2.7L to 3.0L Engine Conversion / Swap
 

After quite a bit of thought (and searching), I've purchased an 81 3.0L engine to mate to my 1976 915 transmission. I've searched and searched and tried to gather as much info as possible for the conversion. However, even so, I still have many questions/concerns.

Felixcontour posted a week or so ago . . . and received some good responses. But since there are no definitive threads on this conversion, I thought I'd start one and document with pics and all.

With the engine comes the SC Tachometer, Flywheel, Computer/Lambda, Ignition, Harness. All updates have been done and compression and leak-down look great.

Here are my questions - I pick up the engine next weekend and trying to get all necessary parts beforehand:

(1) I'm unsure whether to buy the appropriate 81 3.0L fuel pump or to retain/use my 2.7L pump. Folks seem to go either way.
(2) Fuel line adaptation -- After looking at the fuel lines from my model car and with the engine I'm going to put in, does anyone know (a) what specific lines I need to purchase, and (b) if there are any other fittings I need to purchase to make this work?
(3) Oil line adaptation -- My understanding is that I may have to adapt the oil lines. I do not have a front-center or passenger wheel well mounted oil cooler. Do I need to do this right away? Are there any other lines/adaptations I need?
(4) Adapting lambda/computer is a daunting task. Any suggestions or help is greatly appreciated.
(5) My understanding is that the clutch from my 76 915 will mate to the 81 flywheel . . . am I correct?
(6) Anything I missed?

Thanks in advance gents. I really appreciate all the help I've received here thus far. Here's a picture of the subject in question and captures how scared of engine fires (yes, past experience) I was after we fired her up after a 6+ year sleep.

http://lh3.ggpht.com/_n5urvaFtLDg/SY...0/DSC00513.JPG

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Update on Conversion Questions
 

Update:
Okay guys, I've arranged for a pickup truck and for a hoist so I can put the engine in. I've also made some great headway with the help of a few other Pelicans (Felixcontour, avt007, KR8) in creating a parts list and answering the questions I had earlier. My big concern is getting all of the parts I need, and understanding how to mesh the electronics from the 3.0 with my '76 chassis. Here is a list of parts that I think I will need:

Parts List:
(1) SC Fuel Pump
(2) Fuel line adaptation from Fuel Pump to Accumulator (changes from 2 port - '76 to 3 port - '81)
(3) clutch (will reuse my '76 Sachs, but need new hardware - see below)

(4) Resurface '81 flywheel
(5) new flywheel bolts
(6) new clutch pilot bearing
(7) new crankshaft seal behind flywheel
(8) tools for the clutch/flywheel: flywheel lock, clutch alignment tool, flywheel bolt tool, breaker bar

Do I need any other parts?

With respect to my questions above:
1- I think I'll opt for the SC fuel pump

2- I need to change the lines to/from the fuel accumulator. Someone mentioned that I can just plug the 3rd port. Is this correct? Or can I adapt another line?

3-I want to try and reuse the clutch pack and pressure plate. What parts should I inspect or replace?

4- Thanks to Rob (avt007), I believe I have a template for understanding what the terminals in the big 14-pin connector coming out of the back of the SC motor will be. I do need to figure out how to adapt this to work with the '76 chassis. He listed the plug pin locations as follows for his '80 SC (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.

http://forums.pelicanparts.com/uploa...1233012636.jpg



How can I find out what the pins on my corresponding chassis harness connection mean? And how can I adapt this to work?


5- Discussed under 3-8 above.

I could really use some help on this one. Thanks in advance guys.

Rick - did you ever figure out how to convert from your 3-pin CDI to the 6-pin CDI? I don't understand the wiring diagrams enough to figure it out.

I don't know if maybe someone else can explain how to do it, in really simple terms.

(Yes, I understand that MSD is better, but I'm on a budget!)

you have to use the 6 pin with the 3.0 dizzy. you may want to just go with the MSD.

If memory serves me right... you will have to change the purple tach wire. The 76 body doesn't have the purple wire to the 14 pin connector. Rest of colors/wires match up. Get a wiring diagram for both cars.

I used the existing fuel pump. Still need to add a relay so pump doesn't run all the time.

Using 6 pin box.

Same car...76 body, 81 3.0.

Jim

I thought at in 76 the fuel pump relay was added as an extra safety measure (so that if the engine stopped and the key was in the "on position" so that it wouldn't continue to feed fuel to the engine).

This thread seems to confirm:
http://forums.pelicanparts.com/showthread.php?t=105831&highlight=adding+fuel+pump +relay

Help?

Rick,

You are correct on the "safety measure" of the pump not running without the engine.

My car was more of a basket case and was most likely missing the relay. What I meant to say was "my" car still needs the relay. Sorry for the confusion.

Jim

lamda
 

rick, adapating the lamda system is very easy. the ecm and harness is all self contained package. you just have to drill a 24mm hole in the rear lower seat area for the harness to go through, and run the two power wires to the front fuse box. i highly recomened using it. it make for a much more smoother and powerful car, plus, make for a lot of afr adjustment while in open loop (richen it up) and still get excellent fuel milage while idling and part throttle.

plug
 

and jim is correct. the only wire different in the plug is the tach. (its not there)

The comments on the plugs matching up confirms my research using wiring diagrams. If you're concerned, open up the car side connector and compare wire colours.

this has been really helpful! thanks for the replies guys, and thanks rick for starting the post.

Update 2
 

Some progress to report. I collected the 3.0L engine from San Jose and brought it back to Sacramento. It looked great and everything went smooth (thanks to a hoist when both loading and unloading and a nice porsche hoist adapter and a good friend).

http://forums.pelicanparts.com/uploa...1233605207.jpg

A couple of points in my favor with the engine I bought.

We pulled off the clutch, pressure plate, and flywheel. The clutch plate measured a 8mm thickness. I know there are many who say that you should replace the clutch "while you're in there". But from my research an 8mm thickness indicates the clutch is close to new and therefore does not need replacement.

The flywheel looks good (no scoring or scratching) and therefore does not need to be resurfaced or replaced.

The seller included with the engine everything I need for an extremely simple conversion. (a) computer, (b) wiring harness, (c) ignition box - replacing the Permatune box, (d) SC tachometer, and (e) accumulator.

The engine drips a bit of oil. Before installing into my 1976, I think it'd be wise to address some of these issues. From this picture you see that I suspect the oil breather hose/gasket. The dirt and guck collecting in this area is why I suspect this.

http://forums.pelicanparts.com/uploa...1233605237.jpg

Also the hose in the back of the air boot for the CIS shows cracking and should probably be replaced.

Plan:

At this point I think I've come up with a pretty good plan to address all the issues and install the engine. I'm hoping this whole process takes a month or two at most.

Purchase these parts:
- Lithium Grease (for all electrical connections)
- 12-guage? wire for tachometer
- Throw out bearing ($140.50)
- Pilot bearing ($26.00)
- 9 flywheel bolts ($4 X 9 = $36)?
- Flywheel seal ($15.25)
- Clutch alignment tool ($9)
- Oil Breather Hose
- Oil Breather Gasket
- Breather Cover Gasket ($2.25)
- Oil


(1) ELECTRONICS: I need to install the computer brain under the passenger seat. To do this -- and connect the wiring between the brain and the engine -- I will drill a 25mm hole from the engine bay to the cabin and run the necessary wires to go to the computer brain and the extra line that will run to the updated SC tachometer.

The only thing I'm not certain about this one is how best to wire the power source for both the computer & to the engine bay.

(2) CLUTCH/FLYWHEEL: Re-install clutch. Since the clutch disc looks like it has minimal wear and the flywheel shows no signs of needing to be resurfaced, I'm going to replace all the parts that are advised, save the clutch disc. From what I've researched, I'm still uncertain as to whether or not to reuse the flywheel bolts. I know on the 6-bolt pre-78 flywheels (1972-1976, I believe) the flywheels are only to be used once. But I've heard you should replace the flywheel bolts on 78-83 cars -- but I've also heard that you can reuse. Because of the uncertainty I will error on the side of caution and replace these.

(3) OIL/FUEL: Everything appears to mate up beautifully . . . especially with the accumulator the prior engine owner provided.

Rick,

would you mind putting up a picture of the flywheel?
I am looking at a slightly used flywheel right now, and would like to have some comparison.

Thanks.
Christian - your prior engine owner ;-)

Sure thing Christian. I'll take a picture tonight when I get home this evening.

Thanks again for the engine. It looks great.

wiring
 

rick, on the wiring, the two that go to the front can be connected to the fuse box on a source thats hot with key in "run" position only not the accessory position or your frequency valve will be buzzing while listning to the radio. and the rear one can go to your rear fuse panal, its to power up the porsche diognostic tool

Rick, Have a look at your clutch throwout arm (fork), they have a tendency to crack.

3.0 Flywheel Pictures
 

Here you go Christian. Tell me if you need a different angle shot. Tried to include part numbers on the flywheel.

Flywheel shot
http://forums.pelicanparts.com/uploa...1233638901.jpg

9 bolt (not 6 bolt like on pre-78 flywheels)
http://forums.pelicanparts.com/uploa...1233638989.jpg

Shots of part numbers on 81 flywheel:
http://forums.pelicanparts.com/uploa...1233639062.jpg

http://forums.pelicanparts.com/uploa...1233639119.jpg

Hope these help.

As just a quick update, I took off the steering wheel tonight to figure out how to connect up the SC tachometer.

The electrical female electrical/bulb fittings are the same on both tachs. Here's how I've numbered it:
http://forums.pelicanparts.com/uploa...1233639370.jpg
These are the bulbs, etc. for 1-5 that goes on the top row.
http://forums.pelicanparts.com/uploa...1233639660.jpg
These are the bottom spade connections. I believe the purple stripped wire (the one on the top) that goes into "1a" is what is connection I need change/adapt for the SC.
http://forums.pelicanparts.com/uploa...1233639533.jpg

In the next couple of days I'm going to figure out how to drill hole to the cabin, bolt down lambda/ecu/computer brain and the other wiring.

Special thanks to Alex (foreground) and Fernando (background) for their help this past Saturday.

http://forums.pelicanparts.com/uploa...1233639990.jpg

Tach Wiring
 

Can someone/anyone help on the tach conversion?

There are three parts of the conversion that I'm confused with.

(1) I have the updated tach itself. The back connections look identical to my 76 tach. The top 5 connections are slots for the little lights. There are 3 spade connections on the bottom. The purple/black wire, I believe, is the one that needs to be updated (or is it all three) to the purple wire?

(2) Where does the wiring for the tach come from on the engine itself? I couldn't find a purple wire on any of the plugs or wires on the "new" engine.

(3) Did you run the wire between the tach and the engine directly? Or did it pass through a fuse or some other device?

Thanks.

Harness wiring hole
 

Here is a pic of the hole for the DME harness.
The rope shows where the wire went.

Christian

http://forums.pelicanparts.com/uploa...1233775604.jpg