2.7'S' or 3.0??

rickeolis · 02-12-2004, 08:55 AM

I've found a local car that is a 1970 911'E' that has a 1979 3.0-CIS engine in it with about 80,000 miles.

I am wondering what would be a better engine and why: My 2.7'S' with Webers and SSi's, or this 3.0 with CIS and SSI's. Both have electronic ignitions, and Carrera plungers installed.

Thoughts?

dd74 · 02-12-2004, 09:04 AM

Depends on what shape the 3.0 is in. It is, in most cases, a better engine than the 2.7 if the 2.7 has not been rebuilt properly.

A '79 3.0 has larger intake runners and ports than post '80-'83 3.0s, but honestly, many have said this makes no difference with the behavior of one model over the other.

What will you do with your 2.7? My thoughts are you can adapt the Webers to the 3.0, stick in some 20/21 cams, and have an engine that's as powerful, if not more than a 3.2. At least it will be much lighter, particularly because of the Webers.

Chuck Moreland · 02-12-2004, 09:14 AM

Better for what? Commuting, racing, etc.

Has the 2.7 been upgraded with timecerts, etc? What cams?

ckissick · 02-12-2004, 09:35 AM

In the same condition, the 3.0 is a better engine. Higher torque, and generally longer lasting. If you put your Webers and SSI's on the 3.0, it's much better. I will soon find out how much better, when I complete the switch of a '78 3.0 for a '74 2.7 in my 1970 911E. I was going to rebuild the 2.7, but found the rebuilt 3.0 for a price that was too good to pass on.

What year/model car is your 2.7 in? The decision to switch to the 911E should depend on the cars, not the engines.

Charlie

rickeolis · 09:39 AM

I'm looking for a commuter that will do weekend autocrosses in the summers.

My 2.7 has been rebuilt, with timecerts, but stock cylinders and cams.

This guys '70 body has better brakes, rust free, and new paint. He's got a 915 tranny, and is basically stock otherwise.

What about expected life of a stock 3.0? How much HP from the 3.0 (stock but with SSI's)?

techweenie · techweenie's Garage

I have a '73 with '79 3.0, so I can testify:

The 3.0 has tire-burning torque -- even with an 8:31 -- but it doesn't have the 'snap' of a well-done 2.7.

Instead of pulling head studs like a 2.7, the 3.0 has a habit of snapping them. but aside from that, Bruce the Authority says 450K miles of good service from a 3.0 is possible.

The SSIs alone are unlikely to make a lot of difference. If you can change over to all the Euro CIS parts, you'll be happier with the premium you will pay for the 3.0 engine. Better yet, slap on some Webers & upgrade the cams.

ckissick · 02-12-2004, 09:46 AM

Oops, I see you have a '69 911E.

I've heard of 3.0's with 400,000 miles before a rebuild. That's rare, of course, but the 3.0 has much more longevity (usually).

The SSI's are supposed to add 15-20 HP, and will put you in the 200 HP range. But with more torque, it will pull nicely, especially in the light 911E.

Get a diagnostic on the 3.0: compression and leak down. The numbers will probably be good, and the engine will probabaly last a long time. If the cars are in similar condition, the '70 is better.

Charlie

Jadams1 · Jadams1's Garage

The 3.0L is a good reliable motor and should last a long time with the exception of the 12 lower dilivar head studs. If any of the lower dilivar head studs break or are broken it will need to be repaired. If you do your own engine work it's not expensive to repair, if you stick to the task of repairing.

Grady Clay · 02-12-2004, 10:18 AM

Rick,

These guys are offering good insight.

The overview is the 3.0SC is a stronger and longer lived engine in stock form. It is a great street engine and good on the track. Of course they get old and need to be brought back to new and better.

The 2.7 is lighter and with Webers is more throttle responsive (MFI is even better). Your 2.7 is fresh and most important you know where it’s at.

Since you are looking at an “E” does it still have the “S” brakes? How were the front struts up-dated? Does it have pinch-bolt or wedge-pin ball joints?

Whatever you do, BUY IT. Buy it knowing what you are buying and at the right price. What is the condition? Coupe or Targa? Who can do PPI?

I assume that your 2.7 has the ~’76 930 fan and pulley. Your climate is the same as Denver, perhaps hotter.

Best,
Grady

Bill Verburg · Bill Verburg's Garage

If your '2.7S' started life as a '2.7cis' of any sort then it isn't the best candidate from a performance perspective, unless the pistons/cams/ valves/valve train etc were upgraded to 'S' spec as well.

The 3.0 even though cis as well is a better platform to start from.

k9handler · 02-12-2004, 11:10 AM

Rick...is that one of Russ's cars?

chuckw951 · 11:41 AM

Quote:

Originally posted by rickeolis
I'm looking for a commuter that will do weekend autocrosses in the summers. My 2.7 has been rebuilt, with timecerts, but stock cylinders and cams. This guys '70 body has better brakes, rust free, and new paint. He's got a 915 tranny, and is basically stock otherwise. What about expected life of a stock 3.0? How much HP from the 3.0 (stock but with SSI's)?

On the 3.0 watch those pesky head studs they can snap at anytime. With your motor you know what you have. Down the road you could upgrade to RS spec P&Cs, S cam and re-jet the carb make more power. At the same I think the focus should be on the condition of the car. Engines can be swapped in and out and rebuilt...but the bigger concern for me would be the condition of the body/rust. I would expect around 180-200 hp from a stock 3.0...though torque is the more important number IMHO. Throttle response from a 3.0 with carbs/SSI is great from my experience. I suppose you'd have to drive the cars back to back to see if you notice the additional power. I liked the CIS in my old 78 targa...didn't have problems with it (other than a bad fuel pump relay but that is another story).

rickeolis · 02-12-2004, 11:39 AM

Chuck- I recall watching as you posted on your engine upgrade, and I was doing mine at the same time, very nice. The car doesn't have much rust, which is REALLY important to me considering why I'm having to make this move...

Smitty- He's trying to sell it for a guy. It's at his shop right now; I looked at it yesterday.

Grady- "Whatever you do, BUY IT."
I'm getting the itch, but the numbers are a bit high I think right now.
"Pinch-bolt or wedge-pin ball joints?" How to tell? Why?
It's a coupe with new red paint, but needs interior badly, and other small issues.
Yeah, the 2.7 I have was done right. 11-blade fan, replaced studs, tensioners, and all. It does get hot out here at times!

Ckissick- Mine is a '69T with 901 tranny, very quick currently.

I'm glad to hear most of you like the 3.0 liter for longevity. It was checked out for compression, leakdown, etc. and passed those tests well according to my mechanic. I would look to do a PPI though.

Grady Clay · 02-12-2004, 12:18 PM

Rickeolis,

’69-’70 911s and 914-6s had a pinch bolt holding the ball joint to the strut. That was later updated to a wedge pin. If you have the early stuff, get rid of it from a safety standpoint.

The later wedge pin is in the first picture here.

Ball Joint split? Replace Shocks too?

Wedge pin has a nut like shown, the pinch bolt has a regular hex bolt threaded into the strut. The wedge pin ball joint has a vee in the pin, where the pinch bolt ball joint has a half round in the pin. Not interchangable.

Best,
Grady

DanTheCat · 02-12-2004, 02:54 PM

What are they asking?

I will again mention the lower head studs in warning. Happened to me...

Otherwise the SC motors are great.

Is the 3.0 stock? This should factor heavily in the price. You'll want upgraded tensioners, pop-off valve, and head studs to make it last. (i think that's all the big items...)

Here's an idea: If you can get the right price for the car, buy it. Stick your 2.7 in (and anything else you want from your current car) and do a nice thorough rebuild on the 3.0 yourself to save some money. You can do some of the easy stuff to get it to ~250hp, and then stick it back in and have fun!

Dan

jluetjen · jluetjen's Garage

Quote:

pistons/cams/ valves/valve train etc were upgraded to 'S' spec

Actually, if it is a CIS-S, all that you need to replace are the pistons and cams. The valves and rockers etc should be fine assuming that they are in good shape.

vash · vash's Garage

or you could sell me your 3.0, cheap. i love alburquerque, in the spring. so that time will be good for me

i used to go mountain biking, doing the downhill runs at that ski slope in your area. i cant remember the name.

fintstone · fintstone's Garage

Don't do it. Go take a cold shower. Breathe into a paper bag. You are still on the rebound. Bet this is the very first P-car you have looked at since your's dumped you. Lots of fish in the sea. Don't get hung-up on the very first one. Look around a bit before tying yourself down. Drive a couple of midyears and an SC or two. If it would just quit snowing, I would come down in my P and do an intervention.

fintstone · fintstone's Garage

You already have a good engine and tranny that will work well in anything from an early car through the late 70's...be patient. Watch for a rustfree roller with the all the "S" goodies.

rickeolis · 02-13-2004, 07:19 AM

DanTheCat, around $8000.00. The interior is shot, and I'd need to get an inspection on it, but from what I saw, it's got strong hardware and little or no rust. If it were just the tub, I'd own it already!

fintstone, I'm with you on the don't jump right in status. I can still drive my car for now, but I'll keep it to a minimum. I'm probably going to part mine out, and the more I sell from it, the more money I'll have to look for another 911. Dude, we still need to grab lunch some time, let me know! I really like your ride from the pics I saw. TTYL-

unfixed, I have a 2.7 right now. The car I'm looking at has the 3.0, and I'd rather keep it in there if I go that route, thanks! Sandia mountain is the name, yes extremely beautiful, especially now with about 2+ feet of snow on it!