CIS on a 3,2 Carrera engine, does that even work?
 

Hi,

a friend has an engine that might be for sale to a resonable price. It is a 1985 3,2 Euro Carrera, the 231 hp version with 10.3:1 compression. The strange thing is that the old Motronic system is entirely gone, replaced with a CIS system.

So, my question; should this even work? Does it work long term too?

I haven't heard the engine run yet, and I don't know if it's completely stock inside or not. My main concern is the compression ratio and the pistons, if they are stock. I guess the cams should work with an CIS, shouldn't they?


Thanks,

Johan

mechanically, it will work, but why? there might be some concern with the cams and C.R. but why? I doubt there will be as much of a HP gain as the stock 3.2 with the correct intake/efi system. What's the serial #?

It might be a 3.0L with 98mm pistons and cylinders. Basically a 3.2L Short Stroke.

Doesn't match up with an 85 as the 3.0 ended in 83. I'd check the engine number as a starting point.

I have no idea why someone would put CIS on a 3.2 - makes no sense to me.

Hi,

thanks for your answers. + 1 on the question "why"....:)

It is definately a 3,2 Carrera engine block, I've checked the engine # and the engine type # and it is what I wrote above.

I have no idea either, why someone would do that. My guess is, that the 3,0 engine broke down, and instead of rebuilding to 3,2 or 3,3 specs, they took the easier way of using a 3,2 longblock. If this was made by a good engine shop, they should have changed the pistons for CIS friendly ones. Unfortunately I don't know.

Regarding the cams, I was under the impression that they had SC cams with more advance?

Anyway, the original question still stands; would this work short-long term?


Thanks,

Johan

What Distributor did they decide to use? I'd worry more about this because the 10.3:1 compression 3.2L Euro won't tolerate much ignition advance at WOT. I have a 3.2L Euro and it's been dyno tested and tuned, I know first hand you can't push ign advance past 30deg at WOT with 93 octane fuel. So the question about the distributor is important.

They must have changed the distributor from the stock 3.2 motronic dist to something else. The motronic dist has no trigger (points) or mechanical advance.

If that dist is not verified and advances timing above 30deg you will have an expensive paper weight after a few WOT pulls!

I am instaling a RoW 3.2 with CIS from a 3.0 in my car tomorrow. It is a new refurbished longblock because of a burnt rodbearing.

We Will use stock distributor and CD box.

On a factory 3.2 (motronic), if my memory skills serve, the intake ports are 41mm. The 80-83 CIS cars are 35 (bigger on 78/79).

I thought the spacing on the studs was wrong, but I went out and measured and they are the same. So if you maybe blended the intakes you could get a smooth flow from the 41 down to the 35? Maybe a small adaptor? Not 100% sure the fuel injectors will work. Spacer plate maybe.

I drive a CIS car every day. Love it to death, absolutely wonderful daily driver. But everything it does well, my husband's 3.2 motronic does better and makes mroe power. And it does it without mix/matching of bits. Pretty easy system too. My husband let me do the wiring and even the troubleshooting which I correctly diagnosed as a defective speed sensor.

I guess the question from me is not "can I put the CIS manifold on a factory 3.2," lots of smart people here, I know you CAN do it, the question is why in the hell you would want to?

angela

Because the motronic is missing, thats why i go for CIS.

The CIS runners are 39mm and the 3.2 intakeports are 40mm.

Soren.911 By stock you mean the 3.0 dissy not the 3.2 dissy.

78/79 are bigger (and maybe euro) at that point, not much difference. Need the CIS pump, accumulator, and ignition system as the 3.2 items are NOT compatible at all...

I guess if I had a 3.2 longblock and a 3.0 CIS system laying around in perfect shape and I had to buy absolutely nothing, then I would probably do what you are doing as well.

But I'd sure be tempted to dig up a 3.2 intake/FI system and do it up right or just put PMO carburetors on it. Those are about as trouble free as CIS, maybe more when you factor in the parts are new for the PMOs.

angela

The 3.0L CIS system measures intake air via the mechanical funnel which in turn mechanically commands the correct amount of fuel for the given unit of air. This 3.0L funnel may run out of calibration at very hi-loads (WOT Loads) and COULD result in lean mixtures at WOT. If this where to happen disaster is at the door as detonation is highly probable. The 3.2L will take in about 10% more air at WOT than the 3.0L so you need to be real certain that air metering funnel doesn't fully open long before max air flow is achieved.

I'm no expert with this type of upgrade and maybe this isn't an issue but it's something to think about.

Hi all,

thanks for answers. You raise a lot of the same concerns as I had.

Just to clarify; I'm not building this engine, it's an engine that might be for sale as-is.

To find a complete Motronic is almost impossible, I mean I'm sure I can find the intake and some other stuff, but finding all the bits and parts at one place is very, very hard. And expensive.

I agree with Soren and Laneco, if you have the longblock and a siezed 3,0, why not?

I have to make sure about the intake spacers, and the dizzy. Thanks for pointing that out.

Sal, and others raising the WOT issue; how do the engine builders rebuilding a 3,0 as a 3,2 or 3,3 handle that issue? As fas as I have understood, that is a popular upgrade for the unlucky Alusil non-reusable cylinder owners? That is the same increase in volume.


Thanks,

Johan

Remember Dane's 3.4 CIS engine....it ran fine. Until one can prove that a properly tuned CIS leans out at 6500 RPM WOT, let's not scare ourselves silly. You run the CIS on the rich side of things on this particular engine, Johan. With a wide band O2 meter, run it and see how the CIS performs. Maybe someone has already done some tuning and the thing runs like a bat out of hell.

They would have had to change the ignition distributor and put the right gear on it since the 3.2 and 3.0 dizzies rotate opposite each other. If they went to that length then chances are they did it right.

Check the distributor. Does it have mechanical and vacuum advance? A 3.2 and 3.0 dizzy are very different visually and performance.

It's very likely that the 3.0L air intake has the extra headroom to run it with 3.2L cyls. However, I think it's best to be sure of this from others that have done such upgrades. This is not the area to install and hope it works as doing so can cost serious $$$.

Johan's engine is already using a CIS.

Search for "rdane CIS" his engine is well documented here.

Just need some finetuning in mine 3.2CIS. But I can allready tell it pulls strong from low rews. I haven`t been over 5000RPM yet, because its new rebuilt.

It runs with stock 2.7 ignitionssystem and works fine.