Thread: exhaust after engine rebuild

yes, Ive had problems with crook engines filling the exhaust with crud...

But they were spewing oil to the extent that it was spitting out the tailpipe. the first run baked the Cat closed (should have been replaced anyway IMHO) which made for some rough running.

If its still smoking after a few good hour long runs theres something wrong... turbo exhausts dont exactly run cool and the oil should be baked out or blown out before say 10 hours worth of running.

Originally Posted by 29dinosaur

My 300tdi was rebuilt (new head pistons, rings etc etc etc) 6 weeks ago and the rebuilder said that the exhaust system would be filled muck from running so long with oil etc spewing into it. The engine runs fine and is back to manufacturers specs but exhaust still is smoking a bit more than I would have expected. Murray (MJK) said that he wouldn't be surprised if this continued for a while.... and that maybe a new system may be needed... what would others have to say?? Have you ever needed to replace the exhaust?? under such circumstances??

I agree, but a new system won't be required. A brisk drive up the motorway will help, or wait for summer and do a few loonngg hills with a boat on the back

Never had to replace an exhaust for this reason.

I would suggest you don't give this new engine any special treatment. IE just drive it as normal, not working a new engine AT ALL will prevent the rings from bedding into the cylinder walls and ensure a lifetime of glazing and oil consumption. No lugging it though, just push it up the odd hill every now and then, and avoid 3000 rpm+ for sustained periods for about 5000km.

JC

Originally Posted by Blknight.aus

yes, Ive had problems with crook engines filling the exhaust with crud...

But they were spewing oil to the extent that it was spitting out the tailpipe. the first run baked the Cat closed (should have been replaced anyway IMHO) which made for some rough running.

If its still smoking after a few good hour long runs theres something wrong... turbo exhausts dont exactly run cool and the oil should be baked out or blown out before say 10 hours worth of running.

Yes it's had that work out - driven c 1000km since and at some high highway speeds and some off road stuff. I guess - what I see in passengers mirror is quite a lot of smoke under labour - but then runs pretty clean. Do some tdi's just sound like tractors anyway as well? (Sorry - I'm pretty naive when it comes to these british machines - only ever driven toymotors before and then not much.) Murray Kingman swears motor is back to spec and it does seem to have plenty of power and is quite torquey for a diesel. I probably shouldn't be worrying - it's probably just me over anxious about noisey diesels. (I'm better with a scalpel rather than a wrench).

Originally Posted by 29dinosaur

Yes it's had that work out - driven c 1000km since and at some high highway speeds and some off road stuff. I guess - what I see in passengers mirror is quite a lot of smoke under labour - but then runs pretty clean. Do some tdi's just sound like tractors anyway as well? (Sorry - I'm pretty naive when it comes to these british machines - only ever driven toymotors before and then not much.) Murray Kingman swears motor is back to spec and it does seem to have plenty of power and is quite torquey for a diesel. I probably shouldn't be worrying - it's probably just me over anxious about noisey diesels. (I'm better with a scalpel rather than a wrench).

Ahhh, what colour is this smoke?? Dark grey is OK under acceleration, Blue is what Dave and I are concerned about, this denotes oil burning. Likewise Black is a NO NO for a new engine, exhaust temps will be very high.
Often, even the exhaust smoke from a perfectly tuned Tdi will look shocking in the headlights of a following vehicle at night, this isn't a concern and is the reason these fail all current emmission regs!!!!
Tractor? We are talking about a 1960's and earlier technology engine here. If MK has set the pump timing to slightly advanced(IE 1.6mm lift instead of 1.54mm) then I expect to hear a bit more detonation etc at low speeds pulling away. BTW, 1.6mm lift is a good idea, even for new engines as this makes them torquier at low revs, allowing less 'lugging' of the engine and better for the bedding in of rings etc.

JC

Originally Posted by justinc

Ahhh, what colour is this smoke?? Dark grey is OK under acceleration, Blue is what Dave and I are concerned about, this denotes oil burning. Likewise Black is a NO NO for a new engine, exhaust temps will be very high.
Often, even the exhaust smoke from a perfectly tuned Tdi will look shocking in the headlights of a following vehicle at night, this isn't a concern and is the reason these fail all current emmission regs!!!!
Tractor? We are talking about a 1960's and earlier technology engine here. If MK has set the pump timing to slightly advanced(IE 1.6mm lift instead of 1.54mm) then I expect to hear a bit more detonation etc at low speeds pulling away. BTW, 1.6mm lift is a good idea, even for new engines as this makes them torquier at low revs, allowing less 'lugging' of the engine and better for the bedding in of rings etc.

JC

Thanks - both blckknight and yourself. I can now see who are the mechanics and who aren't...

As far as I can tell there is an initial black billow (or at least dark grey at start up) and when under a bit of load in low gears at take off points its dark grey. You're right about looking in the headlights at night and that is when I get most concerned... it's a bit scarey..

Your comment about lift is probably what is going on at low speeds ... Murray says everything should be ok and needs no adjustment. I was surprised to hear that with the alloy head in the tdi vs td5, that it did not need any further adjustment or tweaking. I suppose most other drivers in my district are driving td5s and D3s so I'm comparing my beast with newer technologies. I heard a toymotor hilux drive through town this afternoon and it sounded about as noisey as my clunker. Mind you at speed car is nice and I can get to hear 2bl or 2fc on radio nice and clearly.

Just on a quick note - what do you experts reckon about running something like chemtech fuel additive in this new motor? Shouldn't be needed I guess.... will it do any harm??

Oh and how long does it take for the new pistons rings etc to bed in? Will motor runn even more sweetly then??

Originally Posted by 29dinosaur

Thanks - both blckknight and yourself. I can now see who are the mechanics and who aren't...

As far as I can tell there is an initial black billow (or at least dark grey at start up) and when under a bit of load in low gears at take off points its dark grey. You're right about looking in the headlights at night and that is when I get most concerned... it's a bit scarey..

Your comment about lift is probably what is going on at low speeds ... Murray says everything should be ok and needs no adjustment. I was surprised to hear that with the alloy head in the tdi vs td5, that it did not need any further adjustment or tweaking. I suppose most other drivers in my district are driving td5s and D3s so I'm comparing my beast with newer technologies. I heard a toymotor hilux drive through town this afternoon and it sounded about as noisey as my clunker. Mind you at speed car is nice and I can get to hear 2bl or 2fc on radio nice and clearly.

Ah yes, the black billow on start up. This is textbook Tdi I'm afraid. We sometimes have 4 or 5 in the workshop at any time, and if more than 2 or 3 are started up close to each other, the sparrows nesting in the roof drop to the floor, asphixiated. As I said, these engines are planet killing emmision failing fossil fuel depleaters. And I love 'em.

JC

Originally Posted by justinc

Ah yes, the black billow on start up. This is textbook Tdi I'm afraid. We sometimes have 4 or 5 in the workshop at any time, and if more than 2 or 3 are started up close to each other, the sparrows nesting in the roof drop to the floor, asphixiated. As I said, these engines are planet killing emmision failing fossil fuel depleaters. And I love 'em.

JC

Yes but don't they also produce 1/10th the CO2 output of a petrol motor? All mvs are fossil fuel depleaters, so that doesn't worry me as much as the fact that I'm adding to visual pollution... and whatever else escapes from these older diesels.... (I've been to India many times and know plenty about the visual and pulmonary pollution of the myriads of diesel tata trucks and buses over there...)

Are there newer catalytic converters suitable for 300tdi's???


[I'm probably a bit twitchy about the smoke and noise because my local BP garage is 2 doors away and I drive past there 4-6 times per day and I know the owner-mechanic hates LR and thinks I've got rocks in my head to own one.... he's a Ford man...)]