mjtelectrical

There's a horrible knocking coming from deep in the bowels of me 2.0 WRX @01engine with 56k on the clock. It's only just started so I'm hoping it's not done too much damage yet. I'm considering me options, re-build, or a 2.5 short motor, etc.....
It's running 330 with supporting mods, but if I've gotta pull it and re-build it I might as well bite the bullet and go for a forged re-build as I would like to up it to around 400. Whats the general consensus boys & girls?

nampahc01

bite the bullet mate! re build it rite. especially if you want that bhp.

i've just bought a 2.5 forged closed deck from roger clark. hoping its worth every penny but it defo expensive.

for engine, arp head bolts, gaskets, oil pump, water pump, sump, oil cooler modine, belts, filters oils etc i was 3200 all in.

my mate went for a nitrided crank, forged rods and mahle pistons, came with oil cooler modine, pump head gaskets he was 1700 all in.

i think if your going the distance chuck in the 2.5 i've heard on here you need to machine out the standard heads for the 2.5 or if over rev'd the pistons will hit. but then someone said he fitted 1.6 mm cometic head gaskets and his is fine. so im gettin mine machined and fittin 1.6mm gaskets to be sure.

hop this helps

scooby1doo1

iTrader: (7)

As above might as well to a forge job, for safe bhp gains

mjtelectrical

I'm not so sure it's a big end. Could it be a tappet or something else as it wouldn't rev up without missing and spluttering once it started knocking. This was under load on a dyno today by the way so I don't see how rough running / missing could be a big end bearing. Thoughts?

nampahc01

melted piston, big end cld be so bad its hit valves.

you say it was on a rolling road? can the dyno tester not tell you what the engine noise is if he can't then hes not a very good dyno tester!

tappets don't make the same noise as a big end failure mate.

with big end going timing could of jumped or anythin.

regardless of what it is it needs investigation

APIDavid

iTrader: (4)

Melted piston would be my guess from the description of the failure. It is unlikely that the tuner would have had much warning if running flat out on the rollers, as perfect to scrap can be a matter of seconds when a piston breaks or degrades.

There ought to have been some knock detection before the failure, but even then it is usually too late - as the noise is after the failure.

Late rods or steel rods and forged pistons would make sense right now.

If I can help call me and l'll put a parts-to-rebuild package together for you :- 2.0 will be cheaper than 2.5.

Good Luck David APi

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