2.7L Upgrade vs. New Engine

I have a 1976 911S, 2.7L, CIS, Targa that I bought for 6K. I have backdated the exhaust to a 1974 style and installed a sport muffler. I have also installed oil fed chain tensioners, pop off valve, distributor cap and rotor, warm-up regulator, alternator, and an auxillary air valve. The car currently has 76K miles, the body is in great shape and I have installed a new carpet kit. I am torn between trying to update the 2.7L engine, or selling the engine and looking for something else. I do not know if the head studs have been updated. If I were to update the 2.7L, I am looking at removing the CIS and installing 40IDA webers, european P&C's, S Cams. This would most likely cost me around 4K by the time that I am done and I would be at around 210-220 HP. I hear a lot of bad things about the 2.7L. Does it make sense to spend this kind of money on this engine. I would love to hear anyones opinion.

I wouldn't spend $4k on this 2.7L engine. IMHO, if it comes apart anyway, you'd have nothing. For the same $4k you ought to be able to get a 3.0L and have 180hp (204hp if ROW) at stock configuration --- and with a few minor mods could get to the 210hp you want and then later go even higher (see other Pelican board threads from gurus better than I).

Of course, now the 2.7L guys should chime in to disagree...

[This message has been edited by tog (edited 11-15-2000).]

There's nothing like a 2.7 Euro Carrera spec motor when it comes on cam. But if I were you I'd just buy a complete 3.0 or 3.2 because you're more likely to have success with a swap versus building a motor from scratch.

I have been wondering about the same thing at some stage.

I don't know about the costs involved, but would imagine you could sell your existing engine and buy a 3.2 for the same money as mentioned above (net cost of $4k, result 217hp(?) + whatever the exhaust gives you, and heaps of torque). This will be understressed, reliable, idle well, etc.

The other option has worse fuel economy and probably won't run as well, but is more "original" and will sound and feel very very cool. I have never been fortunate enough to drive a 2.4 911s or a 2.7RS, but I have been in a few "cammy" cars, and it is real buzz when it all starts to happen.

My 2c

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Cameron Baudinet
1975 911S

[This message has been edited by CamB (edited 11-15-2000).]

First, I am not sure if you can get the mods that you suggested for only $4k, unless you plan on doing the work yourself.

And, it seems like you should consider performing a total rebuild with time serts which will probably result in a cost much higher than $4k.

The newest SC motor you could find ('83) is still a 17 year old motor and you should be concerned about head studs breaking in a motor of this vintage, unless the motor has been rebuilt recently. The studs can break from age and corrosion, and this problem is starting to show up in these motors. You can spend alot on a SC rebuild as well.

I would read the Chapter on Engine Mods in Bruce Anderson's book first. A 2.7L is a remarkable motor when it is rebuilt properly and without the smog equipment that plagued these motors from '75 until the aluminum SC motors were released. You must time cert the studs!

A 2.7L 7R case is the choice for building race motors in this class and is the same block found in the RS. It's too bad that the 2.7L has gained such a poor reputation from the American 'smogged' motors.

After exhaustive research, I decided to build a 2.7L 7R race motor for my '72 911T. The rebuild and performance mods will cost about as much as it would cost to buy a nice SC (not just engine, but whole car!)

I am building the motor with Nikasil cylinders, forged pistons, Solex cams and Weber 40IDAs. Also time certs and a shuffle pinned case. I am also using Raceware studs and many other performance and 'durability' mods.

IMO, you can rebuild the 2.7L the right way or rebuild the 3.0L the right way, but both will cost much more than $4k. If you get a low mileage SC motor that has never been rebuilt, you still have at least a 17 year old motor with potential head stud problems that can be just as costly as a 2.7L to repair.

You can make your 2.7L reliable, you just have to pay for it!

Best regards from a biased, early mag case lover!

Kurt


http://www.911restorations.com

Kurt, keep us all posted on your 2.7 upgrade. That's going to be one amazing 911 when it's done!

Is Motormeister still on target for the November 30 deadline? There's a POC event at Willow Springs in early January. If you have any plans to track the car, it would be fun to see both of our black, early cars out on the track at the same time.

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Jack Olsen
1973 911 T (3.6) sunroof coupe

John,

I have the same model car. I was toying with the idea of back dating the exhaust.
Was there any improvement with everything else stock? I know this is a must to see any performance gains after ditching the CIS.

IMO the car is what it is and should be enjoyed. I would leave it alone.
A modified car is rarely worth a fraction of the money spent on it.

Jack Olsen's car however, is an inspiration to us all & I can see the attraction.

I would save the money, which will be big $$'s in the end and put it towards a later model car that has the required performance.

Jon Green: I have removed the smog injection pump, installed used SSI heat exchangers, and a used B&B sport muffler and I noticed a big difference. After months of hunting for the parts, the total cost was around $900 (used) and it was definently worth the money. The stock car started at 165HP and I estimate that I am at (180-185HP) now. This upgrade would have cost around $2,200 if you bought all new parts.

Kurt: You are probably correct in the fact that the cost would be higher than 4K. I have found a used pair of webers for 1K and a used set of Euro P&C's with 10,000 miles for $850. I looking at an engine re-build kit for around $1,700. I would still need machine work, potential re-jetting of the webers, gaskets, and possibly the installation of raceware studs dependant upon what I find. I would absolutely perform the head stud upgrade if I were to go ahead with the modification. Kurt, you have basically captured my dilema. If I sink lets say 5-6K for a total engine rebuild and upgrade, I can be confident that I have a strong 2.7L engine, but do I still need to be concerned about the magnesium case after the head stud upgrade. I am leaning towards having a completely re-built 2.7L to my specs versus a standard 3.0L or 3.2L that has some miles on it.

On another note, I find it weird that the 2.7L is always critized (with good reason), but one of the most covetted Porsches is the 1974 Carrera RS, which has a 2.7L. Does this engine have the magnesium case?

I have driven a 3.0L CIS and I liked it. I have not had the chance of driving a 2.7L, weber, Euro P&C, S cam car. The engine that I would be looking to build is one of the recommendations in the Bruce Anderson book. The other option being the MFI route, and I cannot find parts anywhere.

John said: On another note, I find it weird that the 2.7L is always critized (with good reason), but one of the most covetted Porsches is the 1974 Carrera RS, which has a 2.7L. Does this engine have the magnesium case?

Yes, the '73 2.7L Carrera RS uses a mag case, specifically the 901.101.102.7R mag case with the 97-mm cylinder spigots.

Magnesium cases were used from early '68 through '77 - 2.0L, 2.2L, 2.4L and 2.7L.

Bruce Anderson specifically recommends the 7R case if you are building any of the above engine displacements up to 2.7L or even 2.8L. Bruce says this 7R case is stronger than "all but the first sand-cast-aluminum crankcases, and enjoyed all of the updates that came from evolution."

The 2.7L is quite misunderstood by many, IMO.

Best Regards,

Kurt http://www.911restorations.com

Originally posted by JackOlsen:
Kurt, keep us all posted on your 2.7 upgrade. That's going to be one amazing 911 when it's done!

Is Motormeister still on target for the November 30 deadline? There's a POC event at Willow Springs in early January. If you have any plans to track the car, it would be fun to see both of our black, early cars out on the track at the same time.

Jack:

Still on schedule - I am having some additional work done, so it is probable that the additional work will extend the original schedule.

I do plan on taking this car to the track! Perhaps we can meet for an event, as you suggest. My driving skills are pretty rusty - I attended a one week class at Bondurant's school at Sear's Point, but that was well over 10 years ago! I have not been to a track in at least 10 years.

I need to hone my skills before a consider running with your extremely powerful and beautiful creation! I think you will have me beat on a bhp/lb ratio basis.

Best Regards,

Kurt http://www.911restorations.com

[This message has been edited by kurtstarnes (edited 11-16-2000).]

Kurt, I have one other question. What do you think about the Euro 2.7L P&C's vs. the Andial P&C upgrades for the 2.7L which brings it to 2.9L, I think. I know that this is also mentioned in the Anderson book.

Originally posted by John:
Kurt, I have one other question. What do you think about the Euro 2.7L P&C's vs. the Andial P&C upgrades for the 2.7L which brings it to 2.9L, I think. I know that this is also mentioned in the Anderson book.

John:

IMO, I wouldn't push the displacement on the 2.7L - if you do, the cost of adding ccs goes way up to do it right! I think Andial makes a complete 2.9L and 3.0L (for CIS and carburetors) conversion for the 2.7L as you stated. My logic says that 2.7L is probably near the displacement edge of what this case can handle, but I am certainly far from being an expert. For the money that the Andial set-up costs, I would bet that these guys know what they are doing.

Sounds like you are on your way to Anderson's 'perfect' 2.7L - you already have the backdated exhaust, sport muffler and oil fed tensioners.

Anderson recommends the Euro RS pistons and cylinders, as you probably know. You can easily spend almost $2k on the Euro 2.7L S pistons and cylinders and I would assume the RS p&cs would cost more new.

Anderson also says to go with the Webers (or PMO now) for more power at the expense of fuel economy.

I am going with rebuilt Nikasil cylinders and new forged race pistons for my 2.7L with compression on the border of street and race applications. Luckily I have acces to 100 octane street fuel and will be using a crank fire ignition.

Cams: Anderson likes the E cams which give a very nice 'streetable' power-band. I chose the middle ground between the late power-band of the S cams and the mid-band of the E and went with the Solex grind. You must use a milder cam if you stay with the CIS.

My experience is that 2.7L engine rebuilds and mods are a slippery slope - one thing leads to another!

To those who say to save your money and buy a later model 911 with more power: SC 3.0 came in at about 172bhp in standard trim for America - you may be beyond that amount of power already with your present car. You could buy a Carrera with around 200bhp, but now you are spending even more money.

An SC is already at least 17 years old and a Carrera already 10+ years old. Both of these models will soon require even more money to rebuild - unless you find that elusive low miles car that was driven only on weekends . . . and you will pay for that too!

. . . the dilema continues . . .

Best to you in your p-car endeavors!

Kurt http://www.911restorations.com

if you can wait about a week i can give you a first hand report on the andial 2.9 upgrade. i am currently in the final stages with andial building my 74 911 s targa up to a 2.9 with 79 cis and upgraded ignition ready for a twin plug ignition once i come up with some more money.

i have ridden in another 74 that andial built to 2.9 and the performance was awesome. the tourque seemed to be full on at very low rpms and stayed almost to red line. i have also had the pleasure of driving a 2.7 rs spec motor that andial built in a 70 911 s. it as well has breath taking power with s motor characteristics.

i believe you can get all performance you can desire out of the 2.7 case.

jim

Jim,
Please keep me informed about your 2.9L upgrade. It sounds like you are planning to stay with the CIS. I will be very interested to hear how the 2.9L CIS engine performs. I am not an expert, but I would assume that the 2.7L to 2.9L upgrade that stays with the CIS will have an increase directly proportional to the displacment increase, i.e. (1-2.7/2.9) X 100 = 6.9%. I am not sure how this will affect the torque characteristics. Good luck on your upgarde and keep me informed.

Jim,
Sorry, I think that the actual increase should be (2.9-2.7)/2.7 * 100 = 7.4%. Someone out there should probably chime in who actually knows what the increase would be.

John,

I think everything depends on the condition of your crankcase, whether any of the head studs have pulled or been damaged over the years! To do anything such as what you mentioned, the case must be gone through by a competent machine shop familiar with the magnesium 911 crankcases, such as Competion Engineering. You must decide whether to TimeSert the case or not based on talking to Andial ... the 2.9 cylinders will fit in a case that has been TimeSerted, but the 3.0 conversion cylinders will not, you must have undamaged stud thread bores, and the threading is extended deeper into the case with a special tap, and longer studs provided with the 3.0 conversion kit.

Webers, 'S' or GE-60 cams, and RS 2.7, or Andial 2.9 or 3.0 p&c sets can/will make a nice running, reliable engine, but it will depend on the crankcase condition you (and the machine shop) find, and depending on how long your engine ran with the thermal reactors, and the environmental conditions under which it ran, you may not be able to proceed with your crankcase!

My recommendation is that if your crankcase has had pulled studs in the past, or has damage now upon disassembly, then the thermal limits of the magnesium case have been breached and it probably should not be used to build a performance engine. If, however, all case stud bores are undamaged, you can proceed with reconditioning the case and any p&c upgrades with confidence.

One thing you have not mentioned is the transaxle, and that must be a part of your planning ... you will NOT be happy with your present gearing and an 'S' cammed engine! A 7:31 r&p change is needed, along with full reconditioning at the same time, i.e. bearings and synchros at the minimum, but possibly new dog teeth and sliders ... and my feeling this puts you over your $4K figure, certainly, but it is something you should consider doing, first, rather than later in your plan! You might be happy enough with improved performance with gearing changes, to allow more time for saving for the 'big' engine improvement program later!

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Warren Hall
1973 911S Targa

On the 3.0 conv. for the 2.7 Andial makes a very quality and popular kit and we also make our own 3.0 conv. kit. Our kit you do "time sert" the case like normal and what is very nice about our conv. you do NOT need any kind of Performance head studs in other words no extra $$$$ on head studs because the cylinders are Birol just like the 2.4"S" so you do not have the expansion like the all aluminum cylinders. You will need to open up the case and heads but they will go right in. We call them the "3.0 big bore kit" others call them a "3.0 cheater kit", see on the out side the look completely stock 2.7, but inside is a lot larger piston then a 2.7, but a 3.0. You can defiantly hear there is a larger displacement in the motor so it is pretty darn hard to hide its a 3.0 inside there .

On camshaft choice they are all the same price $350.00 a set, but you need to ask your self WHAT you will be using the car for before choosing camshafts. GE-40? GE-60? GE-80? Solex? Early S? E? or ?, there are many camshafts out there and bigger is NOT always better and if you choose to go with a lower ratio ring-pinion or stock then this will 100% effect your choice of camshafts.

We have seen it very rare that a 2.7 case could not be machined or reworked back to provide a quality part for the correct application unless it was blown up? Or if it was to expensive to remachine the case over all then sometimes it was cheaper to just replace it.

Some false reasons not to reuse the case:

1. Case needs line bore?
Line boring a case is fine and will not decrease the life of your motor.

2. Hole in case body?
If you throw a rod through the case and you have a Porsche like an original RS or? if the case damage is at an area that does not effect any part of the case that holds the crankshaft or effects the oil system there is no reason to toss the case and loose your factory numbers, most of the case damage is at a part of the case that just holds in oil, Porsche shops have been repairing 3.0, 3.2 and 3.6 cases like this for year.

3. Case needs a second line bore and there is NO second line bore bearings?
You can take the case and have both half's machined to bring the case in more for you can line bore it either back to standard or 1st over. Walt or as he loves to be called "BEAR" at Competition is the best at this work.

4. Studs pulled?
Time sert the case correctly.

5. Time sert area is damaged (hole is larger)?
They do make an over size time sert.

6. Case spigot damaged from rod thrown?
Add metal and re-cut spigot.

7. Spigot face is damaged from cylinders bouncing against face from pulled head studs?
Re-cut spigots face (will need to adjust height with shims after machine work)

8. Age weakening the metal? Fatigue? Ect?
The 2.7 case actually does not weaken it changes shape and most 2.7 cases can be line bored and the spigot face and inner area of the spigots can be remachined to bring the case back to where you need it.

NOW, if you can find a cherry 2.4 or 2.7 case for a good price? Then hey buy it and use this case. But, if you want numbers to match or you cannot find a case that does not need work it self then work with what you already have.

We build more 2.7's in a year then anyone else out there and the only reasons we need to sell one of our customers a case is usually if they have thrown a rod through the case, so before you toss that case away always get a second opinion, it may save you money.

Roy at http://www.motormeister.com

john,

i am planning to stay with cis. i just upgraded to the larger system from the 78-79 3.0 motor.

i will let you know how it comes together. i anticipate an extreamly powerful motor with a very long power band.

jim

Warren, thanks for the heads up on the gearing. I did not even think about it. Would the gearing change only be required if I went to S Cams. If I installed E cams would this still require the tranny mods?

John,

I am quite sure you would enjoy the lower gearing no matter what engine you decide to go with, but either the 'E' or 'Solex' cams are rev-happy enough to need it just like the 'S' engines. And, I have had that gearing recommedation confirmed by feedback from an individual who put an early 'S' engine in place of a '77 2.7 with pulled studs. He told me that 3.875 (8:31) r & p really made starting off in 1st gear unpleasant, and real sluggish in 5th gear as well, much worse than he anticpated!

Take a look at these threads for discussions on appropriate 915 gearing:
http://www.pelicanparts.com/ultimate/Forum3/HTML/003998.html
http://www.pelicanparts.com/ultimate/Forum3/HTML/001192.html

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 11-19-2000).]