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Friday, November 19, 2010

Problem solved

So, what is the solution to cheap offshore aluminum rocker arms? In this case the solution was even cheaper made in USA, stock stamped steel rocker arms. Until the solution sat up and presented itself to me I was contemplating replacing the aluminum rocker arms with some high end quality rockers. Names like Harland Sharp, Comp Cams, Crane, T&D, Jesel, etc.. come to mind here. I was about to pull the trigger on some of the new CompCams Pro-Magnum steel rockers even though the price was dear, when it dawned on me that the 440 Source heads were designed to use an all stock valvetrain. Knowing I had some brand new heavy wall rocker shafts on the shelf, the decision to order some rocker arms from Melling was easy. Yes I knew I would have to wait and measure for the correct pushrod length but that is no biggie. Once I knew the length I needed, the Melling catalogue was again the source for the correct part number. A day later with pushrods in hand and about 15 minutes of assembly had the engine ready for fire up again. The engine fired without fuss and a stethoscope on the valvecovers was used to verify that the valvetrain was quiet and happy. Which it was. After a quick warmup some dyno pulls were made and wouldn't you know it? Horsepower was down about 12 HP but it held on 300 rpm longer (lighter rockers than the aluminum ones) Low end torque was up about 5 ft/lbs but down the same at the peak. The aluminum rockers were a 1.6 ratio versus the steel ratio of 1.5 so giving up that bit of lift and duration cost the engine a little power but not enough to worry about in this case. I will sleep much better knowing the valvetrain is as solid as an anvil now. J.Rob

Wednesday, November 10, 2010

Cheap, Offshore parts + Engine = Broken Engine

I'm sure if you're reading this then you already have a strong knowledge of the internal combustion engine and the components and sub-assemblies that make them run. You may also know that the automotive aftermarket has been flooded with inexpensive, imitation engine parts. These parts are affectionately referred to as "knock-offs".  Today I got bit by knock-off parts. Some time ago I acquired a 511 inch big Mopar from a friend for a screamin deal. The engine had some collapsed lifters (hydraulic flat tappet cam) and just generally needed to be inspected and freshened, Or so I thought. The block was replaced with another 440 block, crank turned, and heads reconditioned. Parts replaced were, lifters, bearings, rings, oil pan, pick-up, pump, etc.. Everything else was re-used. When this engine was initially built by my friend it was not tested on the dyno so we did not have any hard numbers when it came to output. I was never hot on the camshaft choice but it was an extremely good deal and available at the time. I really wanted to know what this engine produced so I reused the original cam. After a long while, here it is on the dyno. After a careful break in we were ready to make some pulls. Then the distributor started acting up which was also a knock off. We dismantled the distributor, replaced some springs, adjusted,tweaked and reassembled. We made a total of 5 pulls and decided to pull the valve covers and try a different preload adjustment on the lifters in the search of a little more power. What we found was several of the adjusters were either broken, on the verge of breakage, or machined incorrectly. Check out the pics! In the one photo you can clearly see how crooked the thread was machined! The closer we looked at the adjusters and the rockers themselves, the decision to remove and replace became quite clear. We narrowly avoided having a catastophic valvetrain failure. The decision was made to replace the entire rocker and shaft assemblies with something of much better quality. The moral of the story is basically that old adage "You get what you pay for". Oh and if you want to know more about the engine's performance on the dyno-leave a comment. J.Rob

Friday, November 5, 2010

SBC Dart Iron Eagle 180's

As the title says I am currently working on a set of Dart Iron Eagle 180cc runner heads. This set of heads was actually on a 385 small Chevy and even though coupled with a very mild hydraulic flat tappet cam it produced healthy power. As tested on our SF 902 this engine produced a best of 436 hp @ 5200 rpm and 460 ft/lbs @ 4200 rpm on pump gas of course. Considering how tame (think stock) this engine was on the dyno you wouldn't really think it could make that kind of steam-but it did. So not being able to leave well enough alone we elected to give this engine a kind of EMC treatment. This 385 SBC will retain the same basic short block and intake manifold (RPM Air-Gap) but will receive a roller juice cam and thoroughly worked over cylinder heads. The goals for this engine are heady- 500 hp @ 6000+rpm/ 480 tq @ 4800-4900 rpm, pumpgas, mufflers, 750-830 cfm carb. Camshaft specification will be decidedly mild-duration @ .050" (expressed in degrees) will not exceed 240 and valve lift won't exceed .600" so it will remain a truly driveable and reliable street engine. Flow testing of the heads today revealed that there is much work to be done! All flow testing was done @ 28 inches of water, 4.030" bore, 2.02" valve. Flow built quickly peaking @ 220cfm at a low valve lift of only .400", stalling at higher lifts. After some mild guide profiling and some short side (s.s.) work  flow rates are now 232 cfm @ .500" with flow flat lining. I'm sure that more s.s. work and maybe a 2.055" valve with no back cut (b.c.) are in the cards. Velocity readings reveal that the s.s. is over loaded with readings of 450+ fps (feet per second). No wonder when we tested the engine on the dyno power hit a wall @ 5300 rpm-the heads are choking it. I suspect the runners are much smaller than the 180 cc moniker, probably closer to 170cc. I'll measure them for volume in cc's next, so I know what I'm dealing with. The video is a short clip of a flow test for anyone who has never experienced one. J.Rob

Wednesday, November 3, 2010

EMC footage in Ohio

So as the title says here is some actual footage from the University of NorthWestern Ohio taken outside of the dyno cell. I believe this engine was Cory Short's big 514 cube Hemi. It made over 800+HP and it rattled your rib cage and made your eyes blur, all through 15 feet of 3.5" exhaust system. I remember having to put down the camera on the cement barrier so that I could block both ears! I'm behind the camers and that's my buddy Joe in the black and instructor Paul Higgins relaxin and drinkin his coffee. Check back daily and leave a comment. J.Rob

Tuesday, November 2, 2010

Testing for the EMC '09 @ Home


So as the title implies I figured I could add more about the engine featured in the most recent issue of PHR. As you can see in the first photo we had to get creative when we had to come up with a cost effective way to mount our air turbine to two Holley carburetors. I came up with the idea of a simple box with 3 holes in it, the boss supplied the tool box, and Joe my compadre made it all work. How did it work? I would have to say that it worked much better than it had any right to. Once that was mounted we were able to record and monitor a lot more data. Although the real important one was air/fuel ratio. As you can  also see the engine was in full drag, wearing mufflers, the actual chassis style headers and ignition system.
In case you wondered our dyno  cell is actually installed below ground level forcing us to route the exhaust system upwards then outwards. All told the length of the exhaust is considerable, terminating into no less than six large truck mufflers. Here's a little vid of one of the last tests before packing up and heading to Lima, Ohio. Enjoy and please feel free to comment and ask any questions. J.Rob

Monday, November 1, 2010

More Resurfacing

Well it's Monday and I received some ProComp Ford heads from a customer that wanted .060" removed from the deck surface. Simple enough right? Yeah this job was a very straightforward no surprises kind of job. Perfect for a Monday really. So with the CBN cutter in the fully retracted position and the PCD lowered it was a matter of 7 cuts and sixty thou of aluminum was turned into "snow flakes". You can see in the pics and video just how nice of a finish modern CBN/PCD cutters can produce. That's about all I've got for this Monday, check back soon and please leave a comment. J.Rob