FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: GJCAT427 on November 13, 2012, 06:34:17 AM
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I`m looking for the demension of the head to tell if they are milled. The thumbprint is not reliable. I measured the distance from the headbolt to the deck on several sets as a guide but there all around.020 difference ave. A drawing would be a baseline to tell if they have been messed with.
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Check out this thread:
http://fepower.net/simplemachinesforum/index.php?topic=668.0
I ended up looking at the distance from the top of the head bolt holes to the deck to get an idea of whether the decks have been cut or not.
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That is where I measured and I seem to get the same demension 3.420+/-. The med riser heads I have don`t appear to have been cut , but the thumbprints on one heads don`t match what I would call normal. All the other heads I have are uncut but I just wanted to be sure on the medrisers as I dont know there history.
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Dave Shoe has some drawings, as does John V. I don't think I can re-send their info without permission.
I know that I would not rely on the bolt to deck dimension too much - we found similar fastener spotface locations must have been considered to be pretty non-critical and were very inconsistant on main caps when installing one of those girdle thingies.
These days I would check chamber volumes and sonic test the deck to get a feel for what you have. Those are the measurements that truly matter. I can understand the perceived value of "virgin" parts, but saying a head has never been decked is like saying a car has never seen rain. Ford decked every head during manufacture and did not consider it a religious excersize, and I wager that darn near every car got wet at least once sitting in the parking lot in Dearborn or on the transport truck or train. :)
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reference for demensions or start with a clean sheet ?
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I`m looking for the demension of the head to tell if they are milled. The thumbprint is not reliable. I measured the distance from the headbolt to the deck on several sets as a guide but there all around.020 difference ave. A drawing would be a baseline to tell if they have been messed with.
My understanding has always been: If the deck has been milled at a smaller shop, you should see circular or no mill marks. If it's factory untouched, straight broach lines will be present.