Tips on freeing up stuck D7 3T?

remove the exhuast manifold, rocker covers and air intake pipe. see if the valves are stuck if you can move em good get a large bore syringe and put a a couple of syringe fulls of diesel and oil mix down each cyl via the valve port.

wait a few days then gently rock the crank back and forwards. if you can pull the side cover give the journals a good squirt of lanolin spray too. oil thinned with diesel or kero would work too its just to lube things so your less likley to do damage.

if that dont work then yes it pull the heads add diesel and a block of wood and give each piston a few love taps and leave it for a day or 2. it takes a week or so top up the diesel each time.

lanolin spray? i have a product called fluid film that is high in lanolin. is this what you are talking about?

Thank you everyone. All great pointers. I use fluid film on my truck in the fall before the nasty salt sand of the winter. Never really thought to use it in more of a penetrating oil application but perhaps it works well? Neil, I will certainly get him to disengage the clutch as well.

Does anyone know the best way to manually turn these motors? My friend is getting all panicky over the thought of having to possibly pull the heads. I dunno. Can't be that bad on one or these dinosaurs. Perhaps could rig up a hoist off the sweeps? I'm any case I think it is well worth the work.

Hi Team,
suggest you first check you have no seized valves on the main engine--if none are found,then there should be a 4 bolt rectangular cover plate on the top of the main engine flywheel housing that has the timing pointer in under it.
Remove said cover and then the pointer and you should be able to judiciously pry on the ring gear teeth--try moving the flywheel back and forth to see if you can get any movement.
Report back your findings and we can go from there--could be the water pump is stuck too.
Cheers,
Eddie B.

If you put the starting engine gear box in low. engage starting pinion and clutch and turn starting engine crank by hand . this will put a large force on the crank .
Also I have freed many by pressurising the stuck cylinder with hydraulic oil.

lanolin spray? i have a product called fluid film that is high in lanolin. is this what you are talking about?

[quote="bursitis post=230432 userid=10813"]lanolin spray? i have a product called fluid film that is high in lanolin. is this what you are talking about?
 [/quote]
pretty much but fluid film is more of a heavy duty coating for protecting metal and timber parts during storage etc. the product i use most is called lanox and is more of a penertrating lube
there is several brands and some have different strength formulas for different jobs. with any of these sprays shake well before use as they do settle out.

i have heard of engines with stuck pistons freed using grease they made a cover plate to bolt over the cyl with a grease nipple in the middle and pumped it full of grease the standard grease gun will develop 10,000 psi.