If someone is going to start looking for a 6 to build what do you want and what do you want to avoid?

2.2

2.4

2.7

3.0

3.2

as all 911 engines are very very expensive to build, I would try to buy a running 3.0. All of the power, easily runs carbs, does not suffer the 2.7 pulled stud problem, and fits into the 914 cavity nicely. Opinions below about the others:

As George said, the 2.7 had head stud problems, but as with anything, the later the better unless you know the quality of the build / builder... then what you want per cost matters...

If you're just buying and plugging... a 3.0 is a good option.

I think a lot of the perceived issues with the 2.7 are urban lore. The stud issues with the 3.0 seem to get glossed over in discussions like this.

I'd ask a bona-fide mechanic/machinist who has seen it all to give you his opinion.

BTW, I have a '74 2.7S. I rebuilt the motor last year after 105K and its studs were fine. I installed SC cams with a M&K muffler and the car really hauls the mail. I recommend the 2.7.

2.7 is a great hot rod motor, especially if you plan it right and have the money. To specifically answer your question. The first 2.7 were not as big an issue. When the thermal reactors were added ( emissions b.s. ) THAT is when the 2.7 became a real The cams were flat, the reactors caused the engines to run hotter than they rightfully should, the head studs were a real issue with either pulling from the heads or flat out breaking ( usually flush with the head) Yes the 3.0 still had stud issues but no where near as great as the 2.7 did. I personally have one of each and plan on full rebuilds, each with different specs, but each just as reliable in the end.

the 2.7's seem to rev a little nicer too
I think the case is more stressed on the 2.7 as compaired to the 3.0... but the components are just enough lighter that they can be built to rev a tiny bit nicer.

I'm about to build a 2.4 for a street car
It seems to rev a bit better than the 2.7 in my book, and I really like the feel of a low-hp, rev happy early type motor.

plus with the 2.4 and carbs it's very "vintage" feeling and still able to get 180hp with out much struggle or expense. Nearly the same hp as a stock 2.7 or stock 3.0..
probably a higher redline, and less torque

brant

2.7s are Great motors in a 914. Yes they did have Stud problems, but if you are finding an engine these days, the studs have probably been replaced. The correct studs to use are Porsche Steel studs, not the Divilar(?). The other perceived problem of a 2.7 (and partial cause of the original stud issue) was the heat that was created by the Thermal Reactor exhaust system that Porsche used to combat the stricter Emission standards of 1974. Again these exhausts have long been scraped as they were more trouble than their usefulness and would not be used in a 914. The 2.7 7R case is much stouter than the earlier 2.2 or 2.4 cases. You can easily make a 200+HP on a 2.7 case. (see my Pro-Built 2.7 in the classifieds)

And yes, while 3.0s are almost bullet-proof, they also had Stud & Tensioner issues

T.C.

So it took me 4 years to get my 2.0L built and into my car

that said it is a sickness and I am already looking to the next step

Found a 2.7 that turns but does not run complete out of a '76 that I can get for under $1k. Maybe a paperweight, maybe a starting point. No idea if it is a G, H, I or K. Still just sniffing it out. But $1k for complete core sounds like a start



Or my neighbor has a '79 911 targa 3.0 SC I could get for < 8K I know history and it runs strong. Part it out and keep the motor

Just not that much in mid-west vs you lucky west coast folks

All 2.7L cases have to align-bored and TimeCert'd. As well many need to be shaved before they're align-bored. That makes for an expensive beginning for a case. After that though, they are delightful and super-light. Used to be they were all shuffle-pinned as well but that process created stress points that generally created a bigger problem than they solved.

I loved mine. Especially the sound through Webbers and a Porsche sport muffler. This 3.6L motor I have now sounds great but it's a completely different timbre. Can't get that specific scream out of it that the 2.7L and smaller displacement machines gave us.

The 993 Divilar, full thread, coated studs are the way to go. Steel studs come loose due to uneven expansion rates......no big deal if you don't mind retorquing the heads a few times till the aluminum is done coldworking (if you don't know what type of coldworking I'm speaking of, ask)......this assumes case savers have been installed.

The 2.7L gets a bad rap. All the motors have weak points and need to be rebuilt to adress these issues. With a mag case just keep it cool and it'll live. That said, if I was gonna do it again I'd use a 3.0L unless I was building to class.

2.7....A great deal since people think they are junk and can be bought cheap.

You need:
1. case line bored and decked
2. stud holes repaired with inserts (many 911 years need this)
3. Pressure fed chain tensioners (they all need that)
5. replace the 5 bladed fan for a later fan
6. install a front oil cooler (anything above a 2.2 needs it despite what you hear)
7. lose the thermal reactors. (a no brainer for a 914)
8. Standard overhaul (replace what's needed)

With the above you get a GREAT engine that will cause you no problems. Repair it right and keep it cool and you'll have a happy engine. No need to hide from a 2.7

3.6

Too much Money

I just drove home from Austin to Houston my 911 today, has an '81 3.0L SC motor. The plan is to put it into the 914.

Everything I've read...the 3.0L SC's are the best aircooled Porsche motor you can get. Yes they do have head stud issues, but that seems to be about the only common issue.

I also got lucky and found a pair of Weber 40IDA3C carbs for an insanely cheap price at a garage sale...and plan on converting CIS to carb.

What's wrong with the 911? Rust? 3.0 liters are Great as well, but to scrap a 911SC for it

It's a 1974 with the 81 motor. I'm not sure on my plans for it yet, but it is a beautiful car with a rust free chassis - but it lacks an interior/rear window, needs a lot of work.. I think I might keep it in storage and work on it after the 914 is complete - or sell it as a roller. Not sure yet.

2.7s pull studs from the soft metal mag cases. Porsche has found the Dilavar studs weren't the answer to the problem, and they've gone back to steel studs. Case savers are a requirement. 3.0 engines break studs, often right down at the deck. An EDM is required to fix this, along with case savers. My guy gets 50 bucks a hole. We just did an SC engine with EIGHT broken studs.
Pressure fed tensioners are OK, but the conversion is major dollars, bucks that could be better spent elsewhere. They CAN fail. I've seen it. A good rebuild of the late SC tensioners and the addition of chain guards sets you back 50-60 bucks in parts and they last for ages.
2.7 engines need a well designed front oil cooler setup. Built 2.4s might, too.
As for weight, everything that moves is the same weight between a 2.7 and a 3.0, with the exception of the pistons. I doubt they rev any more freely.
A 5 blade fan works fine if you have the correct fan ring and drive pulleys. The urban legends regarding the subject are like most urban legends ..............

That said, if I were building a performance motor for my car, I'd build a 2.5 based on a 2.0 S crank and an aluminum case, with ported big valve heads. The machinists I use say they can get me right about 200 HP from a street drivable 2.2, so a short stroke 2.5 should be a revvin'n fool, and have even better HP.

The Cap'n

here are my #'s at the wheel with DC 40 cams 9.5:1 comp single plug, and PMO's....taking a 15% loss for driveline that puts me @ 220 hp at the crank and I will tell you it had more but my revlimiter is set @ 6750....
Click to view attachment[

Build a 2.7 right and it should be fine. Thermal Reactors took down a lot of them and gave them a bad rap.

All have to be rebuilt. All will cost money. 2.7 will give you some nicer torque than the smaller motors and still rev as Brant points out.

That said, a 930 block (SC motors) is kinda bulletproof, There have been stud issues there but, 3.0's done right are set-it and forget-it.

Well, Cap, remind me to not have you build a 2.7L.
My home built has been running fine or 10 years...with a rebuild at 7 years of age.
Both the *993 Divilars* and the Carrera tens have worked flawlessly.

Here's the latest chassis dyno sheet.....but hay, I'm just an amateur with no preconceived notions.

There is a mod to make the hydraulic tensioner failsafe. The other issue is they can leak.
The 993 studs are getting spendy, so I'd use Supertec studs.
Many of the 2.7 used alusil cylinders, they can be reconditioned but your stuck with stock pistons, unless you replate them with nicasil.
A 2.7 that had reactors will also have worn out guides.

Done right they are a good engine, I have a 2.7 core with casesavers and steel studs if anyone is looking. I'm going 3.0.

The Cap'n's dream engine would be nice, but that Al case and squirter machine work needed will set you back $3k alone.

go for the best

I installed a 1974 2.7 out of a U.S. 911S Carrerra back in 1986. With Webers it was the best sounding engine I have ever heard. I used go back and forth through the Alameda tunnel just to listen to the engine. I also used a stock 911 2.0 flywheel and clutch. The engine matched the stock 914 gearing quite well and was a blast to drive. Then in 2000 it started pulling head studs and lost most of its power. At the time my choice was to spend $6k to overhaul it or buy something else. I ended up buying a used 1984 Euro 3.2 motor for $5200. I miss the sound of the webers, but the driveability and reliability of the motronic fuel injection is amazing. The down side now is that 1st gear is to low for the 3.2 motor and most of the time I now start off in second. I only use 1st when starting from stop on a hill. If the 2.7 motor has been overhauled properly to address the issues and the price was right, then I would recommend it highly.

Well, JP, I just reread what I wrote. I don't believe I said anything about a 2.7 being bad, or not living as long as anything else. I pointed out that they pull studs unless they're inserted, and the SC broken stud problem is at least as bad, or even worse. I then said I'd prefer a short stroke 2.5. Not that it's necessarily any better, but it does have a certain coolness factor. As for the comment from Mark regarding the cost of the cases, I have 4, so it really doesn't matter all that much to me. I can always sell one to pay for the mods, which aren't as expensive for me as they seem to be for him. In the time since you built that motor with the 993 Dilivar studs, most experienced 911 machinists and engine builders will tell you they've followed Porsche's service literature and gone to steel studs. What can I say? I also didn't say oil fed tensioners were bad, or that they failed more than the old style, just that I'd spend the money elsewhere. And it's a LOT of money, relative to the price for 2 kits.

The Cap'n

If anyone has one of those old stud pulling nasty nobody wants one motors in the garage they just can't live with, I'll send my shipping address and take it off your hands. Don't want anyone to worry about a motor they just can't stand.

Here is what I learned when I rebuilt my 74 2.7:

1) As stated, alusil can be reconditioned for cheap. I paid $192 to have all 6 cylinders done at Motorworks in San Diego, CA. That saved me a few grand on new ones as urban legend stated you can not do such a thing. Complete, expensive, unfounded, bull shit. The pistons are not coated in nickasil, they are ferrite coated or some such thing. They will be fine.

2) The 74 is the best starting point as that year did not have the thermal reactors.

3) I was lucky, my case had case savers installed. This is a necessity.

4) You DO NOT need an oil cooler for a 2.7. It is dependent on several things. I kept the stock CIS and CR and my engine had fine oil temps.

5) Oil fed tensioners are not mandatory at all. As Krusty said, use the mechanical ones with locks and be money ahead and have one less failure point in your lube system. I have always felt the oil pressure fed ones to be over engineered and unnecessary.

6) The 74 2.7 had a very peaked tq curve in the low band and then fell on its face. As previously mentioned, a set of SC cams, which I got reground for $200, make the curve a nice flat climb that was a real joy to drive.

7) Divilar is crap. It tends to crack and this is a known failure point. Any moisture gets onto the studs and it begins the degradation process. This is a widely known, and proven point. It is even mentioned in the 911 engine rebuild book published by the guy form Pelican (just one easy place to find it, he is not a guru). I forget what I used, but it was proven to be superior in tests. I needed results I could see rather than hand-me-down knowledge from people.

I love my 2.7. It darn near scared the shit out of me on a quick test drive this evening. In a good way...


Porsche 2.7 twin-plug engine by cjcam, on Flickr

JP, as Cap & Dr Evil said, Divilars are not the recommended way to go as they once were. My builder (probably 5 motors a week) only uses Porsche Steel Studs now. This has changed in just the last couple of years. In the original estimate he gave me on my 2.7, he stated Divilar, but when he built he used Porsche Steel. My 2.5 ( built on a 7R case) I'm sure had Divilar.

Picture Porn ( my 2.7 that is For Sale )

Click to view attachment

The 2.5 Twin-Plug on the Dyno. The numbers off the Top of my Head were 218 HP & near 190 Ft/Lbs Torque

Click to view attachment

The stud issue will never be settled here. Suffice it to say that my gurus build with nothing but Divilar( for aluminum cylinders)....that would be Steve Wiener & Rothsport. Henry at Supertech had his designed & produced studs from some kind of stainless with an expansion coefficient similar to Aluminum...not Divilar but similar and he's no slouch. They are sold at a decent price, right Mark?
The Pelican 911 engine building forum has been going around & around about this for years and prolly will for the foreseeable future. Pick your own guru and HIS opinion, but don't tell me mine has no clue.

The 76-77 2.7L has the improved (larger scavenge side) oil pump plus the oiling mod, Doc.....that cost a pretty penny to have done. I would use one of those cases if you can find a straight one. Alusil cylinders reconditioned to size?

I would never use collars on tensioners. If the tensioner fails you don't have any warning like you do with a slowly failing oil fed ten. The collar starts getting hammered on, breaks and the chain goes slack. At best you'll then go buy a bunch of valves. Pick your poison.

Glad i finally got you to see the light!!
But the down side with a cis 3.0 is fittment if you plan to keep the cis intact
I dropped my entire drive train an inch to accomodate with no cutting of body, requiring a modified shift rod on the underside
where as the 3.2 just requires a turn of the intake to fit
while i love my early 3.0
i think i would go 3.2 with motronic if i am going to do it agian

The Supertec studs are about $600. If you decided to go twin plug you'll have a hard time getting past the stock barrel nuts.
If you take apart the hydraulic tensioner you can make a spacer out of tubing, but you lose the circlip. Doesn't matter once the tensioner is installed and then it's bulletproof.

Saying you have 4 Al cases is an apples to oranges argument. On the bird board classifieds they have an asking price of $2k and then you need squirters and the oiling mod.
My 3.0 had no broken studs, but I'll be replacing them anyways.

Only a couple of people have used 2.7 or 3.0 with CIS...has anyone done a 2.7 or 3.0 with a Bitz EFI conversion? Wondering if that'd run cooler. Just thinking out loud.

I'm pretty sure that it's a megasquirt system with all the needed bits and pre-programed with the maps.
That's why the price is so good.
IIRC a member here used it on his 911, try a search.

If the A/F ratio is correct, what the hell would make the engine run cooler over a CIS setup? I've done two CIS setups myself and will do a third soon.

[That said, if I were building a performance motor for my car, I'd build a 2.5 based on a 2.0 S crank and an aluminum case, with ported big valve heads. The machinists I use say they can get me right about 200 HP from a street drivable 2.2, so a short stroke 2.5 should be a revvin'n fool, and have even better HP.]

Agree. I have a 2.5 built on a 2.0. I believe it is an E cam. Love it.

[quote name='Mark Henry' date='Aug 29 2010, 12:46 PM' post='1363069']



I would never use collars on tensioners. If the tensioner fails you don't have any warning like you do with a slowly failing oil fed ten. The collar starts getting hammered on, breaks and the chain goes slack. At best you'll then go buy a bunch of valves. Pick your poison.
[/quote]



Saying you have 4 Al cases is an apples to oranges argument. On the bird board classifieds they have an asking price of $2k and then you need squirters and the oiling mod.
My 3.0 had no broken studs, but I'll be replacing them anyways.
[/quote]

I've been using collars for 30+ years, and 912 valve spring retainers before that, and I've never had a chain related failure on any engine on which they've been used. Ever.

As for the "asking price" for those cases, I had ads all over the place for both plain cases and core long blocks, at a price lower than that, and I don't think I got more than 2 or 3 replies during the several months I was actively trying to sell them. I finally decided to hold onto the stuff.

The Cap'n