, and confusion always abounds when it comes to terminology. Depending just how "old school" the machinist was back in the day, several techniques were used, many having been developed working on Model T & A Fords (and other), sometimes rather "hammer-fisted"! More than likely, spiral guide liners were fitted by your description. Knurling the outer diameter of the guides was often employed on "loose " guides to tighten them up in the head... GEESH! A side note from the very dim dark past: I can remember having a set of new guides and tappet blocks "rifled" ( as in a gun barrel) by a local gunsmith on my Dragbike back in the day. The thought was to improve oiling and performance! I can't say it did or didn't improve oiling at this point, but I remember everything that was really fast smoked (alot) back then...anyway!. The debate about the necessity of valve seals continues to this day!

REgards!

Bigtwin


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