Slapping piston????

  • Thread starter Thread starter Mad Sad Dad
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Mad Sad Dad

Following a thread in another car ng I think that my pistons might be
slapping!?!?! Any ideas folks?
How does one solve piston slap then? Methinks that I might have that too.
Only happens when car is very cold. Usually after 1/4 mile. Sounds like a
metallic woodpecker down there in the engine bay, Volvo 400, 14 years old,
1.7 engine with 85k on the clock. I have used one of those valve cleaner
type liquids - you know, warm engine - pour 50ml into each plug hole, leave
for 20 mins, cover/fill holes with cloths, turn engine for 10 secs and cover
yerself with oil and then drive for 3 miles with a wall of smoke behind you
(only joking with the last bit). Once warm the car is fine and the noise
only happens for a hundred yards or so. It is intermittent - so garage and
me can't get it to produce the sound on order.

Incidentally I do remember a motorbike rally years ago that used to be
called "piston broke". Clever when you think about it eh?
It'll be tricky to get a good mp3 as there's always other louder noises
Click to expand...
around (unless lifes truly about to go wrong in which case switching off is
going to make more sense than running for a microphone ) but anyway I'll try
& look silly
Pinking literaly goes "inck inck inck inck inck" with the emphasis on the c
labouring goes burrgg & sounds like your Dad driving uphill in 5th
piston slap varies dependent on the car but it's more unk unk unk than ink
Click to expand...
ink ink. It's also worse when cold
 
Piston slap?

I don't ever recall having a car with "Piston Slap" but I had Motorbikes
with the tell tale "I have been caned" syndrome. Trouble is with Bike
piston slap is it is always there. You rev up the motor then back off the
revs and you get a nice "Kaggggggggggggg" metal to metal sound, which is
there in a more muted stated on idle.

Yours sounds more like insufficient lubrication at the cam/valves when first
started up. Might even be gummed rings (Oooer Missus)

I don't know how to fix it but I would start with the obvious.
Oil, oil filter change and clean out the oil pickup in the sump. Maybe a
good engine flush run through it. To clear up those hard to reach oil ways.
Regular oil and filter changes would practically negate the use of such a
practice!


Hard to describe a "Sound" using letters the "Kagggggg" is a "K" as
in the phonetic "k" and the "aggggg" is in the back of your throat, like you
are trying to shift some heinous greeny. (Sorry)
 
Yep. last oil change was 5 months ago but it is going for mot and service on
Saturday. Local & reliable garage - so I'll have a chat with them about it.
Piston slap - try a google search and it does exist. Seems more like claggy
valves & oil flow problem to me now.
 
If it is piston slap there's really not much you can do but overbore the
engine and fit new pistons. Alltough i've heard of B230 series engines wich
has developed piston slap around 200K wich ran fine another 100K. I don't
think piston slap can be intermittent. If it's not bad you'll only hear it
when engine is cold, always, not intermiitent
 
With the 1.7 Litre engine, you describe your 400 series as having, It is very
easy to deal with a slapping piston. You replace the cylinder liner(s) and
piston(s) which are slapping. However, as in all things mechanical it is best to
replace all liners and pistons to ensure a matched engine. However, there are a
myriad of other faults which can cause this symptom, such as one tappet
requiring adjustment etc. To be sure check the Renault FAQs on-line as the
engine is a Renault unit. If you have the fuel injected version, injectors can
also make a similar noise. Try fuel and fuel injector cleaner in the fuel tank.

Cheers, Peter.

: If it is piston slap there's really not much you can do but overbore the
: engine and fit new pistons. Alltough i've heard of B230 series engines wich
: has developed piston slap around 200K wich ran fine another 100K. I don't
: think piston slap can be intermittent. If it's not bad you'll only hear it
: when engine is cold, always, not intermiitent
:
:
:
: : > Following a thread in another car ng I think that my pistons might be
: > slapping!?!?! Any ideas folks?
: > How does one solve piston slap then? Methinks that I might have that too.
: > Only happens when car is very cold. Usually after 1/4 mile. Sounds like a
: > metallic woodpecker down there in the engine bay, Volvo 400, 14 years old,
: > 1.7 engine with 85k on the clock. I have used one of those valve cleaner
: > type liquids - you know, warm engine - pour 50ml into each plug hole,
: leave
: > for 20 mins, cover/fill holes with cloths, turn engine for 10 secs and
: cover
: > yerself with oil and then drive for 3 miles with a wall of smoke behind
: you
: > (only joking with the last bit). Once warm the car is fine and the noise
: > only happens for a hundred yards or so. It is intermittent - so garage and
: > me can't get it to produce the sound on order.
: >
: > Incidentally I do remember a motorbike rally years ago that used to be
: > called "piston broke". Clever when you think about it eh?
: > >
: > > It'll be tricky to get a good mp3 as there's always other louder noises
: > around (unless lifes truly about to go wrong in which case switching off
: is
: > going to make more sense than running for a microphone ) but anyway I'll
: try
: > & look silly
: > >
: > > Pinking literaly goes "inck inck inck inck inck" with the emphasis on
: the
: > c
: > > labouring goes burrgg & sounds like your Dad driving uphill in 5th
: > > piston slap varies dependent on the car but it's more unk unk unk than
: ink
: > ink ink. It's also worse when cold
: >
: >
: >
:
:
 
Just had MOT, annual service inc filters, oil etc and new brake pads on
front for £148. Guy said that the noise was the hydraulic tappets with an
oil flow problem and that the new oil change and better quality Castrol oil
(!) should solve the problem. Will find out tomorrow when the car is cold
and has to work hard...... He also said that at 85k miles it would cause
more problems than it would solve to flush the engine oil out as the bits in
the system would be moved around and might cause a problem elsewhere rather
than at the bottom of the sump. I'll take his word for it anyway.
No need to but another car now that the old lady has passed her Test;-))
 
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