2.7 Six conversion questions, Oil cooler and motronic Options

[bigkensteele]

Topic 1: Has anyone ever tried mounting an oil cooler under a GT lid just above the fan, and if so does it keep the temp low enough for DE events?

Topic 2: Has anyone here ever adapted motronic from a 3.2 to work on a 2.7? If so, what is involved? Which distributor? What cam? Stock low compression CIS pistons or JEs?

Topic 3: What kind of power can I get if I keep the CIS but am willing to port the heads, change cams and go to JE pistons?

Please feel free to address any or all of the above? I have a '74 2.7 core that is currently torn apart and ready to send out for machining. It already has case-savers and nikasil jugs, so I am going to stay at 2.7. I have all of the CIS parts, so that is an option for induction, but I would rather do something else (other than carbs).

I will also be running stock 6 heat exchangers and a 911 muffler.

I just can't bear the thought of rebuilding this thing and only ending up with 150 hp, so any tips would be most appreciated.

[GeorgeRud]

My 2.7 has RS pistons, S cams, and Webers with an Electromotive ignition. It put out 199 hp at the wheels, so you can get power. I'd investigate getting the Bitz EFI system if you have the CIS parts. You can't do much more cam retaining the CIS.

[campbellcj]

In terms of the oil cooler, if you really don't want to do a front one then I think under the rear trunk would be better than the engine compartment. Under the engine lid you'd probably not get enough airflow and you'd have the heat coming from the engine baking the cooler the whole time.

I am not an FI guy but my guess is one of the popular aftermarket setups would be easier to implement than the 3.2 Motronic. You'll need to be able to tune it.

[mepstein]

I would talk to one of the really good engine builders like Henry at Supertech. http://www.supertecperformance.com Someone who has a lot of experience building these engines and can get you the power you want depending on your budget. He's pricey but a lot cheaper in the long run than building an engine that your not happy with.

[Mark Henry]

Topic #1 link

http://www.914world.com/bbs2/index.php?sho...=Henry++Schmidt



(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1286650846.2.jpg)

[JmuRiz]

Re: Motronic, I don't think I've heard of anyone using the whole system. Typically people use the 3.2 intake manifold and run something like megasquirt EFI to control it. That's possible with the turbocraft transitional spacers. I think someone on the pelican parts board is doing such a project. If I had a cheal 3.2 intake manifold (prices are going up), I'd give it a try.

[bigkensteele]

Topic #1 link

http://www.914world.com/bbs2/index.php?sho...=Henry++Schmidt



(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1286650846.2.jpg)

That is what I had in mind, and that looks like the cooler I have. Thanks, Mark!

[bigkensteele]

In terms of the oil cooler, if you really don't want to do a front one then I think under the rear trunk would be better than the engine compartment. Under the engine lid you'd probably not get enough airflow and you'd have the heat coming from the engine baking the cooler the whole time.

I am not an FI guy but my guess is one of the popular aftermarket setups would be easier to implement than the 3.2 Motronic. You'll need to be able to tune it.

I should call Steve Wong to see if he has ever done a chip for a smaller motor. (IMG:style_emoticons/default/idea.gif)

[Steve]

A 2.7 runs a lot hotter than an aluminum 3.0 or 3.2. I would go with a front cooler or under the rear trunk with a fan and grill to protect the cooler from rocks.

[bigkensteele]

A 2.7 runs a lot hotter than an aluminum 3.0 or 3.2. I would go with a front cooler or under the rear trunk with a fan and grill to protect the cooler from rocks.

I will not (nor could I) run the thermo reactors used on the 75 - 76 911 motors. The core that I have is a 74 with an 11 blade fan. I will be running either headers or six exhchangers. I am not a metallurgist, but I cannot fathom how the single variable of case material (mag. vs. alum.) could account for any significant increase in thermo-retention, especially when compared to a larger displacement motor.

Not trying to be contentious, but I need to understand how an otherwise equal engine would run hot just because it was a mag. case 2.7 vs. a alum. case 3.0 or 3.2.

Thanks to all for the input.

[gereed75]

I am not a metallurgist, but I cannot fathom how the single variable of case material (mag. vs. alum.) could account for any significant increase in thermo-retention, especially when compared to a larger displacement motor.

Not trying to be contentious, but I need to understand how an otherwise equal engine would run hot just because it was a mag. case 2.7 vs. a alum. case 3.0 or 3.2.

(IMG:style_emoticons/default/agree.gif)
Not an experienced expert in 911's, but thermodynamics is thermodynamics. The heat generated to make say 180 hp will basically be same no matter what the engine is made of. The difference in heat carried away by either mag or AL cases would not be significant.

Timing can make a huge difference in the amount of heat generated by aircooled motors. More advance generates higher peak combustion pressures and can actually produce less HP. If your motor runs hot in a system that otherwise should provide adequate cooling, back off the timing a bit.

I suspect the "2.7's run hot" belief comes from the era when Porsche tried the thermal reactors to meet emissions.

BigKen, I suggest you burn some midnight oil on the Pelican 911 rebuild board. There is much to learn there.

[Steve]

A 2.7 runs a lot hotter than an aluminum 3.0 or 3.2. I would go with a front cooler or under the rear trunk with a fan and grill to protect the cooler from rocks.

I will not (nor could I) run the thermo reactors used on the 75 - 76 911 motors. The core that I have is a 74 with an 11 blade fan. I will be running either headers or six exhchangers. I am not a metallurgist, but I cannot fathom how the single variable of case material (mag. vs. alum.) could account for any significant increase in thermo-retention, especially when compared to a larger displacement motor.

Not trying to be contentious, but I need to understand how an otherwise equal engine would run hot just because it was a mag. case 2.7 vs. a alum. case 3.0 or 3.2.

Thanks to all for the input.

That was my experience. I have also heard the same thing from other people that have owned both. My first six was a stock 74, 2.7 motor with 40 webers and headers. It over heated all the time until I installed a front oil cooler. Same car, but instead of over hauling the motor, due to the common pulled head stud problem, I bought a stock euro 3.2 instead. Same climate, same cooler, but the 3.2 ran much cooler. I loved my 2.7 with the webers. It sounded amazing versus my stock 3.2. But I love the power of the 3.2 and the DME fuel injection is for the most part trouble free.

[GeorgeRud]

When new, the 2.7 liter cars had oil coolers in Europe, but Porsche figured that we didn't need them for our 55 mph speed limit.

With a front cooler, they run just fine and are a nice size for the 914-6 conversions.

[Steve]

I loved my 2.7 in my 914. You can run a stock 2.0 six flywheel and clutch and bolt right up to the 914 trans without an adapter. If my motor was overhauled correctly with race wear studs and case savers, I would of kept it versus going to the 3.2.

[bigkensteele]

I loved my 2.7 in my 914. You can run a stock 2.0 six flywheel and clutch and bolt right up to the 914 trans without an adapter. If my motor was overhauled correctly with race wear studs and case savers, I would of kept it versus going to the 3.2.

I have to say that I got lucky in that my case already has case savers. I have no idea what the studs are, so I will probably replace those to be safe.

I also found a 2.0 flywheel on fleebay, and I failed to inspect it closely when it arrived. I looked at it months later, and it has a few teeth that will probably need to be welded up and filed, if that is even possible.

Really excited about building this motor (first timer), but time and budget won't permit it to go quickly. That is probably a good thing as it will give me more time to learn and determine what I can do about induction.

Speaking of induction, the Bitz Racing Megasuirt kit may be the way I go since I have all of the CIS parts needed, and it is somewhat plug and play. However, I think that his kit uses MS 1, which I don't believe handles spark. I would obviously prefer a solution that handles spark as well.

So much to learn!

[Steve]

I loved my 2.7 in my 914. You can run a stock 2.0 six flywheel and clutch and bolt right up to the 914 trans without an adapter. If my motor was overhauled correctly with race wear studs and case savers, I would of kept it versus going to the 3.2.

I have to say that I got lucky in that my case already has case savers. I have no idea what the studs are, so I will probably replace those to be safe.

I also found a 2.0 flywheel on fleebay, and I failed to inspect it closely when it arrived. I looked at it months later, and it has a few teeth that will probably need to be welded up and filed, if that is even possible.

Really excited about building this motor (first timer), but time and budget won't permit it to go quickly. That is probably a good thing as it will give me more time to learn and determine what I can do about induction.

Speaking of induction, the Bitz Racing Megasuirt kit may be the way I go since I have all of the CIS parts needed, and it is somewhat plug and play. However, I think that his kit uses MS 1, which I don't believe handles spark. I would obviously prefer a solution that handles spark as well.

So much to learn!

If you don't own it already, check out Bruce Anderson's Porsche 911 performance handbook. Tons of information on the 2.7 and other aircooled 911 motors. He has an in depth section on the 2.7 stud issue. The latest release is the best, which I think was the third edition before he passed away. RIP...

[bigkensteele]

If you don't own it already, check out Bruce Anderson's Porsche 911 performance handbook. Tons of information on the 2.7 and other aircooled 911 motors. He has an in depth section on the 2.7 stud issue. The latest release is the best, which I think was the third edition before he passed away. RIP...

I have the second edition, and it is a treasure trove of info. I have never read it cover to cover, but I have read several sections several times. Wayne Dempsey's rebuild book is excellent as well. I would never have the courage to do the rebuild myself if it weren't for that book.

More info on the Bitz kit that I mentioned above.

Bitz Racing

[SirAndy]

does it keep the temp low enough for DE events?

Here are your two choices:

- Install a front mounted cooler now.

- Fiddle with other solutions, spent time and money only to find they don't work well, then install a front mounted cooler anyways.

(IMG:style_emoticons/default/popcorn[1].gif)

[bigkensteele]

Here are your two choices:

- Install a front mounted cooler now.

- Fiddle with other solutions, spent time and money only to find they don't work well, then install a front mounted cooler anyways.

(IMG:style_emoticons/default/popcorn[1].gif)

OK, I get it already. And that leads to my next question.

Has anyone here ever done a trombone style in the fender well?

[mepstein]

Here are your two choices:

- Install a front mounted cooler now.

- Fiddle with other solutions, spent time and money only to find they don't work well, then install a front mounted cooler anyways.

(IMG:style_emoticons/default/popcorn[1].gif)

OK, I get it already. And that leads to my next question.

Has anyone here ever done a trombone style in the fender well?

914 fenders do not get pass through air like a 911. Lots of threads on different oil cooler locations but like Andy said, the front is the most effective. It's just a pain in the wallet to get it there.