987.1 CS Engine Failure - DIY Rebuild?

Hello all! So we had an engine failure at the end of last season. We believe we hurt the engine at the autox, and the ticking started a few days later. We found a ton of metal shavings in the oil filter and found a lot of copper, so we are assuming it's a spun bearing. With that being said, we decided we would go ahead and tear the engine down ourselves. The core is worth the same assembled or disassembled so what the hell! Depending on what the issue is, we may try to rebuild it ourselves as well. Here is our progress so far.

Thanks for the update. Tread carefully. Before you dig in any further, you might want to call Jake Raby at Flat 6 Innovations to see if there are any preliminary procedures before tearing it apart. No use totally ruining a short block because you didn't follow initial steps. My guess is #6 rod bearing.

We spoke to Raby but have decided to go a different direction. I did get my hands on a full shop manual and it details the procedure so we should be good moving forward (although we need to get one special tool). The plan is to tear it apart to see what's what and make a decision from there. Vision has offered to buy the core assembled or disassembled for the same price, so it made sense to do it this way for us. A lot of people will likely cringe (or think we are nuts) but there is a decent chance if it's a rod bearing we will do the repairs in house.

Did you have a deep sump fitted to the car? 996 swirl pots? What oil were you guys using for Auto-X/DE?

I may have posted this before but be sure to look at this. http://www.planet-9.com/987-cayman-...er-service-and-tech/86847-engine-removal-question.html?highlight=rebuild+engine

we did not have any oil mods done to the car. Unfortunately we were ignorant to the issues with the M97. At the time we were using Mobil 1 synthetic , although I don’t remember the viscosity. Raby seems to think this could have been part of the issue. It was a pretty warm day and we were doing back to back runs so it could have broken down..

thank you!

I absolutely admire your bravery! I certainly hope you will succeed! Even if you don't this will leave you with invaluable learning experience which is IMO the most important thing. Good luck and keep the updates coming. And don't forget - as you mentioned in the beginning - the organization of a project like this is one of the most important factors for success!

Thanks! I will be sure to keep everyone updated. It's definitely a big task at hand, but I always believe if someone else can do it, so can I (I mean besides run a 4.2 40 haha). We are talking with some people about what other options we might have for a rebuild. It sure would be nice to introduce something else to the community, as the existing options are SO expensive. Something similar to the 2.85 stroker I built for my 951. Another option is finding a salvage car, as the engine core may pay for the majority of that and then we could use the engine from the salvage car and part the rest out. More to follow!

i like this thread and where its going

Another update!

Thanks for the update. Can't wait for the cracking of the block to see what's what. Remember, it isn't a project unless you have to buy a new tool (or 3).

My thoughts exactly! It's always nice to have an excuse to buy some more tools. We should be cracking the block real soon. Still have our fingers crossed that it's a rod bearing and the damage is minimal.

I have machinist and engineering skills, so made my own special tools and they work great. You will not find undersize bearings for this engine. I had my crank repaired by a crank shop and they "sprayed" the crank back to original. It had a measured .006" damage, so possibly would have ground "clean" at -.010" (-.25 MM). Now at 50,000 plus daily driver miles, I think the repair has failed. I will be designing an undersize bearing for my rebuild this time. Had I known the "spray man" would be taking 8 weeks, I'd have done this the first time.

Awesome, thanks for the heads up! I will absolutely look into the "spray", sounds like a better option than a weld repair!

I am NOT recommending the spray. After I had completed it someone else commented that it wasn't good for but 30,000 miles. I don't know if you can weld a nodular which I think this engine has. I'll post up if my undersize bearings work out.

Real guys showing me how my engine comes apart! Missing bolts like I would. Fantastic video! Thanks. Sent from my iPhone using Tapatalk Pro

Ok, I must have misunderstood you. I thought your only concern was the turnaround time. We should know soon how much damage there is to the crank and can make a decision then. The engine was ran with the knock for less than two miles, and started three times after that. So far the only metal shavings or signs of damage have come from the oil filter so there is still hope.

Haha, thanks! There is no chance we can drop $20k+ on a fresh 3.8 build (as much as we would love to) and don't trust another used engine. So, the only answer is to see what we can do ourselves!

This is great that you posting the vids. Thanks for that! Also I pm'ed you. I will be tearing my engine down soon and would love to get the copy of the workshop manual. Thanks again.

Thanks, replied!

Hey all, here is the next update. We got the other cylinder head off and got everything stripped down to the short block. We should have everything disassembled next week and then we'll know our root cause. I still think it's a rod bearing, especially at this point.

Ok everyone, we finally got the engine all the way torn down. It ended up being a spun #5 rod bearing. The bearing was absolutely toast, not sure how we didn't hear or notice issues before, as this was obviously an issue for a while. We also picked up a M96 engine , all disassembled, with sleeves installed for a 3.8 build. We will be running the M96 heads and doing a complete build so that we can hopefully mitigate the chances of something like this happening again in the future. We still have a lot of research to do on the M96 , and what it takes to turn it into a 3.8 as I'm sure the larger bore alone doesn't cut it. Do we need a 3.6 crank? Interested to see what all will be included when we pick the engine up in a couple weeks.

Fascinating to watch, thanks for doing the videos. Whatever happened to the engine stand mount? It looks at least twice as hard on the floor. Looking forward to the rebirth videos.

Thanks! Well, to be honest, the engine mount adapter is $300+ and we just decided it wasn't necessary to spend that money right now. Trying to do all of this on a strict budget is pretty tough. When the new engine comes in and we start measuring / building it you can be sure it will be on a proper stand and mount.

Entertaining thread, thanks. But you guys are killing me, working on the floor like that

Ha, I can't tell you how many times I've heard that now. We didn't damage anything by working that way, but it was definitely messier and less comfortable than it could of been!

It's not the potential of damage it's 100% the comfort, heck even a bench would have been a godsend. I worked in a professional shop in my youth and I'm confident I could have done what you've done thus far, it's reassembling everything with the correct timing and tensions that looks daunting, can't wait to see the upcoming videos, great work. My father used to build racing engines, he was offered a gig at Indy before I was born but my mother nixed that idea. He worked on a lot of exotic things for their time period including tons of twin overhead cam units but nothing like these modern Porsche engines.

A workbench would have been nice! I’ve got an 8ft gladiator bench at my house, but we’ve yet to move everything to the shop because we are doing the floors. Yeah, disassembly is the easy part! The M96 build is going to require a lot more research and a lot less “shoot first, ask questions later”. I just tell myself if someone else can do it, so can I!

Quote: I just tell myself if someone else can do it, so can I! I admire that spirit and enthusiasm, may I recommend you one day take that idiom to club med.

hahahaha, if I make it that long you know I will

#6 piston is the one that generally oil starves because Porsche didn't think everything thru with turning a 911 engine around to use in the 987 platform. Be sure to put an extended sump baffle in your new engine. Rod bolts are weak and extended runs at redline tend to stretch them. After seeing your abuse inserts, looks like you spent plenty of time at or near redline. Great videos. Thanks for the knowledge they provide.

We will for sure be doing any and all available oil mods, along with upgraded rods, bolts etc. It’s sad that the cars can’t handle that abuse from the factory. Especially considering we’ve had a number of Mustangs, 350Z’s, M3 etc and never had an issue like this before. However, you don’t know what you don’t know and we sure didn’t know that those potential issues were there before it was too late. At the end of the day, shame on us for not researching the platform better. With that being said, I still wouldn’t tell anyone to stay away from Caymans . What a fantastic platform it is, M97 shortcomings and all.

Be sure to treat your rebuilt engine to a new oil cooler. You can't really get them completely clean. Good luck with the rebuild. Please buy the piston pin circlip insertion tools. A loose circlip will ruin your day.

noted, thanks!

Sorry to hear about your M97 but definitely find your videos educational. I hope I don't have to go down this road but I feel I am better prepared if I have to. Good luck with the rebuild. -Moto

Glad to see that it was only a spun bearing. My engine actually grenade at Mid-Ohio, only thing that could be salvaged was the left bank head. Mobil 1 oil but probably related more to starvation than the actual oil type. Raby blames the oil ALOT. Agree with the deep baffled pan. Also consider new oil/air separator. I have a 3.8 built by Vision so I will look at my build sheet as we pretty did everything to make the engine bullet proof. Lastly, make sure you put new coil drivers as they are relatively fragile and don't like the heat.

That would be great, thanks a bunch! We had a lot of oil in our intake, and deposits on the head of the pistons. I’m assuming our AOS wasn’t quite until to snuff for the abuse we were throwing at it. Yeah, Raby blamed our oil as well, but he also said it was scored cylinders which it was not.

I SMH at all the talk about bore scoring. It gets blamed for so much. There's a 30+ page report on bore scoring by some British folks who researched the issue with the 987. Their conclusion was bore scoring would only occur under a series of conditions when tracking your car (and by tracking, I mean more racing than DEing). Since most 987 owners don't fall into this category, chances are bore scoring is not an issue for the vast majority of owners, yet it scares people more than the boogey man. Does bore scoring happen? Yes and possibly to cars that have never seen a track, but probably not enough to be concerned about. It probably happens less than IMS failures. People need to let it go. Maybe Raby is perpetuating the myth and everyone bows to the oracle. IDK. And I hope you didn't take my comments about abuse as finger wagging at you. Not my intention. Porsche used an inferior quality rod bolt. Not your fault that you weren't aware of this. I mentioned it in my previous post because you had a few adventures at redline, probably stretching the rod bolts, resulting in the spun bearing - cause and effect. That's where this thread can help others become more aware of the issue. Your information is helpful to others.

I hadn’t read that study, very interesting! I definitely take issue with certain people propetuating myths and claiming stuff that costs people more money for their benefit. As for the finger wag, I wouldn’t take any offense even if you did. I understand some people will turn their nose up at our abuse, but at the end of the day these cars are meant to be driven, and in my mind, driven hard. Your insight is much appreciated!

Last time I checked Mobil 1 was an approved Porsche oil, it's the easiest to find near me. I change my oil every year due to the accumulated moisture and chemical changes from driving it's never a mileage issue. Jake may be a talented wrench but he's also the President of the Jake fanclub, personally I find that off putting.