My 4.3 vortec 84 FB

[freeskier7791]

Looking good!  Engine building is pretty fun when you know what you are doing

[rk970]

More pics, got one head on and a fancy timing pointer. I also took .132" off he snout of the harmonic balancer for the thickness of the 60-2 trigger I will be running.










The lifter preload I got set at .062"

[rk970]

Working on the 60-2 crank trigger.  I used a lathe to remove material from the snout of the harmonic balancer equal to the thickness of the trigger wheel. (0.132"). I did this so I would not have to use spacers on the water pump or alternator. I also made a centering ring that goes through the pulley/trigger wheel to center on the harmonic balancer.

[rk970]

Vr sensor mount is done.. .025" clearance.  Runout on the trigger wheel I got down to -+ .002" with a few highly calculated taps with a plastic faced hammer.  On another unrelated joy was the flywheel bolts. I got a set of ARP bolts for the flywheel and 85ft/lbs is a pita when your on your back. 

[digitalsolo]

That sensor setup came out really well!

[rk970]

I used 3/16" plate, I uses a U drill bit (.368") so when it bolts to the block it lands in the same position every time.  It's not adjustable for clearance so it took a little bit of hammer work and anticipation of what the welds do when they cool and pull the Metal around.

[digitalsolo]

Should be worth it when done.   I need to finish up a setup like that on the front wheel of my Mustang, so I feel your pain on the tedious-ness of being that exacting.

[Cobranut]

I did mine without welding.  Has a bit of adjustability so easy to setup.
I'm using a GM 58x sensor, since I plan to go back to an internal reluctor whenever I tear the motor down.

[rk970]

It runs
https://youtu.be/Th1sBiaEHXE
Got 200 miles on it and the plugs are clean..
1st oil change at 100 miles, I know its normal but I still cringe with the metallic paint look..
anyhoo I am changing the oil again tomorrow.  1st two oil changes are at 100 miles each, then 500, 1000, 1500 and 4k after. 

[rk970]

Just an update, 800 miles on the engine so far.. 
I used a spare output on the ecu to control the wb02 controller.  When rpm goes over 750 a 30 sec timer starts before it comes on. It has a relay on the positive feed of the sensor heater circuit. I also pulled +5v from the MSII board to power the wbo2 controller.  I did this to gain accuracy that voltage offsets can introduce when the controller has its own 5v regulator.



So as I got 800 miles on the engine I started to push it a little harder.  Power was dropping off a cliff @5100rpm.. Having 106lbs on the seat and 270lbs over the nose of spring pressure was not cutting it.  I was in the process of shimming the springs up another .060"  (1.800" to 1.740") to get the seat pressure up to 122lbs and 287 over the nose. After I got the 4th cyl done I remembered that I had another set of springs.. 128 on the seat and 320 over the nose @1.800 installed height and 7gram heavier. 




I also pulled the intake manifold off because it was seeping oil from the back, I did not put enough RTV on the corner were the china wall meets the cylinder head.  I put in a set of Morel 6504 lifters since I was sick of all the noise the ls7 lifters were making.  I shimmed the rocker pedestals also .020" (due to the valve job). My lifter preload came in at .038 to .042" with the stock length 7.200" push rod (considering the block is decked .025" and the cam has a .060" smaller radius base circle) 
The axle on the old lifters are swaged the Morels use a wire retainer on both ends.

top-line 2148 on the left (ls7) Morel 6504 on the right.
It is a lot quieter now, like a the faint sound of a singer sewing machine. Not the angry 12 elf's with little hammers. What surprised me was the change in the VE table.  My 4400 @100kpa bin went from 94 to 103, everything up from  4000rpm and 75kpa needed more fuel.  Its quite entertaining now, if I roll on in 1st @1800rpm its leaves a copious amount of rubber on the road, if I catch 2nd before the rev limiter hits I can carry it through 2nd gear also.  Oil level on the dip stick does not move in 200miles.
All the pain and misery a project can cause just melts away when you mash the skinny pedal down..

[FC3S Murray]

Nice clean FB! Congrats on everything running smooth.
Your angry elf comment made me spit out my coffee this morning laughing! Great description!!


Strange about the VE improvement with the lifter change....what ever came about this? Defective pushrod seat?? Sloppy roller??

[spacevomit]

Maybe it was floating the valves because the spring pressure was insufficient. That would lower dynamic compression.

[rk970]

Well the marks on the stems from the valves rotating, usually caused from spring surge/bounce. It was definitely a condition of insufficient spring pressure/rate.  I consider the valve springs a maintenance item and will be replacing them every 15~20k miles. 
As to the lifters, 3 had a stupid leak down rate.. like you can push on the rocker arm and get the lifter to bleed down in 4sec.  The Morels have better QC (lower and more constance leak down between lifters) and are a much different design..   

[freeskier7791]

Well the marks on the stems from the valves rotating, usually caused from spring surge/bounce. It was definitely a condition of insufficient spring pressure/rate.  I consider the valve springs a maintenance item and will be replacing them every 15~20k miles. 
As to the lifters, 3 had a stupid leak down rate.. like you can push on the rocker arm and get the lifter to bleed down in 4sec.  The Morels have better QC (lower and more constance leak down between lifters) and are a much different design..

Glad to see that everything is working out for you,  I am looking at those Morel lifters now, my stock lifters are super noisy, but guideplates and roller rockers can do that.

[rk970]

No pics but another update.
I pulled a valve cover as preventive precaution to take a look see at the valve train.  Some of the valve springs looks somewhat not concentric with the valve stem.  I aired up #1 cyl and pulled the springs and put in the check springs (I did not want to keep compressed air on it all day).  I kind of have a love-hate thing with comp cams. The springs are comp 26918 supposed to be 125 on the seat at 1.800in.  Went to a friends shop to check the springs,,guess what.. 108lbs at 1.800 and not very parallel, tossed em in the round file.  Pac-1219 @ 1.800 shows 138 on the seat and 315 over the nose. It now will pull hard to the rev limiter.  HR cams are nothing like setting up a sold flat tappet cam (I have much more experience with thoses)
My 35ahr U1 agm battery is dying, (I have a 56f capacitor across the battery that was masking it).  The battery was 8 years old after all.  I was having a hard start issue and it was driving me nuts trying to tune it to start, it was cranking fine but voltage was dropping to 8.9V
Updated the firmware on the MSII to 3.4.4  don't know why but it seams to run better on it. 
19 mpg mixed hoon/city/10%hwy.
I will dig one of the comp spring springs out of the bin and post a pic soon. (I Was kinda pissed about that one)
 


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