A610 in the Rat's nest

No ...I can't even get to it as yet

I meant the 610 internals... I know what "normal" 3 litre internals look like In fact, you're a CAD man, model a 610 piston will ya?

*cringe*

No ...I can't even get to it as yet

I meant the 610 internals... I know what "normal" 3 litre internals look like In fact, you're a CAD man, model a 610 piston will ya?

Yeh ..right .....the Winter evenings will just fly by ...I've officially hung up my CAD mouse

Send me one and I'll do it then....

The Precious !! No ! nasty Spunky ...you cants have it ..
Bit of scuff on the skirts ,this being the worst .Wear on one of the cams .
I've lost the bit of paper with the compression figures on it innit and also cleaned my sent box so hope Rob still has the PM

I sure do

1.130psi
2.155
3.135
4.120
5.160
6.100

Hi Lee,
Which piston has the worst skirt damage? - front right in the direction of travel?
Was there any piston slap when cold? (most A610's seem to suffer from this)
How similar are the pistons to the Laguna items?
Many thanks
Lee

Was there any piston slap when cold? (most A610's seem to suffer from this)

Yes

I'm logging all the wear etc as I'm not overly sure how many 610 lumps have been pulled .....certainly there is no first hand data available .) MrF may have some in the vaults though .
# 3 shown

I've heard three Venturi 300s all wth the same sound, even with relatively low mileage. Now, about modelling a piston...

No 3- is that one of the middle pistons or an end?
According to the PRV book CR is the same as some Lagunas, hence the question about piston shape vs a Laguna.....

Is the book right? If so there is a simple way to quieten down the engine, otherwise we need a (large) batch of A610 pistons made......at Macon, every A610 I listened to had a degree of slap when cold (but I only listened to a few).

Maybe the 20 year celebration would be a better check?

Cheers
lee

Due to the crap exhaust manifolds running extremely hot with the extra 50 BHP over the GTA T, is it not possible Renault allowed a little more expansion clearance/tolleranceon the bores on the oringinal spec build to allow for the extra heat.

Does this noise diminish once hot and only make it from cold?

Just a thought since they all make it, the noise that is?

Si21

RH bank pulley end .
Not got a Laguna piston out in the fresh air so can't say as yet .Have they always been slappy ? Anyone had one from new ??
Most of the wear is on the thrust side of the skirt . Although # 1 ( up 'tother end ) shows equal amounts of wear on both sides almost as bad as # 3 .

According to the PRV book CR is the same as some Lagunas,

lee

The book states the CR in the Z7X-R engines is 7.6 to 1. UK Lagunas have this engune code (that I've seen). This is correct for the A610 but nonsense for the Laguna. I suspect turbo blocks were used for boggo NA engines when demand wasn't as high as expected, hence the under piston oil jets on the Lagune not present on the Safrane.

Hi Lee,
Which piston has the worst skirt damage? - front right in the direction of travel?
Was there any piston slap when cold? (most A610's seem to suffer from this)
How similar are the pistons to the Laguna items?
Many thanks
Lee

The 3ltr n/a pistons are a different casting, and I would be reluctant to push one into turbo service. This is mainly because the amount of material between 1st and 2nd ring is a little marginal for the additional heat loading from a turbo app.

Si, if the piston skirt is seeing incremental heat loading due to the cat then you would be into detonation long before that. Most of the heat is carried out by the top ring don't forget chaps.. and you are looking at probably only 20% ish going out the skirt. The top of the piston at the ring lands is no where near the bore - so this has nothing to do with clearance / piston skirt shape design.

The slap is pretty much down to the very short skirt on the piston i.e. piston rock at TDC, look at the pin position to skirt. This isn't ideal, but locked in the design - where does that come from... come on guys - think - it's a long rod motor... the ring package placement (down the piston) is pretty much determined by thermal properties - combustion and keeping the rings alive, you have a 73mm crank throw, and a long connecting rod dictated by the engine geometry... so the pin position is always close up to the rings on all PRVs... The reduced skirt is to cut mass and friction... The PRV is a big compromise...

This piston can be found else where, but I ain't telling ya... I have some. I also have the Laguna and 24V pistonies...