Knock, knock - who's there? Here is your crankshaft... REPAIRED!

[michaltalbot]

So, today on circuit, my engine took his moment and started knocking. Combination of hot weather, high oil temperature and several visiting red zone of the rewmeter, wasn't so fine for my crankshaft. 3 laps I was following the WRX STi and than I had to finish the race. So on saturday I will demount it to see what's happend. Half an hour after leaving the car standing, the oil gauge was so hot, that I couldn't touch it by my fingers! For circuit racing the oil cooler is a must. But there were some things why I wanted to demount the engine for 3 years, but I didn't, so now it's the time

[Anders Dinsen]

Sorry to hear that, Michal! Good luck finding and correcting it!

/Anders

[Jon Weywadt]

Hello Michal.
Bad luck. It sounds like lubrication to one of the push rod bearings failed and it wore out.

It is a little late for you now, but I can recommend this product from RVS for your rebuilt engine

http://www.rvs-tec.dk/00008/00014/

It is a nano ceramic compound you pour into the engine oil. What happens is that the stuff builds up in the microscopic pits on the friction surfaces so you get closer to normal tolerances and the surface becomes super slick. They claim that the engine will not seize up if driven up to 200 km with no oil pressure.

I put the stuff in my Murena prior to the problem I had with my cooling pipes. When I lost all coolant while in a rush hour queue, I managed to drive it home the last 2 km without damage to the engine. Without this stuff I believe the over heated parts would have scoured the friction surfaces.

[michaltalbot]

Well, as I though, is just one bearing

[Oetker]

Doesn't look good.
Are you going for a total rebuild?

[michaltalbot]

Main bearings are fine, I will measure the crankshaft and if it will be possible, I will brush only the small end bearings + new bearings. Is very possible, that one piston-rod is extended a little, so if we will find used one with the same weight I will change only one, if not, it must be the whole set. But all this 4 years when I repaired for first time, there was a little oil leak somewhere near clutch, and one year ago one boot on right axle was broken, and I all the time said that I will do it "later" so now is the time to do it all, to have it perfect. And at the end of this month it must be back on circuit

[Oetker]

I hope you can find all the parts needed.
This engines are becoming more difficult now.

[suffolkpete]

From the photo, it looks as if the shell has seized on the crankshaft and spun round, in which case the con rod is almost certainly damaged.  No wonder it knocked, it was probably the shell loose in the con rod.  If you can only get one rod, a good engineering shop should be able to balance them for you.

[michaltalbot]

Well, Murena is on the road again

But the repair was much more complicated than it seemed to be on the beginning... When we domounted the crankshaft, we've found that 5th main bearing was completelly damaged - and it was also the cause of massive oil leak between engine and gearbox in last months. But why...?
I've bought a crankshaft (used but excellent condition), drove the cyl.block for making the alignment of main bearing houses and crankshaft + flywheel to balancing. Is known, that 5g of unbalance is bad, so I had 12g on my flywheel (!!!) and 7g/6g (left/right) on the crankshaft. After balancing it was 0,17g on the flywheel, 0,16/0,18 on the crankshaft and 0,17/0,18 on the completed asseble. So this was the reason why my 5th main bearing was gone...
Also we've found another problem - when we completed the engine 4 years ago, we've chose the best oil pump from 3 which I had, but I didn't knew that this one was originaly from P505 and it is 8mm lower, so this was the reason why my oil pressure gauge went to 1 in every corner...
So now, we've made it perfectly (I hope ) and yesterday we've put it back into the car. Also in the meantime, one specialist made complete renovation of my gearbox.
I'm so happy to drive Matra again

[Oetker]

Congratulation on a job well done and nice that you tell the problems you encountered.
The story about the oil pump will make me alert to measure things.
Most of the 2.2 engines I hear and see have some vibrations from the engine in the car.
Engine mounts are one point, but I also have the feeling that flywheel and crankshaft take part in this to.
Do you notice any difference since the engine is better balanced?

[suffolkpete]

When I rebuilt my 1.6 engine earlier this year, I had the the whole clutch, flywheel, crankshaft and pulley assembly balanced, as well as having the flywheel slightly lightened.  The balancing only cost about £60 and it was money well spent in my opinion.  There is a big difference in the smoothness of the engine.

[michaltalbot]

I think that it is a difference. For first 1000km I'm not going over 3000 rpm, and touching throttle gently, but the car goes from 2000 to 3000 rpm very very fast and I have to gear up and up again, I couldn't imagine what will happend above 4000 rpm, where this "S" engine starts to pull strongly. I paid cca 70,-Eur for balancing, but just when I saw that I knew that it's the best way how to spend 70,-Eur When they started, we felt strong vibrations in the floor! The man, who is doing balancing for more than 40 years, told me, that his machine is sitting on 27 barrows of concrete when he finished, we just listened the air whizz (if it is the right word).