Worn valve stem seals - can I reduce the smoke?

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greenapple
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Worn valve stem seals - can I reduce the smoke?

Post by greenapple »

Hi!

My garage has finally said the smoke is too bad on my BX 19 TRS - 1989, 100,000 miles - to give it another MOT. I have been told rectifying the problem - replacing the valve stem seals - will cost about £300 and parting with that kind money is very unlikely to happen. Is there an easier way to reduce the smoke to something more reasonable?

I've read about all sorts of things that might help, from using thicker oil than 15W/40, Lucas Oil Stabilizer, indeed even through to using thinner oil.

I'm realistically looking at squeezing another year or two out of her. She's not in bad nick apart from this so it seems a shame to give up on her.

I'd be grateful for any advice please! ;-)
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Post by jeremy »

You may be able to replace the seals without removing the head. The basic probolem is holding the valves in place while you remove the collets and springs - but some people fill the cylinder with thin string or rope and wind the piston up to hold it against the valve heads.

The rest of the job is removing the camshaft, compressing the valve springs and removing collets and springs and old seals. Compressing the valve springs may cause some amusement.
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docchevron
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Post by docchevron »

I reckon it's doable with the head on. Just make up a simple tool, ford CVH stylee, and away you go. I've never tried it on a XU engine but I've done it on TU's and other none PSA stuff so cant see it being a problem for the old XU.

There are various additives available that could help short term but it's not a fix. Try FORTE seal conditioner (it's good stuff but not cheap and doesn't last long before the smoke re-appears).

Cheers
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cavmad
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Post by cavmad »

Does the car get a lot of use and is it used just for local short runs? I ask because they can clog up under use if only driven short distances, mostly on choke. It might even be worth draining the fuel it`s it`s fairly old, putting some new `juice` in, adding some decent Stop Smoke and then giving it a damn good thrashing up and down a motorway or bypass?
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Ian_Fearn
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Post by Ian_Fearn »

Bung in a can of 'stop smoke' or whatever equivalent your local motorfactor sells.

I put it in my old GTi and it worked wonders. The car is still going over a year on without smoke.....
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sleepy0905
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Post by sleepy0905 »

This can be done what you need is the following tools from machine mart.
CHT463 Compressed air adapter £4.70
CHT452 OHV Valve spring compressor £15.26
I have got to get these for myself as my TXS is burning a bit and needs it valve seals doing but i dont want to remove the head these tools allow you to do it on the car you only need to remove the camshaft, bucket and shims.
Hope this helps :D
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Post by Kitch »

When my 16v started doing this a couple of years ago, I changed the oil for Castrol RS 10/60w. Its pricey, but it worked a treat. Car ran better full stop and the lift off blue smoke stopped.

IF you do try and change them, just take the head off. GOt to be more hassle than its worth leaving it on with the valve compressor etc? 8v's are easy to have the head off. Do the H/G and cambelt while you're there and you know your engine is gonna be sound for more years to come.
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greenapple
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Post by greenapple »

Thanks for all your advice!

Yes, I've seen things on the internet about the rope or air idea. Nothing quite down to my level of expertise though, I'm afraid, as I've never attempted anything like that before. Might be a good opprortunity to try though! Anyone know of a how-to with pictures on? I suppose taking the head off is an option - theoretically I will have nothing to lose if I get to that point.

She actually hasn't been used for a year - just started regularly and run for a bit. The smoke was getting to be a problem before though. There was definitely a lot of smoke on the ten miles to the garage, but it had certainly lessened a lot by the time I got there.

Here's my plan then:

Do an oil/filter change and use some thicker oil - 20W/50 perhaps (or 10W/60 as just suggested) - and substitute the last litre or whatever with some decent additive that is supposed to help the seals etc (suppose I could just do the oil first and the additive if necessary).

Refresh the fuel.

Give it a blast.

If none of this works, admit defeat and either do the stem seals myself/pay for it - or give up.

What do you think?

Theoretically, once I've got it back from the garage it will be off road again, so does anyone know how long I should run it to see if the oil idea is working - or will it definitely need to be put under some load?

Cheers again for all you help, it's much appreciated!
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Post by Kitch »

When I bunged the 10/60w in the difference was nearly instant.

When the seals go, they harden and crack. Oil seeps through these cracks and down the side of the valve and is then burnt. If you put thicker oil in, it doesn't allow as much to seep through, sometimes it stops it totally. So the difference should be pretty much as soon as you try it, but give it a hard run to clear the breathers out etc. Just to be fair.
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greenapple
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Post by greenapple »

Thanks Kitch. I think I'm going to try some 20W/50 purely because it will cost a fraction of the 10W/60. Hopefully it will make a difference.
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cavmad
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Post by cavmad »

Don`t give up on it Mr Apple, I think it`s worth doing and maybe easier than you think. Refreshing the fuel, adding some stop smoke, changing oil and filter and then welting it are all pretty easy and cheap to try. I think it`ll be worth a go and if it does get you another MOT then jobs a good un, if not it won`t have cost you much and you were expecting to do the work on the head anyway.
Good luck and keep us posted mate!
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Barnsley BXer
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Post by Barnsley BXer »

Cavmad,is your solution to every problem,to thrash the car to within an inch of it's life?If that's right,my car is due a good thrashing as it seems to be slowing somewhat.Maybe I'll replace the air filter and give it a good hammering :D :D :D :D :D
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Mike E (uk)
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Post by Mike E (uk) »

I had this problem on my 8V GTI.

20w50 oil helped a bit, but once the seals have gone hard, the only real answer was to change them.
Mine failed at 80,000 miles- so you have done well to get to 100,000.

If you intend to keep the car at least a year, it is well worth getting the job done.

When I took the old seals out of mine, they were so hard I suspected the Citroen dealer had given me the wrong replacement seals because they appeared to be a totally different far softer material.

I would not put any oil thickening gloop into the engine, you may end up with a far more serious engine problem if the oil does not circulate properly.
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Post by Philip Chidlow »

My GTi auto has done coming up to 160k and has never had the seals done, but now there is a slightly embarrasing chuff of blue smoke on (warm usually) start up. I've use stop smoke but not thicker oil (still 10/40w I'm afraid) and it seems to cure it for a while. But the real 'killer' is short runs and hot weather. After a good blast up the motorway (like today) it isn't so apparent. and it only got it's new MOT this July so can't be that bad.

Having said that I have been quoted £250 to do the seals, but I have a bit of a weep from the camshaft seal and I don't think the engine's breathing right so will give it a more comprehensive overhaul by next Spring and that should give me a bit less smoke! Hopefully another MOT and even a tad more power?
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cavmad
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Post by cavmad »

Barnsley BXer wrote:Cavmad,is your solution to every problem,to thrash the car to within an inch of it's life?If that's right,my car is due a good thrashing as it seems to be slowing somewhat.Maybe I'll replace the air filter and give it a good hammering :D :D :D :D :D
"If in doubt, give it some clout", that`s my motto :lol: . Actually it does do wonders before an MOT and really can help.
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