SOHC to DOHC conversion - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

CrazedPanda · 10-18-2006, 10:42 PM

Ive seen a lot of threads about swapping an entire SOHC KA engine for a DOHC. my 1990 240SX has relativly low miles on it but im wanting to put a DOHC cylinder head, intake, etc into it without swapping the whole engine. Does any one know if there are any problems with this and what does the whole process involve?

**Phlip** · 10-19-2006, 06:21 AM

Not worth the time, money, effort and all that other bullshit.
It has been discussed and is "possible," if I remember correctly, but by the time you've blown the cash in doing so, you could have your single cam boosted, or have swapped in a twincam, and possibly damn near have IT turbo.

Long story short: Don't bother, the ends would not justify the means

Duzzes_Wild · 10-19-2006, 06:28 AM

you might as well just do a full swap, i find engines and tranny's for free or almost free all the time

im in the process of the doing the swap right now as a matter of fact, but mostly bc the shell didnt have a engine in it but its a 89 sohc chassis

revd34 · 10-19-2006, 06:34 AM

edit:
don't bother with just swapping the head. do the whole engine.

**mrmephistopheles** · 10-19-2006, 06:38 AM

No, the OP is talking about slapping a DOHC head onto a SOHC block.
It's been done, but it's a PITA, especially if you don't know what you're doing.

CrazedPanda · 10-19-2006, 05:16 PM

I know my way pretty well around an engine, and if i dont know something i have a lot of people around me who do. but are the wiring harnesses any differnt? I want to put a turbo on it later, I just want the extra cam to increase flow. also will I have to use a PS pump from a DOHC and a distributor and other things? what parts can i just keep and reuse?

projectRDM · 10-19-2006, 06:01 PM

If you've read any of the threads you wouldn't be asking these questions.

Using a DOHC head requires the DOHC steering pump, rebuilding the lines, and converting the distributor over to run off the idler gear. You also have to modify the head a great deal, and there's plenty more changeovers past that.

CrazedPanda · 10-19-2006, 06:35 PM

alright it does sound like just swapping the whole motor over will be the easiest option. thanks

**Phlip** · 10-20-2006, 12:28 AM

^^^ You know, I really DID tell you that 12 hours before you bothered to accept that answer, right?

CrazedPanda · 10-20-2006, 05:10 AM

yeah i know, just needed to hear ir a couple times.

*NemeGuero* · 10-20-2006, 05:21 AM

Hey, just swap the whole engine.

(in case you still weren't convinced.)

CrazedPanda · 10-20-2006, 03:33 PM

thats definitly the plan now, plus i can do some work to the DOHC before it goes into the car

10-18-2006, 10:42 PM	#1
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	SOHC to DOHC conversion Ive seen a lot of threads about swapping an entire SOHC KA engine for a DOHC. my 1990 240SX has relativly low miles on it but im wanting to put a DOHC cylinder head, intake, etc into it without swapping the whole engine. Does any one know if there are any problems with this and what does the whole process involve?

10-19-2006, 06:21 AM	#2
Phlip Yes, I look like that Join Date: Mar 2002 Location: In my supervillain's lair Posts: 27,980 Trader Rating: (19) Rides Gallery: Phlip Feedback Score: 19 reviews	Not worth the time, money, effort and all that other bullshit. It has been discussed and is "possible," if I remember correctly, but by the time you've blown the cash in doing so, you could have your single cam boosted, or have swapped in a twincam, and possibly damn near have IT turbo. Long story short: Don't bother, the ends would not justify the means __________________ Weirdo And I write too!

10-20-2006, 12:28 AM	#9
Phlip Yes, I look like that Join Date: Mar 2002 Location: In my supervillain's lair Posts: 27,980 Trader Rating: (19) Rides Gallery: Phlip Feedback Score: 19 reviews	^^^ You know, I really DID tell you that 12 hours before you bothered to accept that answer, right? __________________ Weirdo And I write too!

10-20-2006, 05:21 AM	#11
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	Hey, just swap the whole engine. (in case you still weren't convinced.) __________________

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10-19-2006, 06:28 AM	#3
Duzzes_Wild Leaky Injector Join Date: Aug 2006 Location: asheville Age: 37 Posts: 93 Trader Rating: (0) Feedback Score: 0 reviews	you might as well just do a full swap, i find engines and tranny's for free or almost free all the time im in the process of the doing the swap right now as a matter of fact, but mostly bc the shell didnt have a engine in it but its a 89 sohc chassis

10-19-2006, 06:34 AM	#4
revd34 Zilvia Junkie Join Date: Oct 2006 Location: burbank, SoCal Age: 38 Posts: 338 Trader Rating: (2) Feedback Score: 2 reviews	edit: don't bother with just swapping the head. do the whole engine.

10-19-2006, 05:16 PM	#6
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	I know my way pretty well around an engine, and if i dont know something i have a lot of people around me who do. but are the wiring harnesses any differnt? I want to put a turbo on it later, I just want the extra cam to increase flow. also will I have to use a PS pump from a DOHC and a distributor and other things? what parts can i just keep and reuse?

10-19-2006, 06:01 PM	#7
projectRDM Post Whore! Join Date: Dec 2002 Location: Atlanta Age: 51 Posts: 13,812 Trader Rating: (12) Feedback Score: 12 reviews	If you've read any of the threads you wouldn't be asking these questions. Using a DOHC head requires the DOHC steering pump, rebuilding the lines, and converting the distributor over to run off the idler gear. You also have to modify the head a great deal, and there's plenty more changeovers past that.

10-19-2006, 06:35 PM	#8
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	alright it does sound like just swapping the whole motor over will be the easiest option. thanks

10-20-2006, 05:10 AM	#10
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	yeah i know, just needed to hear ir a couple times.

10-20-2006, 03:33 PM	#12
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	thats definitly the plan now, plus i can do some work to the DOHC before it goes into the car