Moorron
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| posted on 21/5/08 at 11:50 AM |
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Smoke! is it the turbo?
Hi lads, just some info to help show what im confused about.
My CBR1000F powered MK was burning oil, only at high revs but it was loosing it big time. But i then chose to turbo it, a friend handed me an unknown
T2 sized turbo which has some play in the bearing. I used this to build around and then promtly blew my engine up lol.
Ive just rebuild the engine, all smoke free until it got really hot and started to smoke at idle, very blue too. It clears it self after about 30
seconds but does return at idle from time to time. Im sure the engine it fine, but does this point to he turbo on its way out? the last time i blew a
turbo is didnt do this it just produced a james bond stile smoke screen so im not sure whats going on.
Went to the mot station 1 mile down the road and it doesnt smoke while driving (off boost new engine remember ). But back on the drive it smokes for
30 seconds and then clears again.
Any turbo blowing experts out there know if this is 100% the turbo on its way out?
ps, passed the mot.
Sorry about my spelling, im an engineer and only work in numbers.
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stevebubs
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| posted on 21/5/08 at 12:17 PM |
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Is it really blue, or is it just unburnt petrol?
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RazMan
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| posted on 21/5/08 at 01:37 PM |
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If the turbo has a little play in the bearing the chances are that it is letting some oil by - hence the blue smoke.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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worX
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| posted on 21/5/08 at 02:27 PM |
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I am def no turbo expert, but thats the first thing I'd be looking at even if you didn't say there was play in it...
Steve
quote:
Originally posted by RazMan
If the turbo has a little play in the bearing the chances are that it is letting some oil by - hence the blue smoke.
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jambojeef
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| posted on 21/5/08 at 03:56 PM |
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Any pics of your installation?
Before I fitted my oil scavenge pump mine did similar things, blowing out blue smoke on seemingly weird occasions.
I would disconnect the oil drain pipe and let it run into a suitable container when the engine is idling and see if this fixes the problem (obviously
not for too long).
The other thing is - where and how have you connected your oil feed to the turbo? If its the oil pressure sender tapping (as I have) Ive made a
restrictor for the oil line since it was delivering too much oil and I had lowered oil pressure in the main oil gallery.
Geoff
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Moorron
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| posted on 21/5/08 at 08:47 PM |
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Hi jambo, yes i have took it from the oil pressure connection. it does read very low oil presure (5psi~!) at idle when hot so i was thinking of making
a restrictor up. What size did you make? i think this is the first step i will try.
My turbo is higher up than yours so i think i wont need a scav pump but i may be wrong.
PS, how is yours doing?
there is definatly play in the shaft of the turbo, but was told that sideways play isnt too bad, its in and out play that will creatw smoke which it
has a very small amount..
Sorry about my spelling, im an engineer and only work in numbers.
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jambojeef
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| posted on 22/5/08 at 07:50 AM |
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If you are getting around 5 psi when hot then I would suspect you are flowing a bit too much oil to the turbo. After I mullered my last engine owing
to oil starvation I made up the turbo oil line restrictor which has brought the engine oil pressure up to much better levels.
I get about 12-15 psi when the oil is about 90 degrees at idle and it more or less runs between 50 and 90psi the rest of the time.
My restrictor is 1mm dia. btw.
Mine needs some fettling really - I got it to "work with the turbo" then the winter came and the garage damp issue put me off working in
there. It stutters off boost, is really hard to start from hot and feels like it has tonnes of power (lots of clutch slip) when cool but when warm no
slip at all. It needs a good rolling road set-up and some better airflow to the intercooler I reckon. Having said that the plugs are always a nice
biscuity colour and it does 30mpg on mixed run - how far off can the fuelling be?!?
Geoff
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