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Old June 18th, 2020, 08:08 AM
BobBray BobBray is offline
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Join Date: Feb 2013
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Default Re: 401 vs 432 torque ratings???

I was excited about the new Ford 7.3L when I first heard about it and have been following it closely. It is the first gasoline engine designed primarily for commercial trucks in many many years and it's output figures are good all things considered. Have to say after seeing the 7.3L in person and having a good look at its internals I am not that impressed. It seems to borrow a lot from the GM LS engines, which is good, but other features look questionable. For instance, one of the features of the GMC V-6 was its wide cylinder bore centers. This allowed bores up to 5.125" (478) and still have plenty of water passage between the cylinders. It also provided for wider crank bearings and a lot of block deck surface for a good head gasket seal. The Ford 7.3L has a siamesed bore block and one of the thinnest deck areas between cylinders I have ever seen. In addition, Ford saw cut a cooling passage between the cylinders open to the deck, further compromising the head gasket sealing surface. The block coolant passages are largely open to the deck. I guess with current head gasket technology this will not be a problem in service but I suspect this block might be 'throw-away' come rebuild time and you probably shouldn't consider super- or turbo- charging it with any meaningful boost. No roller timing chain, the 7.3L gets by with old style silent chain and a plastic tensioner, and also has a small separate chain and sprocket driving a shaft turning a rear mount variable displacement oil pump that is actually part of a large aluminum cast windage tray. Really kind of clever but a lot of extra parts. Engine has variable cam timing, but it appears all VVT components are behind the timing cover, not accessible behind the water pump like an LS. Cylinder heads look pretty good port and valve angle wise, but do not appear to have much coolant flow through them. The head bolts are large and threaded deep into the block, but the block casting looks to be very light. The whole engine is only slightly larger than an LS. Overall, I might consider a 7.3L in a Super Duty pickup but I think I like the new GM L8T 6.6L direct injection gas V-8 better. It makes a little less power but I hear the fuel economy is better and you just can't beat an LS/LT for toughness and long life.
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