DI DRIVER BLOG: Michalek Brothers Racing|

Hi everyone, and happy 2022! The past few months have been very busy at Michalek Brothers Racing every bit we continue to go through the car and get it back to race-ready condition. As we stated in our previous weblog, we are in the process of rebuilding the unabridged car from top to bottom. This weblog volition focus on A/fuel engine basics and the engine inspection procedure; specifically the crankshaft and connecting rods.

First, permit's discuss the basics of A/fuel engine combinations to provide context for the type of setups that are available for injected nitro cars. Our performance came with two Alan Johnson Functioning Applied science (AJPE) engines that include TFX -.500 short deck blocks with four.375" bores and Stage 1 muscle heads. Per NHRA rules, A/fuel dragster entries are permitted to run engines betwixt 410 and 456 cubic inches of displacement. The engine's displacement directly affects the motorcar'due south minimum weight using a 5lbs per cubic inch ratio. The rules besides land A/fuel dragsters must counterbalance at to the lowest degree 2,125lbs at the end of the run. Unproblematic math reveals the max displacement an A/fuel car can run while yet beingness eligible for minimum weight is a 425 cubic inch setup (425 ten v = 2,125). Each team has their ain preference for engine setups with the most common setups being 421 and 433 cubic inches (each setup uses a 4.375" bore; 421 = 3.500" stroke, 433 = 3.600" stroke).

Y'all may exist asking why would y'all want to run a combination less than 425 cubic inches? At that place are a few reasons in no particular order: the 3.550" stroke crankshaft required for a 425 cubic inch setup is non a standard size, some teams prefer a particular bore and stroke combination for their setup and believe the shorter stroke is preferable, and when y'all put 95% nitro in the tank the one-time saying, "no replacement for displacement" isn't completely valid – technically speaking.

Now that nosotros accept reviewed the guidelines for A/fuel engine setups, we'll dive into the process we use to validate the components we currently have available and we'll focus specifically on crankshafts and connecting rods (more than to come on other parts of the drivetrain in future blogs). We currently have both 421 cubic inch and 433 cubic inch engines, and since nosotros're on a budget, we plan to go through both engines to ensure we take a strong core that can concur up through the 5+ seconds of hell each component experiences each time we stomp the loud pedal.

Inspecting the crankshaft on an A/fuel car isn't much different from inspecting a crankshaft on a street/strip engine except the consequences of a error are much more plush… We found both of our crankshafts measure out within tolerance on both the rod and chief journals (good showtime). The surface finish on the 421's main and rod journals appeared to be in like-new condition; the 433's main and rod journals appeared to have weathered a previous engine failure and volition need to exist polished before reuse. While looking at the journals of each crankshaft, we also expect for cracks. Historically speaking, cracks seem to announced virtually oftentimes around the oil hole for #1 and #2 connecting rod journal. We couldn't see whatever cracks, but to be prophylactic we sent the cranks to be wet-magnafluxed and they came back OK which is skilful news since nosotros don't have to purchase new $three,500+ crankshafts (no guarantees later the next run, just they're proficient for now).

The connecting rods of any race engine accept a beating; A/fuel engines are no exception. The abuse in an A/fuel engine does not come from high RPM's (the highest RPM's in an A/fuel engine are experienced during the burnout), but dropped cylinders and detonation are particularly brutal on the connecting rods. There are a couple ways to check to see if used connecting rods are notwithstanding in race condition. The easiest and cheapest fashion is to run the cap bolts in and out by paw. If this can't exist done without tools, the rod is junk due to stretch or bending. If the connecting rod passes this basic test, then it can be checked for straightness and length. We utilise a WESCO (fabricated by nitro tuner Johnny W) fixture to make these checks and use a new connecting rod as our "standard" to cheque used rods against ensuring each is within .005" of a new rod'southward length and straightness as our threshold for continued use.

Some other disquisitional bank check during connecting rod inspection is cap bolt length. We utilise a fixture to ensure our bolts accept not stretched and therefore become incapable of achieving the necessary preload to hold the connecting rod together. Our racing budget does non include line items for sacrifices to the aluminum gods so it is critically of import nosotros stay on acme of our used inventory to ensure it is still fit for use.

If there is one matter we have learned since purchasing our A/fuel car, there is no shortage of work; however, that provides ample opportunities for us to go along learning and sharing our insights with you as nosotros make this journey. Thanks for checking out our progress; nosotros'll be back soon with more updates from the reassembly process and a wait into the safety upgrades that we've made to the car!

Corey and Kyle Michalek

Stay tuned for the next MBR blog post, where Corey and Kyle will go over the prophylactic upgrades they've made to their car over the offseason.

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