Spinning a 2.0/2.2

[mcinturff]

If a 2.8SS can be made to spin 8k rpm, then logically, a 2.0 can be made to spin that, or even higher (due to lighter pistons). Correct? Assuming ARP rod bolts, Supertec Head Studs or equivalent. I guess this is why the tachs on the first 911s went to 8k?
I remember reading somewhere that some guys were getting 9k out the 911T (non-counterweighted) cranks; can someone post the link to that post?

When building a high-perf 2.0 (al case), what oil pump do most of you use? And what rods, pistons/cylinders?

Last question: What is the most popular cam choice for a 2.0 carbed high spinner?

I've tried to find all of this information, but the search button will not co-operate.

[gestalt1]

i am interested in this as well. i've heard the non-counterweighted crank is popular in 2l race engines but not over 7500 rpm. the 2.8ss your referring to uses a counterweighted crank. there is an old post showing a 2.7 7r mag case with reducer sleeves (i think by henry at supertec) to accept 2L cylinders, i'm assuming the sleeves would help prevent pulled head studs and the reduced displacement would also help for high rpms. with cast AL cases so hard to find i'm interested in using the light mag cases that can be had for cheap. for cams i've only seen 2 types used; ge80 and 906. for oil pumps i have asked this before but i'm wondering if at such high rpms if the regular 3 rib pump is fine. my thought is that the higher capacity 4 rib pumps would be pumping more than needed at high rpms. i think most would say that you can't have enough oil pump but i think oil distribution is more important - i.e. cross drilling the center main bearing journal etc..

by the way i have had problems with the search button - it seems you get a lot of posts that have nothing to do with the search and posts that you are looking for don't pop up. not sure why.
-matt

[BURN-BROS]

The non-counterweighted cranks are only for acceleration not high rpm capability. Piston weight is pretty close to both the 98mm pistons and the 80mm pistons so rpm is only limited by your budget.
Rods;
2.0liter rods with arps can get to 8000 rpm....but for how long?
Pauters
carrilo
L&N has some billet rods that could do the job.

As far as oil pumps go;

aluminum 4 bar pump from a 3.0 SC would be the minimum requirement
964/993 pump
turbo- better
gt-3-best

Crossdrill #4 main journal
have #4 bearing modified

as Matt has posted, GE80 or a 906 cam but you may be able to play with overlap to get a little more bottom end if you have the minerals to use it on the street.

[mcinturff]

Time to open a can of worms: What do you guys think are the best rods? R&R 4340, carillo 4340, pauter titanium/4340, pankl titanium. 4340 rods tend to be close to $1800, but I have no idea on cost of titanium.
LN cylinders + JE Pistons or Mahle all the way?

The 911S had 9.9:1 compression, so in theory an 81mm piston would end up at 10:1 and would probably not require twin-plugging so long as 93 octane was always used.....? Short stroke = more allowable compression without detonation.

Do the early mag (2.2, 2.4) cases have to be machined when split like the 2.7s?

[kenikh]

If Henry's 2.8SS uses 2 liter 'S' rods w/ ARP bolts, what do you think? Making an 8000 RPM 2 liter isn't just doable, it is done...all the time. Just make sure to use an aluminum case.

[Steve@Rennsport]

Originally Posted by mcinturff

Time to open a can of worms: What do you guys think are the best rods? R&R 4340, carillo 4340, pauter titanium/4340, pankl titanium. 4340 rods tend to be close to $1800, but I have no idea on cost of titanium.
LN cylinders + JE Pistons or Mahle all the way?

The 911S had 9.9:1 compression, so in theory an 81mm piston would end up at 10:1 and would probably not require twin-plugging so long as 93 octane was always used.....? Short stroke = more allowable compression without detonation.

Do the early mag (2.2, 2.4) cases have to be machined when split like the 2.7s?

JHMO here, so take it all with a grain of salt,......

Titanium rods are life-limited parts. Its all about hours and peak operating RPMs. We use Pauter 4340 rods in almost everything except GT-3 Cup motors which get Pankl. Its an excellent, strong, cost-effective and very durable product. Some of these things spin beyond 10K,.........(accidently, of course). Ti rods are for people with sufficient budgets to replace them as required.

Stroke has little or nothing to do with a 911's octane appetite (requirements): that's all about bore size, camshaft profile, compression ratio, AFR's, total timing, piston design, outside air temps and oil temps.

All magnesium cases should be machined and bored back to standard now due to age and the general properties of this material. Once you see that you can loosen the case through bolts, retighten them, and then discover that the crank won't hardly turn, you'll know what I mean,... .

[mcinturff]

Let's say you have a complete 2.2 motor and a spare set of 2.0 cases. Could the cases just be swapped (including spigots bored on 2.0)? IOT, any major differences outside of case material and piston bore?

Do mag motors have aluminum heads? And what heads would be best for 2.0 high spinner?

[Steve@Rennsport]

Originally Posted by mcinturff

Let's say you have a complete 2.2 motor and a spare set of 2.0 cases. Could the cases just be swapped (including spigots bored on 2.0)? IOT, any major differences outside of case material and piston bore?

Do mag motors have aluminum heads? And what heads would be best for 2.0 high spinner?

You can interchange many parts, but just keep 2.2 heads with 2.2 cylinders,...

All 911 air-cooled engines use aluminum heads although the alloys vary betwene turbo and non-turbo heads.

Look at Kenik's heads for some examples of ones that support power beyond 8500.

[mcinturff]

Turbo better I'm guessing?

In Waynes book he talks about a HSr-spec 2.0l engine with 4 bearing cam heads (page 112), does anyone know what heads theses are? Could you use SC/3.0 Turbo or later heads on 2.0 (too big?)

[Flieger]

The cylinder head-stud spacing is greater on the 3 liter and later engines compared to the 2.0 Aluminum and the Magnesium cases. Therefore, later heads cannot be used on earlier engine cases.

In the case (no pun) of the 3.0 RSR and Turbo Carrera 3.0, there was a transition period with the Aluminum case but closer head-stud spacing. The 3.0 RSR had 3mm greater spacing and the SC engines had 3mm greater still. Some of these cases are very desireable for 2.8 short-stroke motors.

[Henry Schmidt]

All combinations are possible.
We have down sized spigots, destroked cranks and modified stud spacings in the pursuit of the ultimate engine.
A 2.0 with 3.0 heads? sure why not.

One slight correction: the 3.0 RSR and the 3.0 Carrera do not have the same stud spacing. 3.0 Carrera and 3.0 SC have the same spacing.

One more thing: the RSR and 3.0 Carrera / 3.0 turbo case is no longer necessary for the 2.8SS. We are now making 66 mm 9 bolt cranks.

[Flieger]

I was talking about the factory designs

Of course, you can do anything with a knowledgeable machinist, quality tools, and strong Aluminum.

By 3.0 Carrera RS, I meant the very limited production RS and RSR follow-up to the 1973 Carrera RS 2,7.

I do acknowledge that I was unclear in my own understanding on some points. Thanks for the clarification.

[Henry Schmidt]

Originally Posted by Flieger

I was talking about the factory designs
edit.............................................

Funny, the first sentence in this thread "If a 2.8SS can be made to spin 8k rpm"..... deals with a hybrid engine that Porsche never build for prduction use.
I thought the thread and the questions in it were talking about what can and has been built. I guess I misunderstood.

[Flieger]

touche'

I was just thinking about the last question about using later heads from a 4 cam bearing engine on an early case.

[Henry Schmidt]

Originally Posted by Flieger

edit....

I was just thinking about the last question about using later heads from a 4 cam bearing engine on an early case.

I'll bite,what does this mean?

[Flieger]

Originally Posted by mcinturff

In Waynes book he talks about a HSr-spec 2.0l engine with 4 bearing cam heads (page 112), does anyone know what heads theses are? Could you use SC/3.0 Turbo or later heads on 2.0 (too big?)

( I thought that the later heads could not be used on the earlier cases )

[Henry Schmidt]

My confusion comes from the "4 cam bearing engine" reference.
If you are referring to the 4 journal cam housings they were used as early as 1966. Mostly on race engines but you see my point. Head type does not necessarily correspond to a type of cam housing. I will concede that you rarely see 3 journal cam housings on 3 liter and larger.

[Flieger]

D'oh,

Now I see.

Thanks