waterprooftoast

Hello everyone, I want to preface this by saying I'm new to to porsche space, a lot of the things I say may be wrong, please feel free to correct me. I came from messing with 2jz's and SR20's, where parts and rebuild guides are readily availible. I am stumped when it comes to any information on the MA1 engine.

So just how realistic is stroking + boring a 2.9L base Cayman engine to a 4.0L? I can't find any stroker kits online, which means the crank, piston, and rods have to be individually sourced (unless you guys know where to find a kit), Can parts from other MA1 engines be used to make this work or custom parts have to be machined? Has anyone done this before?

I understand that all factory 4.0L MA1s from porsche are direct injection and their coolant/oil passages have been extensively redesigned since the 987.2 Cayman. Will I run into fuel/oil/coolant issues if I do make the 4.0L conversion?

I would also like to run fully forged internals, dry sump and electric water pump. Do you guys know where to source these or if they have to be custom desgined as well?

Note: budget is not an issue, I'm just curious about the feasibilty of the engine I just described.

Thanks!

hueyhoolihan

there are engine builders out there that could no doubt do it, but very few DIYers. the flat sixes are a bit of a bother to take apart and reassemble from what i can gather. i've rebuilt simple four-cylinders, but wouldn't want to tackle a porsche six.

... now bracing for the inevitable flood of DIYers relating epic tales of how easy it is....

harveyf

I would say that a 4.0L flat six seems to be the current benchmark in the Porsche world, both factory and aftermarket. You are asking for a pretty big jump starting with a 2.9L block. I am virtually positive Porsche didn't leave that much margin on the table with that engine. If you were to go this route, you would be looking at the entire design scope including cooling, lubrication, induction, and revised fuel flow maps. And at the end of the day, folks would so "Oh, a 4.0L engine. Like the current cars. Ho hum".
Most of the aftermarket is probably focused on opening up the 997 engine to 4.0L, which starts out with a 3.6L block. Check out LN Engineering.

KrisA

Do we actually know that the external dimensions of the 2.9L block is different from the other period MA1 engines with up to 3.8L displacement?

sectachrome

I’ve never heard of anyone doing this with a 2.9. With the 9A1, straight swaps seem more common. Even then, starting with a 2.9 car requires quite a bit of work to make it compatible with the larger DFI engines. There are companies like BGB or DeMan boring out the DFI engines. Because they were only made for a few years with low sales and only in the Boxster/Cayman, there are probably so few 2.9 engines even out there that it doesn’t really make any business sense for tuners to invest in developing it.

Im guessing the juice isn’t worth the squeeze, but as a 2.9 owner I’d love to see it!

waterprooftoast

The Cayman S came with a 3.4L, i just assumed that the 2.9L and the 3.4L block came from identical castings, just different bore/stroke.

waterprooftoast

Thanks for the info, cost is the main reason I'm looking into this. A brand new 4.0L from Porsche costs more than my car (and I thought 2j prices were crazy lol). And since I'm going fully forged internals anyways, it makes more sense to modify my existing block. I'll look into the 3.2L DFI engines you mentioned.

waterprooftoast

Thats the thing... So little information out there and unlike other engine builders, Porsche builders seem to love gatekeeping information its hard to get the industry moving forward.

harveyf

Bore and stroke provided here:
https://www.excellence-mag.com/resources/specs/211

LN Engineering, having sleeved a bunch of these engines, could probably tell you if the blocks are the same.

supercroc

As long as you're not concerned with lighting a considerable stack of money on fire, anything is possible. Unless the project becomes the goal (nothing wrong with that) there might be easier ways to accomplish whatever changes you desire.

Kitc2246

Just to make it clear the base 2.9L engine is port injection, not DFI. Not sure if they still do it, but TPC Racing had a turbo kit for the 2.9.

Glue Guy

I’d say call LN. Myself, I’d be looking for them to do the block work anyway. Not sleeves, but cylinder replacement.

Rick DeMan

The 2.9L block is useless..... the 2.9L is a unique casting and will not overbore. The heads are never going to make power.

The 3.4L and 3.6L carry the same casting and can overbore to 3.8L with stroke and bore change, but the heads will never make big power. Basically a waste of time since the 3.8L engines are readily available.

The 3.8L is the basis for all our 4.0L, 4.25 and 4.5L engines.

MrNoXiDe

Anything is possible but this is one that I hope you can make happen. Would be a killer machine for sure!

JasonGuthrie

Sorry, I live in California... probably can't even paint my car without having it impounded. Good luck!