roy_josef

Well, as the subject line suggests, I'm wondering if there is anything special to this install ie wiring harness, motronic version, sensors etc. I just picked up an 83 with a blown motor and I have a high(er) compression 88 engine I'd like to put in and goooo racing....

iloveporsches

83 did have a different DME than the later cars. So you'll need that, and probably the wiring harness. I think all the sensors should be fine though.

SoCal Driver

2.5 liter?

Most everything on the basic engine is a direct fit.

Use the 83's idle posistioner valve. This is under the middle of the intake manifold.

The larger of the two pins at the rear most engine temp sender is for the gauge. The smaller one is the warning light.

Use the 83's fuel rail, injectors, intake, AFS.

Use the 83's vacuum setup.

The oil filler on the later engines has a larger port at the bottom so you will need the one for the 88 (if you don't already have it).

Use the 88's cam. Longer lift on the exhaust. A few more HP's.

If this is the 2.7 liter engine then you are going to need it's DME and AFS and injectors.

roy_josef

Thanks for the info SoCal, gotta a couple of questions. First off its a complete 2.5, do you recommend using the '83 idle positioning valve, fuel rail, injectors, intake, vacuum and AFS in order to use the '83 harness, or is there some performance advantage over the 88 stuff. I ask because I have an '88 DME harness with the Motronic ECU and it seems like it would be less work to replace the harness with the one from the '88 then have to use some of the upper engine components from the 83 on the 88 engine.

deni durrell

just found this evening that the later cars use a different alternator. one that is rated at 115 amps vs early which is 90a. Also it doens't seem to fit properly or not at all. the lower bolt is bigger than the early one. it most likely would fit, but one would have to do the tap and die thing which would slightly mor ethan challenging in such a tight area. can anyone sell me an early one, or is it parts heaven i go?

roy_josef

My 88 donor engine is totally complete: injection, alternator, distributor, harness, motronic ecu, ac comp, etc, everything to do a drop in/bolt up job.

roy_josef

Looks like I'll have an alternator out of my '83 for you. Check your PM's.

SoCal Driver

The alternator and the bracket may be matched. I'll have to check the remaining parts from my 86 to 83 transplant. Was thinking of using the newer alternator but got lazy. The poly rib belt for the larger alternators has one more rib than the early poly rib belts.

Roy, The easy way to use the newer DME is to swap it and the AFS and leave the rest the 83. The AFS is different from early to late 944's.

If you feel challenged then you will have to swap the harness to use the 88's idle valve. The idle valve is different than the 83 and does require the DME to control it. Don't know how the factory alarm interfaces. Have to check the electrical schematics.

Charlotte944

I'd go with the '88 motor, harness, fuel rail, injectors, and DME. You may need to re-do the vacuum lines to the fuel pressure damper, but every thing else should work as is, and using the later alternator will solve some of the lighting and electrical issues that the early cars have.

One thing that didn't get mentioned is the A/C system. I'm not sure if the early compressor will fit a later bracket, and I don't think early hoses will fit a later compressor, so you may be in for some creative plumbing.

On the other hand if this car is just going to be a track car, then you can use an A/C delete bracket.

Anyway, good luck with your project!

Charlotte944

Wait one! I just realized that you need to use the early fuel rail!

On the early cars the fuel lines come up to the fuel rail from behind the motor, and on the later cars the fuel lines come to the fuel rail from a hole behind the passenger side strut.

One other item is the O2 sensor. The early cars use a single wire connector at the center line of the fire wall, and the later cars use a 3-wire connector. You need to find someone that is parting a later car and ask if they have the connector for the O2 sensor. When you get the connector, go to Pep Boys or where ever and ask for a Bosch 13913 3-wire Heated sensor (About $40.00 as I recall).

On the 13913 the white wires are the heater leads, and the black is the sensor lead. When you splice the connector to the sensor you can use solder and heat shrink on the white wires, but you MUST use a crimp style butt splice for the black wires. This is necessary because the reference atmosphere for the sensor is supplied via the black wire. If you solder the wires together you can seal the wire strands to the insulation and functunally "choke" the sensor.

One other thing that may cause you a problem is the alarm. If your car has an alarm, you cannot use your alarm module with the '88 harness. I recently retro-fitted my '87 with a factory alarm (the harness was there, I just added the horn, key lock, hood switch, and alarm module), and when I tried to use a module from an early car (I had one for my '84, but never installed it), the '87 wouldn't start.

I did some checking, and it turns out the part numbers are different. Fortunately I found one on eBay for about $20.00, so my alarm works fine.

Good Luck!

Granite 944

I put a late into an early a few months back. The water tube from heater core to front of engine is shorter on '88, will need to put '83 one on.
Like above statements, altenator size and brackets are different, and so is the AC compressor ( no big deal if your swapping it all). Also note later cars used a 3 prong setup for thermo valve, early used the 2 prong. Later used a 2 prong temp sensor hookup, '83 use single wire. In my swap, I used the early harness, vacumn system with intake manifold, aux air regulator, water tube, altenator (put brackets for alt and AC on from early one). I used the late DME and AFS using early harness. I also put the 6 bladed cooling fans from late onto the early (big difference in noise!), but you need to use some of the later's hoses to clear power steering belt on the lower, and the drivers side fan on the upper. And you will most likely need the fan connector plugs from later harness. I also used the early thermofan switch. Good luck, and let us know how it works out for ya if you do use the later harness and vacumn system.

SoCal Driver

I would use the coolant bleeder from the newer engine. The one with the bolt. You will have to get a new top radiator hose. The expense is worth it!

Can't recall that the heater fitting was different. Could have been. Was a long night to get that engine in. If you are talking about the extension that goes above the exhaust manifold I used the one off of the 86.

The O2 sensor does not have to be the three wire on the 83's. The extra wires are for a heater inside the O2 sensor. Also about half the cost to replace. Later models have to use it depending on you local smog laws.

On the use of the early fuel rail; the critical seals are at the top of the injectors where they connect to the fuel rail. The lower ones could be rubber bands as long as the intake is sealed -- no pressure.

Those six bladed fans do make the difference. If you can get the wiring harness then splice it in between the temp switch and the fans. I have the one off of the 86.

I found replacing the engine a long but interesting job. Don't want to do it again soon. But I know I could cut down the time it took.