Kaputt - Help Please

[James_Red69]

I havent driven my car much since July - summer holiday in August followed by a bike ride in September (London to Paris) which left me with a broken collar bone after being hit by a car near Maidstone.

Am now well enough to drive so thought on Friday evening I would go for a spin. Car started fine and I let her to idle for 10 mins. After a mile I started smelling smoke in the car, then 100 yards later there was smoke coming out of the dashboard vents.

Obviously I stopped immediately and shut down, my initial thought was an electrical fault but came to realise it was exhaust fumes. Started the car again and lots and lots and lots of blue smoke. Oil pressure light not on (its reliable I believe), smoke again through the vent system and whilst there is blue smoke out of the exhaust its also coming from other orifices of the engine. Oil level low so topped up and drove the mile back home with clouds streaking out the back.

My honemoon is over, anyone got any advice, my initial reaction is that a piston ring has gone? Can I do any investigative work to confirm this (inspect the plugs for signs of oil?) before comitting to taking the engine out or (as I am time poor) giving the car to someone to fix.

James

[Nige]

Don't panic, sounds like the valve covers have popped a seal and spewing oil over the heat exchangers and exhaust. Are you sure you haven't over filled it by accident?

When you run the engine and you remove the oil cap does smoke pump out of there?

[Ian 2.2S]

As Nige says. Smoke out of vents is usually a bit of oil seeped into the heat exchangers. 10 mins after starting it warms up enough to start smoking. Doesn't take much to create quite a lot of smoke. Just need to find out where its leaking from.
Ian

[impmad2000]

I agree with the others, and if you only ran it for 10 mins, and drove 10 miles, it isn't properly hot !! so chances are its a bit overfill. Don't panic.

[James_Red69]

Did a compression test today.........results as follows;

Cylinder 3 plug had very oily deposits on it when removed.

Compression tests as follows;

Cyl1 - 145 to 150 PSI (10 bar)
Cyl2 - 145 to 150 PSI (10 bar)
Cyl3 - 70 PSI (5 bar)
Cyl4 - 145 to 150 PSI (10 bar)

[KS]

Sounds to me like a ring has broken (or you've burnt a piston). Can you do a leak-down test?

[James_Red69]

I am getting advice from various sources to do a 'leakdown' test. Having done some learning on the matter I see how this works but do I need a proper leakdown tester?

Advice from a friend in the trade (but no specific 912 exp) suggests that,....."I cant help with a leak down tester but have never used one anyway. Never heard of one used in the trade either. If you have a reading that low it's going to mean at least the head off. The normal procedure is to do a dry test first then repeat with several squirts of oil down the spark plug hole before you put the gauge in. The oil temporarily seals any broken rings. If you get more consistent readings the problem is rings. If you still have one cylinder 50% down you have a valve problem."

Im not sure this "several squirts of oil down the spark plug hole" would work on a flat engine?

Any advice or do I have to and spend a load on a lead-down tester?

[Bruce M]

Leakdown tester doesn't require the engine to be spun on the starter which is handy if you might be causing more damage. You also need an air supply to use one.

They are a bit pricey for a single use too.

How about a gheto version?
http://www.max-boost.co.uk/max-boost/Le ... tester.htm

No readings though, you have to judge it by the sound/draft.

[smallspeed]

one quick test (requires running of the engine though) for valves vs. pistons is to pull the dipstick or remove the oil filler cap while the engine is running. someone already mentioned it, i think nige..
if you're getting smoke pumping out of either (doesn't matter which) it usually points to excessive pressure in the crankcase due to piston blow-by. helen and larry had a piston ring problem on their 356c after a rebuild, and it spat oil and gas from the dipstick tube pretty heavilly

quick question for the more initiated (might help) - can you remove the check valve from a normal compression guage, turn the engine to TDC manually to create pressure (this is the bit im not sure about on a 911/912) then measure the decay on the gauge against time? might be a bit heath-robinson, but could be a lot cheaper than buying a proper decay tester.. ..its something you have to do on rotary engines to measure compression because of the "multiple cylinders per cylinder" complication