If you're the type to sneak a peek at your Christmas presents early or flip to the back of the murder mystery while still on the first chapter to see whodunit, then you'll love the fact that we're publishing the dyno numbers for our Mondello Performance Products-built Olds big-block destined for installation into Jp's Project Murderous Overkill before we even show you the engine buildup.
Normally, we wouldn't play it this way, but because the info fit so nicely in this issue's "Top Tech Secrets" section, we figured the buildup could wait until next month. So follow along as we rub elbows with Steve Brul and the others at Westech Performance Group to see, with real-world numbers, how certain engine theories and generalities play out in the flesh. And be sure to check back next month to see all the parts, pieces, and planning Mondello Performance Products put into making this Olds 455 one of the most durable, well-assembled Pro Street engines around.
We covered the full break-in procedure for a new engine in the story "The Evil Truck Revisited, Part I" in the July '07 issue. E-mail our Web geek, Jason Gonderman, at jason.gonderman@primedia.com if you want him to put the story up on www.jpmagazine.com.
We always run straight 30W for initial break-in. When compared with 10W-40, which can have either the properties of a 40W, a 10W, or anything in between, depending on temperature and other factors, the straight viscosity of the 30W ensures good protection for moving parts without going too thick or too thin. It's also a good idea to add an engine oil additive such as Comp Cams Engine Break-In Oil Additive to help protect vital components.
Whether you're dealing with a $3,000 or $13,000 (or more) engine, consider contacting a facility like Westech Performance Group for the initial break-in and to get the tune right. Westech has done the initial run-in for literally thousands of engines, and experience goes a long way in preventing damage, properly seating rings, and knowing when to shut down and investigate if something sounds off.
With our 468ci Olds broken in, Brul made an initial pull with the Performance Distributor HEI dialed in to 32 degrees and the 850-cfm Edelbrock Q-Jet bolted as delivered to the Torker and a set of 2-inch primary tube headers. The power numbers told their story, but Brul was more interested in the oil-pressure numbers, which began to fall off around 5,000 rpm.
If the crankcase is too full, the crank and rods can aerate the oil, resulting in pressure loss. It also creates a parasitic drag on the reciprocating assembly. Brul says he's seen a 7hp increase by simply removing 1 quart of oil. Our engine was equipped with a full windage tray, so we knew aeration wasn't a problem-our pressure issues are caused by the Mondello high-pressure/high-output oil pump sucking the stock 5-quart pan dry. We'll swap to a larger-capacity pan in the future.
Power levels generally go up as oil temps rise and the oil thins. We went one step further and drained the crankcase of its break-in oil and refilled it with Lucas 10W-30 synthetic oil. On the next pull, we banged out a recorded 514 hp and 552 lb-ft of torque, adding 3 hp and 7 lb-ft to the previous tally.
It's a general rule of thumb that for each point you raise compression (between 8.0:1 and 11.5:1), you can expect a 15hp gain. The upsides are increased throttle response, more power, and higher volumetric efficiency. The downside is a need for higher octane fuel. For a street engine destined to live on 91 octane, you can usually get away with a full point of compression more with aluminum heads over cast iron. There are a ton of other factors to consider, such as cylinder pressure, combustion-chamber shape, flame propagation, and so on.
However, for our purposes in this brief space, we ran this engine in its old form with iron heads, 9.75:1 compression, and 94-octane Sunoco fuel with minor detonation under heavy load. Conversely, the aluminum Edelbrock heads, with their better thermal shedding properties, tight quench chambers, and relocated plug position for better flame propagation allowed 10.75:1 compression with 91-octane fuel. Granted, our cam specs are way different and the new engine was on a dyno and not in a chassis, but the comparison is there.