[Gach]

Yeah he’s doing valve adjustment wrong.

[Shockwave78]

Originally Posted by Gach

Yeah he’s doing valve adjustment wrong.

why would it be different if the cylinder that was being adjusted was on tdc of the compression stroke? Wouldnt the lifters have to be on the base of the lobe? Im not trying to be stubborn, just genuinely confused as to what difference it would make.

[78w72]

Originally Posted by Shockwave78

why would it be different if the cylinder that was being adjusted was on tdc of the compression stroke? Wouldnt the lifters have to be on the base of the lobe? Im not trying to be stubborn, just genuinely confused as to what difference it would make.

I will let others explain why its different, but basically the cam isnt on the base circle for both valves when a given cylinder is at TDC... but for now just trust it is different and readjust everything following the link I posted. Loosen all the nuts & get the engine on #1 TDC compression stroke and adjust the valves shown in the link... engine has to be on TDC of the compression stroke. If youre not sure how to verify compression stroke just ask, its very simple to do. Then you rotate it as described and do the other valves shown.

This is very important, understand it later but readjust correctly before running it any more.

[Gach]

You don’t have to do in the firing order either. When exhaust starts to open adjust intake when intake starts to close adjust exhaust. That way your on heel of the cam in both events.

[78w72]

Originally Posted by Gach

You don’t have to do in the firing order either. When exhaust starts to open adjust intake when intake starts to close adjust exhaust. That way your on heel of the cam in both events.

That is the best way to do it... but for smaller cams, adjusting certain valves at a certain engine position works very well like in the link I posted earlier. I have done that on cams with ~.480 lift as well as stock pontiac cams I made adjustable.

["QUICK-SILVER"]

Originally Posted by Shockwave78

why would it be different if the cylinder that was being adjusted was on tdc of the compression stroke? Wouldnt the lifters have to be on the base of the lobe? Im not trying to be stubborn, just genuinely confused as to what difference it would make.

Doing one cylinder at a time at TDC Compression is fine. Following firing order it takes two turns of the crank to get it done. 90° at a time.

Just like the directions posted says to do #1 intake and exhaust when #1 is at TDC Compression.

Clay

[78w72]

Originally Posted by "QUICK-SILVER"

Doing one cylinder at a time at TDC Compression is fine. Following firing order it takes two turns of the crank to get it done. 90° at a time.

Just like the directions posted says to do #1 intake and exhaust when #1 is at TDC Compression.

Clay

Good to know it works on each cylinder.. IF it really is at TDC compression for each one. The link posted only requires 1 complete turn of the crank, then can do multiple valves at each position.

Pull the plugs to make turning it easier or bump the starter to get close, then creep up on TDC by hand.

[Stan Weiss]

Originally Posted by 78w72

Good to know it works on each cylinder.. IF it really is at TDC compression for each one. The link posted only requires 1 complete turn of the crank, then can do multiple valves at each position.

Pull the plugs to make turning it easier or bump the starter to get close, then creep up on TDC by hand.

If you look at the graph I posted you can see that you be a number of degrees on either side of TDC and both will still be on their base circle.

Stan

[Gach]

Let me explain cam timing hopefully this helps. Lets say cam card says installed at 109. So you think if you put it dot to dot. Piston on top dead center you should be ok. But thats no guarantee that its actually in at 109. This is why you degree a can in, and its the most accurate way of making sure it’s actually in at 109.

I once got a cam from H-O racing, when I installed it, dot to dot. Piston on top dead center. I went crazy, thing had no power and it was a bigger cam then what was in there, so god it should make a little more power and not be slower. Finally degree it in.

Long story short, I degree it in with heads still on, when we checked it, it was supposed to be in at 108. It turn out to be in at 113-1/2. Come to fine out, a whole batch of those H-O Crane cams ended up on a 114 instead of the 108.

So what I’m telling you is checking the timing Marks and piston being at top dead center while a good idea there’s no guarantee that cam is actually in at 109.
It could very well be in at 112-113 which would be really retarded.

But who knows you could be also experiencing valve adjustment issues. If you get the valve adjustment issues straightened out and still have same issue then I would definitely get that cam degree in.

[Gach]

One more thing, if the base circle on the new cam is bigger then old cam, now that push rod is going to be to long, so why I said try going just a 1/4 turn vs 1/2 turn. Kind of Reason we check for push rod length. Made me think of that when he said backing off the nut then did compression test and compression went up to 175. Obviously it was Holding valve open. We don’t always think to look or compare base circle of the cams. And make sure Valve train geometry is correct.

[Shockwave78]

Originally Posted by Gach

One more thing, if the base circle on the new cam is bigger then old cam, now that push rod is going to be to long, so why I said try going just a 1/4 turn vs 1/2 turn. Kind of Reason we check for push rod length. Made me think of that when he said backing off the nut then did compression test and compression went up to 175. Obviously it was Holding valve open. We don’t always think to look or compare base circle of the cams. And make sure Valve train geometry is correct.

I actually did check the base circle difference, the new cam is 1/8 inch smaller than the factory cam