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Piston slapping then??

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

Reply to
Mad Sad Dad
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Mad Sad Dad let forth with a mighty belch and uttered :

Rebore + new pistons + rings

Methinks that I might have that too.

300yds more like :o)

Once warm the car is fine and

As piston slap is pretty much non-reversible mechanical wear, and it will lessen as the engine heats, how can it be intermittant?, the bore/piston surface is worn. It will lessen as the piston expands, but the wear won't reduce. If the engine isn't burning oil, I wouldn't worry about it. Half my bikes have got slappy and gone on to do high mileages.

Sure its piston slap?, from experience its a tinkly sound that is engine speed related, and worse at low revs/light throttle ( presumably the gas load at higher loads cushions it, or I may just be passing gas, so to speak ). Not usually accompanied by excess vibration.

Still got the lapel badge ;o)

Reply to
Sean

It's caused by excess clearance between piston and bore. Wear, usually. If it goes away when hot then I'd put up with it - probably.

No chemical can provide a cure anymore than with any type of wear. The answer is an engine overhaul.

Reply to
Dave Plowman

The engineering work would probably be more expensive than just buying a recon engine...

Although i would have thought that Volvo engines were as indestructible as the one in my Dads VW Passat 1.8 - since 1986 its managed 196,000 miles, with no signs of piston wear - and still puts out 90bhp :)

Kai

Reply to
Kai Robinson

Not too sure about my engine life - it's a Renault engine, not a Volvo one!! My 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. Seems more like claggy valves & oil flow problem to me now. It'll be cheaper too if that's the problem!

Reply to
Mad Sad Dad

What about 'oversize' rings???

Do any car engines have changable cylinder liners, like big traction engines?

Reply to
Tom Burton

I also remember the Pist -N- Broke Rally and that's how we usually ended up in the good old days.

By the way Muffin the Mule is still illegal.

Regards

Kevin B ( 650cc Triumph TR6R )

Reply to
Kevin B

Solves compression issues but doesn't make a lot of difference to piston slap

Yes, wet linered ones. & you can get dry liners fitted as well but it's rarely worth it compared with a rebore & oversize pistons

Reply to
Duncan Wood

Yes. But they'll usually cost more than a re-bore.

Reply to
Dave Plowman

If you want to hear serious piston slap ......... my mates bmw 525eta blew its head gasket 20000 miles ago. He ran it for a month with a nice oil/water mix going on....before he fixed it. Ever since, it has sounded like a DIESEL engine from cold, really REALLY loud .... imagine the noise of a load of rocks inside an engine ... thats the noise. The amazing thing is .. whilst the pistons may have been polished to nowt, the rings are obviously still tight as it has good compression. How does 190psi sound from a 11:1 compression petrol engine??

Oh ... nearly forgot to say, the pistons are top heavy (the are skirtless) and this probably increases the noise.

-- Regards SDD

Warning: Email reply address is a spamtrap, remove teeth to reply directly !!!!

Reply to
Ahgowonwidya

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;-))

Reply to
Mad Sad Dad

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