Re-Rebuild of a 2.7 - Part II of "My Story"

[kstar]

Many may have read the thread regarding my rebuild experience. I don't want to engage in deep commentary about the "rebuilder" and the "experience", but I will be posting some pictures soon.

A shuffle pinned case was on the build sheet, but when the case was opened up this week . . . no shuffle pins. Also, the bearings were excessivley worn; what you might expect on an engine that made 100k+ miles or more. My motor had about 4-5k miles. P & Cs were at .004, which is considered on the edge of "used" and making a heck of a racket. Front and back crank journals were undersized - many journals were quite "worn". Also, standard washers were used on the case through bolts when a chamferred washer is required for proper cylinder to case sealing.

So, I am having Black Forest here in San Diego do a total rebuild.

Keep in mind the 7R case is timeserted and has the 993 style head studs - the crank bore is being verified now.

1) Andial/Mahle 2.9 or 3.0 P/Cs with case spiggots opened up;
2) PMO 40mm carbs (to replace the Weber 40 ID"T" carbs provided by the original "rebuilder");
3) Web-Cam "GE-60" grind cams;
4) Twin Plug heads and another Electromotive crankfire unit (already have one) if compression dictates;
5) Raceware rod bolts;
6) Two new cam towers because the originals were belt sanded by the "rebuilder" and covered in copious amounts of some type of putty like sealant (pictures to come!);
7) All of the other details a reputable shop does to get the job right.

I will also have some pictures of the fan and fan shroud that I am polishing, as well as the upper valve covers that will be polished . . . many many many hours of sanding and many many hours at the 'wheel'. I am also refinishing the shroud as the original "rebuilder" simply sprayed some red paint over my yellow "T" shroud - dirt, grease and all.

I have spent a fair amount of time here at Pelican reviewing the archives making sure that all of the above modifications will work. I think I may have it right. Of course, there will be a controversy regarding modifying a 2.7 to a greater "volume" output, but I think 3.0 liters may possibly get me in the door of the SCWDP Christmas Party . . . maybe.

I would appreciate it if anyone has any further comments or recommendations as I procede with this re-rebuild.

Happy Holidays and (your God here) Bless All!

Warmest Wishes,

Kurt

[Wayne 962]

Hmmm, Kurt, it sounds like you may be playing the old stock market trick - throwing good money after bad. The 2.7L motor is a good motor when everything is fixed, but I'd hardly recommend increasing the bore of the magnesium case (and adding additional stress). Some would argue no problem, but the aluminum cases have proven their reliability time and again.

If you're going thru all this trouble, why not just upgrade to the 3.0L aluminum case, or take an early 2.0L aluminum case and modify it.

The bad news is that your 2.7L will always be a 2.7L, and as you have found out the hard way, just because the engine rebuild paperwork says one thing, you can't guarantee that it was actually done correctly. If you go to sell the car, you will be seriously in the hole, and you will be hard pressed to convince anyone in the know that your 2.7 is worth more than a good aluminum block 3.0L (it won't be).

My recommendation - cut your losses, and go with what will provide you power/increased resale value/reliability/and value for your $$$.

It's not that I'm knocking the 2.7L engines - I'm rebuilding one now for my new book. You just have to put them in perspective. It's not a wise investment to spend a lot of money on the 2.7L rebuild. If you can do one for relatively low dollars, then great. But if you're into the $6-$8 range, then you're better off in the long run buying a used 3.0L and rebuilding it.

Just my opinion, I'm sure there are many who will agree, and many who will disagree...

-Wayne

[Matt Holcomb]

Kurt,

If you're going to add GE-60 cams, then you won't need to increase the bore! Trust me!

I've now got more than enough torque thanks to my GE-60s, and more power than I'll never need with the standard bore.

I've just had to re-register my old Merc because my Carrera 2.7, with an estimated 270bhp, is just too damn fast now for street use -- I was on track to lose my licence!


Matt Holcomb
1974 911 Carrera 2.7 Euro
1975 Mercedes-Benz 280SE
Dedicated Homepage
Engine Rebuild Homepage
Porsche Owners Gallery Profile
Pelican Gallery Profile

[jksinuc]

Kurt,
I thought that ithe recommendation for a 3.0L displacment is 46mm PMO/Webers. I would have to look in the B. Anderson Handbook to confirm. He has a formula to determine the carb size for various displacements, but I thought that the largest displacement to run on 40mm's is 2.7L.

Good Luck. I am just starting to gather parts for my 2.7L rebuild. Please keep posting, as any additional information would be greatly appreciated.

Happy Holidays

[kstar]

Thanks for your replies!

1) Wayne: The motor will not be raced, but may see some time at local autocrosses so I am not too worried about the increased volume causing problems. While Mr. Weiner and some others say that one should avoid upping the volume of a 2.7, there is also a group that says it will work fine if done properly. I think Andial's Mahle P & Cs are probably the best way to get more volume.

Of course, my 911 is not an investment and I can never hope to get a fraction of what I have spent on it! Resale is not a concern.

Also, I think a 3.0 is a great idea but I do think I will face additional costs in that conversion above and beyond what is slated now. Also the aluminum cased motors are heavier and will take my "period" bastard 911 to a intergenerational bastard!

I must say that I like the idea of the 3.0 -> 3.2 conversion as outlined in B.A.'s book! I will do some more research on this topic and a cost analysis . . . and heck, I might even end up folllowing your advice.

From time to time I think it is good to remember that one of the greatest Porsches of all time had a 2.7!

2) Matt: If I only knew the secrets of your very powerful 2.7 I would be trying to have them replicated now. 270 hp from 2.7 would be so very nice! Perhaps you could give me a hint in a private email?

3) jksinuc: I think B.A. says to use 40mm carbs on a 3.0 - using the formula you refer to.

I'll keep you updated as I sort through this process.

Season's Greetings to you all,

Kurt
kurt@starnes.com

[Jim T]

You really shouldn't let them just get away with it, if they charged you for items and services that flat out, no way to dispute it, just simply were not there.

Thats tough to turn the other cheek on and simply ignore. I think all things considered, their quietly refunding you all the money you paid to them would be a great deal for them.

[Jim T]

s

[kstar]

Noah and Jim:

I am making plans to allow the "party" to make things right. That's all I should really say at this point.

Thanks for your messages and happy holidays!

Regards,

Kurt

[RoninLB]

I'm with Wayne on this one. A 2.7 is a 2.7, period. If you want more displacement dump the 2.7 I rebuilt my 2.7 as a 2.7 Spent plenty on it.
46 will work on a 3.0 at a low end cost, IMHO

[kstar]

Looks like my re-rebuild of my 2.7 will probably not happen.

Just spoke to Black Forest and the case crank bore is out of spec and needs an align bore. So with some undersized crank journals and oversized bearing saddles things would get "funky".

I'm going to be saving all of the "old" parts for possible actions in the future yet to be determined.

Looks like Black Forest may have a cherry 3.0 case and some twin-plug heads. I would use the Andial P/Cs and take the motor to 3.2Ls. Basically I may end up having a "proper" motor built up from good, in-spec parts. Probably go with 40mm PMOs and still run the GE-60 cams. Will also be installing a B&B oil cooler as this motor will most likely need additional cooling.

Somehow I am angry now, but yet at peace - hard to describe the feeling.

Thanks for everyone's input and I will try to document the 3.0 to 3.2 build in the days and weeks ahead. Since the motor builder is local I have good access to the project.

To anyone who is considering a rebuild, a local shop is a major plus. Also spend as much time as you possibly can researching any prospective rebuilder. It can be a difficult and costly exercise if you chose the wrong shop.

Happy Holidays!

Regards,

Kurt

[Wayne 962]

Someone politely pointed out that I appeared to be bashing the 2.7Ls. Not so, I'm rebuilding one for my book right now. They are probably one of the more popular motors to rebuild and use (especially for 914-6 conversions) because they have lots of power, and are less expensive than the 3.0Ls.

Rebuilding your 2.7L can be rewarding, both economically and power-wise. I don't terribly recommend building up the 2.7s for the following reasons:

- The mag case will always be weak, and a liability under power loads, and also when you go to sell the car
- The money spent on upgrades is a better investment when you add them to a 3.0L instead.

Unfortunately, there's a large price difference between the 1977 911s and the 1978 911SC. These two cars are nearly identical, except for the engine, which basically builds the 2.7L discount into the 1977 model.

The 2.7L engines can be made to run reliable for many, many years, and some even have straight out of the factory. However, if you are planning on spending $$$$$, I would recommend that you start with a stronger case.

That's all...

-Wayne