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Intermix/Cracked head repair

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Old 05-26-2009, 06:54 PM
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Dharn55
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Default Intermix/Cracked head repair

I thought I would provide an update on the solution to the intermix/cracked head problem on my 2000 996. For those of you who havenít seen the previous threads, last September, 8 months after the expiration of my EasyCare extended warranty my car developed an intermix problem, with significant amounts of oil in the coolant and coolant in the oil. Initially I tried to change the oil and top off the coolant to see how long before the intermix reoccurred, but it seemed to happen immediately (although some of this might have been residual contaminated fluids in the engine and cooling system).Therefore it seemed that a new engine would be required, and with the economy limiting the budget I parked the car for the winter.

This spring I started work on the car, first checking the oil cooler for any problems, but quickly determined that this was not the source of the intermix. Then I dropped the engine and begin disassembling it. Soon I found the crack in cylinder head 1-3, cylinder 1 at the inner exhaust valve seat, which you can see in the photo above. This seems to be a very common problem, and the most common area for cracks in the heads of M96 engines.

Now I considered four or five alternatives, a remanufactured/rebuilt engine, a used engine, a used cylinder head, a new cylinder head or fixing the crack in the head I had.

The replacement of the engines was out of my budget. Porsche now wants over $12,000 plus a core for a remanufactured engine (this is through Sunset or Suncoast, the list is much higher), and only warranties the engine if it is installed by a dealer. I wanted to stay married so that option was quickly ruled out. Looked at some sources for rebuilt engines, but they seem to be $7,000+ and somewhat of an unknown quantity. Used engines seem to be $5,000+ and are also an unknown quantity.

I checked out the cost of a new head, which list for about $2,700, and Sunset and Suncoast were about $2,400, and the 1-3 heads were in Germany so over a month away. The parts department at Suncoast did lead me to a dealer in the Chicago area who appears to have the only new 1-3 head in the states, and would let it go for approx $2,400. But I found out that Porsche only warranties the head if it is installed by a dealer. Seemed like a lot of money for a head without any warranty. So I scratched that alternative.

Next I tried to find a good used 1-3 head, but they are very scarce. Several wreckers had 4-6 heads but no 1-3 heads. Found a set of heads through a member in Florida at an incredible price, but I asked the member, who is a Porsche tech to check the heads for cracks. He said he had never seen a cracked head but would gladly check the heads. A little penetrating dye showed that the 1-3 head was cracked a cylinder #1, inner exhaust valve seat. Found another set, but when they were checked 1-3 was also cracked. Do we see a pattern here? Found another set in NY, but they were from an independent/Ebay seller who could not tell if they were cracked. He said he would refunds the money if they were cracked, but we could not agree on a price, and I was worried on getting the money back. Cracks in the 1-3 heads seem to be far too common. I spoke to Jake Raby and he told me that in a 10 day period they tore down 5 engines for big bore upgrades, and 4 had cracked heads, although only one had developed an intermix problem. But we all know that cracks donít get better, and it is probably only a matter of time until the other cracked heads would lead to problems. Jake said he would certainly not use a cracked head so he was sitting on the engines until a solution could be found.

So I decided to have the head repaired. Kind of figured that with so many heads cracking in the same area maybe a repaired head would actually be stronger. Sent the Head to Costa Mesa R&D, where they have experience with repairing these heads. Here is a picture of the repaired head, it is supposed to be delivered to me on Friday and I hope to be back on the road in the next week or so. The cost of the repair was $503, including a valve job and drilling out a frozen bolt on the cam sensor and putting in a coil, plus about $30 shipping in each direction.

I am keeping my fingers crossed that this is the solution to my problem. Wish me luck!
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Old 05-26-2009, 08:27 PM
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DFC
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Wow! I hope this works out, thanks for the update.
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Old 05-26-2009, 10:30 PM
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Wow! Wish you luck and hoping you succeed.
You may have just found a new business for yourself.

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Old 05-26-2009, 11:37 PM
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Let me know how this ends up.. That is a very critical area for repair and it appears that they did a very good job.

I can't ever risk a repair like this, so even though we have the capabilities to make the same repair I have held off on doing this for Customer's heads to date.

I may take the cracked heads we have,repair them and then put them on a used core and punish the hell out of it and overheat it and see if the repair holds in a harsh environment with a failure being induced.

Glad to see that you are making progress.. Call me if you need anything during reassembly.
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Old 05-26-2009, 11:42 PM
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How is this kind of repair accomplished? Is there some way to ensure that the entire crack has been filled? I'm just thinking that if the entire defect isn't sealed that you'll still have a propogation point for a future crack. Great job on pursuing an alternative and keeping the community up to date on your progress!
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Old 05-27-2009, 12:16 AM
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Hope it works for ya doug.

usualy a repair like that would involve drilling each end of the crack and then welding and grinding, looks like a fantastic job to me though.
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Old 05-27-2009, 09:17 AM
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Looks great! Best of luck. Please keep us updated.
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Old 05-27-2009, 09:08 PM
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Dharn55
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When I originally called John Edwards at Costa Mesa R&D I told him I had a cracked head on my 996. Before I even had to chance to say much more he basically said "oh ya, at the inner exhaust valve seat on cylinder #1, happens all the time." So he knew exactly where it was cracked before I told him and said he had fixed many of them in the past. Appraently they cut out a significant amount of metal in the area and weld in new metal, then machine it as required. He said that he had lots of repaired heads out in the field running in cars. I asked if he had ever had one recrack. He said yes, but never in the area of the repair, always somewhere else.

With the number of cracked heads out there it seems that there is some defect in either the design or the manufacturing process. This is one of the reasons I was reluctant to buy a new head. alot of money and if Porsche hasn't changed the casting/process what are the odds of the new head cracking. And when Porsche said they would not warranty a new head unless it was installed by a dealer the choice was amde for me, no new head.

Based on my experience and search for a head it seems to me that there are probably alot of cars with cracked heads that have not yet caused a leak, and some of them may never do so, but others are ticking bombs.
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Old 05-27-2009, 11:51 PM
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Good luck with this one. I have had very good luck over the years with repairs on cracked heads. I see it as a logical, cost-effective, high-probability-of-success solution.
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Old 05-28-2009, 09:39 AM
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Paul 996
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Nice to know that there is a reasonably priced way to fix this as opposed to replacing the engine. Thanks for the research and great work!
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Old 05-28-2009, 10:56 AM
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Wow, sounds like a great way to save $12k! Assuming if something like that happens on my engine, and I had to pay a mechanic to tear down the engine and send the cracked head to Costa Mesa, it would still be reasonable compared to replacing the engine, I bet?
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Old 05-29-2009, 09:50 AM
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Subscribing
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Old 05-29-2009, 12:35 PM
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Can't wait to see if this solves this. Great work and keep us updated.
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Old 05-29-2009, 12:52 PM
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great job on researching this particular problem... this will help alot of folks out in the future. Please keep us posted.
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Old 05-29-2009, 12:55 PM
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I wish you the BEST of luck and hope this works for all of us.
You may have saved the Rennlist Community thousands from your research.
Thank You!
Your posting and pictures have been invaluable.
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