deck height measurement

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Avispa

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deck height is the distance from the center of the crank to the top of the block, right? how is this measurement taken?
 
Deck clearance is from the top of the piston at top dead center to the top of the head mounting surface with no head gasket installed. A simple depth gauge on a flat beam long enough to bridge the cylinder with the heads off will measure it. Even an accurate metal ruler can give a close estimate. So a zero deck would mean the piston top is exactly even with the top of the block at TDC.

Right, deck height is the distance from the centerline of the main bearings to the block face on which the cylinder head mounts. That is designed in to the motor and can only be changed slightly by milling the block. I'd say a poor boy way to measue it would be with the crank in measure down to the rod mounting surface at TDC and BDC. The deck height would be the TDC measurment + [(TDC-BDC)/2].
 
Thanks, appreciate the info, so for a machine shop to machine the deck for deck height to make sure all pistons are in the holes at the same height, they would first have to make sure the decks were equidistant from the centerline of the crank, right?
 
I haven't seen it done but I highly doubt a machine shop would use a crank installed to take the measurement from cause a crank's throws aren't always perfectly what their spec'd at. I would assume they use a bar mounted in the main bearing bores and measure off that. You'd take what measurement you get and add half the diameter of the bar.
 
that makes sense, the bar diameter would be the same as the crank, or the could machine it down to half the diameter except for the main bearing area and take a direct measurment from that, I was just wondering about this since i haven't seen it done before or heard exactly how they did it.
 
http://www.bhjproducts.com/bhj_downloads/catalog/lo_res/BHJ_08Catalog_p06-08.pdf

BHJ Block tru

is what a machine shop needs to square the block....you need to supply the machine shop with crank stroke...rod length and compression height on pistons...

they can then figure out what your deck height needs to be...

1/2 the stroke plus rod and compression height of piston.....

take look at this machine...found it by goggly bhj block tru

http://www.arruzzahighperformance.com/Package/Machining.html
 
okay, thanks for the info, hope i wasn't the only one that didn't know how it's done 8)
 
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