383 Vortec/TBI Build Thread

74 Shortbed · Sep 7, 2017

I agree, but if you have to grind it don't let it get hot keep dipping it in water.

Daveo91Burb · Sep 7, 2017

Thanks fellas. I just ordered what I'm pretty sure is correct length ARP stud kit on Amazon. $9 shipped, probably best all around plan.

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74 Shortbed · Sep 7, 2017

Daveo91Burb said:
Thanks fellas. I just ordered what I'm pretty sure is correct length ARP stud kit on Amazon. $9 shipped, probably best all around plan.

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Yes, most definitely..

Daveo91Burb · Sep 9, 2017

MikeB said:
Yes, use the 1.6 rockers if your heads can handle the lift. Check carefully because on some Vortec heads the spring retainers will hit the guide seals at .450" lift. Really. Also, the pushrods may rub the edge of their guide holes. Maybe neither will be an issue with the very low lift of the stock cam.

So what's best way to check this stuff? I was just going to install two lifters/pushrods/rockers as a mockup and then get each to full lift and check coil bind with a feeler gage but the lifters won't be pumped up and solid. That will affect my measurement correct? I think I can take those two apart and replace springs with washers to make them solid? What tool do you need to take apart lifters? Needle nose pliers do it? I'm using used, stock oem vortec rollers.

74 Shortbed · Sep 9, 2017

I use old solid lifters for mock up..

Daveo91Burb · Sep 10, 2017

I don't have any solids, unfortunately. Not sure where I could even get a couple of solid rollers.

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74 Shortbed · Sep 10, 2017

Bummer, I used to have a few laying around but they got in the way and I **** canned them just kept two for myself.

MikeB · Sep 10, 2017

Daveo91Burb said:
So what's best way to check this stuff? I was just going to install two lifters/pushrods/rockers as a mockup and then get each to full lift and check coil bind with a feeler gage but the lifters won't be pumped up and solid. That will affect my measurement correct? I think I can take those two apart and replace springs with washers to make them solid? What tool do you need to take apart lifters? Needle nose pliers do it? I'm using used, stock oem vortec rollers.

Don't worry about coil bind because retainers will hit seals first. Also, I have seen solid lifters with different cup height than corresponding hydraulics.

To determine how far the valve will move before the retainer hits the seal, I typically remove the valve spring and install a light test spring. (If heads are already installed, bring the piston up so the valve won't drop into the cylinder. Or stuff some rope in the spark plug hole.) If you don't have a test spring you can simply pull upwards on the retainer to hold the valve closed while you or a helper take the measurement with a 6" machinist ruler or possibly calipers. Do at least one intake and one exhaust valve per head. You may find a .020"-.030" variance. I did.

On my Vortecs, the seals weren't pressed on fully, so I tapped them down another .050" or so using a socket and an old seal. What you want to end up with is .050"-.060" safety margin. For example, if the cam gives you .450" lift at the valve, you'd want at least .500" valve travel. I was able to get around .510" travel as I recall. I later went to LS6 beehive springs and Comp Cams retainers & locks to end up with around .560" -- good enough for .510" valve lift. The difference is due to the Comp cams retainer sitting higher on the valve.

Valve fully open. Pull up on retainer and measure how far it travels.

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If necessary, tap down seals using a socket and old seal to get .050"-.060" safety margin.

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Daveo91Burb · Sep 11, 2017

MikeB said:
Don't worry about coil bind because retainers will hit seals first. Also, I have seen solid lifters with different cup height than corresponding hydraulics.

To determine how far the valve will move before the retainer hits the seal, I typically remove the valve spring and install a light test spring. (If heads are already installed, bring the piston up so the valve won't drop into the cylinder. Or stuff some rope in the spark plug hole.) If you don't have a test spring you can simply pull upwards on the retainer to hold the valve closed while you or a helper take the measurement with a 6" machinist ruler or possibly calipers. Do at least one intake and one exhaust valve per head. You may find a .020"-.030" variance. I did.

On my Vortecs, the seals weren't pressed on fully, so I tapped them down another .050" or so using a socket and an old seal. What you want to end up with is .050"-.060" safety margin. For example, if the cam gives you .450" lift at the valve, you'd want at least .500" valve travel. I was able to get around .510" travel as I recall. I later went to LS6 beehive springs and Comp Cams retainers & locks to end up with around .560" -- good enough for .510" valve lift. The difference is due to the Comp cams retainer sitting higher on the valve.

Excellent, thanks. All makes pretty good sense to me. So if the valves pass this clearance test, I won't have to worry about the coil bind?

Guess I'm finally going to get to use my valve spring compressor that a friend gave me a while back.

Heads aren't installed yet - kind of nice to be able to do this test without them being installed.