Need your opinion (rebuild vs replace engine)
 

I have a '74 911 with a 2.7L CIS engine that has approx. 68,000 miles on a rebuilt engine. I have the telltale signs of a pulled or broken head stud (I haven't had time to pull the valve covers to check yet). I'm debating whether or not to rebuild it or buy a 3.0L SC complete motor with ss exhaust/CIS/fuel pump/everything for $5500 from a local guy that I know and trust. Obviously, I need to get the details about the 3.0SC engine (mileage, leakdown results, etc...), but it comes with the SSI's, which I desperately need as my heat exchangers are rusted out and shot.

This car is my "summer daily driver" and does not get driven hard. I do not track the car, nor do I intend to. I am looking for a dependable engine and the 3.0L really appeals to me. Maybe I could pull my old 2.7L out, rebuild it and sell it or just part it out and offset some of the cost of the 3.0L? I have never done this kind of work before, but I'll get Wayne's book and research everything first. I wanted to get your collective opinion. Thanks in advance!!!

Hi Art,
I've been down the same path with my car. If I was to have a chance to "do-over" I would probably go the route of buying a replacement motor. For the money I put into my rebuild I could have had a 3.6.

Troy

when this rebuild took place were the headstuds done before? if it's just a headstud, just replace them...buy some SSI's for $759 and be done...

You omitted the 'replace with a 3.6L' option.

The "3.6L option" is a 15k option, though, isn't it?

When I replaced my 2.7 two years ago for a 3.0, I did it mostly out of security reasons. I did not want the 2.7 to go south on me, though it showed signs of doing exactly that, and I didn't want to be stuck without an engine. Hate to say this, but you might be in the same boat as I was - and in your case, as in mine, the clock is ticking against you with the 2.7 before breaks. In short, it's easier to unload a somewhat working engine than one that's not running at all.

If it's more than just a head stud issue, be warned: rebuilding a 2.7 is a difficult and time-consuming task. It gets pricey fast, since there might possibly be machining involved due to potential warping of the magnesium case, not to mention the other niceties that could accompany a rebuild such as pistons, cams, better fuel delivery, SSIs, etc.

Meanwhile, if your options are to buy a 3.0 for $5,500, I'd highly recommend that. That engine bolts right into a '74. Be sure to exclude the lambda equipment - it's not needed. You don't even need your old hand throttle. The 3.0 fires right up. Just stick the engine in and drive the hell out of it.

Another side benefit is you can easily sell the 2.7; there are many people on this board looking for them for such things as 2.7 RS cores 2.8s or just stock 2.7 replacements. Most likely your old engine can offset some of the 3.0's cost.

One more thing to consider is the 3.0 you're talking about probably has 50 or 60 pounds more torque than your 2.7 and about 50 more horsepower.

All-in-all, it's a cheap deal. I'd jump on it if I were you.

Good luck! SmileWavy

Dave,
Those HP and torque figures you quoted were tongue in cheek, right? The 1974s and 48-state 2.7s were around 175 HP. I think 3.0s were 180.
Troy

Guys,

Thanks for the advice! I'm leaning toward the 3.0L, especially because I don't have the full docs from the previous rebuild and I don't know how well it was done, the heat exchangers are shot and the 3.0L comes from a local rebuilder whom I know and trust. He said the 3.0L comes with ignition system, brain, wiring harness, etc... everything needed to bolt it in and drive. I'm not an engine rebuilder, but I think I could handle a "drop and replace". I can then try to sell the old 2.7 (which runs really well) and offset some of the cost of the new engine.

Dude, spring for another $500 and get the 3.2 with motronic. Much friendlier system for modifying, and based on the bullet proof 3.0.

Hi Troy: I've never understood what tongue in cheek means... :D

But alas, no: considering that the initial post may have been talking about a 150 hp standard 2.7 (at least that's what I thought he was talking about), in comparison to an SSI-equipped 3.0 that should put out about 200 hp, I'd say at least my horsepower figures are on target. My torque figures, however, were more a guess.

I was faced with a similar dilemma a year or two ago and it just made the best sense economically to replace the 2.7 with something better. I ended up getting a 22k mile (rebuilt) 3.2 with about 245hp for a total cost of about $7k (engine price + all the miscellaneous stuff to swap it). To get 245hp out of my 2.7, it would have cost me alot more than $7k. Heck, just rebuilding the engine would have cost a large percentage of that same $7k.

I sold my beloved 2.7 (I really liked that engine) for $1500.

Also, like was mentioned above, there's not alot of power difference between a 2.7 a 3.0 liter. Obviously the torque is very similar as a 3.0 liter is only .3 liters larger than a 2.7. My 2.7 was rated at 176 ft-lbs of torque, I believe - the 3.0 liters were very similar.

Mike

He could, but bear in mind the 3.2 is about 60lbs heavier, and is not a direct bolt-in as the clutch's pressure plate needs to be notched.

Oh, and the connecting rods on 3.2s are definitely not based on the 3.0.

Actually, it's the gearbox housing that needs to be notched (in one position) and it only takes about 20 minutes. Not a good reason to avoid the 3.2...

The hp and torque of the 3.2 really makes it attractive over the 2.7 though. Getting the same power out of a 2.7 would cost alot of money.

Mike

If 60lbs is what keeps me from not having a CIS system, so be it. Don't get me wrong, its a very reliable system, tried and true. I'm just a bigger fan of the electronic systems, CIS has been outdated. For plug and play reasons(with very very easy mods), the motronic 3.2 has my vote

Hi Dave,
Yeah, you're probably right. I jumped to the conclusion he was talking about an S.

Tongue-in-cheek; just another one of those phrases that has its root in some long forgotten non-verbal gesture used by Neanderthals to indicate jest, I guess.
Troy

I would go with the 3.0. When my dad and I bought our current porsche the PO had swapped in a 78 3.0 SC with SSI's and deleted all the smog equip and heater blower. The engine runs like a dream and has great power to boot, ask DD74 how it sounds, pretty mean. The 3.0's also have great potential to grow if you ever want to and are strong motors. If the car is just for spirited summer driving the reliability with the CIS will be nice. Plus it sounds like your getting a good deal on it. What year is it by the way and dont forget a leakdown test.

Guys,
Thanks again for the good advice! I am really happy with my 150hp 2.7 (non-S), the performance increase isn't a major factor, the main benefit for me is that I would get a nice, 3.0 from someone I trust to replace my 2.7L with broken/pulled head studs. I don't know about anything but my 2.7L CIS since this is my first 911, and I've never driven anyone else's car... I like the "drop and swap" option instead of the costly and time consuming rebuild...

The 2.7 is not a great engine (the mag case). I would jump on the 3.0 with the alum case. it never hurts to update and get the better stuff. Actually I was going to say that the 2.7 is a boat anchor but I did not want to hurt any purist's feelings. ;)
It was good but just wasn't a great engine. move up and get a 3.0 you will like it better.
sell the 2.7 for about 1500 (that is what I did with mine) with ssi' on it to a guy with a shop. he put it in a VW bus......with the camper top.

Or you could do what I did: go to a 3.0 enlarged to a 3.2, w/SSIs and CIS and get another 35 hp.

Paul

art,

hey i read your post and i am in exactly the same boat,... a 74, BEAUTIFUL 3x black with polished 15x7 and 15x8 215-50-15's in the back with rolled (newly rolled) rear fenders, but i know i need to get engine work done.... got quoted 5k to start a rebulid on a 2.7,.... the 3.0 is sounding good,.. i dont complete on a track or anything like that,... just take turnd hard and my girl out on weekends.... how is your research going, what did you decide to do? i just got the info on my engine recently.... so i am starting what you started... others please feel free to comment or write me diretly.... alexanderg911@msn.com

Alexander