Sgcuda, there's a few interesting questions there. We are looking at a 4.900/5.000 bore space block, but it is number 4 in our current product development plan, so a little while off.

Mostly, builders try to stay under 4.530 although I am sure people have taken them further - just not much of a need to.

Solid vs Water blocks: Interestingly, the early KB blocks that ran top fuel were water jacketed with limited supporting material (wet sleeve). They had proven themselves at 6,000+ hp, so at really high cylinder pressures.
We have a minimum of .300 Aluminum around each sleeve which is already very thick. The main purpose of the solid blocks is not really strength, but to build heat in Alcohol applications.
That said we will be doing runs of solid blocks, and these will be sold as "Pro" blocks for finish machining by our Dealers.

I can't speak for the Indy Blocks, they're pretty good for their intended use. Our engine blocks are a precision-machined piece, with its design roots in powering top-fuel level power.

Here's a picture showing the head-fastener & clamping load comparison.

Some more pictures..

This site really needs a "like" button. I'm seriously considering a wedge block.

fixturing looks really good. do you have any pics of it ? also, what machine are you using, horsepower of the motor, and what is the spindle taper ? TIA.

Looks good. If everything can get machined in the same setup then the accuracy goes way up. Lifter bores are in the correct place and in the same line as the cylinder bores and stuff like that. From what I've seen, some of the other folks move the blocks around from machine to machine for different operations which is why the lifter bores sometimes don't point in the same direction as the cylinders. With that type of machine capability you guys should be able to get everything dead nuts on.

Hello Darren,

Blocks sure do look good. Couple questions:

4.800 bore spacing. So at a 4.500 cylinder bore, there is a total of
.300 of metal between the bore surfaces (I'm assuming they are
siamesed cylinders). What is the OD of a cylinder liner ? What I'm
getting at is, how thick is the aluminum between the bores ?
Then, when overboring the liners, how much overbore can you go, i.e.,
how thin (wall thickness) can you go with the liners ?

Thank you !

Most aluminum blocks are thin enough between the bores when the liners are removed, to cut with a tin snips.

Ive had 8 or 10 kb blocks over the years and still have 5..Not a single one of them have the lifter botes located properly. You can get different cam timing readings from one cylinder to another. Not the end of the world, and not radically different, just different. Also not isolated to the old KB, most blocks are like that even "cnc" machined. I think the problem begins with using the cam bore as the alignment for swinging the block from one bank to the other with it being held on the mains. Lots of distance in those swings, and problems relying on that to create inaccuracies.(also is not cam causing the reading changes)

I'm confident the new blocks won't suffer from these maladies. Would be a great improvement for KB

If the lifter bores aren't in the correct location then that is the fault of whoever designed the machining process. Everything that is performed in the same setup should be very precisely located. The problem is that most of the folks who have made Mopar blocks over the past 20 years haven't taken the time to do the machine setup correctly. They move the block from machine to machine and lose the reference points in the process.

All you have to do is walk thru a shop and you can tell in a few minutes if the block is going to be accurate or not. If workers are moving the blocks from machine to machine then it won't be accurate. If the block is bolted to a tombstone and is in a giant VMC or horizontal and all operations are done in the same setup then it will be dead nuts on unless someone screws up the programming or loads the wrong tool into the machine.

I never visited the old KB mfg site but I talked to a person who was familiar with it and he said it was basically a blacksmith shop. The old KB hadn't stepped up to modern equipment and they were moving blocks from machine to machine and doing hand operations. So of course the lifter bores were out of whack and the cam bearings weren't aligned and all of that kind of stuff. If you don't have the right tool you can't do the job correctly........

I see it on most every block that the process involves the block being pivoted back and forth, even on the same machine/ same process/ same setup using the cam tunnel with a bar through it and one through the mains. Even done on large cnc machine centers.

For sure the old kb place had become a cobblers workshop, but the lifter problem is tough for some reason. Ive even seen it in billet blocks where all points of reference were derived on the start.

Like i said i feel good that KB (NEW KB) will have this sorted out either by doing it, or giving the blocks to competent people to do it.

Just for fun check the cam timing front, to back, bank, to bank on most anything, provided you have a accurate cam. Since in most cases it can't be practically corrected once done, it explains some of the weirdness in individual cylinder timing beyond the normal patterns for different firing orders.

Talk to Chuck at Best Machine about lifter bore positioning. They do it on their Rottler and get it correct. From what I understand the lifter bore positioning from Indy was so bad that Best started to buy the blocks unmachined and they finish them at their shop.

So it doesn't take a huge machine, it just takes a good machinist who pays attention to the setup and gets the block properly fixtured and indexed. Sadly it appears that lots of people have problems doing this. I've heard that Indy, the old KB and even the new block that Muscle Motors was selling all have had lifter bore issues.

Yeah, I know bestM does nice work, and talk to Chuck on occasion. Also watch WJ and Kurt work on getting it perfect.

For sure one of those problems lurking in lots of blocks. Just seems there's always something. I've never had a perfect block, but im sure someone does somewhere lol.

Does factor into my individual cylinder timing program when a cylinder has different cam timing. That is on the ones i take time to check. I was happier when i didn't know they were off lol.

That's just the static part. Now throw on 16 lifters pushing 700lb springs with a 1.5 rocker ratio, driven by a crankshaft that's jumping all over the place, twisting and untwisting as it bends and generally does the Watusi.

Metal doesn't begin to work unless it is stretched or squished. The impression of rigidity that we get looking at parts lying static is totally wrong.

I'd be willing to bet that driving the camshaft from both ends or maybe from the middle would show power gains on high perf engines. I am sure that's one reason why the cams are getting larger and larger in diameter, seeing how the torsional rigidity increases as the cube of the diameter increase.

R.

Andy you're a CNC guy as am I. I use a MAZAK Integrex 1850-V 5 axis and have built block fixturing for what can be considered one setup block machining. Still the cam bore and main bores are an issue. Everything will need a lick with a hone to become true round. Horizontal boring is not near as accurate as vertical unless using a piloted arbor. That right angle drive bore head will not be accurate . As you have pointed out a machinist never likes to break setup. Well it still takes a vigilant machinist as CNC's can do wrong. In fact I was chasing tolerances all over until I tracked it down to a worn X-axis ballscrew. It was worn .024" . $30k repair.... It takes a BIG RIGID machine with power to produce (whether it be accuracy or volume or both). J.Rob

x2

absolutely ! see what happens if a wrong tool is picked up. the fun begins there, and if not vigilant, "stuff" happens in the blink of an eye or quicker. then you hear that "expensive" sound.
rigidity of the machine and fixturing is the key to producing quality parts, as well as sharp [and correct for the task] tooling.
along with worn ballscrews, worn tooling spindles can cause one to sometimes tear his hair out until the problem is found and corrected.
in the CNC machining field, bigger [and more powerful] is usually better, especially in high production.
just my opinion from over 42yrs in this trade.

^^^^^This guy gets it. The RMC pictured will get its [censored] kicked in a production environment. One off OK no problem.

Not entirely true. But having better tools makes it easier and quicker. I have a buddy in Tampa that is an excellent machinist, former tool and die guy and builds kick butt engines. He has all the old school machines, but he has to measure and take his time to get it right. He likes to hold things to .0001" tolerances. He is not cheap though. I spent $1k on brand new Manley Hemi rods getting them fixed since they galled the rod bolts from the factory. We put in new rod bolts and tubular dowels, he ground the caps down and resized the big ends. So I have almost $2500 in the Manley rods, but they are mint. Could have bought Carrillos for that price.

I realize this is not a finished block, but with as accurate as described machining, shouldnt the exhaust pushrod clearance holes intersect the bore/ deck in the same location on every cylinder?