Here are the other parts that...
Here are the other parts that make the bottom end work-Eagle H-beam rods and lightweight alloy pistons from Ross, custom-made for the 4.00-bore 318. Compression ratio is determined by a number of factors: the planned use of the engine, camshaft type and design, and cylinder-head configuration among others. This is why the Hensley crew prefers to talk with you before they begin the process of actually building this crate package. Moly rings will be used to seal it all up.
Tackling The Block
Why the 318? Simple, they're solid, readily available, and cheap. Unlike a 340 or 360, there are literally hundreds of thousands of 318 cores still available. Ken has a number of things he looks for when selecting a block for the stroker process. These include taking basic measurements-which determine what has been done (if anything) to the block in the past, and any potential danger spots that might reveal excessive wear or cracking. He also looks for a pre-'76 casting date. Most 318s are durable engines that can withstand a lot of abuse, but there is no use wasting time on one that might be useless for anything but anchoring a boat.
The first step after the disassembled block is visually examined is to pressure-test it. This is done by using metal plates to cover vital areas, checking and reinstalling freeze plugs, and making sure nothing leaks where it shouldn't. Next comes sonic testing for cylinder-wall thickness-if the block is going to be punched out, this is critical before ever cutting the metal. Like the pinging heard in submarine movies, a sonic test uses sound waves to determine material thickness. Ken especially notes that two blocks cast sequentially can vary immensely. Like the pressure testing, this is very cheap insurance before machine work begins. thorough checks at this juncture will help ensure the final engine both seals well and makes its maximum potential horsepower. these two tests are integral to any engine buildup done at the Hensley shop.
Engine balancing is critical,...
Engine balancing is critical, and here Matt Hensley is using a digital scale to make sure the new rods are within balance tolerances. The lightest of the eight rods will be the baseline, and the others will be massaged carefully to meet that number. All tolerances stated for the products are also double-checked. This is becoming more critical in the speed industry, which is importing quite a bit of hardware these days. Matt and the Hensley crew try to take nothing for granted, summed up in their motto, 'Know, Don't Blow.'
Since the stroker crank will be bringing the rods and pistons where no reciprocating assembly has ever been before, this is followed by clearancing to the bottom edges of the bores. Also at this time, the surfaces inside the engine that might have casting slag or roughness are also cleaned up to ensure good oil return. in race applications, oiling changes will be made now, as well.
After this, the block goes through the machining process. This includes boring and honing using torque plates that are bolted to spec tightness, as well as deck squaring as needed. As with all engine builds, some machine work will be determined by the final horsepower range desired, but Ken believes that boring, honing with a torque plate, and main-bearing clearance clean-up are all necessary, regardless of what the final level of modifications are. Main caps from the stock 318 will be capable in some applications, but HRE uses aftermarket caps when needs dictate them.
Oiling Tricks
To ensure good lubrication for your engine, there are a few upgrades that are well known in the world of high-performance small-block Mopars. For race engines, these mods include opening up the passages between the main bearing saddles and the lifter galley to 9/32 inch in mains 1,2,3, and 4. Also, the area between the rear main, galley, and oil filter area needs to be opened up to 1/2 inch. A crossover tube is also fabb'ed for upper oil flow. Need directions for all this? Hensley Performance has instructions on both LA-series (273-318-340-360) and B/RB (361/383/400/413/426/440) oiling modifications in their 88-page catalog, as well as other technical tips. The primary thing to remember is it will be a lot harder to remove a bit that has broken off inside an oil passage than you might think, so take your time. Once done, take every possible step to ensure the block is completely clean of any fragments. While cleanliness is critical, passage size and changes are not as critical for hydraulic-cammed street applications like ours, so we bypassed that step.
Heads Of State
Cylinder heads are one area that will make a difference in both the final cost and the final power your engine makes. Contingent on how you plan to use your engine, you can go with a set of Hensley's custom-reworked stockers, or go with a flat-out big rpm set that will send a small-block powered 3,000-pound drag car below the 10-second zone.
This view of the block shows...
This view of the block shows the clearancing done to provide room for the rod bolts to clear the bottoms of the bores. To do this at home will require you test fit the crank and a rod to each bore, marking the area to be cut, and then getting out the die grinder. A nice surface is achieved using a finishing roll to polish it up.
Here is our assembled bottom...
Here is our assembled bottom end. If you already have the heads you want, you can purchase the short-block by itself, or even just the balanced internals from Hensley.
Another view of the bottom...
Another view of the bottom end shows the piston location in the bottom of the bore. The final assembly with cylinder boring is perfectly square. All 318 stroker blocks get a minimum .090-inch bore cleanup for a final bore size of 4.00 inch. That big .090 cut number is possible due to the sonic testing done before the block is chosen.
This photo shows why clearancing...
This photo shows why clearancing was needed. The rod-bolt ends and nuts would be cruisin' for a bruisin' without it.
There is no question that...
There is no question that behind every great racing engine is a great oil pump. If this thing breaks, everything else often dies right along with it, so it is critical to make the right choice the first time. The 318 stoker-package receives this high-volume, internally-mounted pump built by Melling, which also does a lot of pumps for NASCAR applications.
It is possible to option out...
It is possible to option out your wet-sump oiling system with the pan and pick-up, which again is dictated by your needs. A street motor may need the simple stock pan (shown at right), Mopar Performance, or Milodon steel replacement unit. Race engines can use the Milodon setup with either the static pick-up and deeper sump, or the swinging pick-up in applications when hard shifts and wheel-standing weight transfer will take the pan and oil to non level positions. Note the sump baffling welded into the aluminum pan. Matt Hensley can also fabricate a custom pan for your car or street rod if that is what it needs. Of course, you could also be the first guy on your block with a dry-sumped 318, but you'd better have your wallet handy.