Marks on Valve Stems
Thread Starter
TECH Enthusiast
Joined: Apr 2004
Posts: 749
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From: Chandler, Arizona
Marks on Valve Stems I'm about halfway into a cam swap. I'm using the Larry tool and the top dead center method for changing out the springs. I noticed some small dents/marks in the valve stems about .6" above the seal after taking off the springs on a couple of the valve stems. I don't know if I made these by tightening the Larry tool too far down or not. I'm thinking the retainer rotated into the valve stem, but that seems a little far fetched. Has anyone else noticed marks? I don't thing they'll affect anything, they are up far enough that they won't be going through the seal during a full stroke.
Thanks,
Glenn
Thanks,
Glenn
Thread Starter
TECH Enthusiast
Joined: Apr 2004
Posts: 749
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From: Chandler, Arizona
Thanks for the response. I came to the same conclusion. I did figure out what was happenining. The Larry Tool rotates so much when you tighten it down that the retainer contacts the valve stem. I modified the tool by bending it to a 20 degree angle so that when you tighten it down it's not at such a steep angle. Worked great, didn't get another mark. I got lucky because the marks are .600" above the valve seal and I have a .581" cam. The max stress in a valve is where the stem meets the poppet valve, plus this has been overdesigned to meet the higher temps in this area. So the area above the seal is pretty low stress compared to the material properties. I did take the one apart that had the biggest mark and smoothed it over just to remove the stress riser.
Thanks,
Glenn
Thanks,
Glenn
Staging Lane
Joined: Feb 2004
Posts: 66
Likes: 0
From: Houston, TX
I used the larry tool with no problems whatsoever!! Are the marks where the valve seal slides up and down on the valve? If you only notice the marks on the exaust valves, id suspect carbon build up caused it! Not the spring tool
Thread Starter
TECH Enthusiast
Joined: Apr 2004
Posts: 749
Likes: 0
From: Chandler, Arizona
The marks are .6" above the valve stem seal. I guess I was turning it down too far and the steep angle was forcing the retainer into the stem. I modified the tool by bending a 20 degree angle between the U section and the bolt hole. Worked like a champ, never got another mark on the stems.
Thanks,
Glenn
Thanks,
Glenn
