JCB 3CII Engine seized- rebuild

[FOWLER MAN]

Hi David,
I haven't had much time to be on here recently so I have only just seen your thread.
Though it's years since I worked on these engines I have seen this all before, and though it's no help to you now, I think I can explain exactly what has happened to your engine.
The balancer unit is lubricated by oil delivered through the same drillings in the block as the No.1 and 2 main bearings. Oil pressure then forces this oil through the drillings in the crank shaft to the big ends.
When the Allen Headed dowel bolts came out of your balancer gear and the shaft slid out of its rear bush, there was no longer any resistance to the oil flow. The oil pressure was lost at this point and oil was dumped instead of being fed through the crank to the number 2 big end which was the first to suffer.
We always made a point of thoroughly cleaning the balancer gear dowel bolts with a suitable solvent and using "Locktite Studlock" on them.
As has been said it is quite possible for the crank to bend after seizing. This is caused by the extremes of localised heat generated during seizure.
Topkit's offer seems your best bet.
Good luck.
Fred

[Dave-OLW]

Have now stripped down the Head and find one of the valve guides broken, the new guide is loose fit. How can I fix this in?

Another question, The manual shows to set the timing of the Balancer Gears one dot on one and two on the other Balancer gear, neither of my balancer gears have any markings. Each gear has a large amount of metal on one side. Does anyone know how these should be set without the markers?

[Jeremy Rowland]

Have now stripped down the Head and find one of the valve guides broken, the new guide is loose fit. How can I fix this in?

Another question, The manual shows to set the timing of the Balancer Gears one dot on one and two on the other Balancer gear, neither of my balancer gears have any markings. Each gear has a large amount of metal on one side. Does anyone know how these should be set without the markers?

Dave my best suggestion to the valve guide would be to get an engineering company to make you an oversize one; I would not think it would be an issue for them to do this, you could also check and see if there are oversize guides available, you would need to ream the hole in the head where the oversize guide would fit anyway. I have never timed one of these engines but I am sure that somebody can help you with this issue.

Jeremy

[Dave-OLW]

On putting new liners in do I just use oil to lubricate as I push them in?
Someone suggested I use Hylomar BLUE sealer, but I think the seals should work without any additional sealer, there is no pitting.

David

[Mrsmackpaul]

There is a proper grease but I guess oil may work ok I wouldnt use any sealer maybe Vaseline as it wont perish the rubber O rings later

Stick the sleeves in the deep freeze over night and push the block out into the sun for a couple of hours should be able to push the sleeves in with the same style of thing as the puller you used to pull them out

No big hammers and if you must hammer use a block of wood to protect the sleeve

Im not trying to be a smart ass here just offering some advise good luck and keep us posted

Paul

[FOWLER MAN]

On putting new liners in do I just use oil to lubricate as I push them in?
Someone suggested I use Hylomar BLUE sealer, but I think the seals should work without any additional sealer, there is no pitting.

David

Hi David,
Oil is fine ,or if you prefer you could even use washing-up liquid.

More important is to check the "standing height " of the liners.
To do this make sure the liner seating's in the top of the block are clean and drop in the liners without their seals.
Push them firmly onto their seating's and carefully check the height of the liner above the block face with a straight-edge and feeler gauge. They should sit between .003" and .006" (thou.) above the block face. If any are low you need to insert shims under the liner lip to correct it. The shims come in three sizes, .003", .004" and .005"
The measurement is taken from the shoulder of the liner adjacent to the block face, not from its highest point.
These liners go in easily so if there is much resistance check the seals to be sure they are properly seated and not pinched.
Fred

[Dave-OLW]

Many thanks for the replies, I shall use oil then. I have the shims which came with the engine kit.

Another question, which gaskets do I need to use gasket sealant on, I know you do not use it on the Head gasket but what about water pump/sump/rocker? All the gasket surfaces look good.

Thanks David.

[Mrsmackpaul]

David I use what we call gasket goo out here I think its Permatex Aviation or some such thing I use it on almost everything O rings if they are on a mating surface the lot except head gaskets those I use copper spray

The only time I dont use gasket goo is if the manual says to use some other special thing


Paul

gasket goo



copper spray

[Dave-OLW]

Thought I would take out the suction strainer and clean whilst I had the oil drained, after unbolting the plate I could not find any strainer or where one should fit. See picture.
Did this 1972 model not have one?
In the Maintenance section of the service manual it shows one, but in the Hydraulics section and in the parts manual it does not show one.

David

[Dave-OLW]

Hi,
I want to run the engine in the workshop when reassembled, I still have the steering pump connected to engine do I need to remove it as it will not have any oil? or will be ok run with no oil?

Thanks David