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348 burning oil on left bank

H

Harry348

New member
My 348 was in storage for 10 years, so now I am retired I have more time to play so the first thing was new cambelts, thermostat, waterpump, plugs etc.

So now we are running and she pulls great and a smooth tickover, the right bank is ok but the plugs on the left bank are all equally black with a whitish tip, there is white oil smelling smoke from the exhaust and oil around the first exhaust joint.

All 8 cylinders have the same 11.75 bar compression, I have reset the resistance in the MAFs and swopped them over with no difference, I have tried the Italian tune up with no difference. (I am chased down the road with white smoke). There is no oil contamination in the water and vice versa. All the 4 plugs on the left bank are exactly the same so if it were a valve stem then surely it would only be one plug. If it was a head gasket then it would affect one or two plugs, I have swapped over the pressure relief valves with no difference. So what is putting oil equally into all 4 cylinders ??? Please help.
 
Others have way better experience than me but my 355 was like that (sort of) when overfilled with oil - the 'sort of' is I cannot recall or explain if the one bank was worse affected - maybe its nearer a pump or oil passage or similar
 
Hi Harry. You seem to know what you're doing mechanically so forgive me if this is a bit obvious but just mentioning it as it's been a while since you've driven the car and things can be forgotten.

Obviously these are dry sump cars so the oil level barely registers on the dipstick until they are warmed up. As such they are very easy to overfill a bit (have had that done by a main dealer in the past). If you open the air filter box, take out the air filter and check the inside of the box and filter for any oil residue. I think if it's overfilled the oil can back up through the breathing system (which I seem to remember is on the lower left of the air box but would need to check) and be sucked into the air intake pipe past the MAF and into that bank of the engine.

Might not be this but it's quite easy to check, if the inside of the airbox and filter have no oil residue on it won't be this.
 
The breather hoses from the oil tank into the main air inlet hoses can definately allow oil to be sucked into the system from an overfilled tank. If you haven't seen it the diagram below shows this relationship. Also, oil can pool in the other blow by hose from the cam covers to the oil tank. Worth checking. If you remove the air box with mafs you can look for evidence of oil in the inlet hoses. As Pete said overfilling is an easy mistake to make with this system. Simple, quick checks and you can possibly discount things if you havnt already..

https://www.ferrariparts.co.uk/diagram/ferrari/348-tb-ts/015-blow-by-system
 
Last edited:
Pangea said:
The breather hoses from the oil tank into the main air inlet hoses can definately allow oil to be sucked into the system from an overfilled tank.
Click to expand...

Had misremembered the breather as going into the airbox rather than the air inlet hose, been a while since I've had it apart. Cheers Nick :thumbsup:
 
Nosevi said:
Had misremembered the breather as going into the airbox rather than the air inlet hose, been a while since I've had it apart. Cheers Nick :thumbsup:
Click to expand...

No worries Pete. I think we are barking up the wrong tree here though. Although I wouldnt take anything for granted oil would probably be sucked into both inlets if overfilled. OP posted elsewhere that the problem existed before he serviced the car. Ten years ago ? Maybe he will get back with some more info on the issue. After that tenth of time being laid up who knows.
 
Pangea said:
No worries Pete. I think we are barking up the wrong tree here though. Although I wouldnt take anything for granted oil would probably be sucked into both inlets if overfilled. OP posted elsewhere that the problem existed before he serviced the car. Ten years ago ? Maybe he will get back with some more info on the issue. After that tenth of time being laid up who knows.
Click to expand...

I think you're right on both counts, Nick - you'd expect both banks to have at least some smoke and if it happened before servicing oil overfill is unlikely to be the cause.

I did read on Fchat of similar symptoms years ago on a car and Pap who's normally pretty good with fault diagnosis said it could be piston rings sticking after being laid up.

"Because the car sat for a while, the rings stick, sometimes seize in the pistons ring grooves. This causes the rings to not seal on the cylinder bores and lets oil blow past and burns it out the back pipes."

Be interested to hear if this has been a 10 year full layup or if the car has been in 'active storage' ie warmed up fully to temperature perhaps every month, all motors and solenoids operated etc. If in active storage the above is unlikely, if sat for 10 years it might be worth looking into.
 
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