The Classic Machinery Network

Folks,

I'm trying to remove the flywheel shroud & so must remove the flywheel itself, can anybody tell me if the large nut as shown in images need to twisted clockwise or anti-clockwise to loosen. I tried both ways with some considerable effort but no stir out of it.

If anyone can give me some tips on how to get the large nut off, i'd appreciate it greatly

Did a quick google, and the first result was a workshop manual, courtesy of David Cornwallis: http://www.davidcornwallis.com/uploads/LISTER_PETTER_T_SERIES_WORKSHOP_MANUAL_EDITION_12_MAY_2005.pdf The flywheel info is on page 54. The document doesn't allow copying, or I would have pasted the disassembly/assembly instructions, but you will probably want to download it anyway. I will say though that the assembly instructions include "Torque retaining nut to 475Nm (350 lb ft)" which may explain why it takes some removing . No mention of left hand thread though, so I would presume it's right hand.

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Best regards,
Kári.

Hi Sean,
The troublesome bolt and lock-tab securing the flywheel is a normal right hand thread. Though it has a big head the thread itself is 7/8" unf.
It should have been tightened to 300 ft. lbs., (that's over 400 Nm.), so it will be tight to undo.
I always used a single hexagon heavy duty socket and bar with extension tube to undo them, (I don't remember the size).
I know because the nut is so shallow it's difficult to stop the socket slipping off.
The flywheel is on a taper so you will probably have to make up a puller to get it off. If you can get the nut moving just undo it a couple of turns, enough to allow the flywheel to release off the taper.
Then get a stout plate cut and drilled to match up to the six threaded holes in the flywheel, you'll need some threaded bar to screw into these holes, (I think they are 7/16 unf.), and nuts to match.
Screw the threaded bars into the flywheel, put the drilled plate over them and use the nuts to tighten the plate evenly against the head of the flywheel bolt until the taper releases. Careful use of a hammer and or heat may help at this stage.

Good luck.
Fred

Thanks Kaos, Fowler Man for the info,
The only direction I could get a small bit of motion was in the clockwise which as you have pointed out would be tightening it even further. I couldn't get a budge turning it anti-clockwise. Its not the first time the nut was removed as there are large chisel marks on the nut, I'd say the previous owners did not have the correct sized socket & so used some brute force.

Is there any chance that I can cause damage to the crankshaft or something else by using the force required to remove ?

Hi,
I can see from your pics. that someone has attacked the bolt with a chisel.
Its not the first time I've seen that. On one occasion the bolt was so badly damaged that I had to weld a large nut to it to undo it.
You should be safe enough from doing any damage to the crank . Wedge a piece of wood between the crank and crankcase to stop it turning.
Fred

FOWLER MAN wrote:Hi,
I can see from your pics. that someone has attacked the bolt with a chisel.
Its not the first time I've seen that. On one occasion the bolt was so badly damaged that I had to weld a large nut to it to undo it.
You should be safe enough from doing any damage to the crank . Wedge a piece of wood between the crank and crankcase to stop it turning.
Fred

Great advice from Fred as per usual the only thing I would add is to make sure that the crankcase itself is also secure else you may find that you are turning the whole engine physically over with the socket and bar; if you have access to an old engineering tee slot table then secure it to that using tee bolts clamps etc.

Jeremy

Thanks Fred,

I remounted the engine onto the dumper first of all because we couldn't get the leverage by holding down by hand. I wedged the flywheel by putting a chisel through the blanking port on the left hand side as you look at the flywheel. I then put a 65mm socket on the nut with a pry bar which was pushed into a scaffold upright. So as you can see I'm using serious leverage, so much that I bent the face of the chisel.

So I tried to lock the flywheel at the opening above the starter motor with chisel again but again I believe I could have caused a crack along previous weld line. Have a look at the images please.

I tried to jog the nut off but no way will it move & I'm afraid I do serious damage given the level of force I'm using. I'll either have to call off the attempt or find some other way to lock the flywheel.

I'm toying with the idea to cut the nut off in sections as close the the thread but I don't know if you'd recommend that ? Is the nut interior thread where the red arrow is pointed at ?

Hi,
The threaded bolt behind the 65 mm head is approximately 22mm. diameter. It is imperial, 7/8 in. with a u.n.f. thread, The bolt head would also actually be imperial, may be 2.1/2 or 2.5/8 inches.
I would hesitate to cut away the head of the bolt as it will then be even more difficult to undo.
I think , if all else fails, and your socket wont grip the nut you would be better off welding a large nut to it say 30 mm or bigger.
If that was successful you could afterwards cut off the nut and, refurbish the bolt head and reuse it.
Fred

Good News,

Had another crack at loosening the nut & on first pull this time, I felt the nut open a touch, checked it & if had moved. I was delighted with that & now have the nut well loose. Then I had to make up a pullers to remove the flywheel using the "B" studs as described on the manual. So far its well tight to the shaft & I don't know if the flywheel will come off without some heat. Would you expect the flywheel to come out with the pullers only ?

Also what other surprises are in store before I can get the flywheel casing off ?

Thanks for all the advice thus far, it's very reassuring.

Try Giving the flywheel a good thump through the starter aperture, turn the engine and thump the opposite side a few times whilst tightening the puller.
Fred