Thinking crazy CAM thoughts

[Justin DuBois]

So yeah, I don’t have the tools to do it right, so I’m looking for ideas on how to set cam gears with web cams “in the infield of the ball park” of a stock advance, if there is such a thing, that I just made up.

I have these CAMs, (see pic) and I want to try them.

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I got this idea, and I wondered if its been done? works, doesn't, never seen that etc.

I think I could bolt in one cam to its resting pin up (DSM) orientation, and then replicate the tooth alignment seen with stock cams in their resting pin up orientation:

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[Justin DuBois]

Here is the example:
Exhaust Web Cam resting position relative to stock intake cam resting position is about one tooth off.

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1G CAMs relative resting position:

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If I correct the AEM gear position to match the stock cam relative position, it moves the degree indicator on the gear to +6deg advanced. +6 is now my new 0deg TDC. Its no wonder why these cams with stock gears ran wonky:

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I can do the same thing with a Web intake cam and stock exhaust cam, to set a relative position

 

[jdxnc]

So what I'm getting is you want to swap the cams and cam gears without redoing the timing? Is it possible? Yeah. Is it sketchy and tricky? Also yeah. Done it.

You'll almost definitely need to reset the tension adjustment regardless to have the proper tension, so at that point, just pull the belt and do it properly.

 

[Justin DuBois]

So what I'm getting is you want to swap the cams and cam gears without redoing the timing? Is it possible? Yeah. Is it sketchy and tricky? Also yeah. Done it.

You'll almost definitely need to reset the tension adjustment regardless to have the proper tension, so at that point, just pull the belt and do it properly.

I don't have the engine out and a degree wheel to set the cam's like your are supposed to. I'm trying this resting offset idea. The WEB cam lobes do not appear well aligned to the stock TDC pin location. A long time ago I threw these on the engine with stock gears and the idle was all over place lumpy.

 

[Justin DuBois]

That’s got to be better than blind right? It might even be within +-1deg

 

[DSMPT]

Here is the example:
Exhaust Web Cam resting position relative to stock intake cam resting position is about one tooth off.

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1G CAMs relative resting position:

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If I correct the AEM gear position to match, the stock cam relative position, it moves the degree indicator on the gear to +6deg advanced. +6 is now my new 0deg TDC. Its no wonder why these cams with stock gears ran wonky:

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I can do the same thing with a Web intake cam and stock exhaust cam, to set a relative position

Maybe I am not understanding what exactly you are trying to do, but if I understood correctly, no this way won't work. Technically what you are doing is copying the stock cam ramp starting point. There is no point to do that since they have different ramp design. And even the starting position would be different each time because you are not using solid lifters or applying oil pressure to the lifters to make the lash always as zero. When the lifters are bled down or pumped up, the cam rests in different position.

That’s got to be better than blind right? It might even be within +-1deg

It's opposite, actually what you are doing is the blind way. You should install them straight as it should. That would be better.

 

[Justin DuBois]

Maybe I am not understanding what exactly you are trying to do, but if I understood correctly, no this way won't work. Technically what you are doing is copying the stock cam ramp starting point.

The resting point is not exact, but it is based on cyl4 lobes and cyl2 lobes under spring pressure fighting it out to hold the cams rotational position on the rollers.

It's opposite, actually what you are doing is the blind way. You should install them straight as it should. That would be better.

I’m listening, but not quite there - because I’ve tried these cams with stock gears which would be the same as AEM 0deg results.

 

[DSMPT]

The resting point is not exact, but it is based on cyl4 lobes and cyl2 lobes under spring pressure fighting it out to hold the cams rotational position on the rollers.

Spring pressure has nothing to do with the valve timing. What you need to pay attention first is lifter's height/valve clearance (lash). This is the reason why you must use solid lifters to degree cams. Without solid lifters, a degree wheel and a dial indicator, you can not know what position you are actually at.

I’ve tried these cams with stock gears which would be the same as AEM 0deg results.

Yes. And that's the way to use them without the tools to degree cams or dyno.

 

[Justin DuBois]

The intake Web CAM set to 0 deg has nearly the same resting offset as a stock CAM.

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I’ll have to re-visit this idea when the new head is on and proven to start with stock CAMs

 

[1990TSIAWDTALON]

It may just be the picture angle, but you look out of time.
Dowels up,
Level with deck, not in the picture.
I would recheck that timing, just to be sure. I had a motor that had head AND deck work and I had mine off. It didn't hurt anything but was 1 tooth off.
Just a thought. Don't want you to hurt anything.
Marty