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Valve Stem Seals 300 Tdi


disco_al

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Anyone know if it is possible to change the VSS on a 300tdi without removing the head?

Obviously the hardest part is to make sure that the relevant piston is at the top of it's stroke so the valve doesn't drop into the cylinder, but that should be fairly easy to accomplish with a bit of common sense

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I've never done it, but i wouldn't mind having a go. Checking TDC of the relevant piston would be quite easy (through the glow plug or injector hole) As long as the piston is at TDC, then the valve will only drop about 1.5mm, which is nothing as far as compressing the spring goes. It would save a fair bit of work if it could be done with the head still fitted.

Les.

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Like Les I think it's worth a try.

I changed the valve springs on my Avenger enging without taking the head off. Petrol I know it was but what's really the difference.

If it was me..

I'd take the heater plugs out.

Piston about quarter down the bore.

String down the heater plug hole to pack things.

Turn piston to as near TDC as the string allows.

Then off with the valve springs. Churchill do make a tool to push the springs down without having to use a clamp over the head.

HTH.

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I can't see what that tool would hook onto to be honest (the edge of the head perhaps?) If you remove the head, there's a risk you may see things you would rather not see - such as huge step at the top of the bore, the rings down the side of the massive gap between piston and bore, and other scary stuff :)

Les. tongue.gif

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As long as the rocker shaft is not secured by the head bolts then it will be an easy job........

Use this type of spring compressor ........... http://www.justoffbase.co.uk/Valve-Spring-Compressor-Lever-Type-OHV-OHC-Sealey-VS168;jsessionid=0a01074d1f434ca5ba1a147e48c78b64c5ff8f97afc8.e3eTaxaQbxmTe34Pa38Ta38Pax50?sc=9&category=213

Ian

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that is where the problem is with the LR diesels of course.....oh well, head off it is then

The rocker shaft on a 300tdi is not secured by the head bolts, so removing the shaft is no problem. Just make sure you undo things in the correct order so as not to bend the shaft and when refitting do not overtighten or you run the risk of stripping the thread out of the head.

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I sit corrected, i was under the impression that the rocker shaft was fixed in by the head bolts. hmm, looks like it could be possible to do without removing the head then.....

I can't see what that tool would hook onto to be honest (the edge of the head perhaps?) If you remove the head, there's a risk you may see things you would rather not see - such as huge step at the top of the bore, the rings down the side of the massive gap between piston and bore, and other scary stuff

that is one worry - true - although as it doesn't burn oil (used naff all on the 1300 miles over the weekend - probably less than 0.1 litre) i'm not expecting any major wear in the bores or block.

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Why are you replacing them then?

Because i suspect i have a problem with them......

Basically, it's like this. When you start it up, and leave it idling for any length of time, as soon as you pull away there is a large cloud of blue smoke, that smells rather oily, this will clear fairly soon after starting off, as long as it doesn't idle for too long.

Last weekend for example, we went to Aberdeenshire for a short break (why drive i hear you ask? because it was nearly £100 cheaper than either flying or taking the train - £140 diesel compared to £230 by train and £260 by plane), we stopped at Gretna on the way up and slept in the car (i know, i'm a cheapskate) and around 4 in the morning it was rather cold, so i started the engine to warm things up, no revving, just straight to normal idle speed. The following morning when we left, the smoke out of the back was terrible, and lasted for at least two miles before clearing - in fact it was so bad that we got pulled by a copper for the "smokey motor". After that, i refrained from letting it idle for longer than necessary, and the problem never came back.

It doesn't use any oil as already stated, and when warm there is no smoke from the back end, other than the usual black smoke you get from a diesel at high ish revs, which leads me to believe that the turbo is fine, otherwise i would get blue smoke under load at all times. Power delivery is fine, and she pulls like a train, economy is also good (averaged 34mpg over the weekend).

So, that is why i suspect that they need doing, as it is idling, oil is building up and running past the seals, and into the cylinders, leading to the large plumes of occassional smoke when cold, as soon as it's off and running and warmed up, the offending seal stops the oil from getting past, and everything is fine and dandy.

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I had similar idling for ages or on overrun for long distances coming down mountain passes in France

It was the Turbo

the low oil pressure as the engine was idling allowed the oil to pass and get burnt

it stank!

Turbo rebuilt by AR turbo and it never did it again.

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I used to replace springs on my race car with the head still in place.

we used a leakdown tester fitting to put 150psi into the cylinder to keep the valve shut, then we used a homemade

lever/hook that went under the rockershaft to pushed the valve retainer down.

I have seen it done with string and a ring spanner, cylinder packed with string and the ring spanner

put on the retainer, then the bloke stood on the ring spanner; I mentioned this when someone asked about doing

this, he didn't believe me so we changed a spring on an old sherpa engine like this.

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I had similar idling for ages or on overrun for long distances coming down mountain passes in France

It was the Turbo

the low oil pressure as the engine was idling allowed the oil to pass and get burnt

it stank!

Turbo rebuilt by AR turbo and it never did it again.

Tony I had exactly the same thing while on holiday. Blue smoke on tickover, clearing when I opened the throttle. No somke on the overun.....We thought it was the crankshaft key moved/ broken. As it was about time for a new timing belt that was changed. Although the key was damaged it didn't cure the smoke. A new turbo did.

mikei

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Another bit of info to throw into the mix - when it was doing it Friday morning, there was a really pungent smell of oil fumes in the cabin as well. A couple of very good mechanic friends (both diesel experts with 50+ years between them) have also suggested an injector fault.

Would it narrow things down better if i remove the top intercooler hose, start it up and let it idle, and then give it a rev or two? Surely if it was the turbo, then i would get smoke from the intercooler hose, rather than the turbo, and if it was engine related ie injector or stem seals, then i would get the exhaust smoke?

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Right, carried out my little test i mentioned inthe previous post lunchtime, completely removed the top intercooler hose, let it idle, revved it a bit - nothing whatsoever out of the intercooler, other than fresh air, large puff of whiteish/greyish/blueish smoke out of the exhaust - so i am suspecting the stem seals giving me grief.

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Mine was less than £150 rebuilt by AR turbo they did a superb job.

That will be my next option, head gasket and stem seals first i think as cash is tight after our Bank Holiday getaway.

Cheers all for the tips, advice and pointers - faultless as always :)

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Rather than throwing money at it willy-nilly, start the engine from cold and run it for a couple of minutes, then pull the exhaust manifold and look for oil in the exhaust ports. If it's coming out of the engine, it'll be oily. If it's coming out of the turbo, it'll only be downstream of the turbine seal.

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I'll have a look inside the old downpipe that's sat waiting to be scrapped as well then, wouldn't it be oily in there if it's the turbo seals? It was only changed two weeks ago, and it has been smoking like this for a few months now (well, since i've had it)

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