Question for the Porsche people

"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
02/12/2014 at 19:08 • Filed to: None

Is the 2.0l flat-6 the same basic engine as the end-of-the-line 3.6l air-cooled engines in the 964? By same basic engine I mean the block. Thinking about it, nearly everything else is exchangeable while still being considered a direct evolution of the original.

DISCUSSION (33)

YSI-what can brown do for you > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:09

I want to say yes, but I am probably wrong.

Gimmi-Sagan-Om-Draken > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:18

I think the main changes with the 964 were a beefed up case, new design for the camshaft housing/chain box, twin plug ignition, higher compression resulted from the changes, there are lots of composite bits that only fit the 964. There could be more, I have a 930 so I don't know the 964 really well.

BiTurbo228 - Dr Frankenstein of Spitfires > YSI-what can brown do for you
02/12/2014 at 19:19

I was thinking yes too, but it's rare that you get an engine built with enough meat in the bores to stretch all the way from 2.0l in original capacity to 3.6l in the final one. Especially if there's a limited capacity to increase stroke, as is the case in a flat engine.

YSI-what can brown do for you > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:22

Well Lamborghini did it for nearly 50 years! I am sure Porsche could do the same for 20. Granted, I know nothing about Porsches road going engines. I do know they used the Metzger for many years in their race cars like the 962 and GT1. That engine came from a road car, and the engine started out as a 2.0l, and was then made into a 4.0l!

So the answer is. . . maybe.

BiTurbo228 - Dr Frankenstein of Spitfires > Gimmi-Sagan-Om-Draken
02/12/2014 at 19:22

Hmmm, interesting. There's only so much you can change before I'd consider it an entirely new engine. 'Grandfather's Axe' it may be, but if everything's different then it's the same in name only.

Still, if the block's a direct development then it's even more of an impressive engine than I give credit for.

Manuél Ferrari > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:23

yeah my guess is no

it would have taken a lot of foresight to plan ahead that much. only way porsche builds the 2.0l with that much meat is if they planned on nearly doubling the displacement using the same block.

it is possible. just going to throw in my guess.

Manuél Ferrari > YSI-what can brown do for you
02/12/2014 at 19:28

hmm, interesting points

BiTurbo228 - Dr Frankenstein of Spitfires > YSI-what can brown do for you
02/12/2014 at 19:34

It's certainly possible, but I have my doubts about the Lambo engine as well. I remember reading about a marinised version of the 3.5l V12, and all the effort they went to to punch it out to 4.2l.

Although saying that, they didn't have access to a longer throw crank so they did it all with boring and adding spacers to the block. The 6.5l V12 uses a significantly longer stroke crank than the old 3.5l/4.0l cars so as a result the bore is only 6mm wider.

If the Porsche F6 is the same between the 2.0l and 3.6l, they'd have to increase the bore by 20mm which is a huge amount. Although, thinking about it, they may have made it extra beefy to assist the air-cooling. Plus, no water-ways you need to preserve.

BiTurbo228 - Dr Frankenstein of Spitfires > Manuél Ferrari
02/12/2014 at 19:40

That's what I was thinking, although it may well be possible. I'm thinking they could have built it very beefy to aid with the air-cooling, and that also means no pesky water-ways to avoid.

Plus, it's not unheard of. The smallest Alfa V6 made by the factory was a 2.0l Italian market turbo version, and you can bore and stroke that out to 3.8l using a factory crank.

Manuél Ferrari > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:48

Those 2.0l Italian market cars were awesome.

Imagine how slow the 2.0l Dino would feel today. Silly regulations. There should have been an exemption for the Prancing Horse.

YSI-what can brown do for you > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 19:51

I know that the bore was getting out of hand on the Murcielago. It was WAY oversquare. The cylinder walls were getting really thin, which is why they changed it out for a new one. That and emissions. The firing order stayed the same on those engines, but it gained 2 more valves, fuel injection, move from wet lubrication to dry. over the years, so is it exactly the same engine? I doubt that, but it was definitely heavily based on the original Bizzarrini design. Kind of like their F1 project was based on the road going engine. It had the same firing order, but it was different in bascially every way to the road going version

Alright, I am done.

banjo cat ghost of oppo past > Gimmi-Sagan-Om-Draken
02/12/2014 at 19:58

I believe you are correct. BT have you checked out Pelican Parts forums? Usually some thread with with a relevant history lesson in there.

In the meantime enjoy my writeup on one client's spec '69 911 with a 2.2 stockish engine.

Michael Delaney reaches down between his legs and eases the seat back > BiTurbo228 - Dr Frankenstein of Spitfires
02/12/2014 at 21:44

Ask and ye shall receive.

http://blog.caranddriver.com/flat-sixy-the-…

Looks like originally an aluminum block, then magnesium in 1969, back to aluminum in 1978. I recall a variety of cylinder liners were used as well - either my 82SC had Nikasil liners or the gen before mine did, can't remember now...

fyjr > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 01:07

It's pretty hard to get from 2.0l to 3.6l and maintain the same bore centers. There isn't enough room to continue air flow (essential for an air-cooled engine) in between the cylinders. The stroke would be headed for diesel dimensions. Not too good at 8000+ RPM. It kind'a means the block, crank, cylinders and heads are different. Sooo, ummm, no.

b-rock > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 03:05

911s don't really have blocks... they have cases.

BiTurbo228 - Dr Frankenstein of Spitfires > b-rock
02/13/2014 at 04:56

I thought they might have a bit of an odd construction. In which case the bores could be exchanged for bigger ones while still having the same core engine case.

BiTurbo228 - Dr Frankenstein of Spitfires > fyjr
02/13/2014 at 05:17

What's odd is that they drastically increased the bores, rather than the stroke. To get from 2.0l to the final 3.6l they increased the stroke by 10.4mm (from 66mm to 76.4mm), whereas the bore's stretched by a massive 20m (from 80mm to 100mm).

I've been told that it's got a bit of an odd contruction, with the bores being a separate casting from the crank-case, which would make swapping them out for meatier ones a lot easier.

kanadanmajava > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 05:48

There is a lot of interchangeable parts and some are continued to water cooled engines too. Even 997 GT3 titanium connecting rods can be thrown in some older air cooled engines. Intake flange pattern is also similar in many engines but the size of the runner isn't.

There was quite big changes in the block when the 3.0 engine was introduced. 930/Turbos, Carrera 3.0 and 3.0 SC are using stronger block (similar but not identical). At the same time the cylinder stud spacing was also widened. The older heads and cylinders are therefore incompatible. If I remember correctly (really rare) 2.8/3.0 RSR uses own stud spacing pattern.

Carrera 3.0 and 930/Turbo block does accept 2.7 crankshaft but 3.0 SC doesn't as it has different bearing journals.

The valve train was modified in both 964 and 993. 993s uses hydraulic lifters. They can adapter to older engines too.

BiTurbo228 - Dr Frankenstein of Spitfires > YSI-what can brown do for you
02/13/2014 at 05:49

Oddly, the early 3.5 and 4 litres are massively oversquare. Bore/stroke ratio of 1.32 for the 4.0l. They increased the stroke massively to get it out to 6.5l, along with punching out the bores, so in fact it's a little undersquare (bore/stroke of 0.99) which is less than ideal for a performance engine. Still, I've also read that they were very close to poking through the sides of the bores with the final versions.

Interesting point about all the changes though. It's a bit like the 'Ancestors' Axe' scenario. Over time, the head gets blunt so it's replaced. Then the handle wears a bit thin so that's replaced too. Over time this is repeated until there isn't a single surviving piece of the original axe.

It's still the axe of your ancestors though.

BiTurbo228 - Dr Frankenstein of Spitfires > Manuél Ferrari
02/13/2014 at 07:10

They're impressive bhp/l-wise, but they're not particularly fast.

I do love low displacement, high cylinder count cars though. They're just like little clockwork machines. Really intricate, but dinky.

They're cool when you've got a little intricate engine in a little car. Slightly less so when you've got a little intricate engine in a bulky one.

BiTurbo228 - Dr Frankenstein of Spitfires > kanadanmajava
02/13/2014 at 07:56

Sweet :) that's exactly what I was after. To me, that points towards there being an early generation of engines that range from 2.0l to 2.7l, and then a heavily revised later version that ranges from 3.0l to 3.6l.

BiTurbo228 - Dr Frankenstein of Spitfires > Michael Delaney reaches down between his legs and eases the seat back
02/13/2014 at 08:11

Fantastic :) thanks man

YSI-what can brown do for you > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 09:24

It started out oversquare and slowly they started adding stroke. In the Countach the bore only increased by 3mm, and the diablo it was only increased by 2. And it appears I have made a mistake. The Murcies engine was undersquare. The 6.2 was just a bit oversquare and the 6.5 was under but only a tiny bit. They bore was still close to 90mm though, which means the amount of metal between each cylinder was decreasing.

I think this is kind of like the Chevy small block, which is apparently the oldest surviving production engine. It isn't even the same engine it used to be, but many still claim it is. A lot of changes were made to it, more so than the Lambo engine. I am not sure what makes people claim that an engine is the same basic engine from 50 years back

BiTurbo228 - Dr Frankenstein of Spitfires > YSI-what can brown do for you
02/13/2014 at 10:27

True :) I got the info from the little engines database I made. Now that you mentioned it I've forgotten the Countach's V12 :S

Yeah, they're wrong about the smallblock. They've gone through 3 major variants as far as I'm aware. The early 350s and such, the middly LTs and the modern LS engines.

Actually, now that the new Corvette's debuted another (maddeningly also called an LT) there's four.

YSI-what can brown do for you > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 11:09

Oh wow! That has everything. Excellent, I saved that to my bookmark bar.

The early Countach V12 was exactly the same one as in the Miura, except it had sidedraft carbs which ended up losing power on the engine. It made less power than the Miura SV.

The small block isn't the same engine it used to be. I want to say they at least share similar firing order, but that has probably changed over the years as well. They also went with 4 cams in the 90s didn't they? The LT5 was a 4 cam, which was designed by Lotus. Apparently it wasn't very similar to the LTs before it. So within the same family of small blocks there is huge variation.

BiTurbo228 - Dr Frankenstein of Spitfires > YSI-what can brown do for you
02/13/2014 at 12:21

Thanks :) it's a little light on early American V8s, especially big-blocks and Mopars. That should be fixed soon though. I should add in carbs as well, or fuel injection if that's the case.

I think it was just the LT5 that had quad-cams. I think Chevy went to Lotus and asked them to design an engine to take on the world, based on the LT1 block (I think). As far as I can tell they did rather well :)

Manuél Ferrari > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 18:48

I love low displacement, high cylinder count cars too!

I want to drive a classic Italian car with a mini V12 one day. The first time I read about the tiny V12s that Ferrari made in the old days I was flabbergasted. Clockwork machines is a perfect term for it. Those tiny engines must be so intricate.

I wish that buyers weren't so obsessed with power figures. Then CAFE could have brought back tiny engines with high cylinder counts instead of turbo charged engines. A 4 or 6 cylinder turbo charged engine makes sense if you want fuel economy and power. If people weren't obsessed with power then we could see the comeback of tiny V8s and tiny V12s. I want a Ferrari with a 2L V12!

BiTurbo228 - Dr Frankenstein of Spitfires > Manuél Ferrari
02/13/2014 at 19:15

I actually have a bit of idea of starting up a kit-car company producing curvy tube-framed coupe/convertible with a 2.0l high-revving V12. Something silly like 9-10k redline :)

The old F1 engines are my favourite. 1.5l straight 8s, V12s and V16s making silly amounts of horsepower. Excellent :)

Manuél Ferrari > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 19:19

THAT IS AN AWESOME IDEA!

Hopefully I can be one of your customers :)

The old F1 engines are so awesome. Great times back then.

BiTurbo228 - Dr Frankenstein of Spitfires > Manuél Ferrari
02/13/2014 at 19:30

I suppose another option would be 1.5l heavily supercharged V12s, just like the old F1 cars.

Now that would be something I'd enjoy :)

A straight-8 wouldn't be bad either:

Manuél Ferrari > BiTurbo228 - Dr Frankenstein of Spitfires
02/13/2014 at 22:05

You gotta make this new company happen!

Would be so awesome

Michael Delaney reaches down between his legs and eases the seat back > BiTurbo228 - Dr Frankenstein of Spitfires
02/14/2014 at 12:40

Absolutely - love your updates on the Spit; glad I could contribute.

fyjr > BiTurbo228 - Dr Frankenstein of Spitfires
02/15/2014 at 22:11

The construction is a bit different than most manufacturers. Most vee's and inline motors are a common crank case and cylinder configuration. Flat or H style have split cases to facilitate crank installation. Cylinder as separate pieces evolved as a simple means of common parts. On an early 4 pot vee-dub, the cylinders were all interchangeable. One casting. The case halves were mirrors of each other.