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Hey all, first thread here, too bad it isn't under different circumstances.
To make a short story even shorter, heard a small rattle that got progressively louder the longer I drove the car. Fast forward the next day to my indy mechanic, he tells me they need to pull the engine out - I was suspecting some form of bore scoring which lead to piston slap and as usual with those armchair diagnoses I was off. Engine is now out of the car and the damage has been identified as worn crankshaft originating from cylinder #5. The journal was in rough shape and I could feel an indentation with my finger. Rod bearings on some other cylinders were also somewhat worn out.
My mechanic suggested to try and find a used engine from which we can pull out its crankshaft, change all the bearings (and maybe connecting rods?) OR to attempt to repair my current crankshaft (I have no idea how this would work). We also discussed about potentially doing other reliability work while we are at it. The main issue is that both him and I struggle finding a used crankshaft that is in good condition, he pulled out an m96 engine from a boxster with 90k KM and he told me the crankshaft was no good. What do you guys think of my situation? Would it also be worth it to look at a new crankshaft?
The problem will be the difficulty in locating a good used crankshaft. The second problem will be the crankshaft bearings and alignment. Might suggest a new Porsche short block that you can now get from a Porsche dealer for around $6500. That will have everything you need and comes factory fresh. Have the heads reworked and you will be good to go.
Rewelding and machining a crankshaft is a solution, but it takes skills and about $2K, then you have to get the engine all back together with new bearings and labor so ... IF you can get a short block from Porsche for $6500, I suggest you do that because the other route will get you to $5K anyway. Put the heads back on, ignore the valve job, drive. You'll be done for $10K.
Rewelding and machining a crankshaft is a solution, but it takes skills and about $2K, then you have to get the engine all back together with new bearings and labor so ... IF you can get a short block from Porsche for $6500, I suggest you do that because the other route will get you to $5K anyway. Put the heads back on, ignore the valve job, drive. You'll be done for $10K.
With a failed rod bearing, there will be particulates throughout the engine. The heads will need to be completely dismantled and cleaned. the cams will need to be inspected to determine if there is any damage. Given the amount of effort that will take, you should send them off to have them rebuilt. No point in taking the risk of ruining the new short block.
Hey all, first thread here, too bad it isn't under different circumstances.
To make a short story even shorter, heard a small rattle that got progressively louder the longer I drove the car. Fast forward the next day to my indy mechanic, he tells me they need to pull the engine out - I was suspecting some form of bore scoring which lead to piston slap and as usual with those armchair diagnoses I was off. Engine is now out of the car and the damage has been identified as worn crankshaft originating from cylinder #5. The journal was in rough shape and I could feel an indentation with my finger. Rod bearings on some other cylinders were also somewhat worn out.
My mechanic suggested to try and find a used engine from which we can pull out its crankshaft, change all the bearings (and maybe connecting rods?) OR to attempt to repair my current crankshaft (I have no idea how this would work). We also discussed about potentially doing other reliability work while we are at it. The main issue is that both him and I struggle finding a used crankshaft that is in good condition, he pulled out an m96 engine from a boxster with 90k KM and he told me the crankshaft was no good. What do you guys think of my situation? Would it also be worth it to look at a new crankshaft?
Thank you all!
Reworking the crankshaft isn't a viable option. We tried that years ago and they aren't quality. The repairs don't hold up. I had a repaired crank in our first test engine and it became a 3 pc crank after about 50 hours run time. Don't waste your time or money on trying to make what you have work.
Used cranks can be found, you just have to be patient. We normally stock them magnufluxed and polished for $2-3k.
78 strokes are easier to find as that crank is used in the 2.7, 3.2, and early 3.4s. 3.6 cranks are harder to come by.
3.4 cayman cranks are impossible to find - most customers end up swapping in an earlier crank carrier and smaller main journal diameter 78 crank from earlier engines.
The problem will be the difficulty in locating a good used crankshaft. The second problem will be the crankshaft bearings and alignment. Might suggest a new Porsche short block that you can now get from a Porsche dealer for around $6500. That will have everything you need and comes factory fresh. Have the heads reworked and you will be good to go.
Yes, you're right - finding a good crankshaft can be a waiting game. Thankfully I don't use the car during the winter and I can let it sit for a while. The short block from Porsche includes a crankshaft? Can you order it from suncoast?
Originally Posted by yelcab
Rewelding and machining a crankshaft is a solution, but it takes skills and about $2K, then you have to get the engine all back together with new bearings and labor so ... IF you can get a short block from Porsche for $6500, I suggest you do that because the other route will get you to $5K anyway. Put the heads back on, ignore the valve job, drive. You'll be done for $10K.
To be honest I was hoping to be done for half that!! In all honesty the car is really good and I intend to fix it best I can in order to enjoy it for a few more years.
Originally Posted by Splitting Atoms
With a failed rod bearing, there will be particulates throughout the engine. The heads will need to be completely dismantled and cleaned. the cams will need to be inspected to determine if there is any damage. Given the amount of effort that will take, you should send them off to have them rebuilt. No point in taking the risk of ruining the new short block.
The engine was pulled apart and cleaned - my mechanic told me that the rest of the engine was in a reasonably good shape. I have not inspected the camshaft with him but I will certainly ask him and see if there is any issue on that side. How much would a rebuild cost? I'm looking to get the best reliability out of this unfortunate situation
Originally Posted by Pete Debusmann
I have a good used crankshaft here in NJ
Pete
Hey Pete, what engine was the crank pulled from? Can you give me some more info on mileage and condition? Thanks!
Originally Posted by Charles Navarro
Reworking the crankshaft isn't a viable option. We tried that years ago and they aren't quality. The repairs don't hold up. I had a repaired crank in our first test engine and it became a 3 pc crank after about 50 hours run time. Don't waste your time or money on trying to make what you have work.
Used cranks can be found, you just have to be patient. We normally stock them magnufluxed and polished for $2-3k.
78 strokes are easier to find as that crank is used in the 2.7, 3.2, and early 3.4s. 3.6 cranks are harder to come by.
3.4 cayman cranks are impossible to find - most customers end up swapping in an earlier crank carrier and smaller main journal diameter 78 crank from earlier engines.
Truth be told I would also like to avoid reworking the crank, my mechanic tells me he does this all the time for racing application but I am still not entirely convinced. I looked on your website but I cannot find the crank for a 3.4, will you be having them in stock in the future? Thanks!
Originally Posted by Mark Wilson
OP - sorry about the failure. I've not heard of this before. How many miles on the clock?
Hey Mark, I bought the car used and it had 90k miles. Did a pretty big service (oil+spark plugs, filters, complete brake job) and I drove it less than 500 miles before this issue occurred. My mechanic speculates it is either a factory part that was not built up to tolerance or someone had redlined the car multiple times while cold... Very unlucky whatever the root cause was. I truly like this car so much (exclusive manufaktur build) that I am dedicated to save it!
The engine was pulled apart and cleaned - my mechanic told me that the rest of the engine was in a reasonably good shape. I have not inspected the camshaft with him but I will certainly ask him and see if there is any issue on that side. How much would a rebuild cost? I'm looking to get the best reliability out of this unfortunate situation.
You need to search this 996 forum and read threads about DYI engine rebuilds and owners who have had their engine professionally rebuilt. This will help you understand the items that need to be addressed and the complexity associated with a full rebuild. There are specialty tools and knowledge needed. There is no inexpensive way out. The least expensive solution would be to find a good used motor and install it yourself. You can probably do that for less than 10k, but there is a risk that the used engine could fail in the near future. It's a crap shoot. There are always additional parts you have to buy when you do a big project like this, and it adds up.
Based on your description of the failure, it sounds like a rod bearing disintegrated. Rod bearing failures are often caused by low oil pressure, which can have several causes. A rod bearing failure is not instantaneous, and the failure could have initiated prior to your purchase when the bearing initially wiped on the crankshaft rod journal. Whoever sold it to you probably knew there was a problem.
As far as getting the heads rebuilt, Hoffman Automotive in Athens GA has been frequently recommend. The cost of rebuilding the heads will vary based on their condition, but a ballpark number would be around $2500.
Lastly, you may want to ask some probing questions to your mechanic. What does "disassembled and cleaned" mean? If the engine was truly disassembled and cleaned, you are probably into the rebuild over $1000 in labor at this point. Also, parts being in "reasonably good condition" to me means that only half of them are going to go in the trash. An engine with 90k miles will need a lot of new parts, including parts that weren't directly affected by the failure.
If you love the car and have the funds, ship it to Jake and his team at Flat 6 Innovations in Georgia. If you are going to have your mechanic do a rebuild, he probably (definately) doesn't have the same level of knowledge. He probably can't do it much cheaper either, without cutting corners. In addition, the Flat 6 folks incorporate multiple upgrades that you won't have if you start with the Porsche short block.
You need to search this 996 forum and read threads about DYI engine rebuilds and owners who have had their engine professionally rebuilt. This will help you understand the items that need to be addressed and the complexity associated with a full rebuild. There are specialty tools and knowledge needed. There is no inexpensive way out. The least expensive solution would be to find a good used motor and install it yourself. You can probably do that for less than 10k, but there is a risk that the used engine could fail in the near future. It's a crap shoot. There are always additional parts you have to buy when you do a big project like this, and it adds up.
Based on your description of the failure, it sounds like a rod bearing disintegrated. Rod bearing failures are often caused by low oil pressure, which can have several causes. A rod bearing failure is not instantaneous, and the failure could have initiated prior to your purchase when the bearing initially wiped on the crankshaft rod journal. Whoever sold it to you probably knew there was a problem.
As far as getting the heads rebuilt, Hoffman Automotive in Athens GA has been frequently recommend. The cost of rebuilding the heads will vary based on their condition, but a ballpark number would be around $2500.
Lastly, you may want to ask some probing questions to your mechanic. What does "disassembled and cleaned" mean? If the engine was truly disassembled and cleaned, you are probably into the rebuild over $1000 in labor at this point. Also, parts being in "reasonably good condition" to me means that only half of them are going to go in the trash. An engine with 90k miles will need a lot of new parts, including parts that weren't directly affected by the failure.
If you love the car and have the funds, ship it to Jake and his team at Flat 6 Innovations in Georgia. If you are going to have your mechanic do a rebuild, he probably (definately) doesn't have the same level of knowledge. He probably can't do it much cheaper either, without cutting corners. In addition, the Flat 6 folks incorporate multiple upgrades that you won't have if you start with the Porsche short block.
Spot on. This isn't a small block Chevy. Everything must be quantified. I almost guarantee that the bores will be out of spec and the block will need to be redone, and that's just one of many things.
The cost on the heads above is spot on - we're even a bit more if everything is done that needs to be addressed like new springs, guides, seats, pressure testing, etc.
The M96 engine can't be rebuilt cheap. Those who claim to do so don't own the proper measurement devices to qualify the components or are just ignorant.
If you can't afford to fix it right, a used engine is the best choice for sure.
Sounds like your failure was identical to mine. Here is my crank failure at 50K, much of it at the track due to oil starvation on high G long sweeping turns (shown this before).
. I suspect that your car was tracked quite a bit so I would not try to save the engine. Sure there is a bunch of things wrong with it now. I would only rebuild with the experts like Jake. My learning was all my engines for the track will have deep sumps.
Hey all, first thread here, too bad it isn't under different circumstances.
To make a short story even shorter, heard a small rattle that got progressively louder the longer I drove the car. Fast forward the next day to my indy mechanic, he tells me they need to pull the engine out - I was suspecting some form of bore scoring which lead to piston slap and as usual with those armchair diagnoses I was off. Engine is now out of the car and the damage has been identified as worn crankshaft originating from cylinder #5. The journal was in rough shape and I could feel an indentation with my finger. Rod bearings on some other cylinders were also somewhat worn out.
My mechanic suggested to try and find a used engine from which we can pull out its crankshaft, change all the bearings (and maybe connecting rods?) OR to attempt to repair my current crankshaft (I have no idea how this would work). We also discussed about potentially doing other reliability work while we are at it. The main issue is that both him and I struggle finding a used crankshaft that is in good condition, he pulled out an m96 engine from a boxster with 90k KM and he told me the crankshaft was no good. What do you guys think of my situation? Would it also be worth it to look at a new crankshaft?
Thank you all!
As painful as it may be, you came to the right place for the "truth" about your engine. Proper "rebuilds" are expensive. Improper rebuilds/refreshes are WAY more expensive and ultimately wasteful in the long run, as they will fail and trash the rest of the engine. Do yourself a big favor and read through the re-build threads on the site before you go further on your current course. It's not that it can't be done - it just needs to be done right or you'll be doing it all over again (or selling your car as a roller) if it's not done right. Good luck
The crankshaft I have came from a 1999 996 with 30k miles. It is still in the crankshaft “cage”. The engine had a top end failure (one of the heads was trashed). I just got it last week when I picked up some other non related parts.
You cannot do this for less than $5k. If it were my car, I would buy a $6K short block. Send out the heads for a $2K valve job. Reassemble with new gaskets and a few other things as needed to be replaced. Alone, the parts are running $10K. But this is the devil you know.
The other alternative is to buy a rebuilt engine at $9-$10K, and swap it. I would not buy a used engine from a junk yard. That is the devil you don't know.
Was this before or after you had a deep sump? I'm assuming before...?
Originally Posted by lowpue
Sounds like your failure was identical to mine. Here is my crank failure at 50K, much of it at the track due to oil starvation on high G long sweeping turns (shown this before).
. I suspect that your car was tracked quite a bit so I would not try to save the engine. Sure there is a bunch of things wrong with it now. I would only rebuild with the experts like Jake. My learning was all my engines for the track will have deep sumps.
08-29-2018, 10:35 AM
996.1 C2 crankshaft failure
My mechanic speculates it is either a factory part that was not built up to tolerance or someone had redlined the car multiple times while cold... Very unlucky whatever the root cause was. I truly like this car so much (exclusive manufaktur build) that I am dedicated to save it! 
