2.7 Rebuild.... Advice?

Fishcop · Fishcop's Garage

Hello Gents

I finally splashed out on a 1974 2.7 CIS engine (currently very ugly). I've read all of Wayne's book as well as B.A's. Assuming I have Alusil barrels and the CIS pistons (and that I keep them for the time being), what is my best bet for extracting some power?

On my list are S cams (BA recommends E cams). Can I use them with CIS pistons?. Webers, headers/sports exhaust (don't need heat here in Australia), and a dialed in distributor recurve. Will add hydraulic tensioners.

What else is a good idea?

Thanks

Doug Zielke · 11-04-2003, 07:24 PM

That's great picture, John....to illustrate why *not* to paint the fan. They all look like that sooner or later.

Fishcop · Fishcop's Garage

Have good close look and see what the ham fisted morons did to get the motor out.... GAS AXE! They cut through the tinware and front mount

Tim Walsh · Tim Walsh's Garage

fishcop,
there's not enough clearance in the CIS pistons to clear S cams. If the engine is running ok then I might be tempted to run it as it is(with the new tensioners) and when the extra $$ is in hand swap pistons and cams and switch to webers.

Fishcop · Fishcop's Garage

Thanks Tim. I have a 2.0 in the car at the moment, so I won't bother putting it in the car until it's *right*. I have the webers, and a set of S cams, but you have cleared up my question on the P&Cs. Depending on whether I have Alusil or Nikasil, I will think about getting new pistons and rings right away (or should I re-use the current rings?). Do I have anything to gain from porting the heads whilst having the valves done at the shop?

I know there has been endless debate on the reuse of Alusil/rings and changing pistons, but until I pull the heads off I won't know what I have.

Thanks

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by Fishcop
Have good close look and see what the ham fisted morons did to get the motor out.... GAS AXE! They cut through the tinware and front mount

Looks like they cut off the 14 pin connector and some of those pesky injector lines too. That's the first motor I've seen that was actually worse than the "mint" one PartWerks sent me once.
-Chris

Porsche_monkey · 11-05-2003, 05:41 AM

Insert the head studs and helicoil the studs the studs in the case (but not the perimeter studs).

I just pulled three studs when I re-assembled my case, now I have to dis-assemble, heli-coil, and re-clean.

7R - German for two steps forward, one step back.

JTO · 11-05-2003, 11:21 AM

Yes Chris but did you notice the distributor cap looks really good!

Troy

Fishcop · Fishcop's Garage

Given that I was really only chasing the long block, I'm not too concerned with the bolt-ons or injection system. Incidently I've found that the distributor is brand new... I guess that's one good score.

I've found only one pulled stud, but I do intend to time-cert the case on the rebuild.

jgparker · jgparker's Garage

Fishcop,

Like everyone said, forget either the E or S cams with CIS pistons. It will never work. Totally inadequate valve to piston clearance. Hopefully you have Nikasil cylinders, but don't count on it.

If the 2.7 engine was running when it was removed, you might want to try the webers on the long block as it is for a little while. It's a fun combination and will be an improvement over the CIS. It will have a ton more torque than your 2.0, but will not quite come alive over 4K RPM, like the S-cam engine will. Cracking the long block is a big commitment. You can always go back and do the full rebuild when the CIS core is used up. That's what I did, and I'm glad I did.

Is your 2.7 from a 74-77 911S? If not, you will definitely want to port the heads, since the regular 74-77 911 heads have very small ports.

Thanks,

Fishcop · Fishcop's Garage

Thanks for the advice JP. The engine did not come from a running car (arrived in a crate ex-Japan). But the crank and pistons turn over fine. Preliminary compression figures indicate it's sound. The main problem is that it was obviously subject to weather whilst stored, and when I shine a torch into the valve area a couple of the exhaust and intale valves appear to have light corrosion. So I think I'll have to have the top end done no matter what. Given that I don't know if the case leaks or not, I thought it might be best to just "start from scratch" as my car is running well on the 2.0

The engine is from a 1974 Japan delivery, so I'm guessing I have the small ports.

Porsche_monkey · 11-06-2003, 04:23 AM

Quote:

Originally posted by Fishcop
Given that I don't know if the case leaks or not,

Oh, I'm pretty sure it will ....

JTO · 11-06-2003, 07:25 AM

Based on the color of the shroud, I don't think its an "S" engine. The "S" had a green shroud.

My $0.02.

Troy

Plavan · Plavan's Garage

I always thought "S" motors had red shrouds.... All the S motors I have seen are red.... maybe just the pre 2.7 liter shrouds are red????

Fishcop · Fishcop's Garage

I'm pretty sure that from 74 onwards, the colour of the shroud didn't tell you anything... I've measured my ports and I have the smallest made 30/33. Definitely need a head job.....

jgparker · jgparker's Garage

I think the "S is red, E is green" rule is only true up to '73. My '76 911S had a black shroud. What is the engine type number? 911/92 or 93? Might be hard to see with the AC comprssor still on. I thought all of the ROW 2.7 engines had the larger 35mm ports. Guess not.

Fishcop · Fishcop's Garage

I found an actual reference to my engine in Wayne's book (spec. sheets at the back). I think the quote is "sometimes found with 30/33 ports"... Well I found them! I think I've found an engine with the most-least desirable parts

With Alusil cylinders, 30/33 ports, 8.0:1 compression ratio, and CIS injection this motor is screaming to be masculated!

JTO · 11-07-2003, 01:41 PM

Well, all I can say then is my 75 is an "S" and it has a green shroud.

Troy

RoninLB · 11-07-2003, 09:59 PM

Quote:

Originally posted by JTO
Well, all I can say then is my 75 is an "S" and it has a green shroud.

Troy

my '77 911s Calif smogged had a green shroud......Ron

Wayne 962 · Wayne 962's Garage

Quote:

Originally posted by Fishcop
I found an actual reference to my engine in Wayne's book (spec. sheets at the back). I think the quote is "sometimes found with 30/33 ports"... Well I found them! I think I've found an engine with the most-least desirable parts With Alusil cylinders, 30/33 ports, 8.0:1 compression ratio, and CIS injection this motor is screaming to be masculated!

Definitely can use some work here. I would suggest:

- Replate and use 2.7 JEs
- S Cams
- Valve job (maybe slight enlargement of ports)
- Webers

-Wayne