Doing another engine swap, some questions...

[Rick Lee]

Soon we shall be buttoning up a friend's '77 2.7 CIS engine for install into his '70 T RS clone. Car has a 915 in it now. We're putting on a LWF and new clutch kit this weekend, have refreshed a lot of other parts and now the devil is in the details.

It looks like the original CDI box that was with the 2.7 has been lost. What can we do here - buy a perma-tune kit, new CDI box or what? What sort of electrical connection nightmare are we in in for? Is the tach gonna work? Fuel connections? Did a '70T have two fuel pumps? Will a regular Bosch CIS fuel pump just mount up in the belly pan and sufffice? What's my name? Thanks.

[ckissick]

I'm no expert, but since no one else is responding...

I am currently swapping out a '74 2.7L for a '78 3.0L to go in my '70 911E. The PO to the PO put the 2.7 in, so I don't know how he did it. I have a perma-tune ignition, but don't know if the tach had to be modified. I think not, since the engine still had points. I'll have to modify my tach now, as the '78 engine has pointless ignition and I have to use a CD box instead of the perma-tune.

The electrical connection will not be difficult, as the system changed after 1969 to something more compatible to the later engines.

I don't know about fuel connections. The '74 engine had Webers, and I'm putting them on the 3.0. No fuel mod's are necessary for me. I don't know if you can use the carbs off the T, but for a 1970 RS clone, I would consider trashing the CIS, as it just won't look right. Not to mention performance.

This may be my first correct answer today: Your name is Richard.

Charlie
Montara, CA
1970 911E
1950 VW

[Rot 911]

Richard, the 70T only had one fuel pump. Oh and don't forget to make sure the starter ring gear is on the pressure plate!

[Rick Lee]

Thanks guys. Kurt, I will NEVER make that mistake. It's tatooed on my brain.

I would keep carbs too, but my buddy doesn't want to. Any ideer if the ones from the 2.2 would fit the 2.7?

[al lkosmal]

The carbs will fit the 2.7, but you will need to resize the venturis, jets, etc for that motor. etc. Hit the search engine. Tons of info regarding this.

[Bob Spindel]

I put a '77 2.7 in an early '73 (had MFI, not CIS) which I think is close to what you're doing. I got by with simply replacing the existing fuel pump, up under the rear driver's wheel well, with the correct pump (You need the higher pressure.) for a '77. That's where it was for the early CIS cars. It seems to run just fine. I believe Porsche moved the pump up under the fuel tank to cure vapor lock-like problems induced by warming of the fuel in the fuel tank because of the way fuel circulates through the hot engine compartment and back to the tank, but I could be wrong about this. Others on the list will know. You also need to install the CIS accumulator and CIS fuel filter. The latter is designed for the high pressure CIS fuel system. When you run the fuel line from the pump to the filter-accumulator, use high pressure line. The stuff that's in there now isn't designed for CIS pressures.

Wiring changes were minimal.

[Rick Lee]

Bob, that's good news. Any more ideers, folks?

[Bob Spindel]

Rich,

Am happy to try to help with questions, etc., if you run into a problem. My previous answer was quick, from memory. I have notes about the wiring and probably other things that I could consult to refresh what is fast becoming a lost cause...my memory...

[kstylianos]

Richard,

If the CDI box does not show up, an MSD-6AL will work fine for ~$200. Hotter/multiple sparks will allow him to open up the plug gap a little more and get a bit more lower end response.

What about the return line to the tank...guess it's ok to use the existing line(s)? Replace may be a better/safer option.

[Rick Lee]

Charlie, you know he's all for the upgrade options. I'm sure he'll like the MSD route. Who knows - he may go hog wild a buy a bunch of them.