2.7 needs a rebuild...should I?

[carnitasboy]

I bought a '75 911S not too long ago. I know, I know...it was just so cheap I could not pass it up. It runs OK and it is still a blast to drive. But now there is a major oil leak and there is some valve noise that does not sound good. I need to pull it out to rebuild it. The question is if I should? So I was looking over the forums and there are alot of guys putting 3.0 or 3.2s in their 74-77 911s rather than rebuilding their 2.7s. I know the main reasons why, but I am wondering if I should follow suit, or try to rebuild my 2.7. I have heard that rebuilding the 2.7s can cost up to $25K. I am not looking to spend that much. I have also seen 3.0 engines selling for $2-5K. So I am torn. Do I put my money into rebuilding my current engine, or go with a 3.0 or 3.2? Either way, I know I am going to have to spend alot of time and cash. I just want to make a good decision.

I dont know if my current 2.7 has been rebuilt with case inserts or not. I do know that it is not the original engine to the car. So I think it has been, but that is just a guess.

Thanks for your input.

[Flat6pac]

The biggest problem is in the value. Do you spend 5 to 6 K on a 2.7when the residual value is about $800 to 1K or buy a 3.0 with a residual value of $2500 and spend $ to bring it up to value of $5000/6000
Everyone will boohoo the value of the 2.7 regardless as to how its built.
Bruce

[afterburn 549]

I think you need to actually ID the oil leak and pop the covers for a valve Adj. and see if you need a rebuild or not.
Based on the short paragraph, you have no evidence to condemn it yet

[carnitasboy]

Originally Posted by afterburn 549

I think you need to actually ID the oil leak and pop the covers for a valve Adj. and see if you need a rebuild or not.
Based on the short paragraph, you have no evidence to condemn it yet

Well the reasoning is, I do have an oil leak from at or near the oil cooler. I know that I could fix that without rebuilding the engine, I think.... The other and probably the main reason is the uncertainty of the engine in its current state. It runs, but like I had said before, it has some strange noises. It sounds like the valves. And it being a 2.7, that is not really a surprise. Also I should say that I enjoy working on cars in general so I see it as something that I would like to do.

So that being said, I guess I would be interested if there was a 75 for sale with a rebuilt 2.7 or the exact same car with a 3.0 or 3.2, which one would you most likely buy. Assuming you had to choose between the two... Basically, which one is more desirable.

[afterburn 549]

Hmm....Well if you are set on a course to rebuild need it or not...
The only two things that pop in my mind...If you buy a used what ever it is "used" be it a 3.2 or a what ever.
Once you spend the $$$ on used, now you are condemned to do what it takes to make it work...
So to me Even a 2.7 done proper is better then a used what ever (unless you had a lot of info on it )
Back to my original thought I would do some diagnoses and see what noise is ,what kinda noise .
You said Valve train.....That particular year can have some sloppy guides in it...I would pop the covers and do some looking B4 you just start tearing it apart.
When that happens you have a whole lot of decisions to make...they all cost $$
Are you certain it has never been apart ?

[Ray_G]

I recently had to do the same thing, only my 2.7 had bad guides, and a plugged squirter for the cam and I lost a lobe. I think it comes down to what you want. To me if the car is unmolested I would rebuild the 2.7. Someday the mid year cars that have not been modded might actually be worth something. If it has been modded already I think the 3.0 is the way to go. I was hell bent on getting my 2.7 rebuilt and reliable. I did all the labor myself (except machine shop work). I bought as many good used parts as I could. In other words I bought a set of in spec Mahle cylinders (Nikasil ones) instead of dropping major money on new. Even at that I still spent 5500.00 or so on it. They are expensive, and the list of parts that are needed go on and on. If you do decide to rebuild your 2.7 things you would want to do include case savers, oil fed tensioners, upgraded idlers for the chains, most likely you want to go with Nikasil cylinders. Your car might already have some of those things, mine had nothing except a case that did not need to be line bored. I had Ollie's do my machine work, I highly recommend them. Also get a copy of Wayne's book on how to rebuild engines. As for the cylinders be very careful about buying used ones or identifing yours. Contrary to what seems to be what everyone on the forum says Mahle made Nikasil, and Alusil cylinders. Most everyone thinks that if they are marked Mahle they are Nikasil - that is just plain wrong. Big debate on the Alusils for re-ringing, but if you buy used cylinders make sure the person that is selling them acutally knows what the heck a Nikasil cylinder is. I think I bought 3 sets of cylinders before I got ones that were actually Nikasil.
Good luck.

[jpnovak]

I would personally check the location of the oil leaks and do a valve adjustment to see if this fixes your problem.

there are a few common oil leaks that may seem bad but are easy to fix. The usually require just $25 in gaskets. If the oil cooler seals are leaking this is easy to fix in about an hours time. Don't spend the money if you don't have to.

Now if the motor NEEDS a rebuild the change is up to you. I would do a 3.2 over a 3.0. I like the snappiness of the 2.7 over the 3.0. They seem to rev quicker and feel faster to me. Of course, that is just a seat of the pants description. I agree that I would rebuild the current motor rather than chase someone else's problems. Remember, a used motor will be priced according to condition. The cheaper, the more work needed.

[Targa-ga]

I have a 76 911S Targa with the 2.7 switched over to an '81 3.0 SC engine. I had to place computer control stuff in order to run correctly. Like the 3.0 just fine and good runnner engines. 3.0 is as big as I need for just casual driving around and day trips to the beach.

Your post on 2.7 caught my eye because I had a 2.4 mag case sitting around and decided to build it as a 2.7. So, I bought an old 2.7 engine parts I needed out of a '77 911S and started the process. I had the 2.4 mag 3R case bored out to 2.7 CIS Mahle jugs, AND had the old healy coils removed and the new Coarse Thread inserts pl. I had the 6 Cylinder heads rebuilt complete with new top quality guides and springs, and valves check and or ground as needed. I had Ollie's Automotive Machining in Santa Ana, CA do all the machining of case and heads. I also have the 2.7 camshafts. I rebuilt the crankshaft std with new bearings and crank micro polished and new German made Vermus rod bolts and nuts. I also, splurged fo the New in the box Mahle Pistons and barrels....factory rings installed, comes with wrist pins and circlips.... never out of box except to take a photo.

I know there are people out there that like to bad mouth the 2.7 engine, but rebuilt correctly they can be solid for a long long time. The secrets are, coarse thread stud inserts, oil by pass machining, cross drill your crankshaft, DO NOT reinstall the thermal reactors, place an external oil cooling system, place 930 Exhaust valve covers that have the straight webbing, and a pop off valve so you don't blow out your air box on backfire.

Good luck on what you decide and if you need any of my premachined parts let me know right away. Just put them out FS a few days ago.

Regards, Targa-ga Joe

[afterburn 549]

I agree done "right " with all the mods they are fine . Thats exactly what I did..dont forget the shuffle pin mod

[T77911S]

upgrade to rs 2.8 pistons, E cams, SSI and carbs and you have a nice motor. it will take $3k just to get a 3.0 core.

[tadel001]

I am at the same point as you. I pulled my 2.7 and am working on the rebuild. I decided to stick with the 2.7. Buying a used 3.0 or 3.2 doesn't really get you ahead of the game since you have no real idea on its condition. If you spend the money on the 2.7 rebuild, you can have a powerful engine. In talking with some professionals, they said that the porsche engines are capable of producing 100hp per liter. You can get lots of power out of a 2.7. The 3.0 is nice but the power doesn't seem that much more.

[afterburn 549]

As you guys know, it is the HEAT that kills them, once that is addressed with proper fan, exhaust ECT. you will be fine
I might add, take special care of the end main bearing as they like to leak. I did everything known to man and still ended up with a small drip.
I did not know about the Oversize "O" ring at the time...maybe that would have been the thing to do..........

[effvee]

Hello, not sure if I'm highjacking this thread, is so sorry. I bought some 2.7 heads and I plan to have new and larger valves installed. I contacted the seller and bought his case also. I don't want to buy his used piston and cylinders. How large can a 2.7 be made? Is 90mm pistons the largest one can build a 2.7? Does anyone ever stroke a 911 and relocate the wrist pin height? So if someone can answer the questions of how large can I go with pistons and cyclinders will help. O and a response to stroking the crank.

[afterburn 549]

Ask Henry....IMO they are great..at near stock levels......The more demands you put on them the lifeline shortens relativity
There are those who even Turbo them.! I will not say it should not be done.....I am considering it...Just know it will not last as the mag case is far to flexible.
Larger vales ??? what else are you doing as lager valves will be a pit fall by them selves

[effvee]

Hi, well I'm a VW guy masker-raiding to get the possibilities of a 6 Porsche. I note where members has stated leaving alone the valves and address the intake and exhaust port/runners. So this may be were I will leave the valve option as not doable.

Bore and stroke? Since it is a Porsche I get the feeling that everyone rely upon rpm. Being that the case is Mag, I will Shuffle Pin it. However when I see the way the Porsche cases are made (strong) as opposed to a VW case, I know this case will hold up just fine with less rpm.

Pricing may just run me away, but before I run I'd like to know how large can a person safely go in bore and stroke. I contacted Del West, they said they did not have valves for a Porsche. I have a friend looking into one seller for beryllium seats, I really hope that he don't let me down.

http://www.delwestusa.com/manufactured/steel_valves.asp

I don't need any company that sells/make parts to necessarily have them for Porsche. Because of choice of different stem size/length and guides, I want to know what's out there. Possibly at the end of the day, I may have to choose a valve job, do a little porting and be happy. I want to know mainly bore and stroke first and foremost. I don't want to rev into the 7000's to get the engine to run. I'll see where this road leads

[Eagledriver]

I don't think the value of a 75-77 car will be hurt by installing a bigger engine (unless it's a special model like a Carrera). The extra cost of building a 2.7 will cover the core cost of a 3.0 or 3.2. Bigger engines make more power!

Don't use the oversize O-ring on a 2.7 number 8 bearing! It will pinch in the case and leave you with bigger problems (first hand experience).

-Andy

[afterburn 549]

Someone once stated that the 2.7 is and was the holy Grail for the RSR
The stroke=nothing wrong, leave it alone
the valves if you the later heads (S Heads ?)Nothing wrong there save your $$
People have spent Godzilla's of cash on them . Port and this and that and in the end was not worth the effort.
If you want a nice "drivable" 2.7 read what Noah did under tech notes on the home page
With CIS the usual mods high comp he got 225 Hp If I remember right..That's with reg Ole CIS
So if you did that, took weight out of the car you will SO happy .
You willl be 1000s ahead in all ways

[effvee]

Originally Posted by afterburn 549

Someone once stated that the 2.7 is and was the holy Grail for the RSR
The stroke=nothing wrong, leave it alone
the valves if you the later heads (S Heads ?)Nothing wrong there save your $$
People have spent Godzilla's of cash on them . Port and this and that and in the end was not worth the effort.
If you want a nice "drivable" 2.7 read what Noah did under tech notes on the home page
With CIS the usual mods high comp he got 225 Hp If I remember right..That's with reg Ole CIS
So if you did that, took weight out of the car you will SO happy .
You willl be 1000s ahead in all ways

Hi, I read Noah's notes. Is there a way to contact Noah?

You mention updated 2.7 heads, what number/marking should I look for?

[afterburn 549]

I think Noah Is a moderator here some where.
I think it is all laid out there for ya anyway, doing it that way will give you everything you ever wanted plus reliability
2- The heads can have valves of small size or larger size...do not know for sure how to tell unless you go to "parts and see what is offered, then the option will be in front of you.
You want the larger valve and porting
all else fails ask Henry Schmidt. He is here on the rebuild forum (Super Tech)

[effvee]

Originally Posted by afterburn 549

I think Noah Is a moderator here some where.
I think it is all laid out there for ya anyway, doing it that way will give you everything you ever wanted plus reliability
2- The heads can have valves of small size or larger size...do not know for sure how to tell unless you go to "parts and see what is offered, then the option will be in front of you.
You want the larger valve and porting
all else fails ask Henry Schmidt. He is here on the rebuild forum (Super Tech)

Thanks again