2.7L engines, upgrades and rebuilds

[kav]

I meet many folks at various meets that have 2.7L engines in their Hotrod cars. I don’t know an awful lot about these motors but they seem to be getting more popular to rebuild with more power than stock.

So the 2.7L came in the base 911 form with 150hp?
911S was rated at 175hp?
911 Carrera again rated at 175hp?

What was the difference between these engines to get the HP variations? Did the extra HP come from compression and cams or something else? Were the heads all the same or did they have different port sizes? Stroke was 70.4mm on all? 90mm pistons on all? Was there various injector sizes between the variants on the CIS system?

What makes a 2.7 into a 2.8? 92mm P&C’s? Do you need to change out the heads?

What makes a stock 2.7L a RS spec 210hp? (expensive I imagine because of the MFI?)

These engines run hot so the head studs would pull from the Mag case? Valve stems had issues? If you plan on upgrading for more power you need to add case savers, oil bypass etc.

I’ve heard a great street engine is a 2.7L with 9.5:1 compression, E, Solex or S cams, Weber’s, SSI’s and a sport exhaust? What kind of HP would that combination put out? Can you start with any of the 2.7 variants or do you need to find a ‘S’ or ‘Carrera’?

Lots of folks were not running front mounted oil coolers, is that necessary or just more sensible?

I told you I had lots of questions!

Cheers,

-Kav

[Jack Stands]

That built 2.7 should put out around 200+ rear wheel horsepower. I had that combination in my 914-6 conversion and it was great (but you do need to properly prepare the case with Casesavers, etc.).

[Walt Fricke]

The base 2.7 (74 and maybe 75) had smaller ports, less cam, and less CR.
The S and the US Carrera are the same engine, just flares and logo basically.

The 2.8 (from Porsche) is a race car engine. Yes, 92s, and different heads with larger valves - can't really be duplicated with a stock head.

Buy Bruce Anderson's book - it has a good description of this kind of stuff, and tables showing important parameters for the various models.

[spyerx]

I have a CIS 2.7 (911/85, 1977 2.7 7R, ie lower compression 8.5, cams, etc) with Weber 40s and SSI in my 71. Its pretty good!

I have a 911/85 7R core I bought that I'm building into a hot 2.8 motor. The case is off for machine work now, the core was very clean. At a high level, will be 10.5:1, high compression, dual plug, full EFI/Coil on plug, Motec, PMO or Kinsler induction, custom heads, pistons, rods, cylinders, cams, rockers, etc etc.

It should be fun in my little signal orange T

[RWebb]

7R case to start

add $$:

align bore; studs, kill the CIS, etc. etc.

[Jeff Higgins]

Lots of guys running hot-rod 2.7's up here in the Pacific Northwest. Great motors once all of the "known issues" are sorted, which we typically do when hot-rodding them. Perfect fit for an early lightweight hot-rod. Rev-happy and fun.

I have to admit that this thread kind of caught my eye. Reason being that we have a member of my little hot-rod 911 club that has recently spent some buck$ on a hot-rod 2.7 build. He had Peter Dawes (who worked for/with Jerry Woods for some time) build it. Street motor, 10:1 compression, what appear to me to be (from his build photos) a stock crank and rods, stock-ish port sizes, unknown cams, PMO throttle bodies and some form of EFI. And - wait for it - 287 horsepower. At the wheels.

I only mention this to emphasize that we must be realistic. One eighty-seven is realistic. We cannot spend our way to the kind of power this guy claims, no matter how hard we try. That's decidedly hot 3.6 territory, and even then, it takes a pretty good one. Keep your expectations realistic, understand what you are working with, and you won't be disappointed. 2.7's are great good fun when built right, and we all know how to do that - there are no secrets. Or magic...

[skinnerd]

I'm not believing a 10:1 2.7 can make 287 at the wheels...what's that about 320-330 at the crank? It's not happening in anyone's alternate universe.
I'm shooting for those kind of numbers with a 3.6 that been sufficiently massaged. My 3.6 will have a higher compression ratio, good cams, ITB's, MOTEC, the
best headers out there and a GT3RS muffler. I'm hoping for something around 335.

That said, 2.7's can be great engines if all the I's are dotted and T's crossed. My 8.5:1 MFI 2.7 made 230 at the crank and I was stoked.

[Walt Fricke]

Peter is a hell of lot better engine builder than I am. I'm really just an engine assembler.

My 2.7 with Mahle 2.7RS pistons (nominal 10.5 but not that hot), twin plug bigger ports, stock crank and rods, RSR light flywheel and pressure plate, Weber 46s, twin plug crank fire, Elgin 315 cams, and headers and stingers, made 220 at the rear wheels. I was hoping for maybe 240, which would be about 100 hp/liter. Porsche got 110/L out of the 2.8 RSRs. Torque curve was such that optimum shift RPM was 7,600. Race motor, though it idled nicely about the paddock.

I had to switch from the mag case to a sand cast one, though, after a wrist pin retainer had an issue, and during the teardown to fix that the inserted studs, green Loctited in, started backing the coils out. So I didn't get to see if the mag case was up to it in the long run.

It's on the shelf now, as the 2.8 semi-clone with Electromotive EFI/crank fire dynoed at 250 at the rear wheels. Again, I was hoping for RWHP of about 270.

Spyerx, what cam did you choose?

[spyerx]

Originally Posted by Walt Fricke

Spyerx, what cam did you choose?

Not yet decided. The way the motor is being built it will rev past 8 but want a more streetable motor, the car won't be tracked, canyons mostly. So would like it to come on around 4.5 and have the fun zone from about 4.5-7 with a 7.5 or so redline...

Builder has a few options just need to decide. I'll give up some top end WHP for more drivability.

I'd love to get 250 wheel :-) I have to build it for crap 91 Octane / E10/15 CA fuels BOO

I'll get a thread going in the engine building forum. This is JUST beginning as the case is in queue for machining. Goal is "done" by Luft in April.

[Neil Harvey]

I posted some photos and descriptions of parts we are developing for these early engines in the rebuilding forum. These are our idea's of what we think can be done.

[spyerx]

Yes. Light, strong, low friction. Classic case & installed look, with modern induction, engine control, and internal materials.

[911pcars]

Enough info about these upgrades to write a book or two about the topic. Done. Get the ones by Bruce Anderson and Wayne Dempsey, about $20 ea. Also, tons of info in the PParts forum archives.

[spyerx]

Originally Posted by 911pcars

Enough info about these upgrades to write a book or two about the topic. Done. Get the ones by Bruce Anderson and Wayne Dempsey, about $20 ea. Also, tons of info in the PParts forum archives.

while both books are great, and especially bruce's for the historical primers and guidance, neither one of them is modern, with the last update to Bruce's book I have sitting here 3rd edition in 2009.

So yes, both books are invaluable resources, along with Pelican. But if someone is wanting to push the technology used on these engines (particularly with induction/ignition controls), they aren't current. The pelican engine forum does have lots of great info. their info on the internal mechanicals is very valuable.

Of course, that only matters to someone who's not looking to stay full period correct or OEM.

I think a good example of this is what Emory is doing for the engines on his cars now.

[911pcars]

Originally Posted by spyerx

while both books are great, and especially bruce's for the historical primers and guidance, neither one of them is modern, with the last update to Bruce's book I have sitting here 3rd edition in 2009.

So yes, both books are invaluable resources, along with Pelican. But if someone is wanting to push the technology used on these engines (particularly with induction/ignition controls), they aren't current. The pelican engine forum does have lots of great info. their info on the internal mechanicals is very valuable.

Of course, that only matters to someone who's not looking to stay full period correct or OEM.

I think a good example of this is what Emory is doing for the engines on his cars now.

Unknown what the OP is planning. It sounded like he wanted some basic info. with basic early 911 engine mods. With that info under his belt, he can venture into state-of-the art, whatever that means.

What is Emory doing on his engines now? Just wondering.

Sherwood

[kav]

I think these engines are so under rated. They get such a bad rap over the years because of the known issues and there were much more affordable candidates out there at the time. Now those other candidates (3.0, 3.2) are getting so expensive to buy a core I feel like the 2.7L is making a come back!

I'd be very interested in a 2.7L core for cheap and building it up to a great street motor in the future. Getting in the 200 wheel HP range in my little narrow body 911 seems to be the sweet spot.

Anyway I bought Bruce's book.

Cheers

-Kav.

[911pcars]

The last Mg crankcases appeared in 1976, thus there may be issues with a Mg case at this time in history. Perhaps a machine shop can inspect for potential return-to-spec machining. Or get a hold of a rebuild menu from an engine machine shop to get an idea of potential cost.

Here's a link to Ollies:
Home Page

Sherwood

[al lkosmal]

Originally Posted by Jeff Higgins

Lots of guys running hot-rod 2.7's up here in the Pacific Northwest. ...... wait for it - 287 horsepower. At the wheels. ..... 2.7's are great good fun when built right, and we all know how to do that - there are no secrets. Or magic...

I'm with Jeff on this...I have built a few 2.7RS-ish engines......9.5:1 JEs, various cams, headers, sport muffler etc. These are good for 230HP or so.....185 to the wheels... ......which is a butt-load of fun in a light 911 or 914-6 hotrod.

Producing another 100 HP at the wheels would take some serious juju!

regards,
al

[kent olsen]

Aw yes the 2.7L. I replaced the 2.4L in my 72 many years ago, basically a stock engine. Ran it for years with not serious issues as I reduced weight in the car which is much cheaper than building an engine. When I decided to bite the bullet I was told by many that the Mag case could be expensive to make serious HP. I decided to go with the 3.0L. I found an 83 in a wreck and commenced to rebuild it with the help of Mike Bruns in Florida. I wanted something I could drive the daylights out of and then take home and adjust the valves and change the oil once a year. We built it to turn 8000 rpm (just in case) and twin plugs, only 9.5 cr, 40mm webers (later opened to 42mm), and a cam recommended by my friend Jeff Higgins with a lower torque peak. With my rev limiter set at 7200rpm and my 915 transmission each shift drops to 4000rpm and the torque peak is at 45-4700rpm, (217ft/lbs and 245Hp at 68-6900rpm) at the crank. 20,000 miles of track days and highway miles and she has been bullet proof.

One shift linkage failure on a track day which caused the engine to rev to 8000rpm. Mike said if it's not making any noise and no metal in the sump magnet your good to go. That was 6-7 years ago.

[spyerx]

Not to diverge too far off OP topic...

Originally Posted by 911pcars

What is Emory doing on his engines now? Just wondering.

Sherwood

He now has 2 options, both designed in collaboration with Rothsport. A carb model and an EFI model. Custom cases based on 964 with 2 cylinders lopped off. Buddy having driven the EFI version said their are INSANE especially in the light cars.

In his words: $325k + the wait to buy an emory today is worth every penny, and look, one sold on BAT yesterday for $500k. But the wait...

Originally Posted by 911pcars

The last Mg crankcases appeared in 1976, thus there may be issues with a Mg case at this time in history. Perhaps a machine shop can inspect for potential return-to-spec machining. Or get a hold of a rebuild menu from an engine machine shop to get an idea of potential cost.

Here's a link to Ollies:
Home Page

Sherwood

Yes that's right. You have to have a good core. I picked up mine here (the car has a 77 7R in it, which I'm just running, it's stock with webers now and SSI). I paid more but the case and everything are really nice, and looks like it already has case savers. It's off to ollies yesterday for measurement and evaluation on all machine work. I have a thread going on rennlist on the build...

Originally Posted by Jeff Higgins

Lots of guys running hot-rod 2.7's up here in the Pacific Northwest. Great motors once all of the "known issues" are sorted, which we typically do when hot-rodding them. Perfect fit for an early lightweight hot-rod. Rev-happy and fun.

I have to admit that this thread kind of caught my eye. Reason being that we have a member of my little hot-rod 911 club that has recently spent some buck$ on a hot-rod 2.7 build. He had Peter Dawes (who worked for/with Jerry Woods for some time) build it. Street motor, 10:1 compression, what appear to me to be (from his build photos) a stock crank and rods, stock-ish port sizes, unknown cams, PMO throttle bodies and some form of EFI. And - wait for it - 287 horsepower. At the wheels.

I only mention this to emphasize that we must be realistic. One eighty-seven is realistic. We cannot spend our way to the kind of power this guy claims, no matter how hard we try. That's decidedly hot 3.6 territory, and even then, it takes a pretty good one. Keep your expectations realistic, understand what you are working with, and you won't be disappointed. 2.7's are great good fun when built right, and we all know how to do that - there are no secrets. Or magic...

287 wheel seems quite optimistic. I'd be happy with 250 crank at a reasonable redline.
I think the magic on this (if you can call it that) is using modern induction / EFI systems with lots of inputs and controls (like dual lambda and knock, etc) to control and allow great running in all conditions. For me, this is a big driver of doing a build as I'll run the car up from sea level to 7k+ feet and well, the fun zone is up over 5k and you know how carbs start to behave outside of their tune range. Call it character, I call it annoying.

Given my car weights 2100 lbs, skinny, 71T that 'looks' stock, this should make for a fun little sleeper hot rod. Unfortunately this will also mean some trans work, and like a set of 7R with a 215 squeezed in the back. Rest of chassis is sorted.

[kent olsen]

Well I've been a carburetor guy forever and webers on my 3.0L 1972T since I pulled the 2.4 and installed a 2.7 many years ago. My friend Paul Abbott who operates Performance Oriented has spend years learning and upgrading old webers into what today are as good and in some cases better than PMO's.

My 3.0L will pull right up to the 7200 redline without any issues. In fact one time I was at Oregon Raceway Park, eastern Oregon, a rather short course, it was running so well I didn't hardly shift and keep it in a lower gear running 5500-7000rpm thru half the course. With only one short 4th gear straight my oil temps started getting to high so I would shift up but she was sure singing.