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

alexander911,

It sounds like we're in the same position. I've just begun this whole adventure, but I'm leaning towards buying the 3.0L engine from the guy I know. I'd rather do a "drop and swap" than an entire rebuild. My 2.7L runs great, so I think I can sell it "as is" or part it out, not sure yet... Good luck!

IMHO: Pull the valve covers, and if you verify that there are problems, get the 3.0. otherwise, drive the 2.7 until there are problems (if ever).

art,....

well sounds like your in good shape if yours is running perfectly.... mine isnt at the moment, sluggish a bit. i am not a mechanic AND i just relocated to southern cali so i am in uncorfortable waters at the moment..... my mechanic is 500 miles away in san francisco.

i am also dripping oil alot.... although i saw a great bumper sticker at a recent swap meet, "old porsches dont leak oil, they just mark their spots"

so it was nice to read someone else same year having the same rebuild/swap issues.... but i got quoted 5k to start and up to 7k,.... yikes.....

Alexander

One more datapoint: Rebuilding the 2.7 correctly (with the machinework to the case) is more expensive than rebuilding the 3.0. If you buy a used engine, make sure you get compression and leak down numbers and get to at least hear the engine if not drive a car with it in it. If it has good compression and performs well, it will serve you for quite a while. These engines generally wear out very gradually.

George

george,

what are leakdown 3's? (sorry for the bonehead question as i am not a mechanic!)

Hi Art, I think it is sound advise to go with the 3.0 litre engine. I would check the head stud first to make sure that is your problem. You might only have an exhaust gasket or exhaust manifold leak.

alexander911:

Time to buy Wayne's engine rebuild book. :D

Leak down is a static compression test. You stick a hose into the spark plug hole when the piston is at top dead center and both valves are closed. You put pressure in there and then see how much / quickly it leaks out.

The leak down is a bit different from a dynamic compression test where you also stick a hose into the spark plug hole but then just see how many PSI the engine will produce by cranking it over.

Hope this helps. If not, do a search! ;)

George

George,

Thanks for explaining what a "leak down" test is, I'll get one of those done on the 3.0L as well as listen to it run on the stand before buying it. I'll post the test results when I get them. Thanks again for the good advice!

By all means, go with the 3.0

Bobby,
I like your quote from "Stripes", that always makes me laugh! They don't call me "Psycho" for nothing!!

I replaced the 150 hp 2.7 in my '74 with a 3.0 and am quite pleased. for just a few more thousand than it would cost to rebuild my 2.7...I got a great 3.0..totally rebuilt and installed in Costa Mesa, CA (one day down time) and with a 2 year, unlimited mileage warranty. The additional performance is great and the car starts and runs like a Toyota. If you do have a 3.0 rebuilt, make sure you know exactly what you want going in. I wanted hotter cams, etc and saved a lot of money building the engine I wanted the first time.

im in costa mesa also, and have a 74 2.7, looking to eventually make that move,.....

how much did it cost you?

where did you go?

I bought mine from Henry at Supertec. He posts a lot on the engine rebuild thread. he really knows his stuff and he has a couple of great wrenches. He will make that 3.0 look like it was installed in your '74 at the factory. You can see the finished product (my car) at:
http://www.pelicanparts.com/gallery/fintstone/
He will pretty much build to suit your needs. He found the 3.0 core and had it rebuilt and ready to install when I arrived. Since I had him add a lot of performance parts, my price would probably not be a good indicator and you should call him or drop by. When he gives you an estimate...that is the price...none of the price creep that some shops do. Be warned...he will not halfway do it. He uses a lot of new parts and is not super cheap...but certainly reasonable considering the quality. I imagine that is why he stands by his work and offers such a good warranty. There are some prices and examples of his work on his website:
http://www.supertecperformance.com/

I am not an engine swap freak, unless you are talking 3.3 turbo. But I don't like 2.7s either. Go and get a 3.0. Put it in drive and the piss out of it. Pound it. It can take it. As for 3.2, I own one too. Motronic never felt to me like god's second coming. Feels no better than my 3.0. The day I feel a big difference in either of my cars, then I'll change my mind either way. You will be happy with the 3.0.

Sell that 2.7 while it's still worth some money!

Before you sell your 2.7, keep in mind that some engine builders will want/take the 2.7 as a trade. You certainly will not get top dollar that way, but there are definite advantages to driving the car to the shop one day with the 2.7 and driving away with the 3.0 installed the next. Especially if you want to have them swap over your exhaust, etc. Also, you can probably get the installation done for approximately the cost of shipping your engine to them and theirs to you. That means you will have an expert checking out the clutch, cooling system, etc and doing the final adjustments/tweaking.."while they are in there."

Art--it sounds like you have an answer in your head, so do it. A well rebuild 3.0L form someone you trust. Then go for it! It's a no-brainer in my mind, as you're not looking for the max performance, a 3.2L doesn't need to be considered.

You can then part-out your 2.7L for some extra money, or take your time, and work on re-building it to somethings with more power when you decide you need it.

Go with the 3.0L...it sounds like you're really comfortable with the seller, and the idea of the swap.

I took a look last Friday and sure enough, the barrel nut for cyl #3 was rolling around loose. I put it back on the head stud and torqued it to spec and it held and so did the others on that side. I didn't check the other side yet. I know it's inevitable that the stud will continue to pull and the barrel nut will loosen again... I'm hoping to postpone this until the fall as we are beginning our home improvement project now. Unfortunately, I need to wait until the fall (October-November) to get the "drop and swap" done. I checked the receipt for the rebuild the PO had done on my engine and in 1994 the bottom end rebuild was done with valves, rings, etc... But the cylinder head studs were not replaced, so I must still have the original studs on the block! They held for 30 years, which isn't too bad, but my '74 doesn't have thermal reactors and it does have the front-mounted, Carrera-style oil cooler, so that must have helped!

What are you talking about? Your engine is falling apart! Is your roof leaking? You have to get your priorities straight. The 911 first, then the house! It's all in the presentation to the better half. "Honey, if I don't fix the 911 now, it will blow up and that would be very unsafe". :D

What a bummer, that someone would do a top end and not redo the case.

George

i have met a bunch of guys who feel a rebuilt 2.7 is like a badge of honor. personally, i would go for the three liter. as i understand it. a 3.0 from a 78 or 79 is the easiest swap.

i ended up, going with the 3.0 too. but i had to buy the entire car around it. :)