Resolved Gsc Billet S2 cams / valve openings

[FIBA M - EC17PSE]

Hey so these cams are new to me and only ever been on stock cams so its now all fully being reworked and the cams are bigger I know that.

My main concern is the valves and whats open and whats not!
Cyl 1 is all closed.
Cyl 2 ext is open
Cyl 3 intake is open
Cyl 4 both are open and exh is open more.

Now if the blocks set to TDC then the pistons are at the top on 1-4 so the head having cyl 4 valves open is going to be a problem. Is this normal of GSC cams and are they really that close to being on the overlap on opening and closing?

Its all torqued up and lifters bled down as I always have done when removing them. But thats not keeping them open but the cams are.

So just wanting to clarify these cams are like this?
I have yet to turn the cams to see the cycle as I dont have a wrench with me for that but will do tomorrow. But any knowledge until then would be great.

Thanks Bobby

Pics attached and fyi the lower valves are exhaust side.

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[pauleyman]

I'm not seeing what you're seeing at #4 and the cams aren't dowels straight up. Put a set of gears on it and put a tool in between the gears and then see where the valves are. I would recommend bolting down the head with all 4 pistons in a neutral position then rotate number 1 up once you've got head on and dowels up. Then install belt.

 

[DSMPT]

My main concern is the valves and whats open and whats not!
Cyl 1 is all closed.
Cyl 2 ext is open
Cyl 3 intake is open
Cyl 4 both are open and exh is open more.

It's normal. It would be like that when you set the cams cylinder #1 in the end of compression stroke on an engine that has 1-3-4-2 firing order and valve overlap. How much opening would depend on the cam profile though.

Now if the blocks set to TDC then the pistons are at the top on 1-4 so the head having cyl 4 valves open is going to be a problem.

If the problem you are referring to is the cylinder #4's piston to valve clearance at TDC because all the valves are open due to valve overlap, then no, usually that's not a problem.

Is this normal of GSC cams and are they really that close to being on the overlap on opening and closing?

So just wanting to clarify these cams are like this?

It's normal, not only GSC cams. You still have a head gasket thickness and valve relief depth, so you would usually have more clearance than you imagine. How much clearance you have is depending on the cam profile, the piston top design, valve size, head gasket thickness, cylinder head thickness and block deck height though. Usually no need to be worried if everything is off the shelf parts and if you have proper valve springs.

 

[FIBA M - EC17PSE]

Thanks for the replys chaps.

I put the cam gears on and alignment tool and for the gears and cyl 4 did close a bit more. So i guess it is down to the larger profile and overlap of the lobes.

I wanted to make sure this was normal and ok before I go to far and needed to check something else out

Thanks all