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D8h-d8k (d342)
- Thread starter Pathull
- Start date
Nige
Senior Member
TC tractors is your man for a question like that. Send him a PM if he doesn't respond to this thread.
Brodiesel
Senior Member
According to my crankshaft book, there are 5 varieties of the crankshaft but they all have identical dimensions and interchangeable castings numbers. The only clear difference is the "VIN." The stroke, rods, mains, fillets, and thrust widths are all identical. Actually on one of the cranks it says the rod journal is 3.6240-3.6250" where as all the others say 3.6230-3.6250", but honestly I think thats a misprint. Definitely get a second opinion because I have ever even worked on one of these.
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tctractors
Senior Member
The 235 hp cranks and blocks are not able to be increased to 270hp as in the D8H if I recall the bearings are wider in the block on 235 hp engines, the D8K had 300hp from the start, this was first with the counterbore block, (the Non Spacer Plate engine) the Spacer plate engine uses the same component parts just with a lower block deck hight that allows the liners to sit on top of the cylinder block not in a counter bored hole, the spacer plate is just that! building up the deck hight to the standard spec, the crank will fit into both style of engines that are 300 hp rated, the issue with the early engines is also the rear crank seal area and the seal type. tctractors
p.s. The D342 was first fitted in to the 14A D8 (non Turbo) a common part that fits near all D8's with the short piston is the Pin holding the piston to the rod.
p.s. The D342 was first fitted in to the 14A D8 (non Turbo) a common part that fits near all D8's with the short piston is the Pin holding the piston to the rod.
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235Hp 46As used aluminum alloy main and rod bearings (thicker)...we did up HP to 270hp; just requires increasing rack travel and turbo change. Down side to increased HP, melts exhaust-to-turbo gasket manifold surfaces when operating under continuous high load, e.g. ripping for agricultural, grape vineyards. Cat did sale spacer plate cylinder blocks as a upgrade replacement.
Hey TC tractors, don't quite understand, I'll let you know what I want to do, I have 2 D342 engines one is an early one (230 hp) out of a D8H and one is a late one (300 hp) out of a D8K the D8H block is cracked but the crank is good and the D8k block is good but the crank is stuffed I want to pull the crank out of the D8H engine and put it in the D8K engine can it be done??
Cheers
Cheers
tctractors
Senior Member
Sorry for my slack response but I am rubbish at times, anyhow your 235 hp engine is from a direct drive tractor so could well have an early style rear crank seal, the last D8H direct drive tractors did have the 270hp engine in, but I do have a detailed list of why the 235 hp engine was found Not suitable to increase the HP up to the 270hp that was standard in the later D8H tractors, just twisting up the pump was not the Cat answer, I will print up more tomorrow from the script sent out by CAT on HP increase.
tctractors
tctractors
It looks to me like if you want 300 hp in an old D8, refit the motor with a 3406B and derate it, and lower the high idle to about 1500 rpm. Might have to do some machine work for an adapter plate, and some mounts.. I guess I see this all wrong. I just like to keep the old stuff running. would be neat though..
tctractors
Senior Member
Oldirt, the main issue would be the engine speed, the D342 in D8's runs between 1200 and 1350 ish rpm then through a drive divider torque converter set up so its low speed stuff, the 3406 pumps power out past 2'000 rpm this would not fit in well with the drive line, the D342 was an engine built near only to power a D8.
tctractors
tctractors
This should make it easy to work out- will a crankshaft Part number - 4M0447 fit into the D8K tractor with serial number 76V00670 I don't want to change any horsepowers around or anything stupid like that I just want to make one good D342 out of two bad ones!!! Cheers
tc.. I know the rpm difference, but was just thinking out loud. most truckers that still run that motor have them screwed up to well over 600 hp and routinely run down the road at much less than 1500 rpm. I meant that derating the motor to 300 and slowing it down would most likely not hurt anything and it would still work with the old tractor.
I just thought it would be an enjoyable project .. not necessarily cost effective.
I just thought it would be an enjoyable project .. not necessarily cost effective.
Answer: NO the 4M0447 crankshaft will not work because of the different rear seal!
230hp cylinder block 'I think' used a different rear main bearing cap, large square cap that required cocking rope to seal the oil at the sides of the cylinder block. I checked with local Cat dealer's old timer, he says you can't use the flywheel housing off of the 230hp on the 8k engine.
8K crankshaft? Re-grind to 0.025" or 0.050" undersized and oversize Outside Diameter bearings are also available 0.025".
tctractors
Senior Member
Engine Horsepower Increased
The flywheel H.P. was increased from 160 to 180 on the D7E's, also from 235 hp to 270 hp on the D8H Tractors and 583 Pipelayers, the following engine improvements were made to effect the H.P. increase, New Crankshafts with larger diameter main and rod bearing journals, separate crankshaft gears, piston type rear oil seal, longer main bearings for added support,new rod bearing that are .5" narrower and narrower connecting rods to accommodate the narrow rod bearings, stronger cylinder blocks which are stronger in the area of the main bearing saddle struts for additional crankshaft support, it is not considered economically feasible to adapt these engine improvements to earlier tractors.
this might help? tctractors
p.s. the changes start at D8H 36A 4649 D8H 46A 12885.
The flywheel H.P. was increased from 160 to 180 on the D7E's, also from 235 hp to 270 hp on the D8H Tractors and 583 Pipelayers, the following engine improvements were made to effect the H.P. increase, New Crankshafts with larger diameter main and rod bearing journals, separate crankshaft gears, piston type rear oil seal, longer main bearings for added support,new rod bearing that are .5" narrower and narrower connecting rods to accommodate the narrow rod bearings, stronger cylinder blocks which are stronger in the area of the main bearing saddle struts for additional crankshaft support, it is not considered economically feasible to adapt these engine improvements to earlier tractors.
this might help? tctractors
p.s. the changes start at D8H 36A 4649 D8H 46A 12885.
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Aust clearing
New Member
Can anyone help out I'm chasing a right hand sprocket and hub for a D8h 22a
Aust clearing
New Member
I can still get the gears and pinions but not the hub and sprocket new or second hand here