Swapping out a 2.7 for 3.0

[KR8]

I'm swapping out my 76 911s 2.7 engine for an 83 911sc 3.0, is there a step by step instruction posting or manual?

[Ricks911s]

Stay tuned KR8 -- great minds must think alike b/c we posted the same question at the same time. I encourage you to comment on the thread I just started so we can centralize the conversion process.

We are both going to have to deal with the lambda/computer system.

Thanks

[avt007]

Hi guys,

I'm doing the same thing- see here; 76 widebody project
I've asked many of the same questions, but really haven't had much response so far.
At this point I too am looking at the fuel pump/line business. I have the SC pump, but I think the lines may need changing. I have gone over all the wiring on the engine, and figured out which wire does what. Next step is to go over the car side of things and see how they match up.

[Gunter]

I'd suggest you'll get the Bentley SC Repair Manual which has the detailed description of all components necessary to run a Lambda 3.0 liter.
It also shows the electrical diagrams so you can wire it correctly.

The distributor on a 3.0 runs ccw, not cw like the Bentley says.

Trigger signal for the Tach has to be dealt with since you're changing the set-up from points to impulse and a 6-pin CDI module instead of a 3-pin.

Clutch? Can a 3.0 mate with the 915 from a '76/'77 ??
Can the input shaft handle an SC-clutch?

[Ricks911s]

Thanks for chiming in Gunter.

Here's what I've derived from the Workshop Manual. The 76 915 trans clutch will mate to a 81 flywheel, but the 76 flywheel will not work. As I understand it, the reason for this is because in 78 they changed the flywheel and then again in 80. The flywheel change in 78 required 9 socket head screws and an updated bushing. In 80 they retained the 9 socked head screws but updated the bushing again. The bushing with needle bearing on the 80-83 flywheel attaches to the transmission housing on the 915 whereas on the 78 bushing is between the flywheel and the driveshaft.

The upshot? The flywheel needs to be retained and fits but the flywheel from the mating engine needs to be retained in order for the setup to work.

This further negates your second question "Can the input shaft handle an SC-clutch?" because the shaft handle is dealing with the 915 trans clutch . . . not the SC engine.

This is based on research and not on experience. So if I'm wrong, someone please chime in. Next weekend when I mate the 81 engine to the 76 915 trans, I hope to prove this true.

[Gunter]

Originally Posted by Ricks911s

Thanks for chiming in Gunter.

The bushing with needle bearing on the 80-83 flywheel attaches to the transmission housing on the 915 whereas on the 78 bushing is between the flywheel and the driveshaft.

Please, clarify: No pilot bearing attaches to any transmission housing; it's always the crank or flywheel. Pilot bearing is very important; a good fit is needed to prevent all kinds of symptoms. By "Driveshaft"? You mean crankshaft? Or 915 input shaft?

The pilot bearing (Needle bearing) on my '80 is lightly pressed into the flywheel and attached with 3 smal bolts to the crank

The upshot? The flywheel needs to be retained and fits but the flywheel from the mating engine needs to be retained in order for the setup to work.

???

This further negates your second question "Can the input shaft handle an SC-clutch?" because the shaft handle is dealing with the 915 trans clutch . . . not the SC engine.

Criteria would be that the splines on the '76 transmission take the disc from an SC-clutch and that the lead-diameter from the 915 input shaft fits into the pilot bearing of the '80-'83 flywheel

Next weekend when I mate the 81 engine to the 76 915 trans, I hope to prove this true.

Let us know what you find.

[T77911S]

im still a little confused on this. when putting a 3.0 in a 2.7 car, you use the flywheel from the 3.0, correct?
i looked up clutches, if i understand, the 2.7 and 3.0 P-plate and disk are the same, but the through out bearings are different? so i can take the P plate and disk from my 2.7 and put in on the 3.0.

[Ricks911s]

Short answer is yes (I think).

The flywheels are different. Our midyear (74-44) cars have 6 socket heads that secure the flywheel. On 3.0s there are 9 socket heads.

The clutch/pressure plate where changed in 1972 (look to Wayne's 101 project book, it further elaborates) to the 225mm diameter which was used until the G50 was introduced (1984).

My understanding from the workshop manual is that the flywheels changed to the 9 sockets, which is why you have to keep it. The throughout bearing shouldn't matter, I believe, since the clutch is the same.

Maybe other can explain this better. . .

[avt007]

Here's a copy of another post I did. I'll post some T6 information and others as well, including pics, in the next couple days.
DISCLAIMER; this is my engine, yours may be different.
My 80 SC engine has the following wires;
T14: The big 14 pin plug at the left rear corner of the engine.
Looking at the back of the plug, with the wires coming out the bottom, the numbering of the pins is from the top left (#1), then top right (#2), working down to the bottom right hand pin (#14). Here are the pin numbers, colours, and purpose of the wire, for my ‘80Sc 3.0:
Pin # Colour Purpose
1. yellow starter solenoid
2. no wire connected
3. grn/blk oil temperature sensor
4. grn/red oil pressure sensor (for oil pressure indicator)
5. grn/yel Backup light switch
6. grey Backup light switch
7. no wire connected.
8. no wire connected
9. grn/wht oil pressure switch (for idiot light)
10. red/wht power for WUR, temperature valve, supplementary air valve
11. blu (x2) from” D+” terminals on regulator and generator
12. blk/vio from ignition box, to tach (tach signal)
13. yel/blk heater fan motor power
14. red generator output.

__________________
Rob
76 widebody project
86 Carrera Coupe
99 Boxster-written off

[Ricks911s]

This is fantastic Rob. I will check this against my engine this weekend and then we will have two examples of whether this model works.