Cylinder Head assembly

This installment will detail the set-up and assembly of the cylinder heads, including valves and valve springs.  One of the most time-consuming element of the entire build, careful attention to detail is required here to ensure the valvetrain is durable and remains in control at high engine speeds.  Here are the springs and components.  Eibach single springs, titanium retainers, hardened steel spring seats, locks and shims.

I've posted before about the tedious work to shim the valvesprings.  At the bottom of this picture is the coated steel shim.  I got hundreds of these NASCAR take-off shims from Ebay for next to nothing, they work great.  First step was measuring the valve stem height from the base of the spring pocket.  I didn't take pictures of that, but it requires a simple cylindrical aluminum fixture with a 1" dial indicator at the top.  I used a 2" standard to set the initial gage height, then the actual height of the stem is measured.  Other inputs you need to set up the spring heights are the thickness of the spring seat (.040" in my case), and the retainer to tip distance (.150").  My valve stem heights were: 1.5825"-1.5895" intake, and 1.581" to 1.591" exhaust.

Next step was to install the new valve stem oil seals, and lubricate the valves with Torco.  These oil seals are low profile, so will clear very high lift cams.

Before putting it all together, I used this valve spring tester to make sure all of the springs were still in spec.  Measured a brand new one, then checked all 32 against that standard.  Variation was minimal, and all were within spec, however, I did replace the three weakest ones just for peace of mind.  Weak in this case was 5 pounds lower than the others.  Probably would have been fine.  I set both intake and exhaust springs up to .060" from their coil bind height.  That required approximately .020" shims on the intakes and .050" shims on the exhaust.  In this case, the intake spring force will be about 6 pounds higher than the first build, and the exhaust about the same.  Intakes are now 63 lbs closed, and 172 lbs open / exhausts are 69 and 173 lbs.

 

 

And here is the finished product, ready to install on the shortblock.



Setting valve spring heights

Not much to report lately.  I have paused the engine assembly while I get the top end ready for installation.  As it stands, the short block is ready to go.

As anyone who's used the ARP head studs know, one of the studs on the exhaust side needs clearancing for the cam sensor disc.  In my case, I need .060" taken off.  From what I've heard from other builders, this varies quite a lot.

I rechecked the piston to deck clearance, and found .003" above the deck.  Much better than I initially thought.  The machinist's deck height measurement must have been off slightly.  Final Comp ratio now 14.55:1

Next major task is setting up the cylinder heads.  New intake valves, so I had to carefully measure the stem height with a fixture and dial indicator.  The valves and seat height were remarkably consistent, yet I still had to shim each intake valvespring to get the exact height.

What a boring way to spend the afternoon.... measuring a few dozen shims.

These were sorted to the nearest .0001".  Probably within the measurement error.  Regardless, I elected to shim the intakes a little closer to coil bind height.  Last time, the intakes were .075" to coil bind.  I intend to rev this engine a bit harder, so I have chosen to set the springs up at .060" to coil bind.  This gives just a tick more spring force throughout the lift curve.

Now the exhaust valves need to be thoroughly cleaned... lots of carbon from the first build.  Then I can set up the exhaust spring heights.  It's a dirty job to de-carbon the valves, no wonder I've been putting it off till now.