First I accidentally put this in past models, new here.

I believe SL, helping semi mechanical friend in my garage. Another caveat, donor car auto, receiver manual. DOHC is from donor. Do all these cranks have pilot bearing/bushing? If not, does the auto crankshaft have to be bored, or just install bearing?

Thanks, Jim.

 

Deleted duplicate post. Moved to a section where it belongs.
I do not know the answer to your question. EDIT: SEE BELOW

You are aware that there are more things that must be attended to yes?
Not trying to be insulting. Trying to be helpful.

 

I am new to your site, sorry if thread not following all guidelines.
As far as other things, that is the main thing I could think of. Never worked on a Saturn. Please enlighten as to other obstacles. My experience is mostly front engine rear drive, some Eagle Talon.
All input/advice appreciated.

Jim.

 

No harm / no foul.

Whenever you swap auto to manual or manual to auto and SOHC to DOHC and vice versa (and between years but that's not an issue here so I'll skip), you need to consider

1) Which PCM is going to end up in the running vehicle
2) BCM /PCM/Passlock fun
3) Which transmission you are mating with which engine
4) shifter cable bushing (if Manual)
5) clutch?
6) Rear main seal

1) To run the DOHC, you'll need to use EDIT: the PCM from the receiving vehicle (SOHC manual) or a DOHC PCM from a 2000-2002 s car manual tranny vehicle. Off the top of my head, I'm trying to think of what might be different on the wiring harnesses between the DOHC and SOHC --- do some detective work to be sure the SOHC harness will accommodate all of the DOHC's sensors. If not, now's the time to swap in the DOHC harness.

EDIT: Saturn switched to a new PCM n 2000 that was able to handle being programmed for EITHER SOHC or DOHC. That cut the variations from 4 down to 2 ---Auto or Manual. Now I'm aware

2) The BCM should be the same as it is the same model year. However, if you swap A donor DOHC PCM into the SOHC, the PCM and BCM will fight. Until they are synched, the car will not run. I THINK when you swap PCM or BCM the relearn procedure must be done at a GM dealership. Don't remember. It's out on the web.

EDIT: IF you keep your BCM as is (recommended) you'll have to do a local BCM relearn for the BCM, ignition switch, and PCM to get all synched up, then a Passlock relearn to get the security system to allow you to start the car. Passlock sucks, but your buddy likely already knows that.

Be sure to save the other BCM as a spare. Used ones if you can even find them are 1/2 the value of the car.

EDIT: I would not try to drive a DOHC on an SOHC PCM to get the PCM flashed (necessary) and the BCM flashed (not a bad idea -- this way you know they communicate)

3) Transmission considerations

SOHC manual = MP2
DOHC namual =MP3

Without changing the tranny to an MP3, the DOHC isn't going to feel as sporty nor will it seem to have the get up and go. Though the torque vs RPM curves are somewhat similar, the DOHC is geared lower in the lower gears which gives you that feel of acceleration off the line. Let's face it, it's a 124hp car. All I'm saying is that a DOHC mated to an SOHC manual won't drive the same as the gear ratios are different for an SOHC tranny than for a DOHC tranny.

As it is a manual tranny, you SHOULD be able to get away without any Service Engine Soon (SES) Light throwing codes about the tranny mismatch, as the manual is pretty dumb as far as electronics go.

4) I'm going to assume you left the shifter cable connected to the shifter ball at the bottom of the shifter.

Even if it has already broken once and been replaced with a variety of half *** solutions, go to ebay, look up the seller saturnbushingman at replace your shifter bushing NOW (yes, break out the old one). His products do not fail when installed properly.

5) If your buddy plans to keep the car for a while, he may want to consider doing the clutch while everything is apart. Just sayin.

6) Not uncommon to have rear main seal issues. It's 16 yrs old. Your choice.


My goal in bringing all this up NOW is not to freak you out -- it's to inform you that things may not come out the way he wanted if he was/is unaware of the differences I mentioned. And the electronics issues are unavoidable.

Some GM dealers won't even touch Saturns anymore.
Some will only reflash PCMs and BCMs to the programming called for by the VIN, which is of no use to you.

(Oh, keeping the BCM with the PCM retains the correct mileage on the engine as the mileage is stored in the BCM and cannot be reprogrammed)

Basically you need to find someone with a Tech II GM tool and access to the flash file library to make it happen.

----------------
YOUR ORIGINAL QUESTION

I cannot find any difference in cranks betw the engines. There are no cranks specified for manual vs auto. So I would say just install one in the identical fashion as you removed it from the SOHC when you pulled it.

 

Derf, excellent thank you. Some I have covered, some unaware.

1. PCM swap from auto car, have complete car.
2. Swap BCM also/Passlock?
3. Going to have to be P2 with DOHC, I understand your logic.
4. Unaware, thanks.
5. Will see how his budget is.
6. Will seal fit over crank flange?

PCM Power Train Control Module.

BCM ?

Passlock, found procedure. OK.

Tried to get on here yesterday, said user invalid, email invalid.
ok today.

Thanks, anything more lemme' know.

jim.

 

I posted reply but not showing.
derf thank you so much, some of this aware some not.

1. PCM from donor DOHC
2. BCM form donor, I have found Passlock procedure.
3. Looks like P2 with DOHC, should be better than now.
4. Unaware will do
5. Check budget.
6 Will seal fit over crank flange?

Thanks for your input, if you think of anything more please advise.

jim.

 

6. Of course it will, it's 1 piece, DOH.

 

OK -- too late at night for me to answer questions.
1) PCM

Contrary to my earlier assessment, upon checking the part numbers, the PCM in the receiving car (for the MANUAL tranny) is the one you need to keep in there.

It used to be for the earlier generations of S cars that there were 4 PCM variations
SOHC Manual
SOHC Automatic
DOHC Manual
DOHC Automatic

Apparently, they went to a different PCM design in 2000 to 2002 which allows the PCM to be configured for

DOHC or SOHC, Manual
DOHC or SOHCm Auto

End result: You can:
1) KEEP the existing PCM in the receiving car. Not confident that an SOHC PCM will run a DOHC at all....will need to be reflashed

2) Buy a junkyard 2000-2002 S car PCM from a MANUAL DOHC car. That will still likely need to be reflashed based on year it came from but at least it should start the car. Your choice.

Final Answer. Promise.

2) The BCM in the RECEIVING car should say put---it has all the options for your car correctly programmed into it. It will not fight the PCM until after it is reflashed to a DOHC PCM.

3, 4 -- unchanged.

5) People get anywhere from 100K to 300K on an OEM Saturn clutch if that helps.....

APOLOGIES FOR THE ERRORS ABOVE.

Should not have replied while sleepy.
I actually fell asleep in the chair while writing the response

Peace

Derf

 

derf replied to PM but I'll put here too.
How does PCM know what it is talking to? It sees, MAP, TPS, IAT, CPS, O2, so unless SOHC vs DOHC sensors are different impedance, what is the difference?

Thks.,
Jim

 

How DARE you make me think about the minutia of this ****. (j/k)

Interesting case you make; O2 sensors front and back are identical, EGR valves are identical and would have same duty cycle, MAP is MAP, IAT and ECTS are the same, TPS is identical.....etc......
----------------
How does the PCM know what (engine) it is talking to?

I would say, in general, without some checksum being calculated and matched maybe to the BCM that tells it, I don't think it has a ****ing clue.

You could rewire all the same inputs from a 2001 LS1 2.2 into that PCM. Yay for you. Will it control the engine? Dunno.
----------------------------
The question you need to ask is "will this (SOHC) PCM, as programmed, expecting specific parts to be present on the engine, actually RUN THE (DOHC) ENGINE without damaging it --- or will it RUN AT ALL?
----------------
Assume SOHC PCM, DOHC engine

The fuel injectors are physically different. Diff part numbers. I don't know the nature of the difference and am too lazy to look it up. Likely not a difference impedance-wise, likely in the flow volume and injector pulse width times programmed into the TPS response curves (fuel vs rpm=>air/fuel mix tables=>Front O2 tries to adjust air/fuel mix b c it is too rich (since SOHC PCM calls for less fuel per unit time than the DOHC PCM would BUT they are higher flow DOHC injectors), PCM shortens the pulse width to what it thinks will correct the rich condition, but these are DOHC injectors, so it is still probably dumping fuel........repeat feedback cycle, repeat........

Will it ultimately run the car? From personal experience, I do not know as I have never had occasion to try.
-------------------------
Do Saturn folks much more knowledgeable and familiar than I with the particulars indicate an SOHC PCM will run a DOHC? Never saw anyone say it works. Never saw anyone say it doesn't. Every Saturn swap recommendation by others I've ever read includes using the appropriate flavor of PCM to match the engine/tranny combination.
------------------------

So the answer to your question is : it has no fucling clue what motor it is trying to control, BUT the RESPONSE to some of the inputs and the ASSUMPTION the PCM is making that the parts present will all behave exactly the same as an SOHC setup will more likely than not lead to a non-operational mess.

Maybe.