Cayman 3.4 engine into Boxster S 3.2

[recycledsixtie]

I can relate to this thread from the seller's viewpoint a few years back. I had never seen the CEL come on while the engine was running in my old 99 Miata. I sold it in the morning to this gal and the boyfriend was with her. A few hours later I get a call from the new owner and she says in an assertive voice " I have the CEL lite on. What is it about this car you are not telling me about?" I said that I had never seen the CEL lite on before which was true. I told the owner before me and the Pres. of the local Miata club. They both offered to go down and read the codes.

The boyfriend must have settled her down and later fixed the offending O2 sensor.
If it was me that sold you your Boxster I would have refunded you some $$$ but not everybody is like me.
Guy.

[Gelbster]

Here is link to a post on this Forum where the car had exactly the swap we are discussing.So it is doable -the question is:
1. how to deal with the electronics?
2. and is a Tiptonic O.K. for a manual recipient ?
If someone covered this in all the vital details, plese tell me.
http://986forum.com/forums/boxsters-sale-wanted/47049-2000-boxster-996-3-4-engine-swap-located-souther-california-77k-orig-miles.html

[opus69]

That 3.4 engine is from a 2001996. If I read you correctly you were thinking of installing a 3.4 Cayman engine. The older 996 would be a more compatible swap. Same displacement but quite different w electronics.

[cheetah]

I did the swap a few years ago. Physically the swap is not that hard. Spacers to lower the engine and transmission (the new Cayman S engine cover might take the spacers place now).

One also needs the Bentley book to see both wiring diagrams. There are some sensors that changed, so wiring changes while relatively simple, are needed. This new engine also has the variable lift solenoids, so those need wired to the DME. I think that maybe a dozen pins needs moved.

Vacuum lines are different. I also installed a IPD manifold so which made it probably even more so.

I used my existing fuel rail, so I had to make some adapters to mount to the new engine.

If I remember right there were two different 7.8 DMEs. I believe that the correct one needed was from a 03-04 Boxster / Cayman. I think the later 7.8 had more memory which gave issues in making the DME, immobolizer, and key to handshake. You will have to tow the car to a dealer so that they can flash these to all match one another.

The car ran, but a new flash was needed by Softronic to make everything correct. They did an awesome job of helping me get it exactly the way that I wanted (like removing ALL e-throttle delays).

I also kept the oil / coolant heat exchanger from my 3.2L since it was larger.

I did all work with the engine and transmission on blocks on the garage floor. That way I could ensure the wire lengths and vacuum lines were all factory looking. I installed the engine and transmission into the car together (requires the car to be lifted very high), but I didn't feel like installing them separately.

[Gelbster]

Cheetah,
Thank you for your overview of adapting the 3.4l engine to an older Boxster. You clearly did a lot of investigative work and seem remarkably unintimidated by it ! If you had made a detailed build thread or video for it -that would have been very popular.

[Gelbster]

I contacted Softronic regarding the DME swap mentioned in this thread. The reply I got may be useful to others contemplating this 3.4l swap:
I wrote:"Hi, I am replacing the engine in a 2001 Boxster S 6-speed with the 3.4l engine from an '06 Cayman Tiptronic. The 7.2 to7.8 DME change alarms me Do you have a 'plug&play' unit to magically make the new 3.4l engine function correctly? Including the ABS ?
Thanks."
Reply:
"Sorry no on the ABS as the old system is a 7.2 and the 2006 Cayman uses a 7.8 so the coding is different and other issues like the cluster etc.
Best, Scott"
So back to the rebuild. Thank goodness the engine had the Raby/LN /Pelican spin-on oil filter mod.

[Topless]

With so much frag floating around in the oil I would be shopping for a clean 3.2L motor from a dismantler and give it a minor update (IMS and chain tensioners) rather than spend 100 hrs on that one only to have it potentially fail in a short time. Just too much opportunity for unseen issues to bite you later.

YMMV

[Gelbster]

It will be an interesting test of the merits of the Raby/LN/Pelican filter upgrade.
The engine did not seize. Just rod knock.Or what I speculate was rod knock.
So far there is no bearing debris anywhere but the pan and filter. But it will be a week or two before I have results from further dismantling. The oil was otherwise clear and seemingly recently changed.
If Cheetah/Softronic had a simple 3.4l conversion plan , I would have jumped at that chance because that engine has only 8000 miles,is from a friend, and is $3000. But the
'02 Boxster S/06 Cayman difference and the Tiptronic issue seem too much of an obstacle - for me at least.
If the spin-on filter saved the engine it will be a spectacular endorsement of such an inexpensive(compared to a rebuilt engine) modification.
And just to repeat ,the original 80,000+ IMS was perfect when removed and the LN dual row ceramic replacement is also perfect.No IMS hysteria here.

[cheetah]

I know that different years had different ABS systems, but my 02 had no problems or issues with the ABS.

[Gelbster]

Hey Cheetah,
Wayne's book mentions that the 2002 has a few DME/CAN compatibility advantages compared to my '01. I have no clue if that is a critical difference that made your 02Box/Cayman 3.4l swap a success. And that is the problem - there are lots of unknowns in this swap issue and they are potentially insuperable- or trivial.
For example, if you did exactly the same procedure on my 2001 Boxster S 6-speed but used the $3000/8,000 miles '06 Cayman Tiptonic donor engine I found - would it work like yours did? I can't find anyone in the Boxster community who has done exactly that and shared the knowledge. There are lots of gung-ho generalizations ,but no comprehensive details. By comparison,ask which Miata engines fit which older/younger Miatas and there is a huge amount of comprehensive info. That's a pity because the Boxster project is many times the cost and complexity of the comparable Miata engine swap.
This project we are discussing even stressed Jake Raby!So what hope an over-enthusiastic noob Boxster mechanic like me?