bonesetter

iTrader: (9)

Can it be nothing untoward for a tuned (in this particular case a ~330bhp MY99 STi) engine to have a 'clatter' at tickover?

Brief spec is as follows:

STi9 Nitride crank
Manley H beam rods
ACL phase 2 race series bearings
ACL race series big end bearings
Mahle Powerpack pistons

The sound seems to be coming from the left of engine. If your ear gets right over the turbo area the tapping can only be described as quite loud and becomes a clatter. Soon as the rpm picks up it goes away (I picked up on this when the engine was warm so not sure if it happens when cold)

Seller said it has always done this (12K rebuild) and he mentioned it to his builder (very reputable) who said it was down to the type of pistons and bearings used and was nothing to worry about...?

barnshaw

iTrader: (1)

dont uprated forged pistons tend to give you a more tappety engine anyhow?

dazdavies

iTrader: (22)

If it is piston slap it should be quieter when the engine is warm.

It could also be one of the valves with a slightly larger than spec clearance.

Rob-S

iTrader: (5)

Agree with Daz, it should get quieter when warm.

prodriverules

iTrader: (52)

I'll be honest and say I'm yet to hear what I term as quite subaru engine and when they get forged it usually only gets worse
But there is a limit as to how loud before it is not right it can or should be so without hearing it ,its hard to say one way or the other imo mate.

greatgonzo

iTrader: (1)

I'm no expert but if it was due to a forged engine why would it only come from one side?

biggazvr6

iTrader: (8)

My newly forged engine is a bit clattery when cold. I thought at first it sounded fecked! 4 specialist have loomed at it and all agree it's just a sweet sounding forged motor. When it warms up it's sweet as a peach. Mines got Mahle pistons in so could be a factor with them. As said above tho there has to be a limit to how noisy it is before it's classed ax buggered or possibly the type of noise it's making. Mines getting mapped Thursday. I'll let you no if it let's go!!!!

dazdavies

iTrader: (22)

Mahle are usually one of the quieter ones du to their construction.

I'd put my money on a single valve clearance being on a little on the large side.

Carlh

Mines noisy as hell when started up (piston slap) soon gets quiet after 3-5 minutes though.

ditchmyster

iTrader: (7)

Yep quiet they are not, i think it's all them horses clipity clop clipity clop

djmisio85

What kind of clutch do you have? I know that twin-plate clutches can be very clattery at idle... but goes away when you rev.

The OP mentions that his engine is clattery when warm... so doesn't sound like pistons...

burns

iTrader: (1)

Mine sounds like a diesel until it hits 80deg C and then it's silent. Been like that since it was built 5 years ago.

bonesetter

iTrader: (9)

Thanks for the replies.

Should be quieter, or completely quiet when warm then...? Unless it's a valve clearance issue.

What could the worst case scenario be?