lt1 to lt4

[CamaromanZ28]

94 camaro z 28 is going to have a lt4 motor dropped in .What problems should I be looking at on this swap . PCM anything close to that .

[Injuneer]

Is it out of a Corvette? If so, you will need to swap over all the accessory brackets on the front of the engine. They are completely different on a Corvette and an F-Body.

You will need to swap the fuel rails. The Corvette fuel lines come from a different direction.

You will need to swap the passenger side knock sensor from your Z28 (4.4Kohms) to the LT4 engine passenger side (100Kohms). The Corvette engine has another knock sensor on the drivers side. You can just leave that one there disconnected, or swap the block drain plug from your engine.

You will have some unused sensors on the LT4 engine, because its OBD-II and your 94 is OBD-1. You just leave them unconnected. That will include the crankshaft position sensor, EEC purge flow sensor and some connections to the AIR system. Not sure where the LT4 has the AIR pump, that may need to be relocated to match your LT1.

The PCM and wiring harness will be compatible with just about everything, except the knock sensor mentioned above. You will need new PCM programming. The "stock" LT4 cam is not much different than the stock LT1 cam. It just has more gross lift because of the 1.6 roller rockers. But the LT4 engine has larger injectors, so that needs to be entered into your stock PCM programming. You will want the rev limiter RPM raised to match the LT4 engine capabilities.

You should get an LT4 knock module and install it in your 94 PCM. It filters out the noise from the roller rockers and reduces the chance of false knock causing knock retard.

Not sure about the oil pressure sensor. I think the Corvette sensor might have more wires, because it also measures oil temperature. The LT1 doesn't read the oil temp sensor. I think the Corvette sensor might also interlock with the fuel system, but as long as you wire it correctly, it will work with your F-Body setup. Some very early 94's had the oil pressure sensor above the oil filter, while later ones had it on top of the block, right behind the rear edge of the intake manifold.

The LT4 engine has a "vented" Optispark. Yout 94 does not. You need to make sure you have the air supply source hose connected to the air inlet elbow, right in front of the throttle body. There won't be a hole there. You will have to drill one in the rubber, or get the 95-97 inlet elbow. The vacuum source for the Opti comes from the drivers side of the intake manifold, but that hose should come with the engine.

The LT4 engine will not have an EGR valve, or the EGR vacuum solenoid. I would recommend swapping that over from your LT1, although not many people will agree with me.

Look for differences in the PCV system. Your LT1 pipes the vacuum from the PCV valve in the middle of the drivers side intake manifold, to a port a few inches behind the valve, using a short U-shaped tube.

That's all I can think of off the top of my head..... I'm sure there will be some other differences.

[BadRag]

Not a 94', but wouldn't the LT4 Kit from PACE be easier for the swap on my 97'....tho I do have the OBD1 swap on my PCM from BadZ28 for "other" goodie's on my LT1.....just seems easier to do the "package" than the engine swap....Thought's ?

[Injuneer]

Buying a complete LT4 engine gets you factory 4-bolt mains. It also gets you a higher 10.8:1 compression ratio. It leaves you with a smaller cam, since the LT4 "conversion" kit includes the HOT cam, which is not used in the stock LT4.

It also gets you some parts of questionable value, like the reverse-camber piston rings, an overweight cam sprocket to cancel out some unwanted torsional vibration in the cam, among others.

You really need to look at the comparison of the LT4 to the LT1 to understand all the +'s and -'s.

http://www.malcams.com/legacy/misc/LT4.htm

One thing I forgot above..... the Corvette LT4 harmonic damper may be a different width that the LT1 damper. Won't align correctly with the rest of the accessories.