Hi i was told by everyone that you can put a Dohc head on a Sohc block and it will lower the compression.To build a turbo motor.So i went and put new exhaust and intake valves and valve giude seats and lapped the valves in my Dohc head. I had it checked for warpage and it was milled 5 thousadths. So i put my motor together .I finally started it this afternoon. With no boost. And it ran great for awhile then i gave it just alittle rpms and when it reached idle it stalled. So i check the timing and it skipped a tooth. I went to retime the car and found i couldnt turn the camshafts over when the piston was at TDC. But before i started the motor the first time i timmed it it did the same thing and when i went to turn it again they moved fine so i figured what the hell its ok. Then today when i went to timew it again i find it doing it again and my dad is like whoooa thats not right and im like what the hell.He asked me if what eevryone is telling me is correct about the head swaps. What the hell is wrong here. The engine did not make a single noise like the valves were hitting the pistons.

 

Are the roller rockers the same between exhaust and intake sides. Is there a valve lash adjustment on the Dohc heads or is there sumthing im missing that im doing wrong here. If the pistons and the head are that close this is not Low compression.

 

ive never seen that happen unless your out of time, do you ave all the DOHC timing parts in? are your cams stock?
theres no adjustments, no nothing. obviously it ran so you must have the right cams in the right place.
are you sure your timing it right? line up the notches together on the gears, and i belive both dowell pins go up.

also make sure your cam gears arent on backwards

 

you might have one of the cams off too much and its causing the valve tojam againstthe piston when its at tdc...........try to move the piston down a bit beofre you adjust the cams....

i personally wouldnt of bothered with the dohc head on a sohc block.....
if the bottom end is stock, then you wont be able to run enough boost to bennefit from the lower compression

 

you may have the cams in upside down. that seems to be a common problem with new folks.

 

Well how do you know if the cam gears are in right and the cams are in right. I thought you couldnt mix the cams up because of the cam sensor on the one cam.

 

there is a hole in each cam. make sure they are up at tdc.
you should be able to read 2.0 or 2.4 on the cam gears.
for 2.4's, you can use a 2.0 exhaust cam and a 2.4 intake cam. using a 2.0 intake cam requires rotating the cam magnet 90 degrees.

 

Ok so i checked it and i read the Hanes manual for the NEON. It told me that you have to time the marks and then put the bearing caps on and then time the crank. Is there anything else im missing. how do you keep the cams from spinning while putting on the bearing caps.

 

the cams wont spin when putting on the bearing caps

 

Well i put it together and started my motor yesterday and it runs great, but i sacrficed my damn turbo it blew the seals out i forgot to hook up my waste gate. Im mad but now i need it rebuild. Does anyone know where to get it rebuilt! Any help would be nice.