Valve stem seals

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No. As there's nothing to stop the valve dropping into the cylinder.

Why do you think the stem seals need replacing?
 
I get smoke on every start up, my understanding is that you can pressurise the cylinders with air or use the rope trick to keep the valve in place. But I am not sure if you can rotate the engine to get each cylinder to tdc.
 
I get smoke on every start up, my understanding is that you can pressurise the cylinders with air or use the rope trick to keep the valve in place. But I am not sure if you can rotate the engine to get each cylinder to tdc.
you can rotate it to get two pistons at tdc, then 180 degree put the other two up,1 and 4 pair and 2 and 3 pair, diesels have flat top pistons with very little clearance between them and the head at tdc, petrols have a combustion chamber hence various methods of filling the void
valve on the rock is when both valves on one cylinder are both partially open ones shutting ones opening theres an overlap at the same time the opposite piston ie if its 1 on the rock no 4 piston both valves will be fully shut
 
So you think it is possible without removing the head.
Anything is possible. We used to do the stem seals on the Ford CVH by using the string trick.

It's not guaranteed it's the stem seals though. It's wise to check the easy stuff first. The TD4 draws in a lot of oil from the breather and turbo, which is a much more likely to cause of blue smoke on starting than the stem seals.
 
So you think it is possible without removing the head.
its usual on a diesel to use tdc and a tool such as these
shopping

images
 
Will look at turbo first, just had new crankshaft breather on, egr delete, fuel pressure sensor loom upgrade. So as nodge says worth checking turbo for oil leakage.
 
There’s a very useful tool you can get, which fits over the valve retainer/collets. You then tap the tool with a hammer to compress the spring, and magnets then attract the collets away and you can then remove retainer and spring. Done right, you can use the same tool to replace everything when you’re done. Get the pistons at TDC using a long screwdriver as indicator.

I can’t remember then name of the tool, but I borrowed one years ago to do a tractor engine.

Edit: Something like this: https://www.ebay.co.uk/itm/14097380...0eda4441680aa66382469a4fff39825&ul_noapp=true
 
What do those tools hold on to in order to compress the springs?

The camshaft or rocker shaft. They're only much use if the valves are operated by fingers or rockers. The M47 does use rockers, so it might work. There's not much room on the M47 and the cams will need removing to get the rockers out the way, but will need temporarily refitting to act as an anchor for the tool. It's going a long old job, so definitely worth checking other sources of the oil, before attacking the stem seals.
 
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You used to be able to get a rubber softening additive for rejuvenating oil seals etc on engines wynns may do one try searching net for something if you still suspect stem seals but I too feel it is unlikely it's rare nowadays with better materials used etc. just looked wynns oil seal restorer still available
 
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