Riich

Riich

Active Member
I've developed a vibration/rumble that feels a bit like when the engine is under load in 5th. It's not UJ's as I can feel it at idle. The engines got 205k on it, so I won't be suprised if it needs new mains, big ends and thrusts. I recently did the head gasket and noticed the bores had honing marks on them and there was little to no sideways movement in the pistons, so possibly been rebuilt in recent times?

Anyway, is it possible to do the mains without pulling the engine out or taking most of it apart? And if so, is there anything else I can change while I'm at it?
 
Thinking about engines in general, and not specifically the 300Tdi, I suppose you could drop the sump off and change the big end shells, but it's not a job I would relish doing lying on my back, nor I wouldn't guarantee that the job could be done properly.
When you start thinking about the main and thrust bearings particularly the rear main bearing, how are you going to "win" enough space to remove the bearings on the block side without taking the gearbox at least off the end of the crankshaft?
The only way I can see to replace the mains and thrust bearings would be to pull the lump so that you can turn it upside down and get the crankshaft out. If you're going to start doing things properly like getting the ovality and wear of the crankpins checked then it's the only way.
 
brian47 said:
Thinking about engines in general, and not specifically the 300Tdi, I suppose you could drop the sump off and change the big end shells, but it's not a job I would relish doing lying on my back, nor I wouldn't guarantee that the job could be done properly.
main bearings will easily slide round to be changed once all bearing caps are looosr
Click to expand...
 
So all the mains are accessable then? I might as well get some ordered up for the price of them
 
jamesmartin said:
main bearings will easily slide round to be changed once all bearing caps are looosr
Click to expand...
I did wonder about that while I was writing, but almost all the main bearings I've come across have had a small corner splayed out to form a locating notch. In which case, the old main shells would have to be pushed out and then the new ones pushed back in. The old bearings couldn't be pushed out by the new ones being pushed in.
It would still be a job I would not relish trying lying on my back.
 
I've built plenty of engines so I'm familiar with whats involved, but always in a workshop on a bench, previously I was a plant and agri fitter so working under **** with rain and oil running down my neck. I'd imagine this will be equally as unenjoyable.
 
In a perfect world yes, but in the real world when you need it for work every day, then you have to do it the quick way :/
 
I changed all the bearing shells and con rod shells on one of my V8's with engine insitu. Theres a how to in the Range Rover section.

https://www.landyzone.co.uk/land-rover/main-and-big-end-bearing-replacement-gems-v8.271464/

Process would no doubt be similar on the diesel.

Once sump is off, loosen the bearing caps a fraction to allow crank to move easier, but not 'drop' and damage the crank seals.

Remove a beraing cap to be worked on, The using a flattened rivet or similar, locate the crank oil way and insert the rivet, then rotate the crank.....as the crank rotates the rivet will then push the upper shell out.

Once out, slide over the top the replacement shell, and push into place.

Con rods are simpler, undo cap, push piston up and away from crank and remove upper shell.
 
Its developing into a knock now, its hard to pinpoint where its coming from while driving but there are definate vibrations through the pedals. Engine sounds like any other 300 when listening from above, but when underneath I can hear a knock, louder at the gearbox end.

Does it sound like bearings to you?
 
Prob a big end and maybe the start of main wear. Swop the lot while its stripped and hope the top end is ok. That is why i said engine out, bottom end is half a job. Good luck☺
 
Thinking new replacement engine is a more cost effective solution, its on 206k miles - stuff is starting to wear out
 
Riich said:
Thinking new replacement engine is a more cost effective solution, its on 206k miles - stuff is starting to wear out
Click to expand...
New new or used replacement new? If you buy a used one make sure you see it running and its genuine mileage before you part with any cash. The first one I bought smoked and the second one had hardly any honing marks left in the piston bores. Both were sold as low mileage good runners :( I'm getting quite good at rebuilding them now :oops:
 
Out and rebuild your self. At least you know what you have got that way if you have the time. A hone and over size rings. Crank polish and shells. Little end and pins. Valve seals and seats should see you right.
 
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