20v SVT intake cam timing

[BiGbEn]

when putting the timing belt back on a SVT 20v 4age, i noticed that there were 2 marks on the intake cam gear. which one should align to the "backing plate" when piston #1 is at TDC?

i downloaded the 20v manual frm old toymods forums but didnt mention anything about having 2 marks on the intake cam gear.

[takai]

My TODA gears have two marks on them as well. The one further clockwise is marked 5, and the one counter clockwise is marked 4. On the 16v i time off the 4 mark.
Maybe that will help.

[BiGbEn]

mines the stock cam gears running stock cams. and the 2 marks are 90 degrees apart :S

[Hen]

90degrees is a huge difference, so you should be able to work it out.

Set the engine to a known position and then work out about where the cam should be, this should hopefully be in the vicinity of one of the marks.

EG, for cyl 1, set it to TDC at the end of the exhaust stroke. The inlet valves should have just begun to open, so rotate the cam until the valves are just pressed down slightly. Now the one of the cam marks and the backing plate mark should be nearby.

Of course it'd help to know the cam duration and standard overlap (which I don't)

A quick compression check should show if you did it right.

Hen

[BiGbEn]

already had fire coming out the intake throttle

[BiGbEn]

just had a good look at manual and it seems that i got the cam gear marks spot on. i removed the oil cap and notice that intake valve on piston #1 is JUST ABOUT TO OPEN when piston #1 is at TDC. is that right?


assuming i got the timing right, what could explain the fully sik fire coming out of the throttles when trying to fire it up?

[myne]

ignition timing

[BiGbEn]

i thought of that in a way. running coilpacks with microtech. thinking maybe coz batttery was unhooked for quite a while and microtech someho w lost its settings??

basically i had a running 20v b4 with stuffed piston rings. now im replacing it ith another 20v while retaining the same ecu/wiring.

[myne]

I assume it's running a crank angle sensor?
Where is it located? Off the exhaust cam?
Did you remove the exhaust cam?

If you didnt remove the exhaust cam, and the CAS lines up with TDC, then you've put the cam in wrong.

[BiGbEn]

i put the dizzy/crank angle sensor thingy in the wrong way

bloody 20v now i have to pull engine out. wish i butchered my firewall.



also, i thought i might state here for future reference, there are 2 marks on each cam gears. when piston #1 is at TDC, marks on cam gearS should be facing each other. while the other mark should be align to the backing plate.

[myne]

Assuming you've got the cams right, and the 20v's use coil pack like the gze, you might not have to.

Just switch the coils so that 1,4 fire on 2,3 and vice versa. There's your 180 out problem fixed.
your injector timing will be 180 out, but rumour has it that that makes sfa difference anyhow.

[BiGbEn]

i dont know if its 180 degrees off. coz when i was putting it together, i just smacked the dizzy in without looking

[myne]

These are the ones that run off the back of the cam right?
I was of the understanding that they have a slot that the CAS can only fit in 2 ways.
Right, and 180 out. I think there's a little adjustment in the CAS body via a bolt too - right?

[andylaurel]

on a 20v the dizzy is on a half half keyway so you cant misalign it.
on another note, if your quads are shooting flames, could the cams be 180 degrees out and be opening the inlet valves instead of the exhaust valves?

from memory, with mine (ae101) it had 2 marks (dots) on each cam gear but they were 180 degrees from each other (and slightly different sizes) and so i wound the engine over by hand to TDC (compression) and turned the cams by hand to the closest dot. I could see down the oil filler that there was also a corresponding mark on the top of the cam.