frankxhv773t
Permanent resident
Posts: 2252
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« Reply #15 on: 22 July, 2016, 07:29:02 PM » |
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Am I right in thinking worn valve guides give white smoke whereas worn piston rings give a darker, grey, smoke?
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John B
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« Reply #16 on: 22 July, 2016, 08:22:21 PM » |
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Some other tests you could do is determine if the oil is being burnt on the over run (worn inlet valve guides) or on acceleration (worn pistons/rings).
Am I right in thinking worn valve guides give white smoke whereas worn piston rings give a darker, grey, smoke?
Hmmmm ....more interesting points to investigate. Close observation of exhaust fumes is next on the list.  |
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1961 Appia S3
1969 Fiat 850 Special
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chriswgawne
Permanent resident
Posts: 2100
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« Reply #17 on: 31 July, 2016, 10:23:59 AM » |
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The most recent compression readings for the carefully built 5th Series engine in my 3rd Series B20 (which has standard pistons and lightly skimmed heads - i.e not high compression) are 172,164,169,165,170,168 with all readings taken at starter cranking speed.
I have a spare race engine which has high comp pistons and more heavily skimmed heads so at some stage I will try to get some readings from that as well as from a standard run in Aurelia engine in another car.
Chris
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Chris Gawne
Mobile: 07778 216552
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simonandjuliet
Permanent resident
Posts: 2560
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« Reply #18 on: 01 August, 2016, 01:51:34 PM » |
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Chris, I would hate to turn that one over by hand .....
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AmilcarCGS, ApriliaCabrio,S2Aprilia, 2xArdea c'cino,S4 Ardea, Appia c'cino, Appia f'cino,B20s4,R4 Sinpar, R4 Rodeo, 65 Moke, 3xR60 Tractor, 2xToselli 78, Moto Guzzi Ercole,LR Defender, Mini ALL4 JCW, Moto Guzzi Cardellino, Fulvia GT, RE Himalayan
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John B
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« Reply #19 on: 01 August, 2016, 05:04:22 PM » |
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Update......
After a recent long run the small amount of exhaust smoke was black, at tick over speed. I adjusted the carb mixture screw
and there was a noticeable increase in engine speed so adjusted the idle speed screw as well.
Now no noticeable smoke from the exhaust at tick over but when the throttle is depressed there is some blackish smoke evident.
Assumption now is that perhaps the valve guides are not a serious problem and the likely culprit is piston rings being slightly worn.
Oil consumption is negligible so will leave well alone for the time being I think.
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1961 Appia S3
1969 Fiat 850 Special
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Jaydub
Megaposter
Posts: 346
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« Reply #20 on: 01 August, 2016, 07:25:01 PM » |
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Sounds like things aren`t so bad John. You will usually get black smoke when you press the accelerator after idling because older engines tend to have less well designed combustion chambers and do not burn all the fuel mixture efficiently and the richer mixtures created under acceleration tend to exit the exhaust system unburnt. Plus of course possibly worn jets, incorrect float levels, ignition timing and valve clearances. You cannot successfully tune the carb without first ensuring all those things are correct.
As a rule, white smoke is water related eg. Head Gasket problems. Blue smoke is oil related. Worn guides will show up if you back off the throttle when slowing down, the ensuing high depression created in the combustion chambers will suck oil down worn guides. Also on start up after standing awhile and oil has run down the guides.
Black smoke is rich fuel mixture created by the things mentioned earlier.
All the best
John
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1600 HF. S2.
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John B
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« Reply #21 on: 01 August, 2016, 08:32:23 PM » |
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Thanks for your informative reply, valve clearances have been checked and are correct.
I think a carb overhaul will now be next on the list.
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1961 Appia S3
1969 Fiat 850 Special
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lancianut666
Permanent resident
Posts: 1793
Slow but rough
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« Reply #22 on: 02 August, 2016, 08:05:41 AM » |
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Fulvia Coupe S2 Flavia Coupe 1967 1.8 Kugelfischer Prisma 1.6 carb Y10 Fila Y10 Touring Dedra 1.8 Dedra 2.0 Turbo Appia S1
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John B
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« Reply #23 on: 02 August, 2016, 10:01:39 AM » |
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Excellent, will order one now. |
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1961 Appia S3
1969 Fiat 850 Special
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John B
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« Reply #24 on: 15 August, 2016, 03:27:35 PM » |
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Update.......
Kit ordered and delivered quickly, good service from this eBay seller, they also gave me a rebate on the stated delivery cost because it was being sent from Italy and also delivered to Italy.
The carb has now been stripped and rebuilt with the new kit, first impression is positive - only driven 10 km but definitely seems better to drive now. A longer drive required now and then check plugs and exhaust fumes etc.
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1961 Appia S3
1969 Fiat 850 Special
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Jaydub
Megaposter
Posts: 346
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« Reply #25 on: 15 August, 2016, 07:46:18 PM » |
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Sounds promising John. I like the Al Fresco sun lounger with a Lancia as a sun shade, but I doubt it would have the same appeal in the UK!
John.
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1600 HF. S2.
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