371ci Mopar Small Block - Popular Hot Rodding Magazine

371ci Mopar Small Block - Popular Hot Rodding Magazine

EMC 2010

So much has happened since my last post here that I had just about forgotten that the blog I had started still existed. As far as 2010 goes we once again fielded a somewhat hastily assembled entry for Popular HotRodding's Engine Master Challenge. Our entry ran flawlessly and posted a score that would eventually garner us a 13th position in the standings. This would improve our position over our 2009 EMC debut of a whopping 10 spots. I believe we are the only team to feature cast iron W2 cylinder heads in the history of the EMC and the strong output combined with a true street flavour is what landed us our 2nd consecutive feature article in the pages of PHR magazine. I have included the link so feel free to check it out. J.Rob
http://www.popularhotrodding.com/tech/1111phr_skmfx_racing_engines/viewall.html

383 Chev

This was a build that was recently completed and dyno tested. Actual displacement came in at 385 cubic inches due the the 4.04" bore. This engine features the following: EngineQuest 220cc /72 cc straight plug heads,hydraulic roller 231/239 @ .050" 110 LSA ,Scorpion 1.65/1.5 roller rockers,10-1 comp, Air-Gap dual plane, 750 Holley Dbl, 1 3/4" Hedman Hustler's, and Esso 91. So going from memory only, as I don't have any dyno sheets here to look at I will try to keep the results from becoming to convoluted. We tested this engine with two carbs (customer's 750 and the shop 830 HP) and no less than three sets of headers. The influence headers can have on the output of an engine were eye opening and interesting to say the least. First up the engine was initially fired and given a lengthy break in cycle with the 830 carb and the shop's set of Schoenfeld dyno headers with Magnaflow mufflers. Peak output was 480 hp @ 5900 rpm and a fantastic 493 lb/ft coming in @ 4400 rpm. Next round of testing involved the customers  used and abused 1 5/8" chassis ('81 Camaro) headers with no mufflers and the 750 carb. Peak numbers were 445 hp @ 5800 rpm and 480 lb/ft @ 4300 rpm. After receiving the new Hedman's featuring 1 3/4 diameter primaries they  were bolted on and testing was resumed. Power was a pleasant compromise between the full race dyno header and the smallish chassis headers. The engine was now producing a solid 474 hp @ 5900 with torque also in the 470's. What the numbers don't reveal is the "personality" of this engine. The engine fires with a touch of the starter button, idles easily with a little lope and due to the slick hydraulic rollerized valvetrain makes zero mechanical noises.It is also extremely consistent while making best power with only 32 degrees total timing. Easy going and laid back with a speak softly and carry a big stick temperment is how I'd describe this engine. It was built to be a bulletproof dual purpose engine and I think it is a success on all accounts. Here's couple of shots and dyno vids for those that like that sort of thing. J.Rob

EQ Magnum Heads!

I recently started working on some EngineQuest Magnum heads for the small block Chrysler engine and have to say that I am impressed. I won't go over any of the features that make these heads a great iron replacement head here because that info can be found anywhere on the 'net. What I will add here is that with a 2.02" intake valve (it was all I had at the time) and no valve job, and right out of the box they flowed quite well peaking @ 230 cfm at .550". I then applied a quick valve job to make the 2.02" valve at home where a 1.92" valve was supposed to reside and re-tested. Wow, flow was now registering 247 cfm with no loss anywhere in the lift curve. Now I had no real intention of making these into a full on performance head so I used one carbide burr only and opened the pushrod pinch, profiled the guide, blended the bowl and touched the short side. I also have on hand some derelict titanium valves in a 5/16" stem and a 2.19" head diameter to try and make work. After a quick trip to the lathe and valve grinder I now have a set of Ti 2.02" valves to work with. Here's the really eye opening part-Back on the SF-1020 and with a true 4.03" bore and tested @ 28". Peak flow is now registering 272.5 cfm @ .600" . I also cc'd that port and came up with 180cc's on the nose. I plan to install these on a .040" over 360 with a hydraulic cam and dyno test in the very near future. Check back for updates.

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

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

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