[Mk2] [Turbo] Fooked pistons, see what you think!

[diycinema]

I spent the last few days taking my engine out and stripping it down to find this:






No 1 looks fine, no 2 tested 50 psi down and is cracked in various places, three and four are also cracked but compression tested ok!

Can any of you hazard a guess as to why this happened? Could be detonation?

The car is a stock rev 3 turbo. The previous owner had an MBC fitted and mentioned he replaced the knock sensor not long before i bought the car ( )!

Also, anyone got any spare pistons lying about?

[Quigonjay]

what do the tops of the pistons look like?

[diycinema]

They all look pretty similar, here's no 4:



Here's no 2 (covered in oil as i poured a bit in on the comp test).

[Quigonjay]

i'd say that looks like detonation

[-:[KM]:-]

Also, anyone got any spare pistons lying about?

Got 3 standard pistons and rods in the garage dude. You are welcome to have 'em.
A re-ring and shells will get you going again.

Can't you afford forgies though?

Where are you?

KM

**edit**

Deffo detonation by the looks of it. What boost did he run at?

[diycinema]

He never mentioned the MBC and i didn't notice it when i bought the car (was running fine back then!). He had the TVSV disabled and had bled it back up to 13psi when it was sold. I emailed him about the MBC when i noticed it and he said:

"It can go upto 18 psi but obviously puts a lot more stress on everything".

I reckon over enthusiastic use of the MBC (wasn't me!) is to blame for this mess!


Those pistons would be brilliant mate, i'm all the way down south (near Bournemouth) so couldn't really collect them. If i send you a bit of cash would you be able to post them on?

I'm not sure about forgies, i could probably afford them but wouldn't have any cash left over for supporting mods to get the most out of them. My turbo also needs rebuilding

[rmarr1980]

Looks very much like detonation dude.

If you can afford forgies I would still fit them as it will save you a job later if you plan for more ponies!!

Will save you having to re-strip you lump down at a later date.

[diycinema]

Hmm.. i've had a think about this and i reckon i won't end up tuning it much in the foreseeable future so probably best to stick with the stock pistons and save the cash for beer

[Leakie Tbar]

Too much Boost not enough Fuel