Blue Smoke Under Extreme Provocation...?

[macaroni 17 1 Cars]

Hi,

my 1.9 is showing a strange problem, that only after a few very hard miles it starts to chuck out blue smoke from the exhaust. WhenI say hard, I mean 90+ for a good 10-15 mins. If I then slow to about 70, it clears and won't do it again until I floor it for another 10-15 mins.

 

I have rebuilt the head with new valve stem seals and the guides seemed OK. The compression is a solid 200psi across all 4 pots and it runs really well.

 

I guess it is the rings, but why only after a long fast drive and not all the time? And wouldn't the compression be down?

 

Any advice gratefully received.

 

Antony

[Ajr 0]

Seems symptomatic of rings. I don't know if 200psi is normal for the 1.9 gti engine, but the majority of TUs are hitting 250-300psi. BTW you're very local to me.

 

If the rings are worn they tend to leak more the harder you drive it.

[j_turnell 134 3 Cars]

Does sound like the rings to me. Do a wet test and put a spot of oil down the bores and see how much the compression changes.

[Anthony 1,000]

Some kind of breather related issue prehaps? If you're slowly building up pressure in the crankcase under continuous load, eventually oil is going to be forced passed the rings or up into the intake I'd guess.

 

Seems symptomatic of rings. I don't know if 200psi is normal for the 1.9 gti engine, but the majority of TUs are hitting 250-300psi. BTW you're very local to me.

A good ball park estimate of what sort of compression you should be getting from a healthy engine is approximately 20 times the compression ratio - so an engine with 10:1 would be around 200psi or so. TU's that I've tested have conformed to that guideline as well.

 

From a standard 1.9 8v, 200psi compression on all four cylinders is very good.

[macaroni 17 1 Cars]

Thanks for the replies.

 

I did a wet test and the compression readings were constant. I thought 200psi across all 4 cylinders was pretty good and certainly better than before I rebuilt the head.

 

I did wonder (hope?) that it might be a breather issue, but there is no crankcase breather, as far as I can see, is there?

 

AJR, I used to work in Crawley, so even closer! I don't think TUs hit 250psi. mine certainly didn't and that had a severely skimmed head.

 

I'm trying to exhaust all other possibilities before I remove the head again and think about whipping the pistons out.

 

Cheers,

 

Antony

[Tom Fenton 1,526]

The breather doubles up as the main oil filler hose, the filler "pot" is also part of the breather system. I'd check first of all that the main hose down from the filler pot is not kinked and collapsed from going soft- I have seen this a couple of times.

[maxi 36 1 Cars]

Its an 8v, they are all f***ed. They all smoke. Wouldnt worry about it, its behind you so you cant see it!

 

Maxi

[Richie-Van-GTi 70 2 Cars]

I would say its almost definatley the rubbish breather and return systems on the 8v alloy lumps. Anyone following me to and from fcs 07 will confirm just how bad it can be. I know chris had to literally clean his windscreen halfway to get all the oil film off!!

[macaroni 17 1 Cars]

Cheeky Maxi, it doesn't smoke at all, or use oil ordinarily. Its only done 171k miles after all!

 

I'll get a new breather/oil filler cap and check the hoses before I worry about my rings.

 

Thanks chaps.

[luggy 13]

Had a similar issue with my old 1.9 before it was scrapped. 177k and used to smoke when ragged, never an issue during MOT, had 170psi across all 4 pots, stripped it down, had the remnants of the of the oil rings in the sump

[macaroni 17 1 Cars]

Well, just been out and checked the breather system and it all seems clean and clear, apart from the inlet to the inlet manifold, which is blocked. Is this right?

 

Took it for a hoon and caned it hard, with no smoke. So either I've cleared something, or it only does it under prolonged pressure, which it will get tomorrow on the motorway.

 

Haaannnnggg ooonnnn, my breather/oil filler doesn't have any mesh inside it, should it have?

Edited January 13, 2009 by macaroni

[luggy 13]

Haaannnnggg ooonnnn, my breather/oil filler doesn't have any mesh inside it, should it have?

 

Yes it should however one of the first things I did after joining this forum and reading the numerous threads was to remove the mesh form the oil filler as it tends to breakdown and end up in the sump!