Cam timing question on 2.4 with 2.0 gears

[TurboTims]

So I would post this in the tech section but I am not allowed to yet. So I built a 2.4 long rod motor and people say you want to time the motor a half tooth off on the cams. Is this using the 2.4 cam gears? It looks like people are saying do that when using 2.0 cam gears and I just dont understand how this would be equal to installing the cams straight up. I installed my cams with the marks lining up as they should be or as close to it as possible. My motor has been running great. I know this wont be perfect because of the increased deck height but I would think it would be closer then installing the cams half a tooth off.

 

[miguelmcv]

If you are using a 4g63 Cam GEARS,,,,,,,,,, You need the half tooth off.

If you are using a 4g64 Cam GEARS,,,,,,,,,, You need to do the Line marks Correctly.

:: Project Zero G :: - Sirius Engines

 

[1fastlaser]

2.4 g4cs/4g64 with 4g63 cam gears Marking | Galant VR-4 > How To and Info Archive | GalantVR-4.org Mitsubishi Galant VR4 Forum

 

[TurboTims]

...and I have seen that many times but does anyone know why that is the case? Do you just want to run a different degree centerline for the cams when you runs a 2.4 because thats what you are doing...

 

[1fastlaser]

The block is 6 mm taller which changes the cam timing events including with the stroke considering the 2.0 cam gears are marked for. 2.0 motor timing event. If you degree in the cams with adjustable cam gears you can line up the factory marks on the cam gear.

 

[TurboTims]

So people are doing it to change the timing events to 2.4 specs. Are people finding more power this way? Or people just assuming that since its a 2.4 that the 2.4 specs would work best. If people want the same timing at a 2.0 they should use 2.0 gears and line it up like stock. The fact that the block is taller just means the marks may not line up exactly straight but an adjustable sprocket could correct that as thats what I did. Am I missing something?

 

[1fastlaser]

The block being taller changes when the motor or how many degrees the motor will turn to be at actual top dead center. Regardless of what cars you do the motor should be degreed in. My Kelford 272s with my new 2.4 both cam gears had to be retarded 7 degrees while degreed in. The only way to find out if its wrong or how much its off is to degree in the motor even with stock cams. Im sure no one has ever done this.

I ran my old motor with the gears and cams straight up. I think every tooth at the cam gear is 4 which is 8 degrees at the motor...If I remember correctly. The only way to see if anything is right and to get it exact to the motor is to degree the motor in with a cam card, and get on a dyno with adjustable cam gears and play with adjustments.