2.0 GA vs. 2.0 GC, pros and cons Options

[Lennies914]

I have a chance to pick up a 2.0l out of a '75 so I believe it should be a GC case. Are there disadvantages to this motor? Please advise and give your opinions.
Thanks

[Tom_T]

If it's for a stock set-up, then GA had higher output, since the GC was detuned to meet later smog requirements (+/- 86 hp from 95/91 on the GAs IIRC), but it may not matter if it's a core for an upbuilt engine like a 2056 or 2270. McMark or Raby would know better on that.

[SLITS]

Nope .... all the same except for the air injection holes in the heads. Plug the stubs with a 3/8" pipe cap if you're cheap like me or put bolts in the head, long enough with the proper thread to seal the holes in the exhaust ports.

The expensive way is to remove the heads and have the ports welded up from the inside.

[DanT]

I have a chance to pick up a 2.0l out of a '75 so I believe it should be a GC case. Are there disadvantages to this motor? Please advise and give your opinions.
Thanks

remove the smog pump, block the air injector tubes and back date the exhaust....you will have a GA motor... (IMG:style_emoticons/default/biggrin.gif)

[SLITS]

I have a chance to pick up a 2.0l out of a '75 so I believe it should be a GC case. Are there disadvantages to this motor? Please advise and give your opinions.
Thanks

remove the smog pump, block the air injector tubes and back date the exhaust....you will have a GA motor... (IMG:style_emoticons/default/biggrin.gif)

Yeppers .... the exhaust system was the restriction on the '75 - '76 motors that cut the HP down.

I put a '75 in mine .... used the '73-'74 exhaust and capped the airinjection tubes. It would run with the big dogs.

[Lennies914]

(IMG:style_emoticons/default/aktion035.gif) These are all the answers that I wanted to hear! Thanks to all for the input.
It looks like my '72 will be getting a 2.0 and a side shift trans afterall.

[Lennies914]

Nothing changes on the FI? I noticed it has a 044 ecu.

[DanT]

IIRC the ECU and MPS are different for each year...
with a little tweeking it all works fine...

[SLITS]

The correct ECU/MPS for the '75-'76 is an 052 ECU with an 049 MPS.

Others will more than likely work, if combined with the correct MPS. The rest of the equipment is the same.

Since the PCV oil breather on a '75-'76 was unregulated, it was connected to the air cleaner.

The '73-'74 was a regulated PCV valve and was connected to the intake plenum. To avoid sucking oil with the late style, change the Filler/Breather to a 1.7 or earlier 2.0 to get the desire PCV valve and connect to the plenum.

'73-'74 heads also had breather ports connected to an anti-flashback valve connected to the air cleaner. This allowed for the heads to breathe. You can see the bosses in the heads and could feasibly add them (engine out) by drilling the bosses and tapping them for a 3/8" pipe hose barb. This vented the blowby gasses and internal pressures as does the PCV valve.

The '75-'76 type connected to the plenum will experience hi-vaccum on closed throttle and will create a hell of a suction at the oil breather port. With it's big hole, it can suck oil out of the Filler/Breather housing=cloud of smoke.

That's my book anyway!

[EdwardBlume]

Need a trailer, a big truck or a hand?

[JeffBowlsby]

The GC's also ran hotter because of the exhaust reaction tubes, making the heads a bit more brittle.

[76-914]

Didn't I read somewhere that the GC was prone to warp? If so is it just a matter of line boring the case? (IMG:style_emoticons/default/confused24.gif)

[Lennies914]

Need a trailer, a big truck or a hand?

Thanks Rob, but I may need a place to stay when my wife finds out. (IMG:style_emoticons/default/biggrin.gif)
I just told her about the '72 Friday night (picked it up Sat. morning). I'm really hoping if I give the guy full asking price for the car, he will just sell me the drive train. (IMG:style_emoticons/default/confused24.gif)

[Bleyseng]

The GC's also ran hotter because of the exhaust reaction tubes, making the heads a bit more brittle.

What exhaust reaction tubes??


Should have a 052 Ecu with a 043 mps not a 049 which is for a 1.7L..

Yes, it was the whole exhaust system that robbed the hp on the 75-76 setup....switch it to early stuff.

[jk76.914]

GC also does NOT have the second oil pressure relief valve in the main oil gallery, driver's side.

[realred914]

75/76 had fdifferent partnumber injectors also, but heck close enough, I run them on my 74 ecu equipend motor.

if you stay with the tail shiofter, you will need to make your own muffler hangers, stock 2.0 hangers interfer with tail shift trannys, easy to fabricate, some angle stock and a couple holes each, and your done.


late engien harness in a early car will require a wire modification to get the heater fan to work you need add a wire to the fan from the jumper from pins 10-11 on teh realy board hengine harness connector.

have fun

[SLITS]

The GC's also ran hotter because of the exhaust reaction tubes, making the heads a bit more brittle.

What exhaust reaction tubes??


Should have a 052 Ecu with a 043 mps not a 049 which is for a 1.7L..

Yes, it was the whole exhaust system that robbed the hp on the 75-76 setup....switch it to early stuff.

Geoff ... You and Banders can argue the point on the combos. Bosch ESI lists the applications as you state. 049 = '72 - '73 1.7L .... 043 = '72-'75 2.0L

I have run the 052/049 combo on 4 2.0L engines and it performs beautifully.

Injectors .... 019 for '73-'75 2.0L (406 cc/min @ 3 bar),
038 for '75-'76 (400 cc/min @ 3 bar).
105 for the '76 912E (190 cc/min @ 3 bar)

[Bleyseng]

The ONLY difference between a 049 and a 043 is the WOT setting. So if you drive around or AX at WOT you will cook the engine with too lean a AFR..
The 052 has the fuel shutoff and its set up slightly leaner than the 74 044 ECU

[JeffBowlsby]

The way I understand it is that the late style heavy steel manifolds attached to the heads are intended to retain heat and work with the air injection to further burn (i.e. 'react') unburnt fuel in the exhaust gasses, as an emission control device.

Excess heat against the heads is a bad thing of course, but it was needed for emission control purposes. 'He who has no name' said he would not buy late heads because they were always more brittle.

The GC's also ran hotter because of the exhaust reaction tubes, making the heads a bit more brittle.

What exhaust reaction tubes??


Should have a 052 Ecu with a 043 mps not a 049 which is for a 1.7L..

Yes, it was the whole exhaust system that robbed the hp on the 75-76 setup....switch it to early stuff.

[Bleyseng]

Oh, the J tubes...and with the addtional restriction of the HE's yes, it tended to cook the heads both on 914's, 911E's and Buses that had em.