997 GT3 Death Rattle on Start up

[GreigM]

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

[anonymous-user]

GreigM said:

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

Accusump on a dry sump car to avoid tappet noise? Oh pahlease...
Tis normal and harmless (you should worry more about dry pistons than dry tappets) so please forget it.

Edited by drmark on Tuesday 28th September 19:56

[BertBert]

drmark said:

GreigM said:

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

Accusump on a dry sump car to avoid tappet noise? Oh pahlease...
Tis normal and harmless (you should worry more about dry pistons than dry tappets) so please forget it.

Edited by drmark on Tuesday 28th September 19:56

Whilst agreeing that the accusump is not needed, the fact that the car is dry sumped does not itself denegrate the proposed used of the accusump.

Bert

[anonymous-user]

BertBert said:

drmark said:

GreigM said:

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

Accusump on a dry sump car to avoid tappet noise? Oh pahlease...
Tis normal and harmless (you should worry more about dry pistons than dry tappets) so please forget it.

Edited by drmark on Tuesday 28th September 19:56

Whilst agreeing that the accusump is not needed, the fact that the car is dry sumped does not itself denegrate the proposed used of the accusump.

Bert

Oh come on Bert - it's a ridiculous reason to fit the system. That's my point.
Now, time to stop fuelling this thread.
Off to put my GT3 on it's roof so I don't wake the neighbour's tomorrow.

[GreigM]

drmark said:

BertBert said:

drmark said:

GreigM said:

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

Accusump on a dry sump car to avoid tappet noise? Oh pahlease...
Tis normal and harmless (you should worry more about dry pistons than dry tappets) so please forget it.

Edited by drmark on Tuesday 28th September 19:56

Whilst agreeing that the accusump is not needed, the fact that the car is dry sumped does not itself denegrate the proposed used of the accusump.

Bert

Oh come on Bert - it's a ridiculous reason to fit the system. That's my point.
Now, time to stop fuelling this thread.
Off to put my GT3 on it's roof so I don't wake the neighbour's tomorrow.

I never said it was a good idea to fit one - just that it would stop the noise and related wear....

[woppum]

It's part of the character of the car. Enjoy it!

[Henry-F]

sportsandclassic said:

The chatter you can hear is more than likely the gearbox gears chattering against one another and when the clutch pedal is depressed the input shaft stops turning thus the noise goes.
Mike

No Mike, the deafening rattle in my cup car until you depress the clutch pedal it just a tiny bit of release bearing chatter

You are of course correct. I just prefer to think of it in terms of the bearing rattling slightly in the fork as per an older car. It makes me feel better

I was probably posting a bit of a generic reply rather than specific to the op's question / car which was wrong of me.

We, as will you have done, have come across a few instances where seemingly innocent and normal noises are more serious. I can't emphasise enough the importance of getting it looked at if you are at all unsure. If nothing else it will put your mind at ease and allow you to relax and enjoy the car.

Henry

Keep

[BertBert]

drmark said:

BertBert said:

drmark said:

GreigM said:

Is it normal - yes, does it cause wear - ultimately yes. If you want to avoid it you could install something like an accusump to pre-pressurise before start, but a big job for something Porsche see as normal wear n tear. I found it to be worse on the cars with a single-mass flywheel (like the 996 Mk1 Clubsport or RS), but that may just be coincidence.

Accusump on a dry sump car to avoid tappet noise? Oh pahlease...
Tis normal and harmless (you should worry more about dry pistons than dry tappets) so please forget it.

Edited by drmark on Tuesday 28th September 19:56

Whilst agreeing that the accusump is not needed, the fact that the car is dry sumped does not itself denegrate the proposed used of the accusump.

Bert

Oh come on Bert - it's a ridiculous reason to fit the system. That's my point.
Now, time to stop fuelling this thread.
Off to put my GT3 on it's roof so I don't wake the neighbour's tomorrow.

Sorry, being super-nit-picky. Don't know what came over me!

[anonymous-user]

Bert, it's the 993 lot who are supposed to be the picky ones. GT3 owners are supposed to be laid back about noises - because we need to be!

[Pugley]

Lets put this question a different way...............

Is there anyone who owns a GT3 that DOES NOT rattle in some way when started from cold?????

[BertBert]

That's quite a loaded question and as far as I can see not related to the original concundrum. But I'll answer if you insist. I never rattle.

Bert

[B16 FYS]

Pugley said:

Lets put this question a different way...............

Is there anyone who owns a GT3 that DOES NOT rattle in some way when started from cold?????

Yes, mine, but my 2007 997RS.2 has 21,500 million miles on it !!!!!!!! Lol

[3564cam]

hi,
My view on the death rattle is that,if it rattles whilst cranking,prior to starting,that is a problem.As a Porsche specialist,we were asked to get to the bottom of the problem on a particular car.We found the problem,fixed it,hence no rattle on cranking,and also no rattles ,suprisingly,whilst running.Timing chain tensioner blades do break as well as timing chains jumping off the ramp due to over revs on the down shift always seems to be on the left hand bank.Turbos have a distinct rattle at idle due to the turbo scavenge pump gears chattering.

[magsgt3]

My Gen 2 does exactly this very specific noise randomly on start up. It can sit a couple of weeks and not make it or from one day to the next it will. It sounds terrible when it does like something is seriously wrong. Every expert I've asked has instantly understood what noise I'm talking about - this isn't clutch chatter or some little chuntering noise - and they all instantly say its the chain tensioners not having enough oil pressure for the first second or so of start up and they are very clear about this fact and say its nothing to worry about "and they all do that sir". Reading this thread made me wonderthe noise causes so much grief and some cars seem to do it and some not so...is it something easily adjusted, what is the noise exactly - is it the chain hitting the chain guard/ cover while its too slack or something more sinister like the chain jumping of its sprocket and back on,why do some cars do it and others not - would have thought that the tolerance on a mechanical item like this would be very similar from car to car...or is it something to do with the fact some cars spring to life instantly (I know mine does) where as some cars turns over for a second or two? Sorry for all the questions, just interested to get to the bottom of it finally. FWIW my car hardly did it during the slightly warmer weather but has started again as it has gotten colder. Does anyone think blipping the accelerator to increase oil pressure before switching off helps keep oil pressure in that item for the next start up and does anyone mechanically know why the rattle effect is so random as to when it occurs? Again sorry for all the questions - just intrigued.

[Dave 321]

mine only does it after it fires up, not while cranking

[arcamalpha]

Dave 321 said:

mine only does it after it fires up, not while cranking

Mine too. Cranks quietly, then as revs hit about 1500-2000 for an instant it starts, but only lasts for 1/2 second or so until revs come back down to 1100ish cold idle.

Only does it once in every 10-20 starts, and normally when very cold after an enthusiastic run the previous day.

[Ferry]

Here's the definitive info on the GT3 start-up Death Rattle and smokescreen: it's not tappets, piston slap, bearings etc etc, it is simply this: the GT3 has a Sports Exhaust with a Normal and Sport setting selected by a button on the dash: when Sport is selected, vacuum-operated valves in the exhaust system bypass additional silencers giving a lower back-pressure and more noise. When the engine is first started, the vacuum to these valves is asleep, and for a couple of seconds until the vacuum develops, they are at the mercy of the natural pressure pulses of the exhaust, causing them to flap open and closed uncontrollably in sympathy with the exhaust pressure pulses, causing the cacophany: nothing to worry about. As for the cloud of oil smoke on starting, again quite normal: the dry sump system leaves traces of oil around the place, which is inhaled and burnt on startup - again quite normal and not a worry. Guys - get real - part of the fun of owning a race-derived-engined car is accommodating these little idiosyncrasies: enjoy it and stop whingeing!

[nsm3]

Allright our kid - I'm with Ferry (not Brian is it?). I quite like it - mine is as rough as a badgers arse on tickover, makes for a real sense of occasion!

[Pugley]

By way of a follow up on this post I thought my experience may be useful to Mk1 GT3 owners and others.

I was not entirely happy with the comment "they all do that sir" offered by some "expert" OPC's and Indy's. In fact one respected Indy suggested a complete engine rebuild was the likely solution!

Yes - Many engines have a charactoristic brief rattle as oil to shell bearings and hydrualic tappets comes up to pressure.

The noise I noticed was more like the noise of a football rattle being spun around for a few seconds. It could also be just detected whilst the engine was cranking on the starter motor but always disappeared when up to full oil pressure.

My reasoning was that if new engines don't do it then there must be a reason why my of engine of 60K miles was doing every time when started from cold after being turned off whilst fully hot. I tried thicker oil and it made the problem worse!

Enter Steve from JAZ Porsche. He was aware of some issues with this generation of engines and has completely cured the problem by replacing several components in the camchain and valve assembly. (engine out job I'm afraid so opportunity taken to fit new clutch and RMS whilst it was out!)

So - No they dont "all do that sir" only ones that need a bit of work to bring them back to original specification.

Edited by Pugley on Saturday 13th November 16:18

Edited by Pugley on Saturday 13th November 16:21

[porka911t]

I got gt3 gen 1 2008 11 k miles. No smoke on start up and no noises when cold. It does rattle when hot. I have been building engines for 30 years and the rattle on my car is the IMs drive gears they do not have a chain like boxsters 996,997s. Every gt3 I looked at had this noise after a decent run.