Building a small block

[04SilveradoMykk]

The tried and true, dime a dozen small block chevy.

So far I don't have a dime into this, so all is well.

::Monster Garage Voice:: FREEBIE!

85-95 LO5 350, one piece rear main, 4 bolt mains, roller cam block w/ TBI heads the first of the "swirl port" heads.



The motor has had a recent rebuild, .030" overbore and crank turned .010"/.010"

more freebies. L31 vortec heads with complete fuel injection. I already removed the poppet spider.



I already tore the block down and discovered why this motor was put on somebodies backburner. Cyl # 5 had an exploded piston, but did minmal damage to the cyl wall. The minor ring scuff will get taken out with another .010" overbore. BTW, I love the use of the flat tappet RV cam in a roller motor.







I originally intended to throw a stroker crank at this project, but after tearing it down and seeing that a machine shop balanced the rotating assembly I might just keep the crank and with the .040" bore run a 357ci small block. All in the name of empty pockets.

Aside from Cyl # 5 the entire block & heads are in excellent condition. The TBI heads still have the reman heat tabs on them, they are currently up on craigslist. I couldn't get a .002" feeler gauge under a straight edge anywhere on the deck surface. The cylinders have maintained a perfect 4.030" circle without any taper, egging or ring ridge and all of the bearings were un-scuffed. That was a recent rebuild before the mishap. Aparently the story is that the previous owner tossed the TBI for a carb, and had it jetted down so the motor was running consistantly lean & hot. Although I don't see any evidence of over heating.



was bored, so I figured a duplicolor rebuild was in order and dress up while it's on the stand untill I can really get balls deep into it. Nevermind the perimeter bolt VC on centerbolt heads.



So stay tuned for the finished SBC. I am tapped out of expendable income for the month of July... so it will be a couple months before I put it back together.

I've given myself a budget of about $1500 total to have this puppy done, most of wich will be in the valve train.

And yes, before you ask. This motor is for my 04. Wait, so why not a LS/LQ based swap like what came in the truck from the factory?

I'll tell you why.

Because the L31 is the perfect candidate for a 4.3L to V8 swap. The fuel injection is practically identical and all of the 4.3L accessory brackets, serpentine belt system & pullies and engine control sensors can all be used on the L31 V8.

Performance parts for the old small block chevy are just a fraction of the cost of LS parts. I can retain a few currently used 4.3L performance parts. The K&N intake can be modified to work with the V8. The 75mm CFM-Tech throttlebody will transfer over. I already have HPTuners to write the v8 tune. The only custom work to be done will be modifying the trucks wiring harness for two more injectors. Exhaust work, I might as well do a set of long tube headers. And a motor mount adapter plate to adjust for the v8 re-located motor mount provisions.

I can play with gasket matching, port & polish and I plan to upgrade the vortec F.I. spider and clearance the valve guides for a high lift cam.

And finally, what custom street machine isn't complete without a small block chevy... I mean, come on ;)

the Desktop Dyno estimated output for a .040" over vortec 350 with head work, LT4 hot cam & 1.6 RR's.



I also wanted to build another small block chevy reminisant of the engine I had built in college. This one is a .020" over 2 bolt, 2 piece rear, aluminum L98 heads with a summit 1105 flat tappet cam. This motor made it's home in my 1936 chevy rat rod.










Cheers ~Mykk

[chevy7398]

tbi trucks never had roller cams, chevy trucks did not get roller cams until 1996 with the vortec motors, the block you have is the same block from late third gen camaros and firebirds which did recieve the roller cam.

[04SilveradoMykk]

A few snags. I decided against the pistons I originally settled on... availabilty was tough, and everytime I found a place with them the cost kept going up... So instead I decided on some Hypereutectic aluminum flat tops with 4 valve reliefs... the engine kit arrived today and they sent me 70cc dished pistons. Yikes, I am not building this motor for 8.5 compression ratio!

I also noticed that the rod with the exploded piston is slightly tweeked. I have extra 5.7" rods in the shop, but now I need to balance the entire rotating assembly... so if I can find a 383 kit priced right I might still go that way.

[04SilveradoMykk]

I just printed out the wiring ECM schematics for a 2002 G Van 5.7L(0411 PCM) and the PCM harness schematics for my 2004 Silverado 4.3L.

Every single pin is identical between the two computers. The V6 PCM has blank pins where the V8 has the two extra injectors. And where the V8 has EGR pins the V6 is blank... however, even thought the V6 & V8 have injectors in the same pins. They are not the same cylinders, I have a feeling that has to do with firing order.

So we'll see, I'll try my current PCM re-wired and re-tuned.... if it doesn't work I'll snag a 0411 PCM.

[04SilveradoMykk]

Craigslist is great for an engine builder.

Last night a buddy and and I drove down to Phoenix from Prescott ( the worst rain storm) He bought a non-running 1995 Eagle Talon, lol. and I figured I'd find something for myself while we're going down there.

I found a dude who had an entire ZZ4 rotating assembly for cheap!



Forged Crank, Rods, Pistons, Dampener, Flex Plate, Timing Chain Cover, Valve Covers, ZZ4 roller cam, roller rockers all for about the price of a generic Pistons, gaskets, oil pump & freeze plugs rebuild kit.... so score!

[04SilveradoMykk]

Made a EGR block off plate today.



Dropped off the ZZ4 parts at my shop. The part number on the cam is actually a GM Performance parts LT4 hot cam. But I'm not sure if I can trust it. The part number on the rocker arm box is for GM Performance 1.6 roller rollers but has stamped steel stockers inside. So I'll put a mic on the cam lobes and see if the lift is matches a LT4 cam or ZZ4 cam.





Going out of state for a week, I'll pick up where I left off when I get back.

Cheers ~Mykk

[04SilveradoMykk]

A few parts had arrived. The Proform 1.6 ratio roller rockers, Comp Cams beehive springs, retainers & locks... they're just mocked up on the heads. I still need to do all the machine work.



Say goodbye to the stock stamped tin valve covers, they won't clear the polylocks

The geardrive also arrived, and I'm modding the plastic vortec timing cover so the idler axles won't dig thru them. However, I am unsure if the vortec crank position stator wheel will have interferance issues with the geardrive idler gears.

[04SilveradoMykk]

How am I planning on getting this motor in a frame intended for a LS based block?

Motor mount adapters used to mount a LSx engine with SBC mounts in a factory location.



instead I'll mount the plate to the SBC and use LS mounts & 4.8/5.3L frame mount brackets and will drop right on to the GMT800 frame & crossmember

On the adapter the SBC & LSx mounts share a hole, so here is a mock up.

[04SilveradoMykk]

Tomorrow is the start of a new month, wich means a new billing cycle :)

I've got the block ready to go out for a Vat & Mag, another .010" overbore. And the crank, rods & pistons, flexplate & damper will all get a balance.

I've been bead blasting the heads, they will go out for a bowl hawg. Once they get back I'll finish the gasket matching & polish work







I figured I'd get the intake manifold side done of the gasket match while the other engine componants are out at machining.

[04SilveradoMykk]

drilled the pushrod holes out to 1/2" to accept the moved pushrods due to 1.6 ratio rockers.





I also solved the clearance issue between the geardrive idler gears and CKPS reluctor wheel.

By using valve spring shims notched for the crankshaft keyway. I'm able to space the reluctor wheel .120" away from the crank gear. This will give enough clearance that the geardrive idler can rely on the timing cover to keep from excessively walking and interfering with the reluctor wheel.

[Chevyman247]

Awesome dude, good job!

I think I will eventualy move up to a roller valtrain and Vortec heads sooner or later. My LO5 block came from the factory drilled and tapped for roller hardware.

[04SilveradoMykk]

Originally Posted by Chevyman247

Awesome dude, good job!

I think I will eventualy move up to a roller valtrain and Vortec heads sooner or later. My LO5 block came from the factory drilled and tapped for roller hardware.

Thank you, I just read your build thread. Good job!

I was thinking of using the same valve covers that you did. I need tall ones to clear the polylocks on the rockers

[Stucknthemud]

awesome project

[DarkCharisma]

Looks good man, keep it up.

[Chevyman247]

Originally Posted by 04SilveradoMykk

Thank you, I just read your build thread. Good job!

I was thinking of using the same valve covers that you did. I need tall ones to clear the polylocks on the rockers

I am planning on getting some 1.6 roller rockers soon and I need to know if I have to clearance for the pushrods like you did? How much and where did you get your roller rockers? I have LO5 heads with 3 angle VJ and stainless steel valves on now.

[04SilveradoMykk]

Long tube headers are on order. Hooker 2462, guys are using them on their pre-99 trucks. They should work on a SBC in a GMT800 platform.

Originally Posted by Chevyman247

I am planning on getting some 1.6 roller rockers soon and I need to know if I have to clearance for the pushrods like you did? How much and where did you get your roller rockers? I have LO5 heads with 3 angle VJ and stainless steel valves on now.

I haven't read anything saying the older SBC heads need to be clearanced. But I'm not positive.

[04SilveradoMykk]

Droped some more dough on the valvetrain.

Ordered GMPP 12371042; roller lifters, lifter retainers & cage as well as the cam retaining plate.



I also ordered the pushrods. Comp cams Hi-Tech 7940-16



I had some inspiration today, reading Carcrafts Project Humble Pie part II. they got 428 ft-lbs TQ @ 4200 rpm & 401HP @ 5600 rpm with the exact same build I am doing, same engine internals & valve train. except they had a bit lower compression, were carburated & had a stock bore.

http://www.carcraft.com/projectbuild...all/index.html

Test 3 is the LT4 Hot cam with 1.6 RR's on a 4 bolt 350 one piece rear.

[GreaseDog]

you do know about the added drag of the gear drive, right? a good quality roller chain will be much more efficient. not to mention the fact that transmitting crankshaft harmonics to the valvetrain will be hell on it. nevermind the fact that its going to drive the knock sensor crazy.

[gmctrucks]

I agree with greasedog. Engine sure looks good keep us up-dated.

[04SilveradoMykk]

I am aware of the cons of a geardrive, and not just what other guys have posted online.

Because the cam rotates at half the engine speed, the timing gears have a 1:2 turn ratio... a torque multiplier (X2 to be exact) And a SBC roller valvetrain needs how many ft-lbs of torque to rotate. 25ft-lbs to 40ft-lbs maybe, depending on components. Take that number, cut it in half, and that is what is needed by the crank to function the valvetrain.

How much parasitic drain could a gear drive use? in my opinion, none. You need to measure this force in friction. After all, a geardrive is transmitting torque not creating it.

The best analogy I can use is your tires.... cars & trucks come from the factory with narrow tires because reduced rolling resistance on the street = fuel economy. We all put on aftermarket wheels with wide tires and what happens, we loose a slight amount of economy because the contact our vehicle has on the road is alot more compared to stock.

A aftermarket geardrive has two idler gears, but one is mainly the drive gear. If you notice geardrives idler gears usually have two different sized gears. The larger gear is the driven gear on the powerside of the assembly.... now think, how many contact points does a geardrive have between the crank & cam... on the powerside, 2 contact points and how large is that contact area; four teeth (2 @ each point) at the most spanning over 1/4", maybe.

Now look at your timing chain. What is the contact area of a timing chain? 50% contact on each gear (a little more on the cam gear / a little less on the crank but will equate 50/50). Think of the frictional lose and how much energy it takes to keep that chain moving when the majority of the chains length is making contact with it's drag surface

;)

Manufacturers use chains in production engines because of noise. After all, grandma doesn't want to hear her car while driving it to church on sunday.

But think of how many motorcycles out there use geardrives. Even in the 60's the big three had geardriving valvetrain in the straight 6's.

Although the quiet (slightly helical cut gears) geardrive will have noticeable noise...

"There's a saying Milo. If it's too loud, you're too old"



Harmonics/vibrations will be transmitted by the engine block long before the geardrive. Don't believe me? Go hit your engine block with a wrench and listen


As for the Knock Sensor, thats why the gods invented HPTuners

Cheers ~Mykk