Cam timing

[Spyder]

When setting up cam timing, I have heard to zero out the intake cam and advance the exhaust cam 1 or 2 degrees, is this correct?

Thanks.

 

[BogusSVO]

It depends on how your belt drops on.

The cam will Kick a little and throw you off a tooth, before you can get tension on the belt to hold it all in place.

 

[prove_it]

I think he means adjustable cam gears. If so, then the only way to find the best set-up is on a dyno. All cams are different and need different centerlines. There is no magic just set and go. All adjustable cam gears require a dyno to find the right advance or retard.

 

[BogusSVO]

Prove it, yes a Dyno would be best to dial in the cams.

To get close, you can do it in the drive way and use a vacuum gauge attached to the intake.
Adjust the cams 2* at a time, advance the Intake, retard the exhaust until you get highest vacuum reading.

 

[CutlassJim]

To get them dialed in you need a degree wheel and a dial indicator. Then you are advance/retard them on a dyno to move your powerband around.

 

[BogusSVO]

And a pair of solid HLAs so they do not compress under spring tension and fubar your readings.

 

[Spyder]

I rebuilt the engine pretty much to stock.

Used stock cams but had to resurface the head and block so I knew my cam timing would be off.

I did use a degree wheel to find true top dead center then found top dead center of the intake and exhaust cams. The intake was 4 degrees retarded and the exhaust was 3 degrees retarded.

I found in the Galant manual that they specify to zero out the intake cam and set the exhaust cam at 3 degrees. I am assuming that is 3 degrees advanced.

I set my intake cam to 2 degrees advanced on the cam gear because of the 2 to 1 ratio from the crank to the cam. I set the exhaust cam to 3 degrees advanced which sets it to 3 degrees advanced in relation to the crank.

I just wanted to make sure that is what the factory specs called for. As for power, I am not looking for that now, I have no dyno I can use. Or the money to pay for tuning.

Thanks for the help though. I didn't know about using a dyne to degee in a cam.

 

[Spyder]

When I originally assembled the engine, I had the intake cam advanced 2 degrees and set the timing of the engine with a timing light at the recommended 12 degree setting. I have been picking up knock according to my key diver chip and was trying to adjust the cams to see if that had anything to do with it. I did use revised lifters but they are noisy as well.

 

[fuel]

if you are using the revised hydraulic lash adjust lifters with the larger hole, sometimes referred to as '3G' lifters, if they are noisy it would be because they are not getting sufficient oil supply possibly because the head has been shaved too much reducing the oil flow through the supply gallery. I would be pulling the head and porting the gallery hole.

 

[Spyder]

I should be clear, the lifters aren't rattling like someone smacking the valve cover with a ball peen hammer. They just aren't quite as quiet as I have previously experienced.

I ordered the lifters through dsm graveyard. The oil passage in the head was good and I really don't want to take it off. Especially when there are so few miles on it.

Thanks for the tips.

 

[Gizmovr4]

Quoting Spyder:
When I originally assembled the engine, I had the intake cam advanced 2 degrees and set the timing of the engine with a timing light at the recommended 12 degree setting. I have been picking up knock according to my key diver chip and was trying to adjust the cams to see if that had anything to do with it. I did use revised lifters but they are noisy as well.



What engine are you working on? 4G63? base timing of 12 degrees?? I set all base timing at 5deg with the plug grounded out.

Honestly stock motor - why are you even bothering with degreeing cams ?

 

[Spyder]

The final reading when the plug is NOT grounded is supposed to be 12 degrees.

I am using cam gears because the block and head were both resurfaced and my intake cam was off by 4 degrees.

 

[Gizmovr4]

Try grounding the plug see what the base timing is and adjust it to 5 deg! set the cams to zero - Just cutting the head and block will not alter the cam timing by 4 degrees!! or at least I have never seen that! Whatever little the cams are off by will not produce knock or affect drivability!! Not to mention its near impossible to adjust cam timing properly in a motor thats installed in the car.

 

[CutlassJim]

You can't check timing with the plug not grounded. The ECU uses timing to dial in the idle and it jumps ALL over the place.

 

[Spyder]

I will look into it.

The 4 degree measurement was taken several times when I had the degree wheel on and was checking for TDC of the cam in relation to the crank. I re-checked it several time.

 

[prove_it]

Again, without the solid lash adjusters, readings can vary.

 

[Spyder]

I took the reading off the cam lobe it's self, not the roller. The shims shouldn't affect the measurement in that case.