996 Engine Replacement Options

First, let me apologize as I'm sure buried in this forum are some answers to my question. My sporadic reading of the 996 forum has yielded some bits of information and my handful of search attempts have pointed to a few others, but I haven't seen this addressed directly. Question: What options are there for an engine replacement or renovation for a 996? This excludes a stock rebuild, salvage replacement or rebuild. Regardless of whether the M96 has an unfairly bad reputation, I've already had one go bad on me and I'm not willing to roll the dice again. For the purposes of this discussion, also assume that selling as a roller is not is not an option and that the car is going to be kept long term for maximum enjoyment! Obviously, Flat 6 Innovations is the first that comes to most people's minds. For the purposes of this discussion, I'm going to be considering them the gold standard. I've read enough of Jake's post to know that his brusque style rubs some the wrong way, but from the people I've talked to, no one disputes the quality of his work. Now, what other alternatives are there and what are the pros/cons of each? I know the GM engines are one option. I've heard maybe putting a later model 911 engine in. What else is worth looking into?

Not a lot of choices given your requirements. If you are afraid to roll the dice for another M96 engine, you have only two choices left: 1) JR engine ($18-20k) which removes all inherent issues with the M96 engines 2) LS swap ($15k I think) but that's not what Porsche intended Note even 997 engines have some issues of their own plus I don't think it's an easy swap anyway. Also note there are rebuilders out there using LN nickies to reconstruct M96's but the cost will not be much less expensive than JR's.

For the record, forget the LS swap. I already contacted Renegade about this. A cool idea, but you will be into it for at least 25K, between the cost of the motor, the adapter kit, wiring harness, labor etc.. etc., etc.. I see that you are in Texas, so not an issue. But, CA residents should think long and hard about this due to smog issues. It's not an impossibility, but certainly requires some effort and luck.

When considering a swap you have to think about the future even more so than when going with a reconstructed M96. Future buyers are concerned with conversions, and that effects marketability of a car IF you ever decide to sell it. I think its important to keep a Porsche marketable to Porsche enthusiasts, they are the ones who spend money on the cars. There are options, some better than others, and others that just don't make any sense.

Well with a little research and do-it-yourself stuff you can be into an ls swap cheap! I spent under $4k for my swap. Ls1 motor intake to pan: $1500 Adapter plate kit: $1200 Spec porsche clutch: $700 Wiring harness: $100 Motor mounts: $100 in materials (buddy hooked up the welding) Dyno tune: $600 400hp/400tq to the wheels at a fraction of the cost of a tt or gt3. Nothing was bought from renegade hybrids. But for California you would need to buy the GM crate e-rod ls3 motor that comes with a c.a.r.b. exemption to put into any model car and be legal. That costs about $8k from jegs, but that also includes ecu and tune.

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The OP's engine only has 60k miles, can it get away with no resleeving and new pistons? That should save quit a bit if possible.

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More than likely, no. Generally speaking we see .001" of bore deformation (ovality) for every 10K miles of service. There's no way I would reassemble an engine with .006" ovality. We also generally see .0005" of taper in bores per 10K miles of service, and again, I'll not accept that. There are exceptions, where an engine doesn't see these values, but they are few and far between. If these cylinders have this much deformation at let's say 60K miles what will they be at when the clock strokes 100K miles? Will the engine burn oil, lose ring seal and create a ding on my reputation? The chances are too high for me to accept. Been there, done that, and see others take themselves out all the time because their standards are not solid enough, or they make exceptions. I will only reuse factory cylinders if ovality is less than .002" and taper is less than .0015" on all cylinders of the engine. If not, the engine must be reconstructed, and sleeved. To determine bore deformation requires engine disassembly, and the use of the proper precision measuring devices. Once these values are gathered, one can make a decision about what should be done moving forward. Here's one of my cylinder charts from an engine that we measured today. It had 45K miles and had a cracked head. This one is not a candidate for repair, and must be reconstructed, with new cylinders. If someone were to repair this and put it back on the road without quantifying these values, the engine would be a disappointment waiting to happen.

Thanks, Jake. That's very informative. Basically you measure the ovality and taper and base on the current milaege you can predict the wear rate of this engine and any potential issues down the road. Maybe even some current measurements are already way out of spec like cyl #2.

If it were me, here is what I would do. From the other thread I assume a Flat 6 is out of the question at this point. I would buy a used engine off ebay for 6K, ship the car and engine to CA to either UFO motorsports or 9xx mtorosports (they used to be partners). They do a rebuild/refresh with install for $7500 including install and checking and pay for labor 1 way. Total out of pocket would be about $13-14K and you would be back up running in a few weeks with and engine with a warranty for 1 year. They upgrade a few parts but it is not the same as a reconstruction. I had UFO rebuild my motor last year and could not be happier.

Oops, just saw your pic. Add a few thousand to my recommendation. My car has a 3.4 and you can get a used 3.4 for $5-7K. 3.6's seem to be more.

That GM crate motor LS3 is only CARB approved for 1995 and earlier cars in CA btw. So makes for some interesting potentially legal retrofits but 996 isn't one of them. It can still be done but requires a BAR referee cert which is a serious pain

Why not a motor from a GT3? or take care of the one you have and not get worked up about it potentially failing. Keep your eyes and ears open for a motor you want, if it takes a year fine. Do a proper Porsche engine swap / upgrade.

If I lived in TX like the OP and didn't have to deal with the smog inspection gestapo like CA has, I'd do LSx swap all the way.

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THIS is a great solution IMHO

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Cylinders 2 and 5 are always the worst and are generally out by twice as much as all the others. This is de to the open deck design allowing the hottest coolant to these regions, and the cylinders have the least support. There are lots of times where the other 4 cylinders are very close, or at spec, and the two center cylinders are project killers, being way too far out. There's tons of engines that are being "rebuilt" out there for cheap prices that have nothing with the cylinders addressed. The builders are throwing them together cheaply and aren't even measuring the bores (if they even own a bore gauge or know how to use it) and those engines are just a temporary band aid that provides zero resolution to the root of the problem. Ignorance is bliss, and since cylinder deformation isn't visually notable. they think that everything al gonna be ok.

1. if you have an emotional attachment to the car (not necessarily 'love' as JR describes) and money is not an issue, go JR rebuild and get in his queue if not... 2. and you still want to keep your 996, find a good low mile engine for 8-10k (they are definitely out there) and with the right one its likely that you will not have to spend any money 'refreshing' if compression and leak down is good. that leaves you with your core which is possibly worth a fair amount whole are in parts. with any kind of mechanical inclination and skill you can RnR the engine yourself in your own garage and save $$$. total cost maybe 6-12k depending upon how much you do yourself and how much you sell the core for. 3. if you prefer to cash out and buy something else and you have time and space and willingness, part the car out as diablo is doing. lots of work but you'll get more than 5k in roller money and most likely LEARN A TON about the car and how its put together for future reference and wrenching. if not then... 4. sell roller as is, collect your 5-6k and move onto something else 5. there's also the swaps but that puts your nearly into price range for #1 or finally 6. if you want to do tackle the ultimate 996 DIY project, try and rebuild the engine yourself.

Always a possibility, and this year, for the first time ever, I am offering an enthusiast level M96 Engine Rebuild Class. In the past its always mixed DIYr's with Pros, because I didn't have dedicated training space to host many classes per year. Thats all changed now as I have added the training facility.

Jake, as far as how to minimize ovality and tapering, what advice would you give to a 996 owner? Frequent oil changes, low temp t-stat, spin-on adapter, avoid cold starts etc? Anything else? thank you

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Hi Jake, any chance of a class in SoCal this year? I missed the one in Costa Mesa last year.

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No way to really avoid it. A low temp Tstat will help, but we can't make up for Porsche's compromise of cylinder strength at the flame ring (upper most portion of the cylinder) without machining away the old cylinder and replacing it with a more robust billet sleeve. I am not traveling much for classes this year. With my new training facility done here, I'll be staying home a lot and having more classes than ever. We can finally have classes without impacting the regular schedule at the shop. The WTI M96 class may not be held this year, so we can move on to the 9a1 engine classes, which I have already instructed a few times last year. The WTI schedule comes out next month, so we'll see then. I have added the "M96 101" two day class to my class offerings this year, so even if WTI doesn't offer the class, we'll have a more in depth version here.

Hi Jake, when I understand you always stress the ovality and taper issues, I wonder how does it impact the user. Is it a performance issue or a catastrophic issue? We see lots of the 3.6 engines last 100k+ with the stock setup with no issues, that also means the ovality and taper issues do not create catastrophic issues like the IMSB. I totally understand you won't take the chance to reuse the cylinders because your reputation is on the line. However, for a regular user/DIY'er, is it true that one can reuse the cylinders (but use new rings) despite its natural deformation and just accept the inherent non-catastrophic short coming? Or the new rings will not seal or somehow make this inherent weakness worse? Just trying to understand more and your feedback is very much appreciated.

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^THIS if you have some expensive parts on your car. Here are some of my numbers if it helps any: Cost of parts to return my car back to stock: $6,000 - This includes my shipping & packaging costs (using FedEx door to door service), minor paint work, eBay fees for a few items, and some other maintenance items like coolant, tools, etc. - I didn't buy any "junk" parts," everything looks like they belong on a low mileage car - Keep in mind that I had a lot of stuff to buy (almost the whole interior, entire emissions system, entire suspension) but still managed to make it cost effective Income from parting out the car: $16,000 - Almost all of my parts sold within a few days of listing them; to Rennlist members I might add. - The only item left is the roll bar - it'll sell but I just need to find the right buyer - I did all of the work myself. These cars are EASY to work on. In my case, I already knew my way around so most of the parts came off/on in a snap. Looking back I'm not sure if dumping $6,000 back into the car was worth it. If I sold the engine and tranny I probably could've brought in close to $20,000 and then sent the rest of the car to the scrap heap. On the bright side I'm left with a low mileage and 100% stock car that still runs and drives just fine; so perhaps the money spent was worth it..... It looks like you have some decent parts on your car. Don't discount stuff like your aero kit, wheels, exhaust, etc. Those parts are pretty expensive on the used market and they will sell pretty quickly. If you have garage space (I didn't) that makes it even better. I'm thinking you could bring in $10,000+ depending on what parts you have.

Interesting thread about a DC area garage rebuild of an M96. http://www.dorkiphus.net/porsche/showthread.php?t=33667

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Yeah, I read it the other day. The engine has 187k miles on it! Basically they just replaced the main bearings and rod bearings and reused the pistons, rings, rods, and rod bolts. Curious to see if they have any issues after the rebuild. I guess with "free" labor, they have nothing much to loose.

I would like to offer my position on why the original OP mentions that Jake seems brusque to some people. I acknowledge that the OP is not saying that. He has seen others be snippy after Jake's posts. Jake is one of the very few posters that presents answers based on actual and accurate data. He can get right down to business and doesn't have to begin with a setup like "Maybe" or end with "IMHO". I had a phone call with him about five years ago on what "could" happen to my car and he was very polite instead of saying, "call me when you have a problem". As the OP says, Jake is the gold standard and we are lucky to have a man of his stature in the business offer solutions on this forum. He doesn't have to do it but he does because he's a giver. IMHO. :-)

I too appreciate Jakes help. I think of him as a drill sergeant. He isn't really trying to kill you, he's actually trying to save you from dying without having a chance to fight back first.

My 2 pennies. Jake's motor in my 996 sold my car.

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Probably because the buyer had looked everywhere and couldn't find another Raby powered car for sale! They never sell!

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Sorry for the delay in answering. During the week, I don't usually have much time to spend on the internet. This is a really good perspective and definitely one that I'll consider if I can't work something out with Jake. It would definitely be a test of my patience, but I'm definitely a believer that if I'm going to go through the process to get this car back on the road, I'm going to do it right. It's an opportunity for the car to be even better than before!

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Someday, when I retire (still 25+ yrs away), I'm going to build a house with a garage specifically for this purpose. In the meantime, I barely have time to respond to posts on this forum, let alone take on a DIY project like that!

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That's really good info, thanks. How time intensive was the process? I'll keep that in the back of my mind as a fallback option, but I'm not sure that I have the time or the space to take it on right now. It does sound like a good way to get intimately familiar with the car though!

Based on the responses so far, it really does look like the options are a lot more limited than I expected for 996 engine replacements. A lot of these cars were sold, so that actually speaks well to how the original engines have held up. The GM engine swap doesn't have much appeal to me. My FIL is an avid Corvette guy, but I prefer to stick with an porsche engine.

For those of us that would go the Raby route, what are the options there? I mostly see 3.6 bandied about, but I've never been clear on if that is just that the 3.6 is the most popular rebuild or if he is reworking the 3.4s to have a higher displacement. I think I've also seen something about a 3.8, but don't remember for sure. In our case we have an 01 3.4 and when/if it goes I'd ideally like to upgrade the power as well as reliability. So what are the displacement/performance upgrade options from Jake?

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For many years these engines were not worked with at all. When we started the development no one was tearing into them at all. The first year that I offered engine classes I had 5 people interested, today those classes fill months in advance. Back then, anyone working with these engines was laughed at, as others would say "you can buy a new crate enine from Porsche for 5K, why should I learn about them?" and that mindset carried on until the recession hit.... Then that 5K engine went to 12K over night, and no one knew how to work with the engines, because they screwed themselves. At that point we already developed all the components and processes and the first engine program, too. By the time others started working with the engines, they had to learn really fast and they used their customer base to do the development. They couldn't take years and spend the cash required to truly develop the engine. On top of that, they already knew who was at the top of the food chain, and even if they tried to develop something comparative that they were already 10 years behind. The easiest thing they could do was patch the engines up, offer a cheap rebuild and hope that it worked. Thats where everything stands today. The same thing is happening with the 9a1 engines all over again. No one is learning, but we have 5 years of experience with them, including taking them past 4.2 liters. People still don't want to learn, still won't spend the required money to develop, and in a few years they'll wonder why we are so far ahead. In early 2010 I took apart the first 9a1. It was pulled from a car with 11 miles on te odometer and we built it to 4.2L, going as big as we could right out of the gate. Aggressive development is all I'll do.

I see that VERTEX has rebuilt longblocks for the 3.6 for $10,900 plus core charge. That would be a reasonable option assuming whoever is doing the rebuild knows what they are doing and are not just throwing these together (to Jake's point above). Has anyone had any experience with these rebuilds?

If your thinking of tackling the build , search 986fix on YouTube , this guy rebuilt his boxster s engine which is the same, it's got step by step video clips, obviously doesn't tell you everything but you can see if it's something you can handle !! Also I would drop the engine and transmission out, it's worth stripping the engine to see what's worth selling, heads go for good money if ok as do cranks , plus you can see what happened !!

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From 3.4 my Stage 1 is 3.6, Stage 2 is 3.8, and Stage 3 is 4.0. Stage 1 is a developed for street only use. Stage 2 is DE/ street and Stage 3 is primarily track, but is street able. For the 3.6 Stage 1 is 3.8, Stage 2 is 4.0, and Stage 3 is 4.2 For the 3.8 Stage 1 stays at 3.8, but makes 20 more HP, and Stage 2 is a 4.0 There's currently no Stage 3 for the 3.8 base engine. The cylinder heads won't support anything larger. 3.8 heads are my least favorite, the factory crippled them purposely. Same goes for the cams. Stage 2 engines are what we build most often. I don't have these details on my site. I pulled a lot off the site, purposely, and haven't ever put it back.

Jake - what does the Stage 2 and 3 from a 3.6 (ie the 4.0 and 4.2) put out in HP, approximately?

Here is an unsolicited factoid. My engine was freshly installed by Flat six Innovations when I bought the car. I read that stock the cars make 25 MPG. well on my drive home with now 1000 miles on the motor I was averaging 27.2 MPG. I re-set it and also hand calculated the milrage for the whole 400 miles trip. So what ever it is they do I can tell you they do it better.

Wasn't there a guy that put a boxster s engine in his 996? Cost about 4k or around that area.

In addition to horsepower I'd love to see the torque curve on a stage 1 and 2 Raby built 3.6 compared to stock since one of those is the way I'd probably go.

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Torque curve is where it's at... I share torque curves in my webinars.

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If you were averaging 25 MPG in a 996, you were definitely not having nearly enough fun.

Wow, I would be interested in that class. Maybe you could do it at Cypress College in Anaheim. They have a really good Auto Mechanic program there.

even if you do find a CARB-certified LSx motor that can be shoehorned into the 996, you will still be at the mercy of a CA smog referee who can fail you for any emissions-related issues and may fail you even though someone else successfully registered the same setup at the same station the day before. Imagine how much it would suck to drop 15k into a conversion only to learn that you have to trailer it to track days if you actually want to drive it...