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2G Cam Sprocket marks won't align

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lglracer

Supporting VIP
318
61
Jul 13, 2008
Sacramento, California
Hey everyone,
Having a bit of a problem with trying to get the timing marks across the cam sprockets aligned correctly. Current setup is 2g head, hks 272 regrinds, and fidanza adjustable sprockets. I have tried to get them to align and either the inside marks are lower or higher than the outside marks. I've tried stock cam gears and they do the same thing also tried a different belt. I have a question on the regrinds. Do they change the pin location on the cams? I am unsure of how to go about setting the cam sprockets. Everything else lines up. Both pins are up at 12 o'clock. If I set the inner marks lower than the outside do you think the belt will stretch enough to get them straight under tension. I wouldn't think so but just looking for possible issues to look for or fixes I can do.
 
Yes, upload some pics is a good idea. Hard to tell without pics.

I really don't think the dowel pins are relocated. In 80s or 90s when adjustable cam gear was not common, some people used to do that to adjust the valve timing but in general not on cams side, relocate the dowel pin holes on cam gear.
How about the crank and the oil pump sprocket marks? It sounds like you are not properly set the all timing mark or just thinking too much. (Maybe you got confused with the cylinder head top edge line. it is inclined a bit if engine is mounted in car, so do not focus too much if the dowel pins are set at exactly 12 O'clock or not)
And sometimes it doesn't get exactly all line up if you have milled the head and/or the block and/or using a thiner/thicker head gasket. But just a few degree different, won't be that much.
Just make sure to set the cam gears at zero and should try it again with taking your time.
 
Yes, upload some pics is a good idea. Hard to tell without pics.

I really don't think the dowel pins are relocated. In 80s or 90s when adjustable cam gear was not common, some people used to do that to adjust the valve timing but in general not on cams side, relocate the dowel pin holes on cam gear.
How about the crank and the oil pump sprocket marks? It sounds like you are not properly set the all timing mark or just thinking too much. (Maybe you got confused with the cylinder head top edge line. it is inclined a bit if engine is mounted in car, so do not focus too much if the dowel pins are set at exactly 12 O'clock or not)
And sometimes it doesn't get exactly all line up if you have milled the head and/or the block and/or using a thiner/thicker head gasket. But just a few degree different, won't be that much.
Just make sure to set the cam gears at zero and should try it again with taking your time.
I took my time with doing it each time to verify everything was lined up correctly. Ive done about 10 timing belts and never had any issues. The cams and crank all align up correctly, did 6 rotations, and everything aligns again. Its just the alignment marks going across the sprockets are not aligned but pins are at 12 o'clock.
 
Has the block been decked and the head surfaced? That will throw the marks off a tad bit.
Get us some pictures of the marks and we can try to be of more help.
 
might be a dumb question but never hurts to rule out. the fidanza cam gears: dont the have two different pin holes depending on if its a dsm or evo? could one of them be in the wrong pin?
 
might be a dumb question but never hurts to rule out. the fidanza cam gears: dont the have two different pin holes depending on if its a dsm or evo? could one of them be in the wrong pin?
My fidanza's have both holes, but when the marks are correct or close, the dowels are still straight up.
 
So here is where I am at. Everything is lined up. Did my 6 full rotations and verified tensioner pin can move easily. The marks in the middle are low. Now if I adjust it over a tooth the marks at high in the middle. I can do that while everyone is reading this post. I am using the non Evo hole on both cam gears.
 

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looks good to me.. I found out the hard way after fighting with mine over and over that Fidanza is never quite 100% on their markings on the gear. Mine were ever so slightly off as well and it drove me nuts.. to the point where I was about to return the gears and just run the stock setup as they always lined up perfectly. I did the right thing, called on help from some more experienced DSMers.. and kicked myself for not reaching out to them sooner when they said "oh yeah.. that's normal with those gears"..:ohdamn:
 
Here is my concern. Is that the stock cam sprockets do it also. When ive done mine in the past it has always been straight across and perfectly matched up. Just being cautious as I have never ran into this issue. Which way should I setup the fidanza gears. With the marks lower or higher, both pins are at 12 o'clock.
 

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Note where the marks are on the stock sprockets. The intake is on a tooth and the exhaust is between the teeth. Note that the marks on the Fidanza sprockets are a bit off. When the cams are in the correct locations the pin on the intake is at 12 but the exhaust is advanced from 12. IIRC about 3.5 degrees but check the manual. The Sprockets will line up tooth to valley to the bottom of the head like in your picture of the stock sprockets.

Your picture of the Fidanza sprockets looks off to me. The Intake looks advanced (high at the alignment mark) and retarded on the exhaust.
 
Your picture of the Fidanza sprockets looks off to me. The Intake looks advanced (high at the alignment mark) and retarded on the exhaust.
The cam gears with with be advanced or retarded where they are and if I move a tooth the switch being Advanced and retarded.
 
As I said, the alignment marks on cam gears won't line up exactly if the both side intake and exhaust dowel pins are exactly at the same position like what @steve said. This is because inner and outer mark have a half tooth different. So if the inner (middle) alignment marks on cam gears line up then the dowel pin on exhaust cam gear will be about a half tooth (3.75 degree) off from 12 O'Clock position and the outer marks also off from the line.

As @motomattx said, what you have to align is the inner alignment marks, that's why I mentioned not to focus too much to the position of dowel pins, that makes you confused more.

Note, After rotate, the belt already has tension.
While you are putting the belt you are doing that without tension on the belt which means the belt still slightly has a play. When you rotate it, the belt gets tension on it and the valve springs would be compressed.

The tensioner is under the exhaust cam gear which means the exhaust gear will be pulled back (retard) and the crank gear will be pulled forward (advance). The amount of the difference would be depending on how much you have milled the block/the head and how much the belt has been stretched (how old). Also the cam profile.

This is the difference before and after rotate with tension and the difference would affect the valve timing, so that's why you have the adjustable cam gears to adjust this difference.
 
The belt is brand new. So I imagine it won't stretch much. Does the head being milled actually affect the difference of the timing marks? I would thin it would not matter because the tensioner takes up the extra space. As far as I know the head is rebuilt and resurfaced. So now that everything is tensioned do I need to adjust the gears about half a degree? The dowels look at 12 o'clock. Or leave it alone and call it good for now until it gets tuned?
 
The belt is brand new. So I imagine it won't stretch much. Does the head being milled actually affect the difference of the timing marks? I would thin it would not matter because the tensioner takes up the extra space. As far as I know the head is rebuilt and resurfaced. So now that everything is tensioned do I need to adjust the gears about half a degree? The dowels look at 12 o'clock. Or leave it alone and call it good for now until it gets tuned?
If speaking strictly, actually there is a difference on each product's quality. (well it is very little)
Yes, it would affect. But not only milling the head, also the block and the thickness of head gasket would affect. You are right that the tensioner takes up the extra space but which means... for instance, if you shave off total 1mm from the head and/or the block, now the distance between the head and the block is 1mm closer, and the belt is longer = more play (distance gets shorter but you still have the same tooth count/the same length of the timing belt), which means the tensioner would push the belt more and the cam gears/the crank gear move more after the timing belt gets tensioned.

You can adjust half a degree or so, if you would like to. In general, you advance the cam gears slightly to adjust when you mill the head/block (this would depend on how much have been milled). Also this can be adjusted by head gasket thickness. But I don't think you really "need" it. I think most of people are running without realizing/caring about this. And in this case you probably won't feel it much since the difference is very little.
 
Ifor instance, if you shave off total 1mm from the head and/or the block, now the distance between the head and the block is 1mm closer, and the belt is longer = more play (distance gets shorter but you still have the same tooth count/the same length of the timing belt), which means the tensioner would push the belt more and the cam gears/the crank gear move more after the timing belt gets tensioned.
If you mean that the distance between the cam centerline and the crank centerline is now 1mm shorter and creates a small timing offset from stock, I agree.

(unless age as addled me more than I suspect) Remember that the tooth pitch is fixed and the belt doesn't run in a straight line between the intake sprocket and the crank, it runs on a diagonal to the idler pulley and back on a diagonal to the oil pump sprocket and those diagonals reduce the effect of the linear difference in the centerlines on the rotational positioning (timing). On other engines people make adjustable idler pulleys to change the belt path length to account for the difference but you could accomplish the same thing by measuring the cams "centerline" and adjusting the sprockets to line everything up with TDC.

On an engine that is stock, tensioning the belt doesn't change the timing any unless you have messed up. The path length doesn't change from the intake cam to the crank like it does on the tensioner side to take up the slack.
 
If you mean that the distance between the cam centerline and the crank centerline is now 1mm shorter and creates a small timing offset from stock, I agree.

(unless age as addled me more than I suspect) Remember that the tooth pitch is fixed and the belt doesn't run in a straight line between the intake sprocket and the crank, it runs on a diagonal to the idler pulley and back on a diagonal to the oil pump sprocket and those diagonals reduce the effect of the linear difference in the centerlines on the rotational positioning (timing). On other engines people make adjustable idler pulleys to change the belt path length to account for the difference but you could accomplish the same thing by measuring the cams "centerline" and adjusting the sprockets to line everything up with TDC.

On an engine that is stock, tensioning the belt doesn't change the timing any unless you have messed up. The path length doesn't change from the intake cam to the crank like it does on the tensioner side to take up the slack.
Yes. I meant that if the distance between the center point of cam/crank changes, the valve timing will change, too. (we call it center point in japan, sorry maybe the word is japanglish)
 
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