Who has done the factory short block swap?

There�s lots of talk about the factory short block swap as an option for a blow engine. I�m curious to hear from owners who actually went this route. Are you happy with the results?

I did it, happy with the results, and did all the work myself. I would do it again in a heartbeat if I found another roller near me in a similar condition. Note, I chose this option because my crank and at least one con rod was trashed, replacing these parts alone is expensive and the short block option came with many other new parts at a low price. Since this was my first Porsche and I had never driven it before I bought it, I was not in love with it (yet) so couldn’t justify an expensive FSI build, although I have no doubt this would have been a superior technical decision. The car ran perfectly from the first start-up and has not had any CEL or other issues in the 4000 miles driven since. It is important to note the other parts I replaced at the same time, AOS, oil cooler, coils, plugs, oil filter conversion, scavenge pumps, etc, and the head work I outsourced. I would do it again in a heartbeat if I found another roller near me, although if my next one has a good crank, etc I would consider a rebuild with nickies, IMS Solution, overbore, etc., still doing the build myself. Here’s the link to my thread on the build. https://rennlist.com/forums/showthre...errerid=188196

@Coopduc Thanks for the info and for the riveting build thread. I read the whole thing - really nicely done thread and a beautiful result. I wish I could do a project like this myself, but I don't have the space, time, or tools. So, I'll be sending this out to indy shop. Even with someone else doing the work, and getting the heads done, it ends up less expensive than most rebuild options, so I'm leaning towards this solution. I didn't see in the thread which short block you ordered. Was it the standard 996-100-996TX or the X51 block 996-100-951TX? Someone on another thread linked a a new X51 short block for just $5,100, which seems like a great price vs. the regular short block for $6,900.

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Are those both 3.6 motors?

Mine is a 3.4 motor, here is the p/n label

I'm not sure what an X51 short block would do for you. From what I've read, the X51 bits would be found outside the short block (except the baffled oil pan). See Loren's post here: https://rennlist.com/forums/996-foru...1-package.html

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^ Adding this comment from @rogazilla since it's on-topic here. Originally posted on the rebuild thread https://rennlist.com/forums/996-foru...bs-vertex.html

@808Bill Those are the part numbers for the 3.4. Coopduc and I both have 99s. @Coopduc Thanks for the part number and photo! I'm thrilled to see a new water pump was included with standard short block. @cds72911 My understanding is the earlier 3.4 motors had more differences in the lower block than the later X51 kits. That being said, the main benefit I'm looking for in this case it to save $1,000+, as I found the X51 short block on sale.

I thought that the X51 block was the same than the regular one, being the differences on other parts, like oil pan, headers and so.

The main issues we see with these come from who is tasked with prepping the cylinder heads to be fitted onto the shortblock. The same goes for assembly. The factory shortblock is OK if you have someone that’s extremely capable working with the cylinder heads, and if you are okay with accepting an engine that’s just like what you previously had from the cylinder decks inward.

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@Flat6 Innovations What are some common errors made by less-capable engine builders when working on the heads in particular?

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You name it. We see hacks screwing things up more and more everyday. At times its because they let the customer dictate what they will have done, based on cost. That should never happen, the machinist is in charge, and if the customer wants something done half way, they should be turned away. In most cases people simply do not understand the inherent issues with these engines, and they botch things that lead to other failures. Typical mistakes include reusing valve springs, trusting valve seats on the heads that are known to have low interference fit seats (but they don�t know that, because they lack experience wit these heads) as well as improper decking procedures. From a performance perspective they make ports too damn big, kill velocity and they do it because they think bigger is better. The #1 issue is making repairs to heads that are damaged from traumatic experiences on the prior engine, when those heads should be thrown away. Typically the people buying these short blocks are on too tight of a budget, or too tight of a timeline. Calendars, clocks and shallow pockets waste money every time. They have to experience this to understand it, then they come crawling our way with a sob story. I�ve stopped even responding to those messages.

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Haste makes waste, as I learned early in life. I concur with Jake 100%. We see shops or even at time, DIY guys, that will spend all the money on just Nickies alone, or a go the route of shortblock or longblock, and then cut corners and re-use components that should be replaced because they exhausted their budget. While SSF was handling the RND program, changes had to be made to include things like a new AOS, oil cooler, vent tube, break-in oil, as well as to come up with very explicit guidelines for installation and break-in, as we found shops would reused items like used oil coolers and the AOS, among other components during a build, to keep the complete job price under a certain threashold to get the job. It's kind of like walking into a dealership to buy a car and they whip out a four square and ask you how much you can afford to pay each month. They will sell you the cheapest car they have at the highest price to meet your monthly payment expectations. Like with any rebuild or engine replacement, the final result is more than the sum of the parts inside the engine, but also the ancillaries as well as the competency of the shop carrying out the work.

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Then there were the times when the shops would reinstall the old heat exchanger, or other parts onto the new engine, and keep the new parts for their stock. There�s about 10,000 reasons why I won�t let anyone thats not under my roof install one of my engines. The shop isn�t vested in the success of the project. its not their car, and not their engine. The way they look at it they are doing the slave labor, and �making less money than everyone else did�. They slap the engine in, pat the car on the ***, and don�t give a damn what happens. If anything does happen the finger pointing starts and then they say �We did everything right, and followed the instructions verbatim�. Of course they did. Including the time that someone dropped an intake bolt down an intake port, and it destroyed a brand new RND engine. Yes, they did everything right. Yeah, it sucks.

@Coopduc I saw in your build thread that you replaced the plastic chain pads in your heads. What about other parts? Did you replace the valves, springs, lifters, etc. or we you able to inspect and reuse those parts?

I brought the heads to Hoffman Automotive Machine in GA and told them to do check everything and do whatever is needed. They soda blasted, US cleaned, pressure tested, crack checked, milled the face, replaced all springs, seals, etc, and weld repaired 5 stripped header mounting holes. Guides, valves, seats, cams, lifters were inspected by them and determined to be ok. Len Hoffman has been specializing in aluminum heads for years and really knows what he’s doing. I know several Porsche specialist shops also use him. He is the best! https://newsite.hamheads.com/

@Coopduc Thanks for the info. That place looks like they really know what they are doing, and your heads came back looking like works of art. I will work with a local machine shop in the Chicago area recommended by a Porsche specialist, but this is a helpful checklist for evaluating the shop.

The mechanic who's quoting the short block swap sent me some references, and I spoke to a previous customer who did the short block swap on his '02. He's put 14k miles on it in the 4 years since he had the work done and hasn't had any further issues. I was still hoping to hear from some others on the forum who have gone this route. Only two cars here with the short block swap?

Hey OP assuming you completed your short block install, any update?

@oregondave Yes, I went ahead with the short block install and got my car back from the shop last October. With the Chicago winter, I've only put about 700 miles on the car, so I'm still in the break-in period. However, it's running very well and there were no major surprises in the process. I had the job done by a small indy Porsche specialist. In addition to the block swap and head refinishing, I did the clutch, AOS, and coolant tank. The only surpise in the process was replacing the coil packs - one was malfunctioning, so I replaced them all. It threw some codes related to the oxygen sensor when I first got it back, but it seems that was due to oil that had collected in the cats and needed to be burned out. All in, I spent about about $15k for the block swap, head refinishing, and the while-you're-in-there items. If you can find the right shop to complete the work, I think this is the best balance of cost and quality if your engine dies.

�Calendars, clocks and shallow pockets waste money every time�... This should be a sticky.

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Make sure you check your fuel trims. Assuming the original engine suffered bore scoring, bad injectors, MAF, and o2 sensors contributed to that failure and will wipe out the new factory shortblock if these components were not replaced. I spoke to a shop on the west coast that had a factory shortblock score in the same cylinder only 3000 miles. Turned out to be the injector was the culprit.

@Charles Navarro What would you consider to be the acceptable range of values for fuel trim?f

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It's supposed to be 1.0, but I'd say anything within .95 and 1.05 is probably acceptable.

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stupid question but how do you measure fuel trim? And at what point will out of spec trim throw a cel?

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We've seen cars at 1.25% not throw a CEL. You need a durametric at bare minimum. Needs to be a Porsche specific diagnostic tool. Fuel trims shown on a PIWIS II

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perfect thank you!

Won�t a standard OBD2 scab tool give you short term and long term fuel trim values? Do the Porsche specific tools measure something different?

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Someone else would need to jump in here and verify as we only have a PIWIS II and Durametric Pro in our shop.

Some OBDII scanners show fuel trims. I think the one I have does and it's just a $200 scanner. Remember seeing the trim value on a freeze frame but that was a while ago.

Almost any standard OBD2 scanners that have live data will show you fuel trims. Expect it to cost at least $200.

I ended up with the OBD Fusion scan tool app on my phone, which reads live data and only costs $10. As it turns out, my long term trims are running high. Since it's a bit off topic for this thread, I started a new one to explore correcting the issue https://rennlist.com/forums/996-foru...l#post16560580

FWIW,, my Little Bosche bluetooth running their app on my Iphone unit reads out the fuel trims, got it at O'reillys for working on a Honda before I got the 996,, its worked on most OBDII rigs I've tried it on. I got it on sale for 60 bucks..

My son and I did the factory short block, and sent the heads to Hoffman. 3,000 miles later, I couldn’t be happier. Only regret? Didn’t pull the outer seal on the case-split style IMS bearing.

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You can't get to the front seal if you pull the flange?

Pull the flange to get to the rear one, but the bearing and other seal are inaccessible unless you split the engine. I should have pulled the flange. Oh well. Next RMS or clutch...

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Impressive! Congrats on doing it yourself, and I'm glad you're running strong 3,000 miles later.

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In that case I wouldn't have split the case for this. It's a real PITA to put it all back together and then there is the risk not properly installing the wrist pin clips. You'll be fine, don't worry about it.

As this is my decision to address a hole in the coolant sleeve on cylinder #1, a cracked head above cylinder #2, and bore score on cylinders # 4, 5, and 6, I'm interested in finding out how this option went for others. Reviving this thread as to not clutter up the feed. If you've done this, or have any insights it would be great to hear them here. Best,