996 Lifter replacement questions
#1
996 Lifter replacement questions
I'm hoping some folks that have done this before can help me with some questions.
I have a '04 996 C4S with 103K miles in superb condition. My engine is a 996/03. The IMS and RMS, AOS replaced, sparks, plugs all done around 78K and the car just runs great.
What is absolutely driving me crazy though is a tapping sound at idle after the engine has warmed up. This comes from the passenger side of the engine. After a lot of research I'm fairly certain it's one or more stuck lifters. I've worked on engines before and want to do the replacement myself, but have some questions:
1. Are the exhaust and intake lifters the same or are they different?
I have this part #: Porsche: 996 105 041 72 (and alternate BMW: 11 32 1 748 884)
Can someone confirm that those are the correct lifters for both intake and exhaust?
2. To get the lifters out the cams need removing. Will I need to adjust the timing when I put them back in? The guide on Pelican says I can just line up the timing marks on the chain and gears, but I'm not sure about it.
3. I'm considering doing this without removing the engine. I know it would be easier with the engine out but I don't really have the room to do that and although I'm sure it will be a bit cramped, it looks possible. I'm thinking the biggest pain in the *** will be when I break the header bolts removing the exhaust and I'll have to buy a stomski tool to address that. Any comments on doing on on-chassis lifter replacement?
Thanks in advance!
I have a '04 996 C4S with 103K miles in superb condition. My engine is a 996/03. The IMS and RMS, AOS replaced, sparks, plugs all done around 78K and the car just runs great.
What is absolutely driving me crazy though is a tapping sound at idle after the engine has warmed up. This comes from the passenger side of the engine. After a lot of research I'm fairly certain it's one or more stuck lifters. I've worked on engines before and want to do the replacement myself, but have some questions:
1. Are the exhaust and intake lifters the same or are they different?
I have this part #: Porsche: 996 105 041 72 (and alternate BMW: 11 32 1 748 884)
Can someone confirm that those are the correct lifters for both intake and exhaust?
2. To get the lifters out the cams need removing. Will I need to adjust the timing when I put them back in? The guide on Pelican says I can just line up the timing marks on the chain and gears, but I'm not sure about it.
3. I'm considering doing this without removing the engine. I know it would be easier with the engine out but I don't really have the room to do that and although I'm sure it will be a bit cramped, it looks possible. I'm thinking the biggest pain in the *** will be when I break the header bolts removing the exhaust and I'll have to buy a stomski tool to address that. Any comments on doing on on-chassis lifter replacement?
Thanks in advance!
#3
It does sound very similar to that but it's difficult to differentiate that sound from noisy lifters. I forgot to mention that I brought it to my porsche mechanic and he told me it was definitely not cylinder slap, and was very likely a stuck lifter.
#4
The "porsche mechanic " who did the ppi on my car said it wasn't piston slap either. "No way the cylinders are scored, try a different oil"
My cylinder 4 & 6 were completely scored.
post a video of your car idling here. People have done lifters to only start that car back up and realized it wasn't the problem at all. Hate to see you waste that money and effort.
My cylinder 4 & 6 were completely scored.
post a video of your car idling here. People have done lifters to only start that car back up and realized it wasn't the problem at all. Hate to see you waste that money and effort.
#5
The video teaches you how to tell this sound is from the cylinders. You just need someone doing the same to confirm.
The intake and exhaust valves are #5&6 here
http://www.autoatlanta.com/porsche-p...section=103-11
The intake and exhaust valves are #5&6 here
http://www.autoatlanta.com/porsche-p...section=103-11
#7
Rennlist Member
The "porsche mechanic " who did the ppi on my car said it wasn't piston slap either. "No way the cylinders are scored, try a different oil"
My cylinder 4 & 6 were completely scored.
post a video of your car idling here. People have done lifters to only start that car back up and realized it wasn't the problem at all. Hate to see you waste that money and effort.
My cylinder 4 & 6 were completely scored.
post a video of your car idling here. People have done lifters to only start that car back up and realized it wasn't the problem at all. Hate to see you waste that money and effort.
I remember back about 15 years ago while attending Porsche special training class W10 ( water-cooled engines), the Porsche instructor mentioning that the pistons of the m96 had an offset piston pin that helped reduce side loading after combustion on bank 1, but unfortunately they they used the same piston on bank 2 which would increase side loading. I haven't actually measured the pistons to see which variations of m96 had this off-set or if they all have this off-set, but obviously (if true) is a cause of bore scoring that could not be fixed, since there is no other option for factory pistons.
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#9
Being a Porsche mechanic also, I feel the need to take up for the trade a little bit. These M96 engines suffer from bore scoring more than any engine type I have ever seen in my 40 years of being a mechanic. And the symptoms are not typical of other engines that have bore scoring. Any mechanic who does not know how unique and widespread this problem is will find it hard to believe.
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#10
Rennlist Member
#12
Rennlist Member
#13
Being a Porsche mechanic also, I feel the need to take up for the trade a little bit. These M96 engines suffer from bore scoring more than any engine type I have ever seen in my 40 years of being a mechanic. And the symptoms are not typical of other engines that have bore scoring. Any mechanic who does not know how unique and widespread this problem is will find it hard to believe.
I remember back about 15 years ago while attending Porsche special training class W10 ( water-cooled engines), the Porsche instructor mentioning that the pistons of the m96 had an offset piston pin that helped reduce side loading after combustion on bank 1, but unfortunately they they used the same piston on bank 2 which would increase side loading. I haven't actually measured the pistons to see which variations of m96 had this off-set or if they all have this off-set, but obviously (if true) is a cause of bore scoring that could not be fixed, since there is no other option for factory pistons.
I remember back about 15 years ago while attending Porsche special training class W10 ( water-cooled engines), the Porsche instructor mentioning that the pistons of the m96 had an offset piston pin that helped reduce side loading after combustion on bank 1, but unfortunately they they used the same piston on bank 2 which would increase side loading. I haven't actually measured the pistons to see which variations of m96 had this off-set or if they all have this off-set, but obviously (if true) is a cause of bore scoring that could not be fixed, since there is no other option for factory pistons.
#14
Former Vendor
I'm hoping some folks that have done this before can help me with some questions.
I have a '04 996 C4S with 103K miles in superb condition. My engine is a 996/03. The IMS and RMS, AOS replaced, sparks, plugs all done around 78K and the car just runs great.
What is absolutely driving me crazy though is a tapping sound at idle after the engine has warmed up. This comes from the passenger side of the engine. After a lot of research I'm fairly certain it's one or more stuck lifters. I've worked on engines before and want to do the replacement myself, but have some questions:
1. Are the exhaust and intake lifters the same or are they different?
I have this part #: Porsche: 996 105 041 72 (and alternate BMW: 11 32 1 748 884)
Can someone confirm that those are the correct lifters for both intake and exhaust?
2. To get the lifters out the cams need removing. Will I need to adjust the timing when I put them back in? The guide on Pelican says I can just line up the timing marks on the chain and gears, but I'm not sure about it.
3. I'm considering doing this without removing the engine. I know it would be easier with the engine out but I don't really have the room to do that and although I'm sure it will be a bit cramped, it looks possible. I'm thinking the biggest pain in the *** will be when I break the header bolts removing the exhaust and I'll have to buy a stomski tool to address that. Any comments on doing on on-chassis lifter replacement?
Thanks in advance!
I have a '04 996 C4S with 103K miles in superb condition. My engine is a 996/03. The IMS and RMS, AOS replaced, sparks, plugs all done around 78K and the car just runs great.
What is absolutely driving me crazy though is a tapping sound at idle after the engine has warmed up. This comes from the passenger side of the engine. After a lot of research I'm fairly certain it's one or more stuck lifters. I've worked on engines before and want to do the replacement myself, but have some questions:
1. Are the exhaust and intake lifters the same or are they different?
I have this part #: Porsche: 996 105 041 72 (and alternate BMW: 11 32 1 748 884)
Can someone confirm that those are the correct lifters for both intake and exhaust?
2. To get the lifters out the cams need removing. Will I need to adjust the timing when I put them back in? The guide on Pelican says I can just line up the timing marks on the chain and gears, but I'm not sure about it.
3. I'm considering doing this without removing the engine. I know it would be easier with the engine out but I don't really have the room to do that and although I'm sure it will be a bit cramped, it looks possible. I'm thinking the biggest pain in the *** will be when I break the header bolts removing the exhaust and I'll have to buy a stomski tool to address that. Any comments on doing on on-chassis lifter replacement?
Thanks in advance!
Exhaust
https://www.warehouse33auto.com/INA/...996-105-041-72
Intake
https://www.warehouse33auto.com/GENU...996-105-255-25
-Jason
#15
Rennlist Member
Yes, 0.5mm offset on my '02 996 engine. See post #564 here https://rennlist.com/forums/996-foru...l#post13253105