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I am looking at a 65 roadster and in the description it says it has a "decked pad" can someone tell me what that means?
thanks mark #34050
thanks mark #34050
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Re: Decked Pad???
Hi Mark: The engine has had its cylinder block decked to flatten the head to block surfaces, it means, either it has no pad numbers or has been restamped.
jer -
Re: Decked Pad???
Mark------
That means that the short block had its top surface machined in order to true it up and return it to perfect flatness. If a block (or cylinder head) top surface is irregular or "warped" the head gaskets will not seal properly. Sometimes, though, block surfaces are decked routinely when they don't really need it.
In any event, when a block surface is machined by a machine shop, a rotary broach is usually used. Depending upon how deep of a "cut" is taken, the engine ID number and vehicle VIN derivative stamped on the engine pad which is located in front of the right side cylinder bank may be partially or completely removed. Also, the characteristic rotary broach marks will be left on the engine pad, whether or not the "numbers" are completely removed.In Appreciation of John HinckleyComment
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Re: Decked Pad???
Thanks William - one more question - other than re-stamping the pad what does that gain you? or is it something to be very concerned about?Comment
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Clinton VS Clark
Bitten by my own attempt , ( feeble ), at animosity the cookie monster strikes.
jerComment
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Re: Decked Pad???
Mark:
Block decking is normally a good idea if it has been measured for warpage, it insures a correct fit of the head to block and assures head gasket fit and prolongs their longevity if correctly done.
As far as the possible restamp you will fine volumes of opinion regarding restamps in the archives.
jer, AKA WilliamComment
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Re: Decked Pad???
Mark, If the stamp pad #s are gone then the only block #s to look at would be the left rear "casting number" and the right rear "casting date". These two numbers might help to tie down the 65 type motor. Ask the seller what these numbers are. You will also need the build date. Its on the trim plate under the glove compartment. This plate also has the exterior/interior codes.(next to the vin tag) None of this means a whole lot as far as owning a good driving Corvette. The numbers mean alot to the value of the car or if you want to have the car in a judging venue. Otherwise the basic cars' value should be on the lower end of 65s price scale.( this statement should be considered "general" because there are other condition points that should be weighed)Comment
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BROACH?
THIS decking tool is called a mill. Surely it isn't a broach! BUT what the heck do I know? It sure does leave circular milling marks.
Rev. Varooom!Comment
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Re: BROACH?
Dale-----
Why do you suppose that they call the marks often seen on the engine stamp pads "broach marks" and NOT "milling marks"?In Appreciation of John HinckleyComment
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Re: BROACH?
Because they were left by a machine that Cincinnatti Milling built and they named it a broach. The marks left by a vertical mill are called milling marks. But who gives a rat's ass what any of the marks are called. Circular doo-dads ain't right! Linear doo-dads are! The new 61-62 Judging Manual is purged of symantic bull#%*&! No reference to "broach marks" appears. This term has caused more confusion over the last fifteen years than Father's day here in Tennessee! GOOD RIDANCE! Have you never been in the middle of a "Broach Mark" fiasco on the judging field?
Varooooooooooooooooooooooooooooooom!Comment
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Re: Decked Pad???
I suppose you really want the RIGHT answer now!! If you are worried about the engine being up to NCRS grade then you will have to fix (restamp) it. The usual reason that a block is decked is to make sure the decks are the proper distance from the crank centerline. This would bring the pisons to top dead center LEVEL with the block. Because of casting discrepancies this did not happen too often. This is part of the "blueprinting" procedure, usually done by a machine shop. You will probably find other evidence of machine work if you the engine apart. It doesn't Always mean that the block was overheated.ie ran out of water. I hope this helpsComment
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