ZSR Shop Tour
Next, is when we will chase all threads in the block, bottom tap main bolt holes, check that oil galley plugs sit flush and don't require additional tapping, deburr entire block,chamfer cylinders, etc. At this time I will do all oil system modifications and notch the block for large stroke crankshafts. This is typically around a two hour process.
The very first thing I do to a block, whether new or used, is give it a visual overview. Cracks, casting and machining flaws, and previous wear are all things that will stand out during this process.
The deck of the block is then resurfaced on my Berco SPY360-1300 CBN resurfacing machine shown above. I am able to get the proper RA finish needed for MLS (less than 30 Ra, my machine usually ends up 8-10Ra) and graphite head gaskets, and I use a profilometer to check the surface on each block that I do (see above pictures). This is a very important step that a lot of shops do not do. I also use a BHJ "Blok-Tru" fixture on every block that I resurface; this allows me to actually blueprint the block and not just reference off of the wide-tolerance, factory deck. The "Blok-Tru" fixture also:
-Allows me to find a true 45 deg for the V8 blocks relative to crankshaft centerline
-Make even deck heights for every cylinder (if not corrected, this can cause cam and ignition timing inconsistencies
-Correct block for better intake manifold sealing
Using the "Blok-Tru" is more expensive for any shop upfront, and costs more time per block than just setting a block onto the machine without a fixture, but I truly believe that once an engine is together, the little details make or break the deal. There is no better time than now to do it right!
Next up, the block main saddles are honed on a Sunnen CH100 line hone. I hone using fasteners that will be used in the build (typically an ARP main stud). This is again, a step that a lot of shops skip. I believe it is vital to make sure the main bores are straight to each other. Just going from bolts to studs can distort the bores, so this is a step that cannot be overlooked.
All rotating assemblies at ZSR are balanced on a new CWT Multi-Bal 5000 balancer. While there are cheaper options available, there is really no way to measure a crankshaft's balance other than what the machine says. I wanted full confidence in this, which is why I ended up with a brand-new $30,000+ machine. Again, great attention to detail is given to this step in the machining process. I can do any internal or external crankshaft, add mallory metal, or anything the assembly needs.
The finished product before paint and prep:
Here is a little glimpse of our shop and the machining processes that we do to every block that is included in short blocks, long blocks, and bare machined blocks. There are many steps here that a lot of shops will skip, but I can guarantee that no corners are cut at my shop. There are many cheaper options as far as machinery and tooling, but I have chosen to invest completely in quality, and I hope that you do the same with your choices with engine builders. 100% of the machining to my engines is done in-house on my equipment in Camdenton, MO. We do not do this part time or out of a garage; our entire focus is Ford engines.
Finally, the block cylinders are honed on our Rottler H85AX CNC cylinder hone. This is THE most accurate honing machine on the market. We never had ring seal issues with our old Sunnen CV616, but this thing gets numbers we absolutely couldn't achieve with the older equipment. There are so many variables with block material, piston ring material, and fuel being used. Ring seal is extremely important in your engine and this is the most important step for the rings to seal. My methods that I have come up with over time allow a very fast "break-in" (couple minutes typically) and a great seal over the life of the engine. Here are a few other key areas to a great hone job:
-Torque Plates. I use a torque plate on every block that I hone. The torque plate is used to simulate a cylinder head being installed onto the block and the fasteners torqued. If a block is honed without the plates, the bore will distort dramatically once the heads are installed and this bore is no longer round.
-Cylinder finish. A profilometer (or surface tester) is the only accurate way to tell if the cylinder has proper "peaks and valleys" in the hone job. The naked eye could NEVER tell if the surface is correct or not. Different ring materials, fuels, and power adders (or lack of) will require different finishes.
-Attention to detail. Even though this seems like something that doesn't need mentioned, attention to detail is extremely important in any machining process. An employee just grinding through the day and going through the motions is less likely to find small issues than a shop owner running all equipment in-house with his name on the line. Again, there is no better time than now to correct anything that is wrong with your engine. Find a shop that you believe in and receive a quality product in the end.
ZSR engines