The cooling oil and the lubricating oil arrive at the head separately. The lubricating oil is fed up one of the stud holes and into the cam journals. The cooling oil does flow up and down through the barrel, but it is a direct route so probably not designed to have much effect.

I think you're right about the partial seizure from overheating Ken, but until now could see any possible reason for it to overheat. The fins are all reasonably clean, and free from corrosion or flakey paint. And the cylinder was operating under the same conditions as the other side at the time, and both cylinders of the current engine are now.

Looking at the less significant damage on the upper side of the piston, I would think it's fair to assume that the lower side looked similar in the early stages. I've destroyed plenty of small capacity bike engines in the past, and the scuffing and nipped rings are quite familiar. But the only one that showed any significant melting of the piston was one that I believe was running lean, it burnt a nice round hole directly under the central spark plug.

It is of course quite probable that this engine would have stopped much earlier had it been a single cylinder, which is why the damage is much worse than anything I've seen previously.

I wondered if the loss of compression from the nipped rings was allowing enough gas past the side of the piston to generate the heat required to melt it, but I'm not convinced by that.

Scrolling down to page 31 of that PDF the damage shown looks similar, and it is next to an exhaust valve. Could it be that the valve clearance was too small, the valve overheated and started glow-ignition? I'll have to try and lift the valve and look at the seating surface. I thought I did the clearances, but I was in a hurry.

Hi Joolz,
Any news on your engine problems??

I did eventually get around to looking at the valves, and it was pretty inconclusive. I think it looks normal.







The valves on the other side were similar, except that they were cleaner on the backs as that cylinder hadn't been burning oil.
To be honest I'm not much closer to knowing the exact cause.

For comparison/amusement, here's a valve from a different engine that I burnt out earlier.

Other stuff, on the journey back from Spain I started getting an odd feeling like an out of center wheel. When coasting up to traffic lights I could feel one rear corner rising and falling with each wheel rotation, I think this tyre has definitely had enough.



I've now swapped to 165/65 all round, they just fit under the rear wings. However while lying under the car checking the clearance I spotted this.



Oh cock! It doesn't look fresh so may have been there for a while, and it's the same on both sides, perhaps from when I overloaded it with the bike on the back. I can't decide whether to take the arms off to weld them at home, or wait until I can get it on a 2 post lift and use a better welder. Trouble is I need an MOT asap and would have to try and hide the cracks with some more dirt! It would be good to get the arms off, I've never checked the arm bearings on this car, but the brake pipes are such a PITA.

Cant vizulize exactly where that is, but could you not remove the tie rod etc snd swing the arm out the way?

Think (may be wrong) its the knife edge mount on the arm.
Picture taken from somebody else web site - sorry

Joolz just a quick question.....

Putting a beamer engine into a 2cv isn't a solution for releabilty either (when having more power) looking at your report here.

Or is it just you who's having bad luck with it.

Looking over the pages I see several driveshafts-, electrical- even engine -failleurs pop up.... and now your car is falling into pieces.... (probably to higher stress level)....


I think a turbo powered or Supercharged 760cc hybride (Visa/2CV) engine will bring almost the same amount of power definitly the same amount of fun and I think it is more reliable then your configuration..

How do you think about this.... Probably the wrong time to ask this question but anyway....

James and Chris yes it's the Knife edge mount/tie rod bracket that's trying to part company with the arm, the rear right hand one, picture taken from just in front of the wheel.

Geo, I avoided joining in the 'Alternative engines' debate. I'm afraid I disagree, yes I've had a bit of trouble over the last year, but I don't think any of it is specifically because of going down the BMW route.

Clearly the most reliable thing is to stick with the standard power, but that wasn't what I wanted. I agree that a turbo is a good value way to gain more power, and that 40-50hp is not difficult, but more than that will be expensive and unreliable unless you know a lot about engine tuning.


I disagree, there's no way you could get 85hp from such an engine for £1000, (that's what it cost me to fit the BMW, but it could be cheaper) and I don't believe it would be more reliable. I know I only write here about the problems, but the truth is the car has done 15,000 miles(over 24000km) in 13 months. Only 80 of those miles were on the engine that broke, which had a fundamental problem, I'm just not sure what. When on track in Spain I was not watching the temperature gauge in the car, it reached 140*c, no harm done. The engine is German, it is very reliable.

The drive shaft problems were because, I have too much power, it doesn't matter what type of engine makes the power, BMW, tuned GS, or nitro burning boosted Visa.

The only electrical problems were the bad starting, a new battery and starter motor fixed that, it would be the same with any car.

The suspension is breaking because I fucked with it, it has hard shocks, the springs bottom out, I don't slow down enough for speed bumps, and I overloaded it. It's not the fault of the engine.

Anything else? I think I have an answer for them all.

Hope you have done an oil change, if the oil reached 140c its no longer oil...

Good point.