sohc dohc LAST questions (hopefully)

Boris · Post by **Boris** » May 28th, 2006, 2:19 am

I know you're all probably sick of the SOHC-->DOHC questions but I have two more...

Wiring harness: I searched and it looks like the SOHC will work... Can anyone confirm this? Would it be better to go with the dohc harness? Is there another harness out there i should buy?

Aaaand are all the engine mounts the same too??

Thanks, can't wait to start doing this swap... i know everyone thinks that I should probably go BP but just wait and see, this thing will be quick.

ariesdude · Post by **ariesdude** » May 28th, 2006, 5:48 am

Here are some differences that affect wiring -

SOHC
-1 Wire O2 Sensor
-3 Temp Sensors
-Rad fan controlled by the 3rd temp sensor
-Disty has just the angle sensor - external coil
-Does not have EGR
-Does not have VICS
-Uses Vane type MAF

DOHC
-3 Wire O2 Sensor
-2 Temp Sensors
-Rad fan controlled by ecu
-Disty has angle sensor, ignitor module & ignition coil
-Has EGR system
-Has VICS
-Uses Hot-Wire MAF

The front, rear and right (near timing cover) mounts should be similar if not same.

The list is in no way complete - I have also heard that B6DE ecu will not plug in to the SOHC Harness - but hey, if you can make it work - more power to you - literally!

TEAMpK · Post by **TEAMpK** » May 28th, 2006, 12:56 pm

I would go with the DOHC harness.

Josh · Post by **Josh** » May 28th, 2006, 3:00 pm

TEAMpK wrote:I would go with the DOHC harness.

WTF??

you are nutz

use the SOHC harness. how in the heck do you think everyone swaps to a BP or BPT, they dont swap to a dohc harness, thats for sure. way too much hassle for a crappy system. you dont want the DOHC harness at all, its a P.O.S.. use the SOHC harness, and plug in a BP ECU, thats it nothing to it, unless you want to run the VICS then you run a couple wires, thats it. you can even use your SOHC VAF, but i would strongly recomend going up to at least a BP VAF or 2nd gen RX7 VAF. your sohc already has everything you need for the swap. all you need is to get the thermostat housing, and distributor from a BP and your golden, the sohc thermostat housing might work too, i havent really looked, its so you can get your fan relay sensor in there. it is way too much hassle to swap over to the dohc harness, and for something thats a pain in the a-- to tune with its definatly not worth it, especially when you will gain alittle more ponnies from swaping up to the BP ecu, with way less work and money. bottom line B6DE ECU and wiring system is a POS, you will make more power with the SOHC harness and BP10 ECU, more air comming into the engine more fuel, more power, higher redline 7800 vs 6500 (and it will handle the higher revs just fine and will not prematurly wear the valve train out like most suggest). i know what way i would go iv done it. i swaped my DE harness out for an SOHC harness for better tunning

Boris · Post by **Boris** » May 28th, 2006, 11:42 pm

Great. Thanks again Josh, definitely put my mind to ease.

This swap is sounding easier every day

And DAMN a 7800 rpm redline! When you told me it raised my redline I had NO idea it would raise it that much!!

Ahhh can't wait to have a car that can exceed the speed limit

atlantamx3 · Post by **atlantamx3** » May 29th, 2006, 12:02 am

The redline of the BP is 7000 rpm.

http://web2.airmail.net/theman/protegefaq/

And the redline of my old SOHC was 6250... but I had an automatic too.

Josh · Post by **Josh** » May 29th, 2006, 2:51 am

atlantamx3 wrote:The redline of the BP is 7000 rpm.

http://web2.airmail.net/theman/protegefaq/

And the redline of my old SOHC was 6250... but I had an automatic too.

i have had this debate before, but everyone i know running a BP10 ecu redlines at 7500 rpm and it will go alittle further. could be the stock tach is off a bit. i think its more realistically around 7200.

atlantamx3 · Post by **atlantamx3** » May 29th, 2006, 9:48 am

That might be the RPM of the Fuel cut, but the redline is 7000.

ariesdude · Post by **ariesdude** » May 29th, 2006, 1:20 pm

Boris - are you swapping a 1.6L DOHC(B6DE) head onto a 1.6L SOHC (B6ME) block?

or are you swapping a 1.8L DOHC (BP) head onto your 1.6L ? SOHC (B6ME) block? (it doesnt even seem possible without modification to he block)

Which intake manifold are you going to use? B6DE or BP?

From what i have read -
BP is very much the same as SOHC except for VICS (and it is DOHC). B6DE is different in terms of wiring and sensor locations.

Josh · Post by **Josh** » May 29th, 2006, 3:41 pm

ariesdude wrote:Boris - are you swapping a 1.6L DOHC(B6DE) head onto a 1.6L SOHC (B6ME) block?

or are you swapping a 1.8L DOHC (BP) head onto your 1.6L ? SOHC (B6ME) block? (it doesnt even seem possible without modification to he block)

Which intake manifold are you going to use? B6DE or BP?

From what i have read -
BP is very much the same as SOHC except for VICS (and it is DOHC). B6DE is different in terms of wiring and sensor locations.

you cant swap a BP head on a 1.6 block. the block on th e BP is longer so the head is longer too. they wont bolt up. he is swaping a B6DE head on an SOHC block. it can be done, all that needs to be done is blocking off two oil ports on the exhaust side of the head. a 323 DOHC head will bolt rite on, but the ports are smaller so less power.

Boris · Post by **Boris** » May 30th, 2006, 12:51 am

NOPE no BP. Goin with the 1.6L

I was gonna try the head swap. Changed my mind.

I looked at the car, and saw it only has 126 000 km on it. With the head off, I noticed how clean the block looked so I bought the block for $100. But ya I placed the SOHC head gasket onto the DOHC head and it lined up perfectly, so technically I think I could've done the head swap. Still not sure about the whole pulley situation though (tensioner+idler on DOHC as opposed to just a tensioner on the SOHC). I'm sure once I take a close look at it all, I'll realize there's an easy solution to that problem.

I will do a write up about the the engine swap, and maybe take post some pictures of the SOHC head gasket on a DOHC head so that everyone believes it'll fit, once and for all.

mazdamx3sohc · Post by **mazdamx3sohc** » June 11th, 2006, 3:15 pm

oh man oh man oh man.....hes chosing the 1.6 dohc over the bp?......