Heinkel Trojan oiling the spark plug

[lemser]

just bought a Heinkel Trojan (200cc) a few days ago. The “car” is in great condition except from engine dies after few minutes. Engine runs for a few minutes before the plug is oiled and engine stops. If I then clean and reinstall the spark plug the engines runs fine for another couple of minutes before spark plug is oiled again and stops.
Any of you had the same experience and know what to look for oil getting into the combustion system?

Best regards Per Lemser

[Jim Janecek]

well.. you should be using an oil/gas mix, so that would explain how oil gets into the combustion chamber, the question I have is what ratio are you using?

[Big Al]

Revise that. The Hienkel is a four stroke and has ST30 (or ST40 at times, if you run to the book) in its gearbox/crankcase. Petrol in the 'gas' tank. So not much different to a Briggs and Stratton.

The engine will burn a surprising amount of oil if the mix is richened up a little. This is because ST30 is quite light. Indeed it used to be used in two strokes as lubricant prior to the adoption of specifically formulated two stroke additives. So an oily plug could mean a serious issue beyond a weak, or miss-timed spark. Even that is not a cure for heavy oil consumption, of course. It will only get worse.

The engine, being a single splash lubricated unit acts a bit like a pump as it strokes. It has no active breather valve, like the Isetta. So a worn bore (cylinder), rings or valve guides will see oil effectively being blown passed any resistance. The valve guides do not have seals on, a mod that can be made, but since the engines tend to run hot this needs to be good material, like an NSU.

A compression test will confirm a problem and it is then worth removing the head. Remember to take care not to loose nuts, washers and shims down the pushrod port, which is best stuffed up with a bit of rag. Once gone, never to return, unless your very lucky. Its Mr Engine rebuild time. On removal of the head you may find a build up of carbon holding the valve open, or a burned valve seat.
A positive compression test and high oil use will be valve guides. I believe these are available with valves at a reasonable price. They are fitted using heat and held in place with a long C snap ring.

Prior to all this, it sounds dumb, check you have the correct oil level on a correct dip stick. I have had two occasions where the engine was overfilled with oil. One an own goal by the collector, the other was a cut off dip stick (why?). In both cases oil was forced out where ever it could get out. One was a gnats whisker from hydrolocking. He had done the same thing to his Isetta, that was locking. Either that or there was miscommunication and his 'Conservator' had filled them assuming they were being static stored. Whatever, too much oil is not helpful when running.

[Bob Purton]

Are you feeling ok Jim? Its not like you to make a fundamental gaff like that.

[Barry]

I would like to make sure lemser is giving us all the information before he strips down the engine.

Is it an oiled plug or just a wet one etc. - Carb problems?  choke on?
Is the engine actually using oil?  Is it smoking?

[lemser]

Thanks for the great feedback and advises.
Ive just bought the car but because engine stops after 1-2 minutes I haven't been able to drive it and check if engine uses oil. Its oil on the spark, not fuel.
Engine fires instantly with a clean spark and seems to run fine for the first minute, no smoke, no smell of burned oil, but after 1-2 minute it dies because spark is getting oiled. I can then clean the spark and it repeats..
Where is the choke located? Also, there are 2 adjusting screws on the carb (Bing), which one is for idle speed and which one is for enrichment? (will get the manual etc from previous owner in next week)


Best regards Per

[Big Al]

No choke. It uses an accelerator pump in the needle chamber. Normal cold start is to pump pedal twice and fire her up. Should need no priming when hot.

You have three adjustments on the carb. The air adjustment screw on the body of the carb. The tick over adjustment is the nut and bolt on which the slide stands passing through the carb body under the slide, clearly this should be as low as possible for greatest change in air mix volume in work. The last is to richen or weaken the fuel by raising or lowering the needle on the slide using the holes and clip provided. Tuning is to set a needle position. Then trade off the error between tick over and airscrew until it gets no better. Then raise or lower the needle to see if you can improve the settings.

To check your accelerator pump is there you will find that a loose carb slide is rejected by a spring below to about half venturi when pushed in by hand. With the fuel line open pushing down the slide and immediately releasing it should bring a squirt of fuel with it. The car will tick over and accelerate slower without the pump in, as it is a pressure operated one way valve. So if your mix is weak you will not be able to increase fuel delivery, without the pump action, to stop stalling. A number of cars are running with non operable accelerator pumps due to ignorance of the set up.

These carbs can be buggers to tune as they leak air and are often worn badly. So if its inconsistent that will be why. The worst habit is rev cycling on tickover. An amount of wear allows play, that tickles the accelerator pump to inject fuel upping the revs. With the revs up the vibration stops tickling the accelerator pump so the revs die back down till they do so again and round we go on a cycle of surges. Hopefully you have a good carb.

Engine on the plug is a bad sign, I refer you to the above tests.

[lemser]

Thanks Big Al. Think I will try to find a specialist in Denmark to have the engine checked and fixed. If full compression, then its most likely worn valve guides, right? How much compression should be measured for a healthy engine?

[Jim Janecek]

Are you feeling ok Jim? Its not like you to make a fundamental gaff like that.

Well that explains why every Heinkel / Trojan I work on always runs like crap!

[lemser]

Just an update. I removed the valve cover and discovered that two of the four nuts (the two nearest the spark plug) for the cylinder head was loose. I could turn them almost 1½ turn. I was not able to check the two nuts rear as their is no space because of valves. The result was that im now able to drive for 5-10 min before the plug gets oiled and engine dies. Does this make sense?
I will try to figure out how to check/tighten the two nuts rear. With a little luck this will fix the problem without an engine rebuild.

Best regards Per

[Big Al]

Crumbs. Its always something you thought nobody would do.

You have to get the engine on the firing stroke so both valves are unloaded by the pushrods. You then loosen the four 10mm pinch bolts on the four ali hoops of the head. You may now use a drift to remove the two shafts holding the valve rockers on. As previous, block the pushrod hole with a rag as several shims are likely to be on these shafts. Remember where they came from.

Now the head nuts are exposed. Tighten down all four equally. Re assemble the valve rockers taking care not to drive any of the four bushings in them to the center of the shaft thus obscuring the oil way on the top. Lining up the shims is tricky, I use a small screw driver. be gentle but firm with driving the shafts home. The ali as not strong but neither should the shafts be tight. If done right the valve adjustment will have not been disturbed. Do up the clamps and hopefully your problem is solved.

Pretty easy really. 

[Bob Purton]

Are you feeling ok Jim? Its not like you to make a fundamental gaff like that.

Well that explains why every Heinkel / Trojan I work on always runs like crap!

 

[Big Al]

Are you feeling ok Jim? Its not like you to make a fundamental gaff like that.

Well that explains why every Heinkel / Trojan I work on always runs like crap!

 

Darned single door Zundapps!

[richard]

i well remember that i sold my Trojan , via Mike Shepherd , to a woman in London . Mike had a phone call a week or two later asking how to check the radiator level and how to top up if necessary  NO KIDDING

[DaveMiller]

I filed up my Isetta at a petrol station, and went in to pay.
The girl at the till, in the petrol station, who was taking the money for the petrol, said, "I like your car. Is it electric?"