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Chevy 350 Small Block Build - Part 3 My First Engine Build
Patience, Correct Tools And A Good Book Help Get Our Short-Block Back Together
Oct 1, 2003
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Chevy 350 Small Block Build - Part 3 My First Engine Build
Here's Patrick Swegles' (our first time engine builder) sea of cool go-fast parts. This month Pat assembled the short-block using a master build kit from PAW. He also installed an oil pump, windage tray and deep sump pan from Milodon.
The first step taken by Patrick was to completely wash the newly machined block with soap and water. Once cleaned and air dried, a little oil to the machined surfaces prevented rusting.
The next goal was to determine the correct main bearing clearance. First the bearings were put in place then the crank's journals were cleaned.
The balance of the oil used to coat the block went to good use, as Patrick put the hydraulic lifters into an old coffee can and poured in the oil. This is best to do at least 24 hours before you plan on installing them in the engine.
A quick glance in a small-block Chevy reference manual for the correct specs is always a good idea. Here, Pat was a willing participant.
Checking the main bearing clearance can be done one of two ways. First, you can assemble the main bearings in the block without the crank, torque the caps down, and then use an inside micrometer to determine the ID of the bearings. Then, by using an outside mike and measuring each journal, you simply do the math. A much simpler way is to use Plastigage. This thin, plastic-like material is designed to be placed between the crank and bearing. Once torqued down, the Plastigage is measured and its width determines what the clearance between the crank journal and bearing is.
And finally the cast-iron arm was carefully placed into the block. Note that there is no grease or lubricant used at this point.
Works every time.
One of the other items that Pat picked up from PAW was a complete engine fastener kit from Milodon. One of the components was a set of main bearing cap studs designed to be used especially with Milodon's trick windage tray. As with any fastener, a good lubricant should be used prior to installation.
One area that Patrick got the benefit of better tools and techniques was in checking the crank's endplay. A dial indicator and magnetic stand made quick and accurate pickings of this spec. However, a feeler gauge stuffed between the thrust bearing and the crank's fifth journal does the job just fine.
Patrick's next step was to undo all of the main caps and lubricate all of the bearings. This required removing the crankshaft one more time.
A good torque wrench is an engine builder's most trusted friend. If the book says torque the bolts to 65 and use oil as a lubricant, do it!
Don't we wish more things in life had such easy directions? How could you go wrong with an arrow on top of the piston telling you what way to point it in the bore? Well, believe it or not, you can install them just the way they tell you and still be wrong. That's because they have to coordinate with the connecting rod. And since a piston can go on a rod either way, you have to make sure they are aligned properly. In Patrick's case, PAW had marked each piston/rod combo with an L or R, indicating what side of the engine it needed to go in.
Note the absence of rings. Subsequently, no ring compressor was needed to get the pistons in their bores. It is important to keep the rod bolts from scoring the cylinder walls or crank journal. Therefore, caution is the best thing here.
Checking the rod bearing clearance is an important part of building a reliable engine. As with the crank, the bearing was installed dry and the piston/rod was installed in the block and torqued down.
Again, Plastigage is used on the crank's rod journal. The cap is tightened to its correct torque spec and the squished Plastigage is measured. Voila, our rod bearing clearance was dead on.
With bearing clearances checked, Patrick moved on to making sure that the rings would fit perfectly in the freshly bored cylinder walls. Using another special tool (which only made the job easier), each ring was squared in the bore and the end gap was measured with a standard feeler gauge.
Once all the end gaps checked out okay, it was time to put the rings on the pistons. Even with cool tools to do this task, the job still requires a matter of physical dexterity. Here, the main oil ring is installed.
The two compression rings are installed using a ring spreader. This tool creates even pressure to expand the rings, allowing them to slip over the piston's crown and into their respective groove. Care is imperative here, as these rings can break if you're too aggressive.
With the rings in place, the next operation is to grease the bearings on each side of the rod's large end. This is because two rods on each journal will rub against each other when the engine is running. This rod side clearance will be checked with a feeler gauge once all of the piston/rod combos are in place.
A tapered ring compressor is used to get the pistons into the block. A hammer, such as this trick plastic, lead shot-filled unit from Powerhouse, made this a simple chore for our first-timer, Pat.
Milodon provided the complete oil system for Patrick's engine. Included were the aforementioned windage tray, an oil pump baffle, which controls the oil at the back of the pan, a 7-quart kickout-style pan, and a high-pressure pump with a custom pickup. Note the studs for the windage tray and the steel coupling collar for the driveshaft. The factory shaft uses a breakable plastic collar to connect the shaft to the oil pump.
Here's Milodon's screen-style windage tray. You must fit the tray over the studs and lower the nuts in order to get the correct clearance between the tray and the rotating assembly. Once in correct relation, the bottom nuts are torqued down.
The Milodon special pickup is fit into the pump and has an extra support strap, which is bolted to the pump body. This makes it virtually impossible for it to separate from the pump.
Camshaft installation is made simpler with a tool like the one Patrick used from Powerhouse. With the cam's rear journal in the block's front bearing, Pat coated every lobe and journal with a special break-in lubricant. The special tool simply bolts to the front of the cam and allows you to ease it in the block.
The double-roller timing set fits easily around the crank gear and bolts to the cam with three grade 8 fasteners. Patrick also used a cam locking plate, which has a tang at each bolt head that is folded over to prevent the bolt from coming loose. Pat really liked this idea.
Before the Milodon pan could be installed, the new one-piece rear seal needed to be bolted down. Patrick found the easiest way to do this was to take the engine off of the stand and hang it from the hoist.
Once back on the stand, the good-looking kickout pan was installed.
In next month's final installment, Patrick will finish off his first engine with a set of World Products cylinder heads as well as a host of other bolt-ons like a Milodon aluminum water pump and a new harmonic balancer. Stay tuned.
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