oil leak

[912UK]

Hi right just a thought with all this Le mans talk for next year need to get my car running better.

I have an oil leak. And it is a few drops now is this the start of the end of my engine eg too much pressure.

The history it was a car from the US and it had not run for 14 years I got it back and spoke at great lenght to Harry P and I did all that he said coil off plugs out turn by hand loads of times [&:] Boy hard work. With some oil in the bore. Then with the starter motor and then go for the run. Did all that found the carbs were not working right so had them rebiult. Put them on the car it ran ok done 1200 miles Andy Prill took the piss and tuned them for me at the big Porsche show this year buy ear. And it runs much better. Still need to be worked on mind.

Also when I accelerate hard when the car is warmed up I start to get that nice bursch roar and then a metalic rattle (Andy thinks it is Pinking) Any one had the same I am going to later today check the jet sizes and report back to Andy. BUT get this it does not do this when the car is cold it runs like a dream and this is when I have full confidence in the car and think Le Mans here we come then it warms up and I am back to doing 55mph on the safe side.[]

Also the tappets on 3-4 side seam to be out of adjustmant again[8|]


Any suggestions. I would like to wip the heads off and give them to Andy to do but it sounds like I would not get them back for about a year[&:][&:][&:][&:][&:][&:][&:][&:] When is Le Mans.

Mark

 

[Jon Darlington]

Have faith in the 12 it will get you there.

Classic Le Man is the 24-25 July next year.

Not being an engine man I have got much to say on your problems, just that I hope they sort them selves out!

 

[Guest]

Well... The speed Jon drives at - the oil vaporises at mach 1
PS - got the Cheque!

Mark - It sounds like you want to know - rather than keep on driving it. If you take off the heads you will have a better idea but you might also be opening a can of worms.

What you've listed above, and what I can remember about your tappets in another post... it does sound like you should just do it. At least, if theres no apparent (visable) signs, you can bolt the heads back on - if not send them to Andy and wait. At least you will know.

ohh for xray specs

David
PS... I'm back from the States - missed you all... apart from Evil

 

[912UK]

Smokin.....

 

[Guest]

Found this today from some strange website (HCP Research - USA), dont know if it's true though but...
you will be able to tell us no doubt ...
------------------------------
Alimentary my dear Customer- by Murphy, ANY oil leak ANYWHERE on a 356/912 engine results in oil entering the air stream, being sucked into the fan, and deposited on the oil cooler where it acts like an oil-bath Air Filter, filtering the incoming cooling air of dirt and quite quickly blocking half the outside of the Cooler, and eventually, ALL of the Cooler.

Needless to say, this causes Overheating.
--------------------------------

read more interesting stuff on this here:
http://www.hcpresearch.com/nocturna.html

Dimitri - good article

 

[912UK]

Yes cheers it's Harrys site he died earler this year what a real shame such a nice man

 

[Evil J Guano]

PS... I'm back from the States - missed you all... apart from Evil

Boo hoo... and you said you would ring...

 

[Evil J Guano]

I found this was a good explanation of ignition problems.
I am assuming that the relative engine temp may be a factor in the timing (xcuse the pun) of your pinking. But what do I know!

KNOCK, DETONATION OR PING



This is an intense pressure wave within the cylinder created when a LEAN mix of air and fuel ignites before the spark is delivered.The fuel/air mixture goes off by itself a micro second before the spark plug fires, at that time you have two intense high pressure waves clapping together and that energy wave hitting each other is the sound you hear. The sound you hear is from the actual vibration of the cylinder wall




Under normal circumstances, when the fuel-air mixture in the engine burns, it does so in a controlled manner, releasing the energy that produces the force that drives the pistons. Now, if you think about it, it might seem that the correct time for the spark plug to ignite the mix would be when the piston reaches the top of its stroke. Then, as the mix burns and energy is released, the energy pushes the piston down. The problem is that it takes a certain amount of time for the mix to burn. If you wait until the top of the stroke to ignite it, the bulk of the energy will be applied to the piston only during the latter part of its downward movement.




In order to get the maximum use out of the combustion energy, the mix is ignited while the piston is still moving up. This is called "advance". As the engine speed increases, fuel has less time to burn and advance is increased accordingly. Ignition advance is controlled by the engine management computer. It varies in response to a host of other conditions but the base advance curve is a function of engine speed.




Now we have a new problem. As the mix is ignited earlier, it is not compressed as much and has a tendency to burn at an uncontrolled extremely high rate (it basically explodes). This is called "detonation". When this happens, all the energy in the fuel is released almost instantly. The resulting shock wave slams into the piston which is forced through it by the inertia of the engine and the combustion in other cylinders. The resulting stress on the engine is enormous.



Detonation can be caused by several things not just a lean condition or bad choice of fuel octane: Too much compression and too much timing can also be to blame.




The most common way to describe the sound of detonation is: "like shaking a can full of marbles", but the BEST way to verify the existence of detonation is by reading the sparkplug's. If the plugs are very white, show a very eroded electrode and signs of metal deposits, then you have

DETONATION.




The Cure: Less timing and/or higher octane gas and/or colder plugs.




Higher octane gas is a good safety measure. Is the $.10 per gallon worth that extra risk? Another myth about octane is that higher octane produces more power, wrong. Higher octane fuel is less volatile, less explosive, less prone to detonation.




A more 'volatile' fuel actually produces more energy per unit volume.You just have to watch out for detonation more. That's why higher compression engines use higher octane fuel, higher compression ratio (and higher altitude, lower air pressure) increases the tendency for detonation. Run super unleaded, but don't expect to gain power from the more expensive fuel. You CAN get more power, but it's from running more compression and spark advance.



PRE-IGNITION
This is premature ignition before the spark plug fires, usually caused by something glowing inside the cylinder such as carbon deposits or too hot a sparkplug tip. Do not confuse this with detonation. It is not the same.




Usually pre-ignition occurs when there are lots of "red hot" carbon deposits and unburned fuel in the combustion chambers.




If you turn of the ignition and your stang wants to keep on running, then you have pre-ignition.



The Cure: Eliminate carbon deposits and/or colder plugs, check fuel system.

 

[Evil J Guano]

Its American so excuse the colloquialisms... darn stang! (translation - goodness me what an awful Muscle Car)

 

[Ian Gunney]

I thought all Porsches dropped oil - even the bikes!

 

[Nick Moss]

BMW bikes do NOT drop oil. I have owned and worked on them for over 26 years []

 

[Guest]

that's coz the BMW riders pootle about like mopeds and pop down the shops on fair weather days lol ..... part-timers those BMW riders. Real men ride Kawasaki's not old man machines ..... or even better 2-strokes like my old 'Elsie' (Yamaha 350LC - formula 2 tuned by Terry Becket), but that used to leak some every now and then.

Why do old men ride BMW's - coz the engine sticks out the side and helps them to get on it with their zimmer frames ....ok ok enough BMW bike bashing - seriously they are reliable bikes - plenty of couriers use them.

 

[Ian Gunney]

I meant the push bikes!

 

[Nick Moss]

What push bikes? My BMW does ping when given stick at high altitude, but not at sea level.

 

[Guest]

I have a fairly heavy oil leak. Seems to come from the fly wheel.
Can the fly wheel oil seal be replaced without striping the engine down?

 

[Nick Moss]

Ant

Yes