New Fuel Rails and PRV

As I said in a previous blog post, we had trouble getting enough fuel to the first 427 build at 700 chp.  I believe the fuel system was not up to the task, so contracted Kinsler to develop new rails capable of feeding more than 800 chp.  These are custom made and feature .685" ID, with -8AN inlets and outlets.

I will have to run new lines from the pumps to the rails.  Will feed the fuel inlet into the drivers side with -8AN line.  Connect the two rails in the front--there is no A/C compressor in the way, so plenty of room to route the line.  At the end of the passenger side rail, I will connect the pressure relief valve, set to 75psi.  A -6AN return line will send the excess fuel back to the tank.

With the relief valve set to 75psi, my 30lb Red Motorsport injectors will flow the equivalent of 44 lbs/hr-- enough for over 1000chp.

Mid-winter update

You guys are probably wondering where I've gone.  No posts since September on this project.  Had to spend some time doing other things in the fall, and now it's just too damn cold out in the shop to do much.  Nonetheless, some things are moving forward.

• The cylinder heads are installed on the shortblock, torqued to 120 lbs-ft (ARP studs).  Cams and lifters are in place, temporarily.

• Degree wheel is installed, ready to time the camshafts.

On the advice of my camshaft supplier, I will slightly modify the cam timing to suit the new intake flows and higher compression (14.5:1 from 12:1).  New timing will be ICL: 109 ATDC / ECL: 111 BTDC.  This compares to 107/109 on the first build.  Perhaps idle quality will be a touch better with the less valve overlap.

• Fuel system design continues.  This includes new rails with larger ID, and a new regulator to bump fuel rail pressure to 75 psi.  The Bosch series III injectors handle that pressure just fine, and the better atomization should help combustion efficiency.  We will feed the rail with -8 supply lines (1/2" ID).

• Crankcase evacuation strategy continues to develop.  I am convinced the main issue with the previous build causing oil in the combustion chambers, was due to the flow through the stock PCV system.  At idle the manifold vacuum was sufficiently low (~60-65 kpa) to prevent the valves from closing, thus allowing significant oil and vapor back into the intake manifold.  This time around, I plan to vent the crankcase directly to a catch can.  I'd appreciate feedback from anyone who's done this.  I know it was done successfully on a recent LT5 for racing application.  At 14.5:1 compression, the combustion chambers have to be oil-free.

• The calibration and datalogging setup continues to mature.  I will initially use Tunerpro RT with a custom dash, including a new ALDL stream to monitor exactly the variables I want (such as commanded Lambda).  A NTK wideband output, and a dedicated fuel pressure sensor will be fed into the stock ECM for monitoring.

• And lastly, in a few weeks the top end pieces (plenum, airhorn, cam covers) will be going out for powdercoating.  Not real urgent on that one.

Until next time.

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.

Bottom End Assembly

In this installment, the bottom end rotating assembly is assembled.  To start, I again relentlessly wipe the bores down to make sure they are as clean as possible.  Acetone on a white shop rag, followed by Dexron ATF (note: I used the Dexron III-type fluid, which is conventional.  The Dexron VI is a synthetic.)  The rags came out clean, so the bores must be clean :)  To make sure the crankshaft is also free from debris, I used 75psi compressed air to blow out the oil gallery before installing the threaded pipe plugs.

First up, I installed the main bearings.  These are the OEM bearings, with a dry-film coating from the first buildup.  They showed virtually no wear, so are being reused.  The main bearing studs, and outer perimeter sump studs are installed into the block.  The coarse threads get a light coat of 30wt oil.

 

 

 

 

The main bearings were lubed with Torco assembly lube, and the crankshaft was carefully set into the block.  At this point, I also installed the front crankshaft oil seal o-ring, lightly lubed with oil.  By this time, the A136 Permabond had arrived from Jerry's Gaskets, and was applied to the sump.

 

 

The main bearing studs' fine threads, as well as the washers and nut face were lubricated with ARP's Ultra Torque lube.  The mains were torqued in steps--30 then 52 ft. lbs in the order specified in the service manual.  Finally, the M12 studs on #1, #3, #5 bearings were torqued to 80 ft. lbs.  The perimeter studs were torqued to 24 ft. lbs.  The crank spins easily after all the nuts are torqued.  I also checked the thrust clearance, which was within spec at .008".

 

 

Connecting rod bearings were installed in the rods, lubed with Torco.  The piston rings were carefully aligned, with the gaps at least 120 degrees apart.  The skirts and rings were given a light coat of oil before insertion into the bores.  An ARP tapered ring compressor makes this process pretty easy.  The rod caps and new Carrillo SPS multiphase rod bolts were installed, lubed with ARP Ultra Torque.  The bolts were stretched to the middle of the Carrillo spec, .006", using an ARP rod bolt stretch gage.  The proper stretch was achieved with 58 to 60 ft-lbs of torque.

 

 

Finally, the oil pump, crank sprocket, guides, chains and idler gear were installed.  New seals on the pump, anti-seize on the crank gear, and Loctite 262 on the bolts where specified.  I also took the occasion to disassemble the idler gear and apply some light assembly grease to the needle bearings.  And that's as far as I am going before assembling the heads and timing the camshafts.  Starting to look like an engine again....

 



Rotating Assembly prep and other things

Been a few weeks since I last posted about this build.  An impromptu vacation and a couple of customer calibrations to finish came first.  Several small things have been completed, and at this stage I'm about to drop the crankshaft into the block.  Just waiting on a fresh bottle of A136 from Jerry before I can finish the bottom end.

Combustion Chamber volume:  I measured the volume of the combustion chambers with a 100cc burette.  Since the first build, we are using new copper-beryllium valve seats and larger intake valves, so I needed to confirm the chamber cc's to determine final compression ratio.  Sealed the valves and the plexiglass overlay with white lithium grease.  The results were a little surprising.  the chambers measured 47cc's.  (I was expecting 49cc)--the new valve job reduced the volume by 2cc's.  That leaves the final compression ratio at 14.8:1.  Was aiming for closer to 14:1, but will be running race fuel anyway, so not a big deal.  << Update: after assembling the shortblock and taking accurate piston-to-deck measurements, the final compression is 14.55:1.  The pistons are .003" above the deck at TDC.>>

Piston pin assembly:  Back to the bottom end, I installed the round wire locks in one side of each piston pin bore.  These locks can be tricky to install, but with a little practice and a small flat-blade screwdriver, it got a lot easier.  These are .068" thick round wire locks, and were installed with the ends at 6 o'clock relative to the pin bore.  A bit of assembly lube (Torco MPZ HP) on the piston pin, and ready for the other lock.  It is important to get the pistons oriented correctly on the rods so that the large chamfer on the rod is facing towards the crank cheek, while the intake valve pockets also face the inside of the engine.  Seems simple, but I double and triple checked this before locking the pistons to the rods.

Piston Rings:  This build uses Total Seal AP steel rings.  All the end gaps were set by the machinist, so I won't show that here.  Top and Second end gaps were set at .019".  The rings were marked specific to each individual bore, but the bore dimensions were so identical, they could have been installed in any hole and been fine.  Nevertheless, I installed them in the same position they were set up for.  The oil rings use a support rail because the pin bore intersects the oil ring groove.  The support rail has a raised "dimple" on one side, which needs to face down and centered in the pin bore opening.  The support rails were installed first, then the expander, then the two scraper rings.  These are custom 3mm oil rings, at 14# tension.  The second ring is .043" Napier style, so orientation is important.  The top ring is .043" steel, and is installed with the inner chamfer facing up.  Checked the vertical clearance between the rings and piston-- all <.0015", which is the smallest feeler gauge I have.  Tight vertical clearance is expected with these high end rings and gas ports.

Crankshaft checks:  One other thing I checked at this stage is the straightness of the crankshaft.  I had no reason to believe there was a problem, but checked it nonetheless.  This was done by placing the #1 and #5 upper main bearing shells in the block, and placing the crank into position.  Using a dial indicator on the center crank journal, I rotated the crankshaft a complete revolution.  There was zero measurable runout, so all is good.

The crank came back from the machinist with the threaded oil plugs removed.  Using compressed air, I blew out all the oil passages.  They were clean anyway, this was just a precaution before installing the plugs.  The pipe plugs get a light coat of Loctite 565 sealant before being installed.

Next time I hope to install the crank and pistons and finish the bottom end.

Pre-Assembly Part 1

So, the components are back from the machinist and I've started to prepare things for assembly.

 

Today, the bores were checked for cleanliness.  Wiped down with a white shop towel.  All clean, so a fresh coat of Marvel Mystery Oil on the bores.  The hone finish was right where Total Seal recommended--Rpk: 10, Rk: 30; RVk: 35.

Next task was deburring the piston skirts.  A few of the custom Ross pistons had been touched with a die grinder to get the weights equal across the set.  There were some rough spots on the skirts, which I smoothed with Cratex rubber abrasive.  A quick scrub with soap and the pistons are ready for assembly.

Next week, I plan to install the crank and pistons into the block.  Stay tuned.