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Lau from Denmark has done a complete engine rebuild of the 23C engine in his Massey Ferguson 35.  However, he is having some problems and has written in to see what could be the trouble.  He says…


I have followed the whole rebuild process acording to the fantastic DVD I bought (I also bought the Workshop Manual for the MF 35).

I have recently started up the engine for the very first time.  It was running absolutely fantastic.  But after approx 4-5 minutes the engine slowly stalls and decreases in revs and then completely stalls – almost at the same time the radiator starts “leaking” because of the boiling water in the block.

Everything inside is new – pistons, rings, liners, crankshaft is balanced with new bearings – the WHOLE lot.  What I am afraid of is that the tolerance between the piston through the rings to the liner is to narrow.  I have removed the head now and looked at the pistons and the inside of the liners and they look as they were new – no scratches no ressidue of any kind!  All the spare parts I have bought in the UK – also the Engine Overhaul Kit – 23C.

What would You recommend I do next?

Kind regards from Denmark
Mr Lau Jakobsen

I would think you have a cooling problem.

What will be happening (I suspect) is that the cooling system isn’t working
for some reason.  The aluminium pistons will be overheating and expanding
(more quickly than the iron block) and hence the expanded pistons will
become difficult to move along the bores.   This will create more friction
and even more heat making the engine even hotter and the problem even worse.

What could be wrong?

Either one of the pipes is blocked up or the thermostat is not allowing the
water to circulate or the water pump is not circulating the water or the
radiator blocked.  Other things to look for are gaskets fitted incorrectly
and blocking coolant pathways, or temporary covers (e.g. cloths or tape used to cover coolant pathways during the rebuild) that haven’t been removed. I would take a careful look at all the cooling system components.

The thermostat should begin to open at between 68 and 74 degrees C. It
should be fully open at 85 degrees C – which can be checked by placing in a
pan of water and heating up the water.

Will this have damaged anything?

Hopefully not. If the engine was just running at idling speed in the
workshop then I would suspect that nothing will have got damaged. Things tolook for are damaged piston rings and cylinder head (although you have been in and inspected these).

Hope that helps.

Let us know how you get on.

If anyone has any other theories or suggestions for Lau then please let us know in the comments below.

The Vintage Tractor Engineer.