4G18 sohc to dohc

wei87 · Postby **wei87** » August 23rd, 2009, 6:23 am

hello all..
everyone try before?

wei87 · Postby **wei87** » August 23rd, 2009, 6:24 am

did anyone try before convert 4G18 sohc to dohc head?
dohc head which is 4G15 twin cam ck2 model..

QG · Postby QG » August 23rd, 2009, 3:34 pm

18 views with no reply, well yes.

Well I am guessing that no one ever tried this before, but it would be an interesting project though.

7143 · Postby **7143** » August 23rd, 2009, 8:03 pm

this would be a very interesting project....wei87, tried lining up the heads as yet??

*KRONIK* · Postby ***KRONIK*** » August 23rd, 2009, 9:59 pm

the head will line up on the block yes

but how are u goin to control ur electricals??

the two engines though based on the same 4g1X platform carry significant differences in the way the harness and sensors work in collaboration witht eh ECU

my $0.02 (feel free to correct me if my theory proves incorrect)

SCHOLARS · Postby **SCHOLARS** » August 23rd, 2009, 10:46 pm

if u using the 4g15 head u will also use the 4g15 brain and harnest and u can also maybe use the standard tranny instead of the CVT im just saying im not sure. cuz the timing with the 4g18 and 4g15 will be different so the brain from the 4g15 have to be used but the tranny wiring can be an issue if u using the CVT tranny im not ah electrician but im just thinking of the possibility.

QG · Postby QG » August 24th, 2009, 9:31 am

SCHOLARS wrote:if u using the 4g15 head u will also use the 4g15 brain and harnest and u can also maybe use the standard tranny instead of the CVT im just saying im not sure. cuz the timing with the 4g18 and 4g15 will be different so the brain from the 4g15 have to be used but the tranny wiring can be an issue if u using the CVT tranny im not ah electrician but im just thinking of the possibility.

Makes sense so far... 8-)

blazing · Postby **blazing** » August 24th, 2009, 10:31 am

i was going to truy putting the 4g18 crank in the 4g15... moved on now though

*KRONIK* · Postby ***KRONIK*** » August 24th, 2009, 11:15 am

blazing wrote:moved on now though

hows "DAT" coming along??

SCHOLARS · Postby **SCHOLARS** » August 24th, 2009, 10:06 pm

y u want to put that crank in?????

QG · Postby QG » August 25th, 2009, 12:40 pm

SCHOLARS wrote:y u want to put that crank in?????

I was thinking about that statement....shouldn't the 4G1* series use the same cranks??

So adding in the 4G18 crank into the 4G15 may just be a waste of time.

SCHOLARS · Postby **SCHOLARS** » August 25th, 2009, 10:59 pm

d next issue u may have and im not sure is the setting of the timing at the cams and crank what timing belt are u going to use what top and bottom gears etc.

blazing · Postby **blazing** » August 25th, 2009, 11:29 pm

SCHOLARS wrote:y u want to put that crank in?????

stroke is different 82.0mm to 87.3 mm.
would need to check clearance though. just a project i was going to attempt. 4g18 piston is also slightly bigger by 0.5mm.

*KRONIK* wrote:hows "DAT" coming along??

Slow and expensive..

SCHOLARS · Postby **SCHOLARS** » August 25th, 2009, 11:50 pm

ok well we will see an increase in compression which will generate more torque and HP but u have to make sure the pistons dont slap the valves. now since the pistons are bigger will u have sufficient clearance between cylinder walls and piston and rings or do u have to bore d block? plus with the added capacity increased on the block side u should increase the capacity on the head by increasing flow capability intake and exaust.

*KRONIK* · Postby ***KRONIK*** » August 26th, 2009, 8:40 am

^^^^^^^^^

sounds reasonable :shock:

7143 · Postby **7143** » August 27th, 2009, 9:03 am

^ it makes sense....he would get some more power but when you weigh out the financial factors is it realli worth it??and is the power gain going to be considerabli more??

blazing · Postby **blazing** » August 27th, 2009, 9:26 am

financially it will not make sense, just like turboing the 4g15 wouldnt.. but thats the price of being unique and learning on your own.

I had a spare 4g15 on the ground and was getting a block from the 4g18 free. The costly part would be the vitara pistons i was looking for and forged rods. :lol:

*KRONIK* · Postby ***KRONIK*** » August 27th, 2009, 2:30 pm

hmmmmmmm............

SCHOLARS · Postby **SCHOLARS** » August 27th, 2009, 8:13 pm

cost in the project is the main thing

wei87 · Postby **wei87** » August 30th, 2009, 6:44 am

project done ..im using stock 4G18 ecu back...
should be no problem..im not sure yet....my main worry now is not enough

srnoth · Postby **srnoth** » August 30th, 2009, 4:02 pm

Can't wait to hear how this runs!

SCHOLARS · Postby **SCHOLARS** » August 30th, 2009, 8:35 pm

me to i want to c it run

SCHOLARS · Postby **SCHOLARS** » September 3rd, 2009, 11:34 pm

wei87 wrote:project done ..im using stock 4G18 ecu back...
should be no problem..im not sure yet....my main worry now is not enough

d car driving yet ????????? and u have it tranny or box

*KRONIK* · Postby ***KRONIK*** » September 4th, 2009, 10:23 am

hows this coming along???

QG · Postby QG » September 4th, 2009, 5:23 pm

wei87, you feeling any sort of improvements?

chindian88 · Postby **chindian88** » December 2nd, 2011, 6:46 am

wei87 wrote:project done ..im using stock 4G18 ecu back...
should be no problem..im not sure yet....my main worry now is not enough

so has anyone else ever tried this?
i thinking of doing this as well.

i see you used the coil packs but what did you do with the distributor?
can you use the same timing belt?

yes, i know it's an old post