Need engine knowledge, different camshaft for carbs Options

[914helo]

In reading different threads about people switching from fuel injection to carbs, a different camshaft is almost always mentioned. What should be different about it? Why is it necessary? What about those engines with 4 camshafts? I'm not planning anything radical, just trying to understand. Thanks

[Jake Raby]

The vacuum signal needed for carbs is much different than FI. By swapping to a more carb friendly cam the engine will both run cooler and make better, more usable power.

I have just what you need if you'll shware with us the rest of the specs that you plan on running.. CR? heads? valves? and your elevation.

[914helo]

I have a relatively low mileage (just barely over 60K)Subaru SVX engine sitting in my garage and seemed like it would be a great fit into a 914. However, I also love a flat-6 with Webers. There isn't a kit out there for the Subaru 3.3L to convert to carbs, but tossing around the idea. It has a 10.0:1 compression ratio, making 230 HP at 5400 RPM. I'll attach a scanned copy of a magazine article that lists a lot of the technical data. As for elevation, I'm currently at 2200, but that's rare. Being in the Navy usually keeps me at sea level. Thanks for your advice.

[914helo]

Another picture

[mudfoot76]

I drove an SVX for 5 1/2 years. Great mid range torque. Mated to a suitable 5-spd (or now ppl are swapping in 6 spd) gearbox, and you'll not need to worry about putting in hotter cams, carbs, etc...just fabricate mounts and an exhaust for your 914!

In factory trim, the EJ33 engine will last well over 300k miles with just the standard maintenance. Be warned, the timing belt service is kind of pricey. Otherwise just turn the key and (IMG:style_emoticons/default/driving.gif)

[914helo]

In addition to enjoying pulling out what little hair I have left playing with carbs (why do I still enjoy it?) I am a little concerned with the wiring. I don't have an ECU and connecting all the sensors seems a little overwhelming.

[Mueller]

i wouldn't touch those cams at all, that is not a motor you want to start experimenting on, not cheap for internal parts if you break something (IMG:style_emoticons/default/smash.gif)

I'd go with aftermarket FI with individual throttle bodies before I stuck carbs on it (IMG:style_emoticons/default/icon8.gif)

all the sensors seems a little overwhelming.

how many sensors does it have?? like 5 ???

[mudfoot76]

i wouldn't touch those cams at all, that is not a motor you want to start experimenting on, not cheap for internal parts if you break something (IMG:style_emoticons/default/smash.gif)

I'd go with aftermarket FI with individual throttle bodies before I stuck carbs on it (IMG:style_emoticons/default/icon8.gif)

all the sensors seems a little overwhelming.

how many sensors does it have?? like 5 ???

If you are serious about tinkering with this motor, I suggest you go check out the SVX owner's forum:

www.subaru-svx.net

I think you should have at least six (6) sensors to hook up for proper engine management.

If you are missing the ECU, you should be able to find someone there who has one. Talk to "sxewhodey". After mine was totalled out, he bought it and is parting it out. That has a wonderfully well-cared for complete engine and all the wiring (unless it has already been scavanged)...

His real name is Mike and he lives near Columbus, Ohio.

[fiid]

What Mueller said. This engine should fit nicely in a 914 - but I wouldn't bother going carb. Make a fatty exhaust and get your noise that way.

There are various aftermarket options available. Slight guess here, but here are the sensors.

On the end of the Cam shaft is a VR sensor that reads the CAM position. (on the right staring into the cam belt housing.)

On the end of the crank shaft (top) is a VR sensor that reads the crank position.

(this engine might not have the cam read). The sprocket that fires these is funny for subaru, and only certain ECUs are capable of dealing with it.

On the top, under the power steering pump ought to be a water temp sensor (on a pipe that comes out of the top of the engine) and an oil pressure switch. I think there is also a sensor that bitches when theres no water around.

These guys use Mass Air Flow sensors, so you will probably want to switch to MAP (pressure based) for which you will need to run a vac line or a sensor, and get an air temp sensor into the mix.

In the exhaust manifold somewhere you should have a 3 or 4 wire Oxygen sensor - this is used to tell the ECU about the mixture. (2 wires are heat, 1/2 are the actual sensor read w/ optional ground).

The other wiring is spark and injectors. I think that's all the sensorship you should have.

You could run this engine using a Megasquirt and 6-cylinder EDIS crankfire setup if you wanted to. I think you could also run the KitCarlson EMS (although I'm not sure if it has ports for 6 cyls), both of which are tunable from a laptop. Having an O2 sensor and no turbo will allow you to tune for stoch using the O2 sensor which can be handled in software on the MS (it will mostly tune itself).

Or you could buy something, which would probably take less time on your part.

You could do carbs, but you would probably need something to drive spark for you, which would end up being an ECU, so youd probably end up with FI functionality around anyway - you might as well use it. I would stick a big K&N cone filter on it - you ought to get great perf out of that and some headers, and some nice noises too.

(IMG:style_emoticons/default/beerchug.gif)

Subaru motors rock.