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DOHC HEad on a SOHC

Posted: Wed Apr 22, 2009 10:53 pm
by 97neon
ok i have a 98 sohc .... how hard is it to do a DOHC swap ??? i already have the dohc head , dohc pcm and wiring harness

Joe

Posted: Thu Apr 23, 2009 1:14 am
by sabu
You will need new manifolds, a new timing belt and water pump. A day to work on it depending on how fast you are. Crank pulley puller, beer and a new head gasket with new head bolts. If you can do a head gasket and not get lost you can swap a head. To be honest just drop a 2.4L in and be done with it. 8)

Posted: Thu Apr 23, 2009 6:53 am
by jamieely
With the drop in compression I would guess you will gain nothing from the swap. Will go from 9.8 to about 9.3-9.4 You would be better off leaving the head and switching to DOHC pistons. I just did this yesterday and it kicks ass.

Posted: Thu Apr 23, 2009 9:05 am
by roysneon
New head bolts aren't necessary if they're not stretched.

A new waterpump is a good idea if it hasn't been changed lately.

Posted: Thu Apr 23, 2009 11:05 am
by sabu
For the sake of not doing a job twice and the 40 bucks the head bolts cost I usually replace them anyway. Why take a chance.

Posted: Thu Apr 23, 2009 10:53 pm
by AMM
sabu wrote:For the sake of not doing a job twice and the 40 bucks the head bolts cost I usually replace them anyway. Why take a chance.
well up above u said " you will need" a water pump and head bolts, not "i would suggest them to be safe". im pretty sure thats why roy said that. hell i was gonna say the sam thing he did.


mike

Posted: Sat May 02, 2009 10:42 pm
by 97neon
so swapping out dohc pistons on my sohc would be my best bet ???


thanks for all the info guys !!!

Posted: Sun May 03, 2009 11:55 am
by Ghost Neon
jamieely wrote:With the drop in compression I would guess you will gain nothing from the swap. Will go from 9.8 to about 9.3-9.4 You would be better off leaving the head and switching to DOHC pistons. I just did this yesterday and it kicks ass.
This is often the assessment, but is not correct. I did this swap two neons ago out of despiration, with noticeable gains. Even before the swap, mods included a iceman, atx tb, af/x udp, and r/t mtx. With a dohc head in its place, 2500 to 7k felt more commanding. The swap was, and has always been the best bang for the buck mod for a neon. With the addition of a ebay head and mopar pcm, the car was quite impressive, for the handfull of mods on a stock looking neon. The magnum head is the only comparible head to the dohc, but still is limited in tuning and cam options. And is (in most cases) more expensive.

Posted: Mon May 04, 2009 3:51 am
by domesticated
97neon wrote:so swapping out dohc pistons on my sohc would be my best bet ???


thanks for all the info guys !!!
actually the sohc are better.
sohc: 9.8
dohc: 9.6
a dohc head on an sohc block will have slightly higher performance

Posted: Mon May 04, 2009 11:18 am
by Ghost Neon
Are you running dohc pistons at the moment? If not, you should. Using dohc pistons on either head is better than the sohc pistons. The dohc head and pistons are obviously better, so there is your ideal combination.

Posted: Tue May 05, 2009 12:14 am
by DOHCRT
domesticated wrote: actually the sohc are better.
sohc: 9.8
dohc: 9.6
a dohc head on an sohc block will have slightly higher performance
DOHC head with SOHC pistons will have lower compression. DOHC pistons are slightly domed. Thats why DOHC pistons with a SOHC head will yield around 10.3:1 CR. The SOHC head has 48cc chambers as opposed to the DOHC's 54cc, if I remember correctly.

If you ever plan on running larger cams, go with the DOHC pistons. You will want the extra compression.

Posted: Tue May 05, 2009 8:39 am
by metal_gear_jon
The bowl area on the Dohc head is slightly larger because of the larger valves, so that's why Chrysler had to use the domed pistons. Remember bore X stroke are the same on both engines so this explains the compression ratio difference. But the Dohc heads on the Sohc block would make a good low boost turbo set up, but like DOCHRT said, would be a dog N/a but still run.

Posted: Tue May 05, 2009 4:44 pm
by domesticated
good call, i didnt know they were different. im not much into sohc's. they have a following but dohc always yields better performance