rebuild decision made

Some of you may remember my earlier posts, where I was trying to decide whether to have my 2.7 engine rebuilt or buy a used 3.0 or 3.2. I decided to have my '74 911 rebuilt into a '74 911S by Motormeister. My motor was worse than I expected. I need 3 replacement cylinders and pistons, and it was never Time Serted. Decided to go ahead and have the 2.7S Nikasil pistons and cylinders put in, 2.7S Camshafts, and fly-cut heads for $2000. What do you all think about . . .
Porting the heads and manifolds for more power?
Stainless Steel valves?
Kevlar Clutch?
Turbo stainless muffler?
Line bore on my case and oversize bearing use?
This car is currently only for street use, but of course I want to get as much power and speed out of it as I can.
Thanks for any input.

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David Huffaker
1974 911 2.7L

I'm extremely sorry about the length of this post but the last year and a half have been building up to this there's more but I didn't have all night.

Last year I had my engine rebuilt by MM. It was not a very pleasent experience to say the least. I sent the engine to them on April 14/99. May 3 called them they finally had it apart. Found out all the timing gears were shot due to tensioner failure, top piston groves were shot, valves had been cut once and were no good and the heads and block needed surfacing due to the cylinders moving around.

From that point I was told 5-6 weeks to completion. Didn't think that was too bad so we discussed mods. It needed new valves so I put in the stainless ones and since the heads needed surfacing we decided to up the compression (9 or 9.2 I can't remember) while it was getting machined. I also decided to have the heads and runners ported and polished,replace the 8 gears with used ones,put in used pistons and 24 performance studs (brand?. I also wanted oil feed tensioners put in as well as SSI's and the stainless TURBO muffler.

Several calls over the next FEW MONTHS to find out when its going to be done it finally got done begining of August. They recommended against putting on Turbo Muffler till the engine was broken in. At about 500 miles I was going to the shop to get the valves adjusted. About 120 miles away from the shop the electrical problems began. The distributor rotor burned in half and stranded me in the middle of nowhere. Got the car flatbedded to that shop where I though the mechanic MIGHT be competent. WRONG!! I would have fixxed it myself but home was another 180 miles away. After 6 more weeks without my car I could have more than paid the extra towing bill and had the car running in probably a week or two. The car had a small dent behind the left light which of course I didn't notice till I got home. He denied everything and I was so sick of dealing with him I just let it go.

About a month later the cooler on the engine split and that was the end of the driving season. Only had about a 1000 miles on the engine at that time.

Decided before worrying about the cooler I would try on the muffler. It would not fit under the car. Not even close. Called Roy and told him about this and he said that it should fit. A few of them needed the tips bent a bit to fit propper but the muffler should fit under the car. I asked if I could exchange it but he said that they quit dealing with the supplier. He offered a refund if I couldn't get it to fit but after shipping costs (from Canada) I figured it would be worth the effort to make it work.

That was last fall. This last week I have been getting the help from the welders at work to make it fit. We have finally modified the tubing enough that I can get it to fit under the car. Lesson learned don't get this muffler if it is still from the same supplier.

After finally getting the car running this spring it started acting up again. Wouldn't rev, missing etc. I checked under the cap and found that the rotor was burnt again. Last time it wrecked the Crane HI-6 and PS-92 CDI and coil which I thought caused the problem in the first place. I figured that the wrong rotor had been put in so I ordered the proper cap and rotor from Porsche. Put them in and the car ran excellent.

A couple weeks later a grinding noise stared coming from the back. I removed the fan belt and the noise went away. Put it back on and it sounded fine. A few days later the noise was back and alot worse than before. I ended up pulling out the alternator and found the bearing dissintegrated in the housing. This was the alternator that I had asked Roy to check thoroughly because I had suspected it was loose. They OK'd it, but less than 2000 miles later it was toast!! Since it was no longer rebuildable because the housing was wrecked. Finally found a rebuilt one in Calgary but since it was a saturday I couldn't get it till tuesday. Picked it up and put it in on tuesday but somthing was wrong. After R+Iing it 5 times I figured out it had a burnt out diode trio and it was constantly drawing power when it was shut off. Of course the next closest on I couldn't get till the following week.

After that I took a 3000mile round trip to Michigan and back and the car ran perfect. The power after the mods is excellent. Recently the rotor went AGAIN. This time though it looks like it was hitting the cap. I disassembled the distributor with the help from Warren and I found that the advance plate had worn into the housing. Called Porsche and a new one almost 900 Canadian Called Pelican and they didn't have any in stock finally called MM and ordered a rebuild. Now I am awaiting it and working on the muffler and dreaming of it to be trouble free. It is definitely times like these that make the good times more enjoyable.

The engine has a small leak from underneath which I can't locate. I think its coming from near the #4 cylinder base but I can't tell for sure. It also smokes on startup even when warm. Besides the poor comunication (1-800# doesn't work from Canada) and long time to get it done and alternator and distributor problems and smoke and small leak I am very satisfied with the rebuild. I also have the kevlar clutch and aluminum pressure plate and am very satisfied with way they work as well. Really pissed off with the muffler though.

SORRY about the length of this post but this is the first time I have vented to people that know my pain.

Hope this contained some of the answers you were looking for David..

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'76 911S

'80 924 M471

All my research so far suggests that better power increases would come from a conversion to Webers and running a pre 74 'S' cam.

Of course, this is probably also VERY expensive. I know MotorMeister supplies both, for about $2,000 (carbs) and $300 per pair. This could give you towards the 210hp the 2.7RS has (if you have large enough valves???).

Of course, you will remove the originality of your car by going down this route.

I can't speak for the usefulness of any of the other mods, and will hand over to someone more experienced...

Anyone have comments or experience of carbs/cam conversion on a 2.7S CIS??

Cam

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Cameron Baudinet
1975 911S

Sorry about the spelling.

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'76 911S

'80 924 M471

David,

Everything that you mentioned sounds good to me. I would recommend that you update your chain tensioners to oil fed carerra units. I just got my car back a few months ago after a substantial rebuild and many modifications. I too have the Mahle 2.7 Nikasil cylinders/pistons and the 2.7S camshafts, fly cut heads, etc.

I have been very impressed with the power that I now have...up from 140hp to 223hp. This hp really gets a light weight 911 up to speed!

Check out my website...it is under construction, but I think that it has a bunch of cool pictures. I plan on adding some text to go along with the pics in the near future, along with a change to the layout.

Bill


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William Armentrout
1973 911T
2.7 carerra rs specs
www.geocities.com/william_armentrout

Thanks for both of your inputs. Sorry to hear about all your troubles with the MM rebuild Gary. Hope that was a fluke. Does anyone else have comments on the mods I mentioned?

Now I just can't wait to get my car back. It definitely does take a while.

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David Huffaker
1974 911 2.7L

David, I don't see any reference to the type of carburetion/injection you plan to use with this rebuilt 2.7 'S' engine??? If it is to be Webers, then I suppose an 'S' designation would be proper, MFI would seem to justify an 'RS' label. I see no point to using Stainless Steel valves, stock OEM or Titanium are the only alternatives I see. Anyone trying to sell you stainless is trying to cut corners (save $$$) to what point or end?

The 'S' cams are not the only choices in that 'category' GE-40 and GE-60 come to mind, immediately, but you may want to speak to Jerry Woods about more recent developements, as he was the principle devleoper of the GE-series cams while at Garretson Enterprises! You may also want to speak to the Web-Cam, as they have quite a variety to offer, as well!

I don't really understand what you mean by a 'Turbo' muffler ... there are OEM, 'sport' mufflers based on modified OEM, aftermarket flavors of the 'cheap' and outrageous expensive kind!

A spring-centered '116' clutch disk and pressure plate of the OEM or sport variety will work fine with your 225 hp 2.7 'S' engine.

Pressure-fed tensioners are DEFINITELY needed, and the dual-bushing chain-wheel carriers ('80.5+) ... do NOT accept the use of those carrier 'spacers' unless you are not concerned about your engines' reliability!!!

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Warren Hall
1973 911S Targa

Warren,
Thanks for your input. Here are my responses.

Webers: OK, here's to my ignorance again. I thought getting the S cams, etc. would constitute the conversion to 'S'. My car has CIS. I have been thinking that my next mod would be to switch to Webers, but that is not happenning now. So does that mean I still don't have an 'S'?

Cams: I'll look into it. I assume it will be easy to reach those sources you mentioned by finding them on the web.

Tensioners: It has the Carrera tensioners already.

Muffler: I don't know what Roy (at MM) meant by a Turbo muffler, and I hadn't decided whether to make that switch, but I will look into that too. Any suggestions? I don't want the car to get louder. Just faster, without sacrificing reliability.

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David Huffaker
1974 911 2.7L

'S' cams are being referred to in more than one way here.

On your age of car, ie post 74, the 'S' cams used are fairly mild and designed for use with the CIS system. Upgrading from 1974 911 to 1974 911S spec should get you from 150hp to 175hp (from memory) by way of increased compression. This is NOT the type of 'S' cam being referred to.

The 'S' cams on the pre 74 cars have a much more aggressive profile (with the GE cams Warren suggests being (I think) more aggressive still). They will not work with the CIS system because there is too much valve overlap. For this reason if you wish to run this cam you would need Webers or MFI. The upside is extra power - probably around (if it all works) 210hp like the 2.7RS engines. Downside = poor gas milage (who cares? - not me ).

I am definitely not knowledgable on this subject but if you find someone who is, let me know because it is an upgrade I am considering.

A good reference book on this subject (performance modifications for a 2.7) can be found in Bruce Anderson's book that everyone should own or borrow. Can't remember name, sorry. He suggests using (from memory):

- Webers
- 3.0 litre European Carrera pistons and cylinders (from the 75-77 model)
- 911 'E' cams (ie pre 74)
- slightly enlarged ports
- any other things I forgot

This has a little chart showing about 225hp at the flywheel, which sounds like fun to me!!!!!!!!

Cam


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Cameron Baudinet
1975 911S

David,

The first thing you need to do is get a copy of Bruce Anderson's 'Porsche 911 Performance Handbook,' and, at the minimum, read the chapters on engine evolution, engine rebuild fundamentals, and performance modifications!

Port enlargement of your cylinder heads is REQUIRED to take advantage of the 'S' or other high performance camshafts, and your CIS injection is not compatible with 'agressive' cams, so it must be replaced with MFI injection, or Webers!

OK, there isn't any need to change your muffler ... it is the same as the RS 2.7, already!

Glad you have the Carrera tensioners, but you need to verify that you have the 'late' double-bushing chain-sprocket idler arms.

I am sure you will have more questions after reading Bruce Anderrson's book!

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Warren Hall
1973 911S Targa