BMC 3/42 2.8 JCB issues

[NickH]

Hi all,

The engine in my 2BII is playimg up and I'm struggling to work out what it is. Basically it's running okayish, but loses power and cuts out under load and then is sluggish and 'tight' when attempting to restart - turning over slowly until it builds up momentum to start. (normally is no problem to start, even in cold weather)

when I do get it started, it runs reasonably well, buts sounds harsh at higher revs.

In addition to white sludge appearing on the underside of the rocker cover, the smoke seems whiter and it won't idle at low revs.

I started thinking head-gasket, but don't know these engines well enough to be sure. Any ideas/advice welcome.

Nick

[Jeremy Rowland]

Hi Nick is it pressurizing the cooling system? That would be a sign of a blown head gasket, the white sludge under the rocker cover can be found on BMC engines and just shows that condensation caused by heat has emulsified with the oil in the rocker cover.
If the engine is tight to turn over are you sure that the engine hasn't suffered from a partial heat seizure because that could account for the white smoke, other areas to look at are the radiator (that coolant flows through it) and that it is not so dirty that the fan cannot draw cold air through its matrix, also check the thermostat for correct operation.
Hope that at least gives you some leads.

Jeremy

[philwheelton]

The 3 cylinder engines are the same as the 4s when it comes to liners and head gaskets, you should try a pressure test on the cooling system.

[NickH]

Thanks, Will look into cooling system. One this I did notice was that all of a sudden the water is the rad is full of sludgey material - when it had always been clean before.

Also the rocker shaft and top of the head is really fouled up around where the oil feed pipe attaches. Is this normal on these olde engines?

N

[NickH]

Okay,

I checked and flushed the cooling system - all seems okay

Flushed the engine and replaced the filter and oil. During the flushing process, a knock started, then disappeared, and has now come back. I have uploaded a video of the engine running in which you can here the knock, which seems to come in on a cycle and is worse at high revs - feels like something is banging around in the engine. Link is below. Any suggestions people?
[url]
https://www.youtube.com/watch?v=loRaL7lKb6U [/url]

Thanks

Nick

[martyn williams]

Are you tappets set correctly ? check your oil pressure.Sludge on the rockers is a sign that your machine has not been well looked after in the past, lack of oil and filter changes leading to excessive engine wear.Any bubbles in the radiator ? possible head gasket. Sound like the engine may be due an overhaul. Piston slap ?
Excessive breathing from the rocker cover pipe. Sometimes you may get a diesel knock , crack of injector pipes one at a time if you can.Its only a 3 cylinder so it may cut out.
Let us know how you get on
Martyn

[FOWLER MAN]

Hi Nick,
Having seen and listened to your video, I'm inclined to think, as Jeremy suggested, that your engine has suffered a partial heat seizure.
I'm sure I can hear piston slap, and the way the engine is breathing there must be tremendous blow-by.
I think you'll find at least one piston with broken rings.
A bit of a top ring may even have worked it's way onto the piston crown and be tapping the head.
If the original over-heating problem was caused by a head gasket, at east you will be renewing it in the course of sorting a piston problem. Don't forget to check the height of the liners in the block.
I hope you find a simpler solution, but at least the engines are pretty easy to work on.
Fred

[NickH]

Thanks both. Sounds like what I feared, but at least it'll give me a chance to sort the machine properly.

Will let you know how it goes.

Nick

[NickH]

Me again,

Head now off. Have found that one of the valve springs has collapsed on back cylinder. Others seem quite weak (i.e. can compress by hand). Is that normal?

Front cylinder doesn't look like ignition is great either, so will get injectors checked.

Bores look okay and there doesn't seem to be a lot of piston play movement in bores.

Am planning to drop sump to clean out and may have a look at big ends then.

Any suggestions for check/good practice please.

Pic attached (top is front of engine)

Thanks

[Stormin]

Has something been inside the bore on number three cylinder. Look to be a few marks on the face of the head to right or the valves. Maybe some debris has got sucked in to the cylinder or a piece of piston ring has come loose and found it's way to the top. Doesnt look to bad but would be concerned to find what it was.
Number three injector looks a bit clagged around the nozzle too.