timing question about camshafts

[Brian O Conner]

okay, so I know you have to get the camshafts to be lined up were the lines meet both camshafts but does it have to be exactly a 180 degrees from each other. I notice the cams move four seprate times when your turning them and it doesnt exactly line up a 180 degrees but they do touch each other. Its really hard to explain in words but Ill load up pictures in a few if you guys cant relate.

 

[bewstin]

Your cams are at top dead center when the line on each cam gear is parallel with the surface of where the head meats the block. Both Cam gear lines should be facing each other and the dowel pins on the gears should be facing up.

This link has a pic http://www.dsmtuners.com/forums/newbie-forum/449777-why-my-cas-maxed-out.html

Scroll down and look at the pic of the cam gears, that's what it should look like, notice the dowel pins on the cam gears are facing upwards as well

 

[007jimmy]

yes they have to be exactly lined up.. youll notice right above the center bolt there is a dowl pin on each cam. that has to be facing up and your timing marks on the cam and crank tone wheel have to be lined up as well. if you dont take the time to do it properly and double check it by spinning the motor over 6 times by hand then you could be looking at alot more work then just a timing belt. here is the best pic i have from my most recent build

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[DSM1G90]

Why we roll the crank sprocket six times is due to the 2 to 1 ratio of crank sprocket and cam sprockets being it takes the crank sprocket two rotations for the cam's one.

Six times the crank rotation brings all of the marks back together in line with each other.

True though; cam marks HAS to be dead across from one another when doing belt installs. No, "just abouts", or "close enoughs" are allowed.

-DSM

 

[bullettdsm]

Both Cam gear lines should be facing each other and the dowel pins on the gears should be facing up.

This link has a pic http://www.dsmtuners.com/forums/newbie-forum/449777-why-my-cas-maxed-out.html

Scroll down and look at the pic of the cam gears, that's what it should look like, notice the dowel pins on the cam gears are facing upwards as well

youll notice right above the center bolt there is a dowl pin on each cam. that has to be facing up and your timing marks on the cam and crank tone wheel have to be lined up as well.

No ^

He has a 420a. Dowel pins are one up (exhaust) and one down (intake). They do not have an adjustable cas.

Yes, Brian the lines need to be straight across, in line. Here's a couple of links;
2GNT.com - PROPER_TIMING_MARK_ALIGNMENT
2GNT.com - Timing_Belt_Replacement

MB

 

[Brian O Conner]

Hey gentlemen I got it to turn 6 times and no resistance at all(valves hitting pistons). Also the drill bit in the tensioner can come out and in freely as well BUT!!! in the hanes manual it says to line the cranksprocket 1/2 tooth before the Woodruff key mark. When the cams align on the 6 turn it aligns when the woodruff key is parallel to the crankshaft mark arrow. Is that good is the timing on my engine complete? Am I ready to throw on the valve cover and install this badass machine?

 

[bullettdsm]

Hey gentlemen I got it to turn 6 times and no resistance at all(valves hitting pistons).

By this you mean valves are NOT hitting correct?

Am I ready to throw on the valve cover and install this badass machine?

Nope.

Here's what I do; First I align the cams without a belt (be sure that the 2.0 on the gears is facing out. Or the adjustable cam gears are zero'ed out). Then I slip the belt on the cams only. I then use a quick clamp to hold the belt on the gears (you can use anything from paper clips to zip ties to keep the belt in place). Then I go down below where I have the crank arrow mark (ignore woodruff key, follow the arrow in the links I posted up). I have this just about on the mark (ever so slightly BEFORE the arrows line up). Then thread the belt as it should go (except for the crank. Read on to see how I do that) I then keep some tension on the belt on the water pump side as I put the belt on the crank pulley (basically make sure there isn't any slop on the belt on that side, so that when you tighten up the belt - when bolting down the tensioner - the slop is then taken up on the tensioner side).

When you have it all tightened down, crank it over by hand a multiple of two (2,4,6,8 who do we appreciate ) and check your marks. If they are not aligned, simply do that process again.

I'd like to see three pics; one of the cam gears lined up, another of the cam lobes themselves (the lobes on the number one cylinder with the holes in the cams shown as well) and third pic of your crank arrows lined up.

That will keep us on the same page.

MB