Bad News: I?m Done. Time Stroker it I think...

[diegom6]

Well here are two pics wh I'm taking down the engine and possible to make it stroker. Just noticed this before attempting to put back my fresh head.

I have the S50 3.0L crank, the "i" stock rods I think will work and I was thinking to put the M42 pistons wich has almos the same bore, but I would like to know the pin height, so I will know if is possible to make this combo but not sure what CR will obtein.

Ring just blew, not sure why, happened before in other m20's as well in other bimmer engine not F.I. , so I'm not the first one.

It's a shame because the rest of the engine are in good condition and I will have to overhaull/stroker this engine just for the 5th cylinder mostly, the 6th has a little crack int he first ring also, but less and has a little scratch int he cylinder wall, 5th cylinder wall got the worst part check!


Gizmo316i I think can help me about those m42 psitons specs, he told me once about it, not remember well. How do I contact him? ( I think I wrote wrong his nickname)



See the cracked ring at the top right part:

[NickG]

Cracked/broken rings on the back cylinders usually indicates an overheating problem. Check the cooling system and the mixture (too lean will overheat the chamber).

[dom]

Was that you who welded water passages and made a post about it?

[techno550]

My money is on detonation being the culprit for those broken rings.

[diegom6]

Was that you who welded water passages and made a post about it?

YES.

Techno S50, I think you are right, it pinged in the past many times due th elack of a good fuel magnament but that's a old story now, I have the MS wich is a fuel & spark controller.

[dom]

Were you using that welded head when the damage occured? By welding those water channels you pretty much lost most of your cooling capability since water can't circulate and cool the block and the head. Once the block, pistons and head are too hot it's very easy to detonate. What gave you an idea of welding it in the first place?

[techno550]

Were you using that welded head when the damage occured? By welding those water channels you pretty much lost most of your cooling capability since water can't circulate and cool the block and the head. Once the block, pistons and head are too hot it's very easy to detonate. What gave you an idea of welding it in the first place?

The welded passages may be too small, but they didn't appear to be so from the pictures. The head gasket has varying size holes to control coolant flow. Most of which are practially pinholes near the front to promote flow to the back of the head. The ones at the back of the head aren't large by any stretch of the imagination either.

[diegom6]

Were you using that welded head when the damage occured? By welding those water channels you pretty much lost most of your cooling capability since water can't circulate and cool the block and the head. Once the block, pistons and head are too hot it's very easy to detonate. What gave you an idea of welding it in the first place?

NO! if you read carefully the first thread, you will see that found this damge while I was trying to put back the welded head . I didn't run yet the wleded head and again it won't have issues with temperature. Check the block and the head gasket shape you will see is sealed so it doesn't disstub the water flow.


Been done before.

[dom]

Sorry, I assumed you completely welded water passages like they do on drag racing engines.

[diegom6]

Sorry, I assumed you completely welded water passages like they do on drag racing engines.

No prob!

[BlownM3]

Sorry, I assumed you completely welded water passages like they do on drag racing engines.

They don't weld the passages they fill them will block filler.

[Juker008]

Cracked/broken rings on the back cylinders usually indicates an overheating problem. Check the cooling system and the mixture (too lean will overheat the chamber).

What does it mean on the front cylinders?





Juker008