Timing chain rattle on start up gone, but why?
05-29-2021, 01:53 PM
#1
Track Day
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Timing chain rattle on start up gone, but why?
Hi Team
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
05-29-2021, 05:41 PM
#2
Maybe your chain tensioners are no longer leaking down between starts? Have you changed your oil recently or switched brands or viscosity of the oil you are using? When I read about start-up rattle on these engines, I think the chain tensioners are leaking down pressure and/or are worn. Start-up rattle can also be an indication of worn chain guides/ramps, but if it suddenly disappears, then I'm thinking chain tensioners and maybe some debris within has been dislodged allowing the tensioner to maintain pressure between starts. I am speculating, obviously, but enjoy the rattle free starts nonetheless.
05-30-2021, 07:55 AM
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Track Day
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Timing chain rattle gone
Maybe your chain tensioners are no longer leaking down between starts? Have you changed your oil recently or switched brands or viscosity of the oil you are using? When I read about start-up rattle on these engines, I think the chain tensioners are leaking down pressure and/or are worn. Start-up rattle can also be an indication of worn chain guides/ramps, but if it suddenly disappears, then I'm thinking chain tensioners and maybe some debris within has been dislodged allowing the tensioner to maintain pressure between starts. I am speculating, obviously, but enjoy the rattle free starts nonetheless.
Thanks for your response. I think you've hit the nail on the head!
The dealer who sold me the Ravanol 10W50 said it has a high milage formulation that soften hardened seals. I took that with a pinch of salt but guess it could be true, perhaps the tensioners are now holding pressure between start ups.
I also thought it might have something to do with running the oil level at around 50% of full but could'nt resolve the logic!
Im going to top up to full today and see if that makes a difference.
Thanks again for solving the mystery.
05-31-2021, 09:08 AM
#4
Fisheagle, I would be very careful about running the oil level at 50% full as the oiling system of the M86/96 engine in these cars is somewhat marginal. One of the primary failure modes of this engine on the track is burned crankshaft bearings due to oil starvation in high G turns. That may be the equivalent of low G turns during normal driving with only a 50% oil capacity. I would also be concerned about oil pressure in general at only 50% capacity. May I ask why you're running the car at 50% oil capacity? Perhaps to reduce smoking? I've been wrenching on cars and motorcycles a long time, and running an engine at 50% oil capacity is a new one on me but, hey, I'm always willing to learn something new!
05-31-2021, 11:33 AM
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Fisheagle, I would be very careful about running the oil level at 50% full as the oiling system of the M86/96 engine in these cars is somewhat marginal. One of the primary failure modes of this engine on the track is burned crankshaft bearings due to oil starvation in high G turns. That may be the equivalent of low G turns during normal driving with only a 50% oil capacity. I would also be concerned about oil pressure in general at only 50% capacity. May I ask why you're running the car at 50% oil capacity? Perhaps to reduce smoking? I've been wrenching on cars and motorcycles a long time, and running an engine at 50% oil capacity is a new one on me but, hey, I'm always willing to learn something new!
Thanks for your insights. Sorry if I didn't make my self clearer, I don't run at 50% oil capacity, it just coincided that the rattling stopped around this level.
Ive now 'topped up' to full - it took 600 ml in 1 500 km of easy driving. So easy in fact that I get 9.5 litres/100 km - or 25 mpg fuel consumption!
Having eliminated one of the variables, we'll see if the 'magic formulation' of 10W50 Ravenol has softened the seals of the tensioners enough to restore their pressure holding capabilities!
06-01-2021, 02:38 PM
#6
Rennlist Member
Hi Team
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
You need to install the 2001 updated spring loaded tensioner.
06-01-2021, 02:41 PM
#7
Rennlist Member
Fisheagle, I would be very careful about running the oil level at 50% full as the oiling system of the M86/96 engine in these cars is somewhat marginal. One of the primary failure modes of this engine on the track is burned crankshaft bearings due to oil starvation in high G turns. That may be the equivalent of low G turns during normal driving with only a 50% oil capacity. I would also be concerned about oil pressure in general at only 50% capacity. May I ask why you're running the car at 50% oil capacity? Perhaps to reduce smoking? I've been wrenching on cars and motorcycles a long time, and running an engine at 50% oil capacity is a new one on me but, hey, I'm always willing to learn something new!
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07-29-2024, 03:16 AM
#8
Hi Team
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
2000 model Boxster S 186 000 km.
Have always had a timing chain rattle on cold start up but many have told me "that's normal, don't worry about it," but as a retired engineer, it always troubled me.
I've been religious about changing the oil at regular intervals and never detected any swarf in the filter as one might expect if the chain is striking an aluminium casing.
Oil consumption is good for this daily driver - about 500 ml every 1 000 km.
Lately though, it used less, about 400 ml over a greater distance - 1 300 km but the interesting thing is the timing chain rattle has gone!
I'm using Ravenol 10W50 since the last oil change - prior to that 10W40, same brand.
We dont get any cold weather here in Cape Town, even in winter which helps with longevity so long as you keep an eye on the cooling system.
Any ideas as to why the rattle should stop?
I just purchased a 2000 Porsche Boxster with 142,000 miles. The car runs absolutely beautifully. However, after about five or six days of no use,I hear a very, very brief rattle at start up. Again, this only occurs after five or six days of no use. I also owned six other vintage cars that I have restored. I have personally rebuilt my Rolls-Royce Silver Shadow engine and I’m absolutely paranoid about bearing surfaces and tensioner performance.
My intuition leads me to believe that this is related to one, if not all three of the chain tensioners. It appears, that the chain tensioners happened to be the original versions (most notably due to the sharp edges the 32 mm hex bolt pattern). Apparently the newer versions of the tensioners have slightly rounded edges. After conducting exhaustive research, apparently there have been three iterations of each of the three chain tensioners since 2000. According to discussions with various dealers, the latest versions of each of the three tensioners for my 2000 Boxster are as follows:
996-105-180-59 (IMS to Crank tensioner mounted horizontally featuring a single circle marking pattern on the 32 mm hex head)
https://www.pelicanparts.com/More_In...05-180-59-M100
996-105-188-02 (Cylinders 4-6 mounted vertically from the top down under the AC compressor featuring a female/inverted 14 mm allen bolt head)
https://www.pelicanparts.com/More_In...05-188-02-M100
996-105-186-02 (cylinders 1-3 mounted vertically from the bottom up featuring 2 Concentric Circle markings on the 32 mm hex head)
https://www.pelicanparts.com/More_In...105-186-02-OEM
I must admit that I’m very intrigued by a couple of the testimonials that I have read concerning the use of Ravenol 10W50. Apparently, this brand and viscosity of oil has been very effective in combating and even eliminating the rattle at a very cold start up completely. I suspect that this brand/viscosity maybe more effective in eliminating the oil leak down of each of the tensioners. Just curious if anyone could share results of changing all three of the chain tensioners detailed above?
Curious if I would be better served replacing the three tensioners and using the recommended Mobile one 0W 40 weight which purportedly allows better initial flow of oil during cold start up. However, I should mention that I use Castro 20/50 in the Rolls Royce and nonsynthetic Valvoline VR1 20/50 in my five speed Porsche 928. These are obviously different applications so it’s “neither here nor there”. However, I do have an affinity for the 50 weight viscosity.
Last edited by Kevin Ritter; 07-29-2024 at 06:04 PM.
