SaturnFans.com
saturnfans.com - classifieds - forums


Go Back   SaturnFans.com Forums > Models > Saturn S-Series > S-Series Tech

Reply
 
Thread Tools Display Modes
Old 08-07-2008, 11:46 PM   #1
rabbit_diesel
New Member
rabbit_diesel is on a distinguished road
 
Join Date: Aug 2008
Posts: 2
Default Saturn Engine Swap Dohc to Sohc Please help!

Ok, my plan was to take the DOHC motor out of the 1999 Sl2 that is blown and put the good motor from the smashed car in it which is a 2001 Saturn Sl1 SOHC. I began by looking at all of the wiring plugs under the fuse box in the engine bay and they looked like they would just plug right in. So, I began swapping the motors... I put the Sohc in and plugged in the wires to the fuse box, they plugged right in. I finally got to the point where I could hook up the battery terminals and noticed smoke rolling out from the main power wire going to the alternator, It was fried. So I thought Oh no now what. I looked at the plugs and noticed that the wires from the DOHC motor are in different holes than the SOHC so I started to change the wiring harness under the dash. Now I'm to the point where the headlights are malfunctioning and the windshield washer fluid motor stays on when I turn the key. The motor does start but doesn't stay running. It could be someting simple, but then maybe not. Any ideas would be greatly appreciated. Thanks
rabbit_diesel is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 08-08-2008, 12:31 AM   #2
Low Saturn
Super Member
Low Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to behold
 
Low Saturn's Avatar
 
Join Date: Aug 2003
Location: San Jose, CA
Posts: 15,308
 

2007 AURA XR
2001 SC2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Well....

There is no reason to change any of the cars wiring harness'. To accomplish what you want to do, you need the engine, SOHC instrument cluster for your year car, SOHC PCM for a 1999 SL, SL1, SC1 or SW1. You'll also need the transmission that the SOHC engine came with. Your current transmission that was in your car wont be correct. More so if you have an automatic.

As for the fried wiring, it sounds like you didnt connect the starter/alternator/power wiring correctly.

And why would you do a DOHC to SOHC swap?? Everyone else does the opposite.
...
Mike

-1991 Turbo SL2.
11.809 @ 116.488 mph
www.differentracing.com

-2001 Limited Edition SC2 (#78)
-2001 Chevrolet Suburban
-2007 Saturn Aura XR
-2011 Rally Yellow Chevrolet Camaro 2SS RS
Low Saturn is offline   Reply With Quote
Old 08-08-2008, 01:39 AM   #3
Kal
Member
Kal is on a distinguished road
 
Join Date: Nov 2006
Posts: 178

1996 SL2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Quote:
Originally Posted by Low Saturn View Post
.

And why would you do a DOHC to SOHC swap?? Everyone else does the opposite.
Ya, I was wondering the same thing. Less power yikes. However maybe he just wants the better fuel economy, but I don't think its worth it. I like my DOHC's power. Anyway, sorry I can't be of any help.
Kal is offline   Reply With Quote
Old 08-08-2008, 01:53 AM   #4
rc1488
Master Member
rc1488 has a spectacular aura aboutrc1488 has a spectacular aura about
 
Join Date: Jun 2007
Location: Carmel, NY
Posts: 5,661
 

1997 SL2
1995 SC2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

To change a DOHC motor to a SOHC motor the first thing that must be acquired is a SOHC PCM with the same options as the car its going in to. IE power locks, power windows, AND tranny type.

This is why nothing is working and the engine wont stay running.

The SOHC engine from the '01 will work with the '99 car. You need a '99 SOHC PCM Manual OR a '99 SOHC PCM Automatic.

If you have an automatic tranny in the '99, you also need a SOHC tranny. The SOHC PCM will not know what to do with the DOHC tranny. If you have a manual, it WILL Work, however fuel efficiency may suffer as the gear ratios are different.

Nothing should have to be altered to the wiring.

You will also need a SOHC cluster if you change tranny's.

No the PCM from the '01 will not fit in the '99.

I suggest puting the wiring back to the stock locations. Get a SOHC PCM that matches your car. You should be set after that as long as you dont have an automatic tranny.

Keep us posted. Good luck!
rc1488 is offline   Reply With Quote
Old 08-08-2008, 07:58 AM   #5
twosaturns
Master Member
twosaturns will become famous soon enough
 
twosaturns's Avatar
 
Join Date: Mar 2004
Posts: 2,037
 
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

he said why he's doing it:

"...take the DOHC motor out of the 1999 Sl2 that is blown and put the good motor from the smashed car in it which is a 2001 Saturn Sl1 SOHC."

some people might find a good DOHC to swap in, but he already had the wrecked SL1. sounds like a good allocation of resources.
twosaturns is offline   Reply With Quote
Old 08-30-2008, 01:51 AM   #6
rabbit_diesel
New Member
rabbit_diesel is on a distinguished road
 
Join Date: Aug 2008
Posts: 2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Quote:
Originally Posted by rc1488 View Post
To change a DOHC motor to a SOHC motor the first thing that must be acquired is a SOHC PCM with the same options as the car its going in to. IE power locks, power windows, AND tranny type.

This is why nothing is working and the engine wont stay running.

The SOHC engine from the '01 will work with the '99 car. You need a '99 SOHC PCM Manual OR a '99 SOHC PCM Automatic.

If you have an automatic tranny in the '99, you also need a SOHC tranny. The SOHC PCM will not know what to do with the DOHC tranny. If you have a manual, it WILL Work, however fuel efficiency may suffer as the gear ratios are different.

Nothing should have to be altered to the wiring.

You will also need a SOHC cluster if you change tranny's.

No the PCM from the '01 will not fit in the '99.

I suggest puting the wiring back to the stock locations. Get a SOHC PCM that matches your car. You should be set after that as long as you dont have an automatic tranny.

Keep us posted. Good luck!

Okay so I put the origional dash wiring harness back in and it was quite the releaf to my worries because everything in the interior and the headlights and signal lights are all back to normal again. I used a pcm(located under the dash on the left side) that was from a 1999 with a manual tranny. When I tried to use the key to turn over the motor, the relay for the starter just clicks and the current doesn't make it to the starter solenoid(I replaced the wire that fried). So I had an I idea... I turned the key ON and crossed the solenoid terminals and she turned over but didn't fire. It almost seems as thought it doesn't even know the motor is in... oh ya and the pcm that is above the tranny is missing the smaller plug because it is connected to the 2001's wiring harness, does that matter? I just put the harness in tonight and got tired so that's all the farther I got. I'd appreciate any info... Low Saturn and rc1488 were a big help, thanks

Last edited by rabbit_diesel; 08-30-2008 at 02:00 AM.
rabbit_diesel is offline   Reply With Quote
Old 08-30-2008, 06:01 PM   #7
geartooth94
Master Member
geartooth94 will become famous soon enough
 
geartooth94's Avatar
 
Join Date: Mar 2003
Location: Allentown, PA
Posts: 3,879
 
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

nothing wrong with using what parts are available (free) and saving some gas, esp. nowadays.
...
1996 Dodge Avenger ES: 2.5L V6
geartooth94 is offline   Reply With Quote
Old 08-31-2008, 02:16 AM   #8
Titanium48
Member
Titanium48 is on a distinguished road
 
Join Date: Oct 2005
Location: Edmonton, AB
Posts: 416

1998 SL2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Quote:
Originally Posted by geartooth94 View Post
nothing wrong with using what parts are available (free) and saving some gas, esp. nowadays.
Free parts are good, but I wouldn't expect any gas savings if that SOHC is paired with a DOHC transmission. 2200 RPM at 100 km/h in 5th gear is what saves gas, not 8 less valves.
Titanium48 is offline   Reply With Quote
Old 05-11-2011, 05:09 PM   #9
Pacco46
New Member
Pacco46 is on a distinguished road
 
Join Date: May 2011
Posts: 4
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Hi. I have the same problem except I'm using a 95' sohc to replace a 99' dohc. Is there any other things i might need to know?? Will this app work with the dohc ecu?? thanks
Pacco46 is offline   Reply With Quote
Old 05-11-2011, 05:19 PM   #10
Low Saturn
Super Member
Low Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to behold
 
Low Saturn's Avatar
 
Join Date: Aug 2003
Location: San Jose, CA
Posts: 15,308
 

2007 AURA XR
2001 SC2
Default

Quote:
Originally Posted by Pacco46 View Post
Hi. I have the same problem except I'm using a 95' sohc to replace a 99' dohc. Is there any other things i might need to know?? Will this app work with the dohc ecu?? thanks
You'll need the SOHC exhaust manifold, downpipe and a 1999 SOHC PCM (ecu). And hopefully the car has a manual transmission and you're using the manual for a SOHC equipped car.
Low Saturn is offline   Reply With Quote
Old 05-11-2011, 05:23 PM   #11
Pacco46
New Member
Pacco46 is on a distinguished road
 
Join Date: May 2011
Posts: 4
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

The 95 sohc was manual and the 99 is auto. I already got the 99 auto tranny on the soch but am hessitant to drop it in.
Pacco46 is offline   Reply With Quote
Old 05-11-2011, 05:24 PM   #12
Low Saturn
Super Member
Low Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to behold
 
Low Saturn's Avatar
 
Join Date: Aug 2003
Location: San Jose, CA
Posts: 15,308
 

2007 AURA XR
2001 SC2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Quote:
Originally Posted by Pacco46 View Post
I already got the 99 auto tranny on the soch but am hessitant to drop it in.
Dont. Because its not going to work.

The DOHC PCM will not properly control the SOHC engine. And a SOHC PCM can't control the MP7 (DOHC auto) transmission.
...
Mike

-1991 Turbo SL2.
11.809 @ 116.488 mph
www.differentracing.com

-2001 Limited Edition SC2 (#78)
-2001 Chevrolet Suburban
-2007 Saturn Aura XR
-2011 Rally Yellow Chevrolet Camaro 2SS RS
Low Saturn is offline   Reply With Quote
Old 05-11-2011, 05:27 PM   #13
Pacco46
New Member
Pacco46 is on a distinguished road
 
Join Date: May 2011
Posts: 4
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Well all that work down the drain....guess i got no choice but to replace or rebuild the dohc. Thanks for your help saturn.
Pacco46 is offline   Reply With Quote
Old 05-11-2011, 05:29 PM   #14
Low Saturn
Super Member
Low Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to behold
 
Low Saturn's Avatar
 
Join Date: Aug 2003
Location: San Jose, CA
Posts: 15,308
 

2007 AURA XR
2001 SC2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Quote:
Originally Posted by Pacco46 View Post
Well all that work down the drain....guess i got no choice but to replace or rebuild the dohc. Thanks for your help saturn.
You could always try to find a DOHC engine or SOHC manual transmission. I'd look for the DOHC engine.
...
Mike

-1991 Turbo SL2.
11.809 @ 116.488 mph
www.differentracing.com

-2001 Limited Edition SC2 (#78)
-2001 Chevrolet Suburban
-2007 Saturn Aura XR
-2011 Rally Yellow Chevrolet Camaro 2SS RS
Low Saturn is offline   Reply With Quote
Old 05-11-2011, 05:39 PM   #15
Pacco46
New Member
Pacco46 is on a distinguished road
 
Join Date: May 2011
Posts: 4
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

yeah, I think i will find another DOHC......might even turbo the thing...anyway, thanks again Saturn.
Pacco46 is offline   Reply With Quote
Old 05-11-2011, 06:28 PM   #16
almoore
Member
almoore is a jewel in the roughalmoore is a jewel in the roughalmoore is a jewel in the rough
 
Join Date: Aug 2008
Location: Cleveland,Ohio
Posts: 219

1994 SC2
2006 VUE 3.5L
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

I have replaced DOHC motors with SOHC motors.I have not changed any PCM's,or transmissions.Also ,never had any check engine lights.All of the cars ran great.If you have questions,send me a PM.
...
"No good deed goes unpunished"
almoore is offline   Reply With Quote
Old 05-11-2011, 06:33 PM   #17
fetchitfido
Super Member
fetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant futurefetchitfido has a brilliant future
 
fetchitfido's Avatar
 
Join Date: May 2006
Posts: 15,292
 

2001 SC2
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

I'm getting better MPG with my '96 w/ power mods then my old '97 SC1 ever saw. What MPG gain by swapping to the crappy motor?
...
The proper way to fix a S-Series automatic is to replace it with a manual
fetchitfido is offline   Reply With Quote
Old 05-11-2011, 06:43 PM   #18
almoore
Member
almoore is a jewel in the roughalmoore is a jewel in the roughalmoore is a jewel in the rough
 
Join Date: Aug 2008
Location: Cleveland,Ohio
Posts: 219

1994 SC2
2006 VUE 3.5L
Default Re: Saturn Engine Swap Dohc to Sohc Please help!

Mileage gains are almost nil,but if your new SOHC is a good motor,the power loss is not very noticeable.DOHC motors are getting hard to find and are much more expensive here.I can buy a SOHC with 3000 miles,for 600 bucks.A DOHC with 130,000 miles for 750.So for daily transportation the swap makes sense.
...
"No good deed goes unpunished"
almoore is offline   Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Engine Swap: 01 1.9L SOHC into a 98 1.9L DOHC??? zoopieraymo S-Series Tech 4 09-11-2009 09:35 AM
engine swap DOHC/SOHC? ('96) TomM96 S-Series Tech 2 03-25-2005 12:09 PM
93 SL-1 SOHC to DOHC engine swap gotmax S-Series General 4 12-28-2003 09:42 PM
Engine Swap? SOHC ----> DOHC? ProjectSW1 Mods and Performance 0 06-04-2001 09:48 AM
SOHC-DOHC engine swap SlickSL1 S-Series Mods 33 05-26-2001 01:33 PM


All times are GMT -4. The time now is 04:37 PM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2023, vBulletin Solutions Inc.
SaturnFans.com. The Saturn Enthusiasts Site.