‘Merican Metal Menace sparks to life on the dyno


Through this seem­ingly never end­ing jour­ney through the de­sign, dis­cov­ery, prep, as­sem­bly and tun­ing of a 407 ci AMC V-8, which we dubbed the 'Merican Metal Menace (MMM), our tar­get was 400+ hp and 500 ft-lb of torque, while hold­ing a smooth idle and run­ning on pump gas. Tar­get hit, our bucket of tips and tricks has run dry, and the num­bers are in, as we close the last chap­ter on MMM and let it ful­fill its des­tiny pow­er­ing “Stinky Jeep” ef­fort­lessly down fu­ture trails.

The ther­a­peu­tic jour­ney of tak­ing the mo­tor, that was orig­i­nally scored from a tired Jeep J-truck. and mak­ing it into the trail ter­ror you read about here (and at www.sun­cruis­er­me­ was not achieved sin­gle­hand­edly. Comp Cams, Edel­brock, Mol­nar Tech­nolo­gies, BHJ, Fel-Pro, Di­a­mond Pis­tons, ARP, To­tal Seal and Sum­mit Rac­ing all took the time to lis­ten to our goals and help de­vise a plan to get there. With­out our ma­chine shop of choice (K&S Ma­chine), our lofty goals would have been all for naught. The proper ma­chine tol­er­ances are just as crit­i­cal when build­ing a daily driver, as they are a top fuel drag mo­tor, it’s know­ing what those tol­er­ances should be that counts. K&S Ma­chine in Kelowna, BC, did an ex­em­plary job un­der­stand­ing our parts col­lec­tion fit­ment al­lowances and not only ma­chined, but also bal­anced them to spec. These are not the only en­gine ser­vices of­fered and we took them up on one of the most crit­i­cal they of­fer; a break-in and test and tune on an en­gine dy­namome­ter.

We can’t stress enough the im­por­tance of a proper en­gine break in pro­ce­dure with a fresh mill. Wiped out cams and cooked bear­ings on freshly built mo­tors is a dream killer and hav­ing to call “mul­li­gan” on a build you just dropped be­tween frame rails of your truck is enough to make you kick a

kit­ten. But it doesn’t have to be this way… for a measly $600 you can drop your fresh steel steed off and have the K&S crew in lab coats strap it to the dyno for a proper break in.

K&S took our MMM and rolled it into their dyno cell af­ter months of our put­ter­ing and fid­dling around as­sem­bling the earth shaker. They care­fully hooked it up from bal­ancer to bell­hous­ing, com­plete with a new MSD starter to help turn the 10.75:1 CR mo­tor over. They se­lected from their plethora of parts a Quick­Time 750 CFM carb they run for break in and bolted on a set of Head­man long tube head­ers await­ing our ar­rival. Walk­ing into the cell we were greeted with a tem­per­a­ture and hu­mid­ity con­trolled clean room with a “Land & Sea” dyno strapped to the back of MMM. What a glo­ri­ous sight in­deed. With sen­sors and air flow de­vices em­a­nat­ing from the MMM like a NASA flight deck launch, we were told that the dyno had just been cal­i­brated and we were in for fun to­day.

Some call the ex­pe­ri­ence of start­ing an en­gine for the first time like watch­ing “Your child come into the world”… not bloody likely… freak. You yearn for your child to be good, and no­ble, and just. We were hop­ing for Chuck Nor­ris the V-8 to put his smoke out on his arm and start kick­ing ass in the cell. This isn’t the “Merican Metal Menace” be­cause we like pup­pies and own a snug­gie. We were about to watch Vic­tor Franken­stein bring The Mon­ster to life… I guess that makes us Igor. Dam­mit.

Keith and Stephen from K&S care­fully pre­lubed the mo­tor with AMSOIL’s finest Break In lube and en­sured we had proper oil pres­sure while spin­ning the crank with a ratchet to make sure any air pock­ets were out of the sys­tem. The DUI dizzy spec’d for the MMM was stabbed back home and a crude base­line of tim­ing was set. A fresh fuel cell of 92 oc­tane against the wall was made ready as switches were flicked in an­tic­i­pa­tion of life.

“Click” Fuel pump.

“Click” Room fans.

“Click” Wa­ter pump.

The last “Click” brought a starter “whirr”, which could have been be mea­sured in mil­len­nia for us, be­fore the belch of half burnt fuel coughed its first flame into the col­lec­tor pipes at the back of the cell. The Menace was awake. WHAT HAVE WE DONE!!!

A flurry of ac­tiv­ity sur­rounded the cell as our Flat Tap­pet Hy­draulic Comp XE262 cam’s life on this earth de­pended on the next sev­eral min­utes. Base tim­ing was set at a mod­er­ate 8-de­gree un­til we were sure all was well. Steady oil pres­sure and fluc­tu­at­ing RPM are re­quired to not only seat the To­tal Seal rings for a long life, but also keep as much oil on, in and around the camshaft and lifters for them to wear in a proper pat­tern and harden. For the next half hour, our time was spent watch­ing Keith and Stephen earn their

keep in cer­ti­fy­ing our in­vest­ment as “alive and well.”

To be hon­est, the rum­ble was not what we had ex­pected out of an open header mo­tor with the parts we had thrown at it, it was… well… good? No en­gine shake or wickedly lumpy idle. Oil pres­sure stayed a con­stant 60-psi at any­thing above 1,500 rpm. It was “fine, I guess?” My de­sire for a nasty idle stems from my drag rac­ing gene. We were talked out of the mas­sive bump stick we wanted by Comp Cam’s techs in or­der to keep the power at a use­able rpm for an off-road rig. We had trusted their judge­ment, and be­lieved in their wis­dom. All we could do was wait.

Another “click” shut the ig­ni­tion off and the Menace closed its eyes for a short nap. A nut and bolt check of the hot and smelly mo­tor re­vealed noth­ing out of the or­di­nary. Tim­ing was set, air/fuel ra­tios looked good, oil pres­sure was look­ing great; epic for an AMC en­gine, as they are known for his­tor­i­cally low pres­sures.

It was time for a quick break and then get some real num­bers out of the MMM.

Our goal for the day was not to see what kind of peak num­bers we could eek out of the mo­tor, as this has no bear­ing on what will ac­tu­ally hap­pen in the Jeep, it was about get­ting some ba­sic num­bers and a torque curve for match­ing com­po­nents like gear ra­tios and trans­mis­sion choices. Tun­ing the Menace to squeeze the fi­nal hp was moot as we were go­ing to run Hol­ley’s Ter­mi­na­tor EFI, not a carb; the long tube head­ers in the dyno cell would be swapped for a set of Doug’s Orig­i­nal shorty units that we can ac­tu­ally snake ex­haust through the sus­pen­sion with­out as­sis­tance from a ball peen; the wa­ter thin race oil will be swapped for Amsoil’s 10-30wt Z-Rod lube for longevity; and ac­ces­sories like al­ter­na­tor, wa­ter pump, air com­pres­sor, power steer­ing pump and what ever other par­a­sitic loss items yet to be at­tached will al­ter our hard work. In a nut­shell, we were go­ing to make a few pulls to get some num­bers, but there was no point tun­ing it

to per­fec­tion in this form.

As the lab coats came back from their break, Keith sat at the dyno cell con­trols and merely raised an eye­brow in our di­rec­tion. No words had to be said as we nod­ded in ac­knowl­edge­ment, it was time to awake MMM once again. Fa­mil­iar “clicks” ended with gur­gle as the Menace held fast in the en­gine stand. The only sign of life was the spin­ning crank pul­ley and watch­ing the ro­tor of the dis­trib­u­tor spin un­der the clear cap. Keith re­moved him­self from his pi­lot’s seat and made his way into the dyno cell for a last check. The all clear was given and the room doors were sealed for the run.

At 36-de­grees of to­tal tim­ing di­alled in and the en­gine up to tem­per­a­ture, Keith calmly moved the hand throt­tle to the “wide open” po­si­tion and en­gaged the dy­namome­ter. Our eyes were shift­ing be­tween the com­puter screen, gauges and en­gine at a pace that only time lapse film­ing could catch. Ex­cite­ment, fear, an­tic­i­pa­tion and feel­ings of doubt gushed through our veins as the lone dig­i­tal gauge plated squarely in the mid­dle of the screen rose in sync with our hopes.

The scream of 5,500 rpm was ring­ing in our ears as the throt­tle blades closed and the Menace calmed to an idle. The shop clock ticked away as we awaited the fi­nal re­sults to come in for the first run of MMM… We Did It! As you can see by the dyno chart, we scored 432 hp at 5100 rpm and al­most 505 ft-lb of torque at 3,800 rpm. The menace is of­fi­cially a mon­ster, how could we not be pleased. We started gen­er­at­ing 400+ hp at 4,200 RPM and the freight train didn’t stop pulling un­til af­ter our 5,500-rpm shut­down. Our only cleveite was not be­ing able to power though to 6,500 rpm, per­haps with a roller cam and studier valve springs. Nev­er­the­less, we are plenty pleased with these re­sults. Now I won­der what a healthy shot of ni­trous would do?

As you can see, we have a de­cent power curve with a re­spectable 432 hp. Don’t worry, we’re not done yet.

Many boxes were harmed in the build­ing of Merican Metal Menace.

An MSD Dyna Force was charged with spark­ing life to the big 407.

This lit­tle puppy tells us ev­ery­thing we need to know about how our en­gine is run­ning and pro­duc­ing power.

All bolted up with all the in­tra­venous life sup­port con­nected, we were ready to break in the 407.

Af­ter a good break in, it was time to see if all our hard work was for naught as we pushed into the high rev bands.

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