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Engine block design - Running rough - 09-09-2016
Cat c15, strong block, good deck height,(it means engine block has decent dept from where oil pan bolts on up to where it meets cylinder head, can take a longer conecting rod)rod ratio, rod ratio and engine deck height go hand in hand,the longer the deck height the longer a rod you can utilize when designing an engine,this is all fixed and predetermined on these heavy duty engines, isx- running similar bore and stroke to the cat but with a reduced deck height and shorter rods, shorter rods means the engine rods have more of an angle when in between bdc and tdc in relation to a longer rod where the crank is farther down in the engine block, sharper angles usually mean more liner side loading, perticulerliy on the power stroke, and also means the rod angle changes more rapidly at a given engine speed, meaning you have to be more precise with the isx on injection timing,shorter rod engines generally breath better and is probly one of the reasons why the isx still has the best engine brake in town, and also I believe the shorter rod engine takes less fuel to run at the same displacement which is why cummins is still in the game today while cat is not, cat-built like a brute but to inefficient by today's epa, isx- built to make the dealers money,
RE: Engine block design - schISM - 09-10-2016
Cat built one heck of an engine in the 3400 series(A,B,C all the way thru nxs). The last version, sdp, was a lesson in Rube Goldberg engineering. Still a good engine buried under the emissions garb but it put more than a few truckers in a financial bind.
I've got a bxs setting in the shop that I've been slowly building up. Had the block and head hot tanked and magnafluxed, the crank checked for straightness and micro polished and an adem III ecm for a 6nz conversion once it's all built. After seeing all the components apart and comparing the size of the crank for example with an isx its no wonder these engines can push 2500hp, they are stout.