RS block worth getting?

Hello

Well my mistake.

The street used 7R case will manage over 150-200 000 km without pulling the studs, chances for failures are under 5-10%. At 250-300 000 km 50% have Problems, higher milages are rare as most people pull the engine previous the failure.
At that milage the oil pressure is very low and the heads need a rebuild.

I knew engines with higher milage and they work despite there oil consumption rate and a bit slopines in midrange power. In fact they still pull better then average traffic.

The most failures are on the CIS engines with 5 fan blade and without external cooler. Especially cars in city use.

Standard RS engines have a lower failure rate. Higher output rates seem to force failures.

Generally the engine likes to stay warm and driven long distance.

The heat up and cool down cycles are the critical points. As far I understand it are the 150 HP K&S Alussil P&C worser in failures then the Nicasil Cylinders.

Just becourse they wear out faster and you need to renew them earlier. The new restored pressure and the operation itself seem to stress the patient more then other things. Risk that one off the studs will come loose very short after partially rebuild is high.

Complete rebuild on 7R also forces to heli coil the stud base and aligne bore the main bearing galery. Not doing this is like building a house in the sump. Or respraying a rust bucket.

Grüsse

Thanks Roland for yet another informative post. Right now all I have is the block, the case, the two halves. That's it. Nothing else. I think when I start building this motor I'll make sure it's gonna last a while first, then put some new stuff on, ie P&C's, and whatever can be used as an "used" part will be bought used. I'd like to build a motor that will be powerful, yet last me a while (I'm not saying extracting every ounce of hp out of the motor, just hopefully something like 210hp, like it had in the Carreras they belonged in). Right now my 2.7 has a 11 blade fan, so that's one problem solved there. Also it doesn't have heat reactors; its got headers, so one less heat problem. Whether or not it was warmed up and cooled properly I don't know. I've only had it a while, and driven it less than 2000 miles. So, when the body is restored, I'll start building the motor because who knows how long the CIS 2.7 will last? (it's already got 115K miles on it). I probably won't remember all of what you've said to do but I will keep that in mind. I will sure post something before I start. Thanks!

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Jeff
1976 911S

Hello

First step is to messure the main bearing gallery.

If you have the bare case then all the studs are missing ?

The next step would be to find a crank with rods, Oilpump, intermediate shaft with a good intermediate wheel, chains and many other things.

Best is to find a old aged not worn just stud pulling 2,7 engine to get all those missing items or better a 2,4 S MFI ( and more expensive ).

Then start with the fundament. As all the parts are blueprintet from the factory ( Well thats there minimal standards ) you start to superblueprint to lets say Bruce Anderson standards.

Some things will not generate power but allowing the engine to rev higher without geting in trouble.

The 210 HP statet for the RS engine are the standard numbers. Mostly they had a that more and if you use Sportkolben for higher compression ( remember the RS runs on standard fuel ) you can reach the 240 HP border. But this will stress the case and was maybe the reason why the factory didn´t went so high.
A good made 2,4 S will show a RS his tail end as it also has 200 + HP has similar wights and lower drag. But when it comes to the race track the RS has more tourque and wide wheel benefits to get faster out of the curves and even faster into them.

How long will the 2,7 last ? Thats higher mathemyhtics. Only the engine knows. Some seem to run without problems some allways threw the hanky..or a rod.
Maybe it was the childhood and to less love & patience killed the young engine. Maybe it just happend in the melting pot when the mixture spinned left side instead of right side.

In WW II they made the first jet engines. The strange thing was that the turbine fan blades made at one branch where exploding under high speed while the others lastet longer then the rest.

The difference was in the man who castet them. One was stiring all the time and trustet his feeling while the other followed what the engeniering said. Mix it and speed up.

Guess witch blades lastet longer ?

BTW one company was in Munich at is today still well known as BMW. The other company is in Stuttgart and is today nearly unknown as Mahle. ( Those guys had more luck as there Bus stop was named "Fortuna" )

My own feeling says that the last year cases have not so much failures then the earlier ones. However in germany no reactors and people pressing hughe amont cooling air trough the fins at higher speeds while the engine only has 10-30% throttle load.

Hard to compare to a US stop & go with AC and other things preloaded cooling in hot areas.............

Grüsse

Hello Roland,

Actually I have the case, the two halves, but they are in one piece. I don't know yet if there are any studs missing yet, but they look like they should be replaced. Don't want to take any chances there.

Seems like this won't be a cheap engine to build. What are the differences between the 2.7 and the 2.4S MFI besides the MFI such as crank with rods, oilpump, intermediate shaft with a good intermediate wheel, chains and many other things?

What exactly is blueprinting? Is it like blueprints for buildings where you have a blueprinted layout for everything before starting the building of the motor? I would sure love a 7,300 redline, though. Would something like titanium valve springs make it rev higher without getting into trouble?

I got the 210hp figure from Bruce Anderson's book. Sounds pretty good to me. I don't want to push the motor to its limits, just something nice like 210 (or a tad bit more) and making it last a long time.

What is Sportkolben? Beginner level German can only do me so good. High compression = less longer lasting engine? Like I said, I don't want to stress the motor.

Do you(or anyone) have the hp and torque figures for the 2.4S vs. the 2.7RS? Is it becase the RS has flared rears and fat tires that increases the drag? Not really something that I mind, though.

I'm hoping when my engine was in the melting pot the mixture spinned to the right(correct) side. That'll give me more time to build my motor.

I'm gonna put money on the batch of turbine fan blades that were followed by what engineering said, since you mentioned "mix it and speed up". I assume it is a bad thing to speed it up.

Yes I have heard of BMW and how they used to make airplane engines...and that their insignia is actually propellers in the sky, which I thought was very historical and a nice touch. If they can't (or not allowed) to build planes they'll put propellers on every car they produce.

I have heard of Mahle. Are they really unknown?

I'm glad to know that you're feeling that this case may not be so bad. Like I've mentioned before I will post pictures...once that stupid $*#@ digital camera works again. Once my dad dropped it, it was never the same again.

The person I bought it from is the 3rd owner of this car. The original owner brought it from Germany, and due to some stupid EPA regulations he had to switch the MFI and put on CIS. Don't know if that makes any difference. I also don't know if he had AC on his car or whether or not he is in stop and go traffic. This is an elderly person, don't know if he actually goes out a lot or not. I don't care much for AC though. Thank you for your response.

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Jeff
1976 911S

Hello

The studs will not break if the are not bend or rustet.

The case will get weak and the studs pulled out including the threads.

Those studs are not just screwed in they are reamed in. You just drill a hole and pretab it and then turn in the bolt. The high tourque will flow the aluminium away making the thread. The aluminium gets pressed and will harden up making a reinforcement at the sourounding area. This is jsut like you would forge in the threads. The stud will make his own threads and after cooling down they are massivly clamped.

Hard to achive this later.

So now I need a dictionary will try to get one in the pulic library. To much missing words for further things on that subject.

Other things:


Blueprinting: Just look at a american car magazine at your local newsstand. Car Craft, Super Cevy, Auto Buff, Hot Rod, Chevy Mania. However always one covers a story like 99 Tips to blueprint your engine to the max.

Buy it and read that. This is what Porsche made stock with there engines. They even made more and for more rigid specs as they had to made much more power per Liter then the US engines.

F.E. the 2,7 RS has 210 HP witch gives 80 HP per liter.

Now if you would transfer this to a lets say four bolt main 350 sb chevy this will be 80 HP x 5,7 L = 450 HP.

I know most of those guys claim to have 500 HP+ in there cars. But to give you a number.

The first year IROC was made with Porsche 3,0 911 SCRS witch had I think 250 HP in IROC series.

The following year they used Camaros with 330 HP. Those cars hadn´t been faster.

A solid made 350 will cost as much as a Porsche engine ( well witch has a total less power then ) and will have around 400 HP max.

OH thats the numbers the new Corvette features in there new year. Well Porsche had been there in 1966 with a 2,0 S witch had no TPI Fuel injection and a tricked out to the max V8....but well no catalyc converter too.
OK thats not fair as 35 Years make comparson to hard. Now how about the 996 GT3 ? 3,6 L/340 HP = 95 HP/L incl. OBD II.

Why use a 2,4 S ? Well you just can swap the P&C, the case and adopt all the other parts to RS specs ( MFI, Distributor, Heads ).

Every thing else is similar.

Using a 2,7 S would also add "S"cams, heads, all MFI parts to your list. CIS parts are not so sought after and cheaper.

S and especialy RS parts are allways top priced and they get faster "junked" or wear out. Not becourse those parts where cheap but most people missuse them and after seeing 2,8 RSR P&C ( maybe 4000 $ today ) ramed into a case by a "proffesional" ( Who didn´t flycut deep enough ) i can imagen what will hapen at some hobby engine rebuilder. Also those engines where used hard to the max, have to survive harder overrevs by misshifts and the MFI also has the fuel up problem ( Oil gets thined by unburned gas ).


All 2,0 - 2,7 S/RS have 7300 Redline stock. However you can strech it up a bit to 7500 by doing some preparations and some blueprinting. Even 8000 is doable ( Doubles the price )

Well carillo, Titan and other stuff is expensive and better a good made stock engine with more important low end grunt.
But it is allways usefull to shift at 55 mls from 1st to 2nd :-) Or at 140 mph from 4th to 5 th and hiting the rev limiter at 175 mph.

Sportkolben = Sportpiston.

Made by Mahle.

Yes the Sportkolben do stress mor under full oad. Just make a little kick down switch that will keep you on the 200 HP border unless you really need it. Just then see that fun costs money and much fun equals more money but well thats live.

The 2,7 RS was mainly trimed to improve the tourqe. Total horses where not so important. The big benfit from the 2,7 over the 2,4 S was that you needn´d downshift to speed up faster then a shiftet 2,4 S

Topspeed is very similar as the RS has wider fenders on rear and wider rubber. The added spoilers made it more stable and do add some 5 mph.

However the 2,4 S was statet with some 230 km/h topspeed but made over 240 km/h in most indipendend car magazine tests.

Back then there was a speed discussion in germany and the staate put a speed limit from 100 km/h on the normal streets and several limits ( 130 km/h ) on the highways.

Poor BMW 2002 turbo hits a nerve back then and where beaten up as bad killer car in the puplic.

As Porsche where driven by gentleman drivers and known as fast but solid and friendly to the puplic, didn´t focus to much. Untill the RS came.....First they tried to bann the car complete then they ended with a victory on banning the duck tail.

This is one reason why Mercedes refused to continue the SEL 6.3.

Like I said that happend before we where born back in WW II.
Maybe the BMW workers just had been cleverer and shortent the war....

Those turbineblades wher built into those Jumo engines. There was a little two stroke engine driving then to preload the turbine at ignition. Very complicatet construction and on the precision limits at that time.

The Porsche fanblades do not demand such precision ( Well but they are very precise as the closer they spin to the wall the more effycient they work )

BMW still produces engines in conjunction with Rolls Royce.

Porsche is still Co-developing engines for many comopanys and sometimes they coconstruct Fork loaders, Trucks, Motorcycless, Bicycles, Racebobs, Helicopters or Jet fighters.

Well Mahle isn´t a car company and therefore unvisibly, hidden in many cars.

http://www.mahle.com

They are just specialized OEM who make development for there own future.

But normally most projects are done with Porsche, DC, BMW, VW/Audi

Many F1 engines wouldn´t run without mahle.

Grüsse

Hello Roland,

The studs look rusty, so I'm not too sure if that's still ok. When the digital camera works again I will post pictures. You will see what the case looks like.

I kinda understand what you're saying about how the studs are put in. Basically if you do it right it's not supposed to pull? Or is it once the case gets weak it'll pull?

I will go look into the American hot rodding magazines for blueprinting.

Never thought a solid 350 would cost as much as a Porsche engine. Always thought american iron was cheaper to build. I have a work car with a 5.0 sbc, with only 200hp (an '87 TA). Sounds bad with only 40hp/liter!

When you say swap the P&C, the case and adopt all the other parts to RS specs ( MFI, Distributor, Heads ), what do you mean by that? The only things you don't use on it would be the P&Cs and the case, the rest can be used for a 2.7RS spec motor?

I have a '76 911S. Does this mean I have "S" cams? Is this the same cams as the RS motor? Or is it not a "real" S?

I know S and especially RS parts are expensive. They command a premium whenever they are sold. If the person took care of the motor, made sure it was done right, and didn't always drive it to the max with misshifts, they would last long, right?

As far as redline goes I'm not really too concerned with it. I just love the sound of the engine at high revs. 7,500 sounds good (I don't need 8,000, can't afford double the price).

Carillo (never heard of it) and titanium parts make a better stock engine? With more low end grunt? I'm guessing that's what you're saying. If it's something WAY too expensive I'd probably forget about it. But if it increases life of the engine and doesn't cost significantly more it would be something to think about.

I normally shift somewhere between 3000-4000rpm, but take it close to redline when driving "spiritedly". Is it better (useful=better?) to shift at 55? Once the motor is finished am I expecting that it can top out at 175mph? (ooh I'm getting very excited)

What is the differences between regular pistons and sport pistons? What does it do? And is full load WOT (wide open throttle)? How do you make a kick down switch like you mentioned?

Fun always cost money. I'm not a rich man so I can only have a little fun, otherwise I'd be building a twin turbo motor.

Not having to downshift to speed up sounds good, much more useful in city driving. So...2.4S=more hp and 2.7RS=more torque? I like torque...torque is good.

I didn't know spoilers made that much of a difference, but since I'm living in a state where there is no use for top speed of any kind I guess it wouldn't matter too much to me.

Why did they ban the ducktail? Didn't it improve handling by increasing down force? It's funny how un-car friendly politicians are. I've heard about the Mercedes SEL 6.3. It must have been a real Autobahn burner.

BMW still produces turbine engines? Cool, I didn't know that. I guess my source was a bit off. Porsche makes motorcycles? Where can I get one? I know they tried their hand at bicycles. Very un-cheap. $4200 on a "S" bike, although with dual suspension and disc brakes, still very expensive.

I know Mahle makes a lot of parts for cars, I guess you're saying not too many people know about Mahle, right? And what is the correct pronounciation of Mahle? Which is more superior, P&Cs made by Mahle, or some after market brand like say J&E (or something like that)? Thank you. Oh, and what is Grusse? (Bear with me, I'm taking GER 201 next semester...)

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Jeff
1976 911S