Pistons have cracked

[nova_mad1987]

Hi, I'm currently running a 1.6 sv bottom end wiv a 1.4 top end, 272 cam and r6 bike carbs, i got it running, took it for a road test, the car died and lost all compression, iv stripped it down and found that all of the pistons have cracked between the rings, any ideas? Many thanks

[Will F]

Massively high compression or leaning out due to a bodged fuel/air delivery...

[nova_mad1987]

Plugs are a tan brown colour, could it be anything due to the ignition? Thanks

[Royston]

Massively high compression or leaning out due to a bodged fuel/air delivery...

Was it pinking?

[nova_mad1987]

Was it pinking?
Wot does pinking mean?? Sorry

[Maxfield]

Pre ignition. Fuel explodes due to compression rather that it by a spark. Search Google is best for an explanation.

[Royston]

Pinking occurs when the mixture is lean, it is bit like light hammering sort of sound when the engine is under load, it can be very destructive to your pistons.

The combination of lean mixture/high compression/ignition timingsounds like the source of the failure, any pictures of the pistons?

Was the carburation/ignition set up before you ran it? I suspect not

[nova_mad1987]

It wouldn't rev past 3.5 k

[nova_mad1987]

Think I'm jus gonna give up wiv it tbh, is it now wise to run the 1.4 head on the 1.6 bottom end? I hear of people doin it. I don't have any pictures, but can get some tomorrow.

[Damo]

Its not very wise tbh because the compression will be mega high and as you have experienced you will get problems like h/gaskit blowing piston meltdown etc.

[Andy]

Any pictures of absolute failure for us all to laugh at?

[andy_mk3]

Yeah a 1.4 head on a 1.6 block will make the compression far too high!

[wwmnw]

Would using a multilayer head gasket not benefit the lad or a compression plate?

[Damo]

Would using a multilayer head gasket not benefit the lad or a compression plate?

Just using the proper head for the engine would be a better benefit tbh lol.

[wwmnw]

Just using the proper head for the engine would be a better benefit tbh lol.

True, but having a bit more compression, but not enough to crack pistons etc, would be an improvement over using the standard head. Although I cant imagine a compression plate being cheap or easy to find for one of these engines.

[C612DNM]

D E T O N A T I O N my boy.
It's proper fffed.

I'll have to post some piccies of some of the pistons from one of my V8's. I think it was 5 out of 7 that had chunks missing due to too high compression for the cheap UK gasoline (lack of octane!).

It's amazing what you can learn in the car park at Halfords.

[nova_mad1987]

Lol never mind, lesson learnt, don't always believe wot you read on here about mixing engines, it will be sorted tomorrow, got a spare engine that's been fully rebuilt, that's only done 1000 miles, it's a 1400 nv bottom end with a 14se head, jus hope I don't blow this 1 up lol, luckily the 1.6 block is ok and I have my 1.2 crank and rods, as I'm building a decomp engine for my turbo conversion (don't like hi comp engines any more lol) like was said, I should of double gasketed it and I'm sure it would of been ok, I will try and get some pictures, that's if I get time, as I have a busy weekend ahead of me lol. Any 1 got any 1.6 pistons knocking about :) thanks

[Adam]

Lol never mind, lesson learnt, don't always believe wot you read on here about mixing engines, it will be sorted tomorrow, got a spare engine that's been fully rebuilt, that's only done 1000 miles, it's a 1400 nv bottom end with a 14se head, jus hope I don't blow this 1 up lol, luckily the 1.6 block is ok and I have my 1.2 crank and rods, as I'm building a decomp engine for my turbo conversion (don't like hi comp engines any more lol) like was said, I should of double gasketed it and I'm sure it would of been ok, I will try and get some pictures, that's if I get time, as I have a busy weekend ahead of me lol. Any 1 got any 1.6 pistons knocking about :) thanks
Why who told you use that head/block combination on here?