Deck Height Irregularities
11-13-2006, 06:31 AM
#1
Deck Height Irregularities Guys,
I知 finally getting around to final assembly and I was measuring deck heights today of my rebuilt short block. What I found is the passenger side is all about .016-.017 out of the hole (block was decked) but the driver side appears somewhat off. I知 measuring .018, .019, 020 and .022 from the front to the back with an average of .020 across that side. It just seems that this deck was cut at an angle .
Should I be a bit upset with my machinist or is this reasonable??
With the variance side to side (avg .004),, should I adjust gagket thickness?
Thanks!
I知 finally getting around to final assembly and I was measuring deck heights today of my rebuilt short block. What I found is the passenger side is all about .016-.017 out of the hole (block was decked) but the driver side appears somewhat off. I知 measuring .018, .019, 020 and .022 from the front to the back with an average of .020 across that side. It just seems that this deck was cut at an angle .
Should I be a bit upset with my machinist or is this reasonable??
With the variance side to side (avg .004),, should I adjust gagket thickness?
Thanks!
11-13-2006, 08:11 PM
#6
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I use a Block Pro CNC vertical mill to deck my LS blocks. The reference is off the crankshaft centerline. I find that almost all of the blocks are ~.004" lower in the front vs. the rear.
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11-14-2006, 12:01 AM
#8
decking Howard is right about all used blocks being shorter at the front. The decks are always twisted as well. They will be about .005" lower on the exhaust side of cylinder 1 but less on the intake side. Also, most all blocks I have checked are higher for some reason on the right bank. Same front to rear deck height variance.
New blocks I check are pretty close front to rear but not left bank to right. It is not clear why the blocks tend to sag at the front. Motor mounts may have something to do with this.
In any event, if your block was decked off the mains, it should be a lot closer side to side and front to back than what you have. Use the same piston and rod to check all four corners of the block. Wrap masking tape evenly around the ring land area of the piston until it just fits in the bore. Measure at several points around the piston and average your readings.
Steve
New blocks I check are pretty close front to rear but not left bank to right. It is not clear why the blocks tend to sag at the front. Motor mounts may have something to do with this.
In any event, if your block was decked off the mains, it should be a lot closer side to side and front to back than what you have. Use the same piston and rod to check all four corners of the block. Wrap masking tape evenly around the ring land area of the piston until it just fits in the bore. Measure at several points around the piston and average your readings.
Steve
Originally Posted by howard wolf
I use a Block Pro CNC vertical mill to deck my LS blocks. The reference is off the crankshaft centerline. I find that almost all of the blocks are ~.004" lower in the front vs. the rear.
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Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
11-14-2006, 12:12 AM
#9
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Originally Posted by Steve - Race Eng
Howard is right about all used blocks being shorter at the front. The decks are always twisted as well. They will be about .005" lower on the exhaust side of cylinder 1 but less on the intake side.
Steve
Steve
11-14-2006, 08:09 AM
#10
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Use the same piston and rod to check all four corners of the block. Wrap masking tape evenly around the ring land area of the piston until it just fits in the bore. Measure at several points around the piston and average your readings.
assembly, and/or the piston has rocked in the bore.