Need feedback on a GT3 I want to buy
07-21-2016, 01:50 AM
#1
Rennlist Member
Thread Starter
Need feedback on a GT3 I want to buy
I found a GT3 that fits my desires nearly perfectly; however, it has an issue. It has a weird knocking sound. The sound follows revs. Its not a buzz. It almost sounds like piston slap, but not quite as sharp. It kind of sounds like a collapsed lifter, but louder and heavier.
The car has 33,00mi on it. The history for the car shows that it had a warranty issue where a couple of lifter springs broke. It was repaired by the Dealer the car was bought from. Aside from that it has always been maintained at the dealer, and has has no other issues.
The repair quote for the car states that the oil pump and shaft need to be replaced as well as the cam chain ramps and tensioners. I looked for days to find something on the web (including Rennlist) that discusses this problem but I found very little. According to this site: http://theimssolution.com/ims-101/ , problems similar to what I describe will never lead to catastrophic failure.
What I want to know is what could cause this problem, is it common, is the issue indicative of some other problems, can/should I expect to be trouble free post repair?
One other question I have is, suppose I go through with the sale, are there "while your in there" items I should be sure to have done while they have the engine out? One thought I had was a new clutch and RMS. The coolant pipes are already pinned. What are your thoughts? I worry that I worry too much.
I would move onto another car, but for some reason my gut tells me this is the one. Its the right color, its a Canadian car, it has the right options, the right provenance, and its a 996 GT3. These things are rare up here. Bringing up a US car increases the cost to a point that I lose interest because there are other options I would want to explore.
The car has 33,00mi on it. The history for the car shows that it had a warranty issue where a couple of lifter springs broke. It was repaired by the Dealer the car was bought from. Aside from that it has always been maintained at the dealer, and has has no other issues.
The repair quote for the car states that the oil pump and shaft need to be replaced as well as the cam chain ramps and tensioners. I looked for days to find something on the web (including Rennlist) that discusses this problem but I found very little. According to this site: http://theimssolution.com/ims-101/ , problems similar to what I describe will never lead to catastrophic failure.
What I want to know is what could cause this problem, is it common, is the issue indicative of some other problems, can/should I expect to be trouble free post repair?
One other question I have is, suppose I go through with the sale, are there "while your in there" items I should be sure to have done while they have the engine out? One thought I had was a new clutch and RMS. The coolant pipes are already pinned. What are your thoughts? I worry that I worry too much.
I would move onto another car, but for some reason my gut tells me this is the one. Its the right color, its a Canadian car, it has the right options, the right provenance, and its a 996 GT3. These things are rare up here. Bringing up a US car increases the cost to a point that I lose interest because there are other options I would want to explore.
07-21-2016, 09:50 AM
#2
Race Car
Personally I'd try to make an agreement to buy the car at fair market value once the repair is fully complete by the seller. Possibly make a side arrangement to add funds of your own for any additional work while the car is apart. If it's the right car for you make a strong offer and don't mess around with the only stipulation being it needs to be fixed and fixed right prior to purchase.
If you buy it and agree to repair yourself I'd expect it to be heavily discounted beyond the price of the repair estimate itself since you're assuming the risk of unknowns once you get in there. Could be $7-10k...could be > $20k there's really no way to tell until it comes apart.
Given the noise you describe and diagnosis provided thus far I don't think you could buy it and not repair it and just hope for the best.
If you buy it and agree to repair yourself I'd expect it to be heavily discounted beyond the price of the repair estimate itself since you're assuming the risk of unknowns once you get in there. Could be $7-10k...could be > $20k there's really no way to tell until it comes apart.
Given the noise you describe and diagnosis provided thus far I don't think you could buy it and not repair it and just hope for the best.
07-21-2016, 10:59 AM
#3
Rennlist Member
Is the repair quote from the dealer who has been servicing it? Seems odd to me that at 33k it needs an oil pump, tensioners and ramps, although it likely needs the ramps as a result of the failing tensioners.
It's a red flag for me that the seller hasn't addressed these issues already. Too many potential buyers want a sorted car and will be scared away by this.
I agree with AudiOn19s - either agree to buy it repaired (I'd replace all hoses and plastic line while the engine is out) or heavily discounted to protect yourself.
It's a red flag for me that the seller hasn't addressed these issues already. Too many potential buyers want a sorted car and will be scared away by this.
I agree with AudiOn19s - either agree to buy it repaired (I'd replace all hoses and plastic line while the engine is out) or heavily discounted to protect yourself.
07-21-2016, 02:45 PM
#4
Three Wheelin'
Sounds like the seller wants you to take on his problem...I would walk away unless you know:
* Exactly what the issue is
* How much it will cost to fix
Did you have the car PPIed? What is the rest of the service history like? Regular oil changes? General ****-ness?
Probably time to walk away from this one...
* Exactly what the issue is
* How much it will cost to fix
Did you have the car PPIed? What is the rest of the service history like? Regular oil changes? General ****-ness?
Probably time to walk away from this one...
07-21-2016, 02:59 PM
#5
Rennlist Member
Nice thing engine/tranny is rebuildable. If it hasn't been structurally crashed I have a Indy you trust(not owner) to evaluate what is going on with the knocking noise. If it checks 8-9 out of 10 checks for you- I look further into it vs walking away. Mike
07-22-2016, 11:55 AM
#6
Race Director
I found a GT3 that fits my desires nearly perfectly; however, it has an issue. It has a weird knocking sound. The sound follows revs. Its not a buzz. It almost sounds like piston slap, but not quite as sharp. It kind of sounds like a collapsed lifter, but louder and heavier.
The car has 33,00mi on it. The history for the car shows that it had a warranty issue where a couple of lifter springs broke. It was repaired by the Dealer the car was bought from. Aside from that it has always been maintained at the dealer, and has has no other issues.
The repair quote for the car states that the oil pump and shaft need to be replaced as well as the cam chain ramps and tensioners. I looked for days to find something on the web (including Rennlist) that discusses this problem but I found very little. According to this site: http://theimssolution.com/ims-101/ , problems similar to what I describe will never lead to catastrophic failure.
What I want to know is what could cause this problem, is it common, is the issue indicative of some other problems, can/should I expect to be trouble free post repair?
One other question I have is, suppose I go through with the sale, are there "while your in there" items I should be sure to have done while they have the engine out? One thought I had was a new clutch and RMS. The coolant pipes are already pinned. What are your thoughts? I worry that I worry too much.
I would move onto another car, but for some reason my gut tells me this is the one. Its the right color, its a Canadian car, it has the right options, the right provenance, and its a 996 GT3. These things are rare up here. Bringing up a US car increases the cost to a point that I lose interest because there are other options I would want to explore.
The car has 33,00mi on it. The history for the car shows that it had a warranty issue where a couple of lifter springs broke. It was repaired by the Dealer the car was bought from. Aside from that it has always been maintained at the dealer, and has has no other issues.
The repair quote for the car states that the oil pump and shaft need to be replaced as well as the cam chain ramps and tensioners. I looked for days to find something on the web (including Rennlist) that discusses this problem but I found very little. According to this site: http://theimssolution.com/ims-101/ , problems similar to what I describe will never lead to catastrophic failure.
What I want to know is what could cause this problem, is it common, is the issue indicative of some other problems, can/should I expect to be trouble free post repair?
One other question I have is, suppose I go through with the sale, are there "while your in there" items I should be sure to have done while they have the engine out? One thought I had was a new clutch and RMS. The coolant pipes are already pinned. What are your thoughts? I worry that I worry too much.
I would move onto another car, but for some reason my gut tells me this is the one. Its the right color, its a Canadian car, it has the right options, the right provenance, and its a 996 GT3. These things are rare up here. Bringing up a US car increases the cost to a point that I lose interest because there are other options I would want to explore.
How was it determined the engine needs a new oil pump and shaft? And cam chains and tensioners? One or both of these repairs is an engine out and requires the engine be disassembled. That's expensive.
An oil pump and shaft replacement is very rare. The GT3 with its Mezger engine has a gear driven layshaft. This setup is very reliable but once in a great while the gear on the layshaft comes loose. Bolts back out of the key that drives the gear works loose.
As for the noise, a good tech with a stethoscope should be able to pinpoint the source of the noise and based on this offer a reasonably accurate/reliable opinion as to what is wrong.
My advice is to walk away from this car. If you buy this car you are almost certainly facing a huge repair bill and the news could even be bleaker once the engine is opened up.
07-23-2016, 10:47 AM
#7
Rennlist Member
The GT3 uses a single piece intermediate shaft in lieu of the bolt together version used on the Turbo. Failure of the two piece Turbo shaft is still a very rare event and the Turbo engines have proven to be just as robust as their GT3 stablemates.
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07-27-2016, 12:27 PM
#8
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Agree with Macster, I'd walk away from this one, even if repairs were done before you purchase. I'd have to know the shop/dealer's mechanic well before I'd let them take this thing apart. You might be saving yourself money and worries by passing.
08-06-2016, 11:57 PM
#9
Rennlist Member
Thread Starter
UPDATE:
Wow, this has been a long process. Thanks for your patience.
So the car is at my local Porsche Dealer. They replaced the Tandem pumps and the noise has reduced somewhat; however, it still, to my ear, has quite a lot of lifter noise. I think these are just scavenge pumps that take oil right from the head back up to the oil tank. I did not think that these were common wear items. Are they?
How much lifter noise should there be? It doesn't sound anything like my 993, the gt3 has much more lifter noise.
Karl
Wow, this has been a long process. Thanks for your patience.
So the car is at my local Porsche Dealer. They replaced the Tandem pumps and the noise has reduced somewhat; however, it still, to my ear, has quite a lot of lifter noise. I think these are just scavenge pumps that take oil right from the head back up to the oil tank. I did not think that these were common wear items. Are they?
How much lifter noise should there be? It doesn't sound anything like my 993, the gt3 has much more lifter noise.
Karl
08-08-2016, 12:16 AM
#11
Rennlist Member
Thread Starter
I have not yet purchased the car. I drove it for an hour yesterday and I have a refundable deposit on it. I have not talked to the tech yet. I will talk to him tomorrow. The car has history with this dealer as its been there for every service, and its well known to the sales manager. I plan on buying it on Tuesday.
I just think it odd that the scavenge pumps on the heads needed replacing. After much research I could not find a single other case on the web. I asked for the old pumps to be kept and sold with the car. I wanna check it out for myself. My worry is that after these pumps get run in that the noise will re-appear. It could not find documentation where these pumps were superseded.
I think I have listened to every 996 gt3 video on the web. This car seems to have louder valve train noise than any other I heard; however, it near impossible to get the right sound on a video as most videos are recorded with a phone. The car sounds like a sewing machine; more mechanical and less a combustion process than my 993, but I chock this up to it being water cooled and the 993 being air cooled. At idle the valve train noise (at least I think its valve train noise) is louder than the exhaust note. It revs fine, and it has consistent power through our the rev range.
In fact I think its an evolution of the 993 more than the 996 Carrera is. Its raw and visceral near its limit but the limit is just a lot further out than the 993. The 993 is nice in that I can more easily access its limits, but I never reached the gt3 limits in the test drive. It took a lot more effort to get it to where it seemed comfy than the 993.
I just think it odd that the scavenge pumps on the heads needed replacing. After much research I could not find a single other case on the web. I asked for the old pumps to be kept and sold with the car. I wanna check it out for myself. My worry is that after these pumps get run in that the noise will re-appear. It could not find documentation where these pumps were superseded.
I think I have listened to every 996 gt3 video on the web. This car seems to have louder valve train noise than any other I heard; however, it near impossible to get the right sound on a video as most videos are recorded with a phone. The car sounds like a sewing machine; more mechanical and less a combustion process than my 993, but I chock this up to it being water cooled and the 993 being air cooled. At idle the valve train noise (at least I think its valve train noise) is louder than the exhaust note. It revs fine, and it has consistent power through our the rev range.
In fact I think its an evolution of the 993 more than the 996 Carrera is. Its raw and visceral near its limit but the limit is just a lot further out than the 993. The 993 is nice in that I can more easily access its limits, but I never reached the gt3 limits in the test drive. It took a lot more effort to get it to where it seemed comfy than the 993.
08-08-2016, 02:42 AM
#12
Three Wheelin'
Unless you are getting a killer deal...why else are you still pushing forward with this car? Is the risk really worth it? You clearly have hesitations about the car and the engine...
Also, that image you posted appears to be from 2010 GT3...
Also, that image you posted appears to be from 2010 GT3...
08-08-2016, 03:58 PM
#13
Rennlist Member
Thread Starter
Yeah I know that the pic is from a 2010, but the part numbers are the same and I could not find the right katalog.
Why am I pushing forward? Because I have on occasion been too fussy and lost out on a perfectly good car. I think this might be one of those situations. If you don't mind doing me a favor, could send a quick video of your car at idle? That would be fantastic.
Why am I pushing forward? Because I have on occasion been too fussy and lost out on a perfectly good car. I think this might be one of those situations. If you don't mind doing me a favor, could send a quick video of your car at idle? That would be fantastic.
08-08-2016, 05:30 PM
#14
Hi, I've experienced a knocking/ticking sound on my GT3. It was very loud and followed the revs.. It was almost not present when the oil was cold, but appeared after a 1-2 minutes.. I asked a lot of people, but no one had an answer. I bought the car anyways at a very good price. Taking it home I first recorded the sound with my phone when the car was running 1000rpms. The recording showed that the noise appeared 1500 times per min. This really helped me with diagnostics as I could rule out a lot of things.. It ended up being a fault in the variacam actuator mounted directly to the camshaft. This actuator is rotating the camshaft with some degrees. When the oil was cold with low viscosity it was not leaking internally, but when the oil temperature increased and the oil viscosity increased it started to leak internally between the chambers... As the camshaft "peak" is rolling over the valve it shifts the load direction on the camshaft - snapping the variocam actuator forth and back making this noise... It also fitted perfectly with the frequency of the noise.. (1000RPM = 500RPM on camshaft. For each RPM the camshaft is pushing the valves 3 times. 3x 500 = 1500!)
Even though this might not be the problem with "your" car, at least record the frequency of the sound, and play it in reduced speed helped me a lot. For example I guess that chain tensioners will not have a very stable frequency, more unstable rattle, as other parts have a more stable frequency...
Even though this might not be the problem with "your" car, at least record the frequency of the sound, and play it in reduced speed helped me a lot. For example I guess that chain tensioners will not have a very stable frequency, more unstable rattle, as other parts have a more stable frequency...