Maximum bore?
10-06-2014, 09:10 PM
#1
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Join Date: Oct 2014
Location: South Carolina
Posts: 3
Maximum bore?
I'm in the process of generating my M90 tune and am starting to think about internal engine modifications. My workshop manual specifies oversize pistons of .5mm (.020in) and 1.0mm (.040in). Has anyone installed larger pistons? Has anyone had their block sonic tested to determine the cylinder wall thickness with the stock 3.953 inch bore?
10-07-2014, 08:38 PM
#2
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Join Date: Oct 2014
Location: South Carolina
Posts: 3
SOHC V6 displacement increases?
I've reviewed all of the 4.0L V6 Technical Discussions threads back thru 2010 and didn't find one documenting an actual engine displacement increase - not even a .5 mm oversize piston. Hasn't anyone tried it?
10-09-2014, 12:17 AM
#3
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Join Date: Oct 2014
Location: South Carolina
Posts: 3
0.1777" cylinder wall thickness
An Australian member of the Explorer Forum just posted that he had his 1999 4.0L SOHC V6 block sonic tested and the minimum thickness of the front cylinder walls was 0.1777" near the lower portion of the water jacket. A German member of the forum posted that his machinist thinks that a wall thickness of 0.15" should be maintained. That means that a +.020" overbore would be safe but that a +.040" overbore would have overly thin walls.
Tom Morana told me some time ago that later block cylinder walls are thicker than the early ones. I think there was a block casting change in 2004. Possibly in anticipation of using the engine in Mustangs. If anyone knows the wall thickness of the Mustang block, posting it will be greatly appreciated.
Tom Morana told me some time ago that later block cylinder walls are thicker than the early ones. I think there was a block casting change in 2004. Possibly in anticipation of using the engine in Mustangs. If anyone knows the wall thickness of the Mustang block, posting it will be greatly appreciated.
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