Decking vintage engines

@wot · #1 03-08-2005, 01:14 AM

Probably a minor league question, but how do machine shops deck a block without touching the numbers? I may be doing a rebuild on my matching #s L78, and want to avoid a problem

**MosportGreen66** · #2 03-08-2005, 01:21 AM

I'm sure it varies from shop to shop but isn't it more or less standard procedure for a shop to ask their customers if they want the engine pad to remain intact during the decking?

**JRSully** · #3 03-08-2005, 04:36 AM

They use a special "Bridgeport" machine. Basically what is done is they us the standard decking/milling machine that does the circular motion. Once they get close to the end (stamp pad area), they stop that machine, draw a line where the head ends and the stamp pad begins. They mill the remainder of deck with that special Bridgeport machine that mills/decks in a straight line and they bring it right up to the line they scribed, leaving the original stamping/broaching intact.
make sure you have a guy that has done this before.! This what they did on my 70 L78. Good luck SULLY

P.J. · #4 03-20-2005, 04:38 AM

The machine for milling the block can be a bridge port or a horizontal milling machine. The tool that leaves the machineing marks on the block is a carbide fly cutter. that is a tool about 8 inches or larger in dia which serated to accept carbide inserts
that can be replaced as they dull. The carbide tips can be secured in the tool with a set screw. Then when the tool gets to the end of the scribed line the machine travell is then cross
fed to avoid the vin stamp.
hope that helps
suprss70

Keith Tedford · #5 03-20-2005, 06:07 AM

For a street driven engine, decking probably isn't needed unless the block is badly distorted. Perhaps I've just been lucky.

**WILMASBOYL78** · #6 03-20-2005, 06:34 AM

I agree with that thinking. Resurface heads and clean the deck of the block good. Use quality head gaskets and you shouldn't have a problem. I would be terrified the machinist would slip and remove the vin stamp and letter code. Not worth the risk!

wilma

**scuncio** · #7 03-20-2005, 07:37 PM

Have the deck surface checked regardless of whether you decide to cut it or not. Many BBCs I've come across have needed 0.015-0.020 cut to square them up.

**WILMASBOYL78** · #8 03-20-2005, 09:20 PM

Good advice!

wilma

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