Merry Xmas to me- tick/knock at idle...
12-28-2009, 02:22 AM
#16
Track Day
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Thanks guys for the info... I am relieved that this does not sound catastrophic.
A few questions:
Should I not start the car if, in fact, it is a lifter issue? ie: Will I cause more damage to the engine if I start the car?
Does a lifter fix require the engine to be removed?
There is a possibility of an issue with the exhaust as my driveway is very steep and prior to the noise, one of the exhaust tips dragged the ground as I was backing out. It happes occasionally though I try to be very careful and back out at an angle to avoid it.
What would I expect to pay if this is an issue with the lifters?
A few questions:
Should I not start the car if, in fact, it is a lifter issue? ie: Will I cause more damage to the engine if I start the car?
Does a lifter fix require the engine to be removed?
There is a possibility of an issue with the exhaust as my driveway is very steep and prior to the noise, one of the exhaust tips dragged the ground as I was backing out. It happes occasionally though I try to be very careful and back out at an angle to avoid it.
What would I expect to pay if this is an issue with the lifters?
12-28-2009, 07:08 AM
#17
If the lifter it is only partially operating the valve causing a loss of performance. It's OK to run the engine. I do believe the engine does need to be removed to get to the lifters. If you ever do an oil change make sure after starting the engine that you don't rev or high idle the engine for at least 3 minutes giving the car enough time to spred the oil to all the parts. All the air has to be displaced by the oil so 3 minutes is a good number.
Call for an estimate from the shops you are debating to get the car looked at for repair. Good luck not scraping the exhaust leaving the driveway. Kind of torques the exhaust a bit and the brain a lot more having to hear it scrape. I hope it hasn't cracked your headers after seeing one mans post about prices he can't believe for just one sides muffler.
Best of cruising to you.
Call for an estimate from the shops you are debating to get the car looked at for repair. Good luck not scraping the exhaust leaving the driveway. Kind of torques the exhaust a bit and the brain a lot more having to hear it scrape. I hope it hasn't cracked your headers after seeing one mans post about prices he can't believe for just one sides muffler.
Best of cruising to you.
12-28-2009, 09:38 AM
#18
Race Car
If the lifter becomes clogged/ obstructed oil cannot move into or out of it due to the obstruction and the fact that the oil does not pass through the lifter. When these lifters become clogged they simply stop functioning amd once the obstruction occurs its a bit late.
Ever tried to free up a completely clogged drain with drain-o before?? It works well on partially clogged drains, but not those that are completely obstructed.. Same goes here, especially when the oil feed orifice in the lifter is less than 1mm in diameter.
Based on that sound file and the fact that I have heard no less than a dozen of these same sounds in the past two months (that were bad lifters) I am confident the noise is a lifter. I'd not make such a statement without great confidence because of people just like you. (Of course you'd love it if I were incorrect-)
Have you ever held an M96 lifter in your hands???
Ever tried to free up a completely clogged drain with drain-o before?? It works well on partially clogged drains, but not those that are completely obstructed.. Same goes here, especially when the oil feed orifice in the lifter is less than 1mm in diameter.
Based on that sound file and the fact that I have heard no less than a dozen of these same sounds in the past two months (that were bad lifters) I am confident the noise is a lifter. I'd not make such a statement without great confidence because of people just like you. (Of course you'd love it if I were incorrect-)
Have you ever held an M96 lifter in your hands???
Unless there is a mechanical breakage or blockage resulting in seizure, very few stuck lifters will not work themselves free. I assume that you realize there would be performance issues if a lifter was indeed collapsed?
Do you even know what 70+ psi of oil will do to most obstructions?
12-28-2009, 09:41 AM
#19
Race Car
Thanks guys for the info... I am relieved that this does not sound catastrophic.
A few questions:
Should I not start the car if, in fact, it is a lifter issue? ie: Will I cause more damage to the engine if I start the car?
Does a lifter fix require the engine to be removed?
There is a possibility of an issue with the exhaust as my driveway is very steep and prior to the noise, one of the exhaust tips dragged the ground as I was backing out. It happes occasionally though I try to be very careful and back out at an angle to avoid it.
What would I expect to pay if this is an issue with the lifters?
A few questions:
Should I not start the car if, in fact, it is a lifter issue? ie: Will I cause more damage to the engine if I start the car?
Does a lifter fix require the engine to be removed?
There is a possibility of an issue with the exhaust as my driveway is very steep and prior to the noise, one of the exhaust tips dragged the ground as I was backing out. It happes occasionally though I try to be very careful and back out at an angle to avoid it.
What would I expect to pay if this is an issue with the lifters?
12-28-2009, 10:18 AM
#20
Burning Brakes
There is no reason for myself and 1999porsche911 to further engage in pissing contests. He doesn't care for me and I don't care for him so we should agree to disagree and both stop directing attacks toward each other.
A collapsed lifter usually won't hurt performance notably at the seat of the pants. On the dyno they generally only hurt torque figures. Horsepower is generally not affected as much since the loss of valve lift isn't as notable at high RPM.
Generally when lifters fail the driver has become accustomed to the performance of the vehicle over time and will not notice a slight degradation due to a one or a few failed lifters. I have seen an engine with as many as 22 failed lifters still run fine, but it did have a choppy idle. The owner could not tell his idle was choppy until I fired up another 996 next to his that was running correctly.
The biggest complaint that we see with clients that have failed lifters is poor fuel economy due to a loss of chamber filling on the cylinders that have the failed/ clogged lifters. It usually takes several bad lifters to create a loss of fuel economy or a loss of power. A number of the cars we see with failed lifters/ clogged lifters never make a sound as pronounced as the one in the sound file that was posted and a few have came from dealers where they were diagnosed with zero problems.
Yes, I have two cars at my facility right now for bad lifters, finished another the week before Christmas and did 3 jobs in November.
The lifters in these engines do not see 70 PSI of oil pressure. The operating pressure of the oil system further up stream may be as high as 70 PSI but no where near that at the lifter valley, especially after the valley and it's passages have become partially obstructed themselves over time.
When a lifter becomes obstructed the oil pressure feeding it isn't high enough to dislodge obstructions.
Its all imaginary though.. even that sound bite. Damn I have a great imagination!
The only damage that can be done from running the engine for extended amounts of time with a bad lifter is a slight mushrooming of the valve tip due to the valve lash thats present with the lifter thats not totally "pumped up". This takes thousands of miles and generally isn't a common occurrence.
A collapsed lifter usually won't hurt performance notably at the seat of the pants. On the dyno they generally only hurt torque figures. Horsepower is generally not affected as much since the loss of valve lift isn't as notable at high RPM.
Generally when lifters fail the driver has become accustomed to the performance of the vehicle over time and will not notice a slight degradation due to a one or a few failed lifters. I have seen an engine with as many as 22 failed lifters still run fine, but it did have a choppy idle. The owner could not tell his idle was choppy until I fired up another 996 next to his that was running correctly.
The biggest complaint that we see with clients that have failed lifters is poor fuel economy due to a loss of chamber filling on the cylinders that have the failed/ clogged lifters. It usually takes several bad lifters to create a loss of fuel economy or a loss of power. A number of the cars we see with failed lifters/ clogged lifters never make a sound as pronounced as the one in the sound file that was posted and a few have came from dealers where they were diagnosed with zero problems.
Yes, I have two cars at my facility right now for bad lifters, finished another the week before Christmas and did 3 jobs in November.
The lifters in these engines do not see 70 PSI of oil pressure. The operating pressure of the oil system further up stream may be as high as 70 PSI but no where near that at the lifter valley, especially after the valley and it's passages have become partially obstructed themselves over time.
When a lifter becomes obstructed the oil pressure feeding it isn't high enough to dislodge obstructions.
Its all imaginary though.. even that sound bite. Damn I have a great imagination!
The only damage that can be done from running the engine for extended amounts of time with a bad lifter is a slight mushrooming of the valve tip due to the valve lash thats present with the lifter thats not totally "pumped up". This takes thousands of miles and generally isn't a common occurrence.
12-28-2009, 02:19 PM
#22
Burning Brakes
The lifters are at the furthest extremity of the oil system.. Because of this most of the contaminants in the oil (not filtered) end up finding their way to the lifters. Because the lifters only have one orifice to allow oil into them they become small "filters" that collect lots of debris.
I am away from the shop through 4 January, but when I return I'll post pics of lifters I have dissected that were no longer functional. I have pictures of dozens of bad ones, not just one or two. Very seldom does a lifter fail due to anything more than being obstructed.
Extended oil drain intervals that are a major contributor to this issue.
It has become so common that I am shooting a DIY DVD on the topic with the step by step instructions for lifter removal and replacement in March. This can be done at home for advanced enthusiasts that have a tool box and some patience. Most shops have never ventured this deep into the M96 engine, they are certainly capable but most are just intimidated by the engine enough to not want to do the work. If they goof up it can cost them a new engine for your car. The DVD will build confidence for everyone because the work is simple.
I am away from the shop through 4 January, but when I return I'll post pics of lifters I have dissected that were no longer functional. I have pictures of dozens of bad ones, not just one or two. Very seldom does a lifter fail due to anything more than being obstructed.
Extended oil drain intervals that are a major contributor to this issue.
It has become so common that I am shooting a DIY DVD on the topic with the step by step instructions for lifter removal and replacement in March. This can be done at home for advanced enthusiasts that have a tool box and some patience. Most shops have never ventured this deep into the M96 engine, they are certainly capable but most are just intimidated by the engine enough to not want to do the work. If they goof up it can cost them a new engine for your car. The DVD will build confidence for everyone because the work is simple.
Last edited by Jake Raby; 12-28-2009 at 02:36 PM.
12-29-2009, 12:44 PM
#23
Track Day
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Thnaks again for the info. When I get back to California I'm going to check the car for exhaust leaks, have the oil changed (any brand and weight suggestions?) and take a short drive to see if the problem persists. Any common places to check specifically for exhaust leaks? Should I be able to feel the leak with my hand or should I just go in and snug up all of the bolts?
Thanks!
Thanks!
12-29-2009, 11:21 PM
#26
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LVDELL,
I had the oil changed just after I bought the car in August (about 3000 miles ago). I took it to an indy shop that works primarily on P-cars to have the fluids changed and the car inspected. I did not ask or request a specific type or weight. I know it was synthetic and I'm pretty sure mobil 1. When I get back to LA I'm getting the oil changed because it's time and because of this recent development. Do you have any suggestions as to weight, etc...?
I had the oil changed just after I bought the car in August (about 3000 miles ago). I took it to an indy shop that works primarily on P-cars to have the fluids changed and the car inspected. I did not ask or request a specific type or weight. I know it was synthetic and I'm pretty sure mobil 1. When I get back to LA I'm getting the oil changed because it's time and because of this recent development. Do you have any suggestions as to weight, etc...?
12-30-2009, 01:30 AM
#27
Jake, are there any oil additives or detergents that can be added to the oil a few hundred miles before a scheduled oil change, to maybe get some cleansing agents into the engine to keep the krud out and the various little orifices inside everything clean? I know some folks (Macster?) talk about a Techron dose before an oil change. Any recommendations?
12-30-2009, 09:10 AM
#28
Nordschleife Master
LVDELL,
I had the oil changed just after I bought the car in August (about 3000 miles ago). I took it to an indy shop that works primarily on P-cars to have the fluids changed and the car inspected. I did not ask or request a specific type or weight. I know it was synthetic and I'm pretty sure mobil 1. When I get back to LA I'm getting the oil changed because it's time and because of this recent development. Do you have any suggestions as to weight, etc...?
I had the oil changed just after I bought the car in August (about 3000 miles ago). I took it to an indy shop that works primarily on P-cars to have the fluids changed and the car inspected. I did not ask or request a specific type or weight. I know it was synthetic and I'm pretty sure mobil 1. When I get back to LA I'm getting the oil changed because it's time and because of this recent development. Do you have any suggestions as to weight, etc...?
If you can, find out what you indy put in during the last oil change. It should have been on the invoice? If you are feeling DIY, then oil is one of the EASIEST things you can do on your car. We'd be glad to help if you need some steps to get it done.
Happy Motoring!
I have, others should follow........