Seconds out... Round 2

[Vtec6000]

Think @jesse888 has hit the nail on the head. Ultimately there's been detonation in all cylinders. Head gasket symptoms where the wall of cylinder one starting to break down and then it's just let go completely.

The new block should be here this weekend. Hopefully crank is ok as it was in good shape. Will need a bare head as head internals are good but I'll probably go for new valves anyway.

Selling my house this week so limited in what I can do till that's sorted but thinking about getting an 18c4 complete engine to get it up and running short term and building a monster over the winter.

That's not detonation, that's damage from debris that made it's way from cylinder 1 into the other cylinders, it's very common when something like this happens for debris to get fired back up the intake manifold from one cylinder and then be ingested into the other cylinders!

 

[jesse888]

Is DET not little white marks on the Pistons/spark plugs etc?
Do we think that this failures just a freak thing then?

 

[Vtec6000]

Is DET not little white marks on the Pistons/spark plugs etc?
Do we think that this failures just a freak thing then?

No, typically on plugs you will see specks of black and/or shiny specks of basically piston material if detonation has occurred. Given that this engine was on a super safe run in map i.e low rev limit, very conservative timing with timing zero'd above 3/4 psi and boost cut also set to 3/4 psi and no vtec operation it would IMO be almost impossible for det to occur so I think that can be ruled out! Unless of course someone had a play with the ecu....

When a engine lets go like that at 4000rpm so much damage occurs in a very short space of time making it very difficult to diagnose what exactly happened. Given that it was running hot and filling up the expansion bottle prior to letting go I would say perhaps there was a issue with the liner.

 

[jesse888]

Learn something new everyday!
Suppose it's a good job this happened now and not on the dyno.

Rush job from the machinist perhaps? I mean the engine would have ran fine before rob forged it so makes you think something along that process has weakened the cylinder wall.

 

[robthedoc]

No changes to Ecu other than boost increased to 4 psi from 2 as over taking was almost impossible.

 

[Wazer]

I'm sure @Wazer had his old b20 sleeved. Worth finding out who done it

Yes, fair few years ago now. Engine is still going strong I think. I had a company called Advanced Motorsport & Engineering do it for me - they are based just on the outskirts of Silverstone and have an excellent dyno facility there aswell. God I miss that engine, alot.