paulwrxboro

'err, i think we've found your misfire, madam..' - VZi, the UK's largest VW forum, community and sales

if its true its amazing

J4CKO

iTrader: (1)

I thought initially no way, must be a wind up but as the other three were ok and functioning normally and this one had no compression at all, not even any to blow by it may have happened, however wouldnt there be loads of fuel poured into the offending cylinder ? I am thinking that potentially it just made the whole rest of the engine one giant void filled with fuel vapour through the inlet valve and then partially let out by the exhaust vale but I would expect the oil level to rise and be full of petrol.

Surely it would run like a total bag of **** like any four cylinder down by one and I would expect the conrod/little end to be smashing into the cylinder wall.

On balance, I would say its very unlikely this isn't a windup.

ALi-B

iTrader: (1)

I've seen similar happen:

Old Transit with a 2.0l pinto came in running on three cylinders and making a horrendous squeeling sound like the water pump had seized.

Actually the screaching sound was the remains of a piston going up and down in the bore Drove fairly well considering most of the piston was in the sump.

what would scooby do

fyi - a wind up IMHO

TH3_5T1G

iTrader: (15)

Sorry but as a mechanic i've got to get my two pence in.
It's BS due to many factors.
1) oil isn't thinned with petrol
2) Rust on cylinder walls, they would be coated in oil as there aren't any psiton rings to keep the oil off the cylinder walls.
3)It would have been tapping like a River dance show
4) Drove ok? I don't think so. 3 cylinders is never great to drive, let alone the fact that the amount of fuel vapour being drafted back into the intake through the crankcase vent (if not mixing with oil and thinning) would make the car run too rich to perform well on even 4 cylinders.
There are many other factors but i think i've started making my point.
Someone didn't think the prank through too well

paulwrxboro

wouldent the petrol burn as normal ?

TH3_5T1G

iTrader: (15)

Some might, however i'm sure most of us know that it is the vapour of petrol that is flammable and not the liquid so i'll explain why most it will not be burnt
Another reason the compression of the comustion gases is so vital, other than aiding in pressure for the power stroke, is to stratify the fuel. In stratification the fuel turns into its vapour form. Now, if there is no fuel stratification then the fuel will not burn properly due to still being in liquid form and hence alot of fuel lingering in the oil and crankcase vent.

ALi-B

iTrader: (1)

Also, the crankcase is pressurised (albeit slightly), so it would just blow the crankcase gases out the inlet valve (which will have vacuum residual from the other cylinders) of the cylinder with the missing piston (and the exhaust valve would further pressurise the crankcase).

Unless its direct injection, fuel is injected into the inlet manifold not the combustion chamber. Albeit onto the back of the inlet valves (assuming individual multipoint injection), but if its there is no piston sucking air, and the cylinder is being pressurised by the crankcase via the other operating pistons, not much atomised fuel is going to get past - its just going to blow back into the inet manifold.

That would enrich the mixture to the other operating cylinders, but the oxygen sensor would compensate that to some extent (until the ECU reaches its adaption limits).

All in theory, of course; Putting it into practice may reveal some interesting results.

Having said that; Beetle/microbus owners have been kown to effect emerency repairs on engines with a failed bearing/ring/piston by sawing off the conrod at the big end and leaving out the rod, piston and pushrods on the failed cylinder. All working to good effect (well, lasting long enough to limp back home). Unless thats a VW old wives tale too

StickyMicky

Thread is gone?

ALi-B

iTrader: (1)

Yup, probably a hoax then.

There's also a vid somewhere on youtube of some american inline 6 pot being revved to destruction: It sounds like its about to give up, then it ejects a rod out the side of the block.

Then the engine picks up speed and carries on running again