Attila the Jav: We Tear Down Our AMC 360By Brian Lohnes Posted 06/26/09
Being an eternal optimist has its pitfalls. Mainly it's the times when you've talked youself into thinking something is a lock when it really isn't. Such is the case with our smog-era AMC 360 that will find its way into the gullet of Attilla the Jav, BangShift.com's former dirt-track stock car 1968 AMC Javelin.
Our delusion was that we were going to score a cheap motor from Craigslist, check the bearings, make sure stuff was decent, mess around with the heads a little, throw a bunch of bolt-on parts at it, and beat on the car until the lakes froze and we'd go ice racing.
It sounded really good on paper but reality would rear it's head and send the original plans packing.
As you'll see in the gallery, the lower main bearings are beat to hell. Ironically, they are beat up due to the reason that we were attracted to this particular engine in the first place. It spent it's life in the front of a Jeep Wagoneer that was used as a plow truck for decades. Not thinking through that information we jumped on the deal. The 1974 model year engine only has 55,000 miles on it and cost us a reasonable $200.00.
Let's think about plowing for a second. It's a high load, low RPM affair. It's obviously done in the cold weather, and if anyone has ever driven a plow truck before, the temptation to use it as a four wheeled bulldozer has taken everyone over at one time or another.
The first thing we noticed when we started to pull the motor apart is that the oil that remained in the engine has a strong odor of gasoline, lending us to believe that the carb was not properly adjusted and this thing sat for months at a time until snow duty called and it was put to its punishing work. Junk gas, a wonky distributor, and a heavy foot trying to relocate snow banks seems to be what ultimately did these bearings in and has us thinking that a 10 or even 20 cut on the crank is necessary to clean things up. The caps show evidence of walking, a sure sign of big time detonation.
The good news is that literally everything else with respect to the motor looks great. The pistons look fine (we were going to reuse them, but are now debating adding some compression), the factory rods are in satisfactory shape, and the innards of the motor were clean and showed no sludge at all.
Our plan right now is to assemble a budget minded (yep, we're broke too!) motor that'll live it's life under six grand, make lots of low-end grunt, and hold together while churning a set of spiked tires on the frozen lakes, running down the strip, and hopefully (fingers crossed) make a pull or two at Maxton.
Enough yapping. To the photos!
Comments + Post your comment!
Written by realsteelfreak
Jul 13 2009
Glad to see things coming together, do we get pics of the new hardware?
Written by Brian Lohnes
Jul 13 2009
Factory 1975 64cc castings. The height of the smog era!
Brian
Written by Tom Slick
Jul 13 2009
damn the bad luck... lmao.
What're your heads cc'd at? You did buy a burette right? :P
Written by Brian Lohnes
Jul 13 2009
It woulda been, but those pesky folks at Weisco and K1 Technologies have been far too gracious and provided us with a brand new set of Forged slugs and 4340 H-beam rods.
Damn them...HA!
If you are shopping for AMC parts, check those guys out, this is a totally new piston design to the market for the 360 and 401. They sent us flat tops, but dished pistons are available.
Brian
Written by Tom Slick
Jul 13 2009
Is it close enough for a hone and a set of rings? Polish the crank, new bearings, spray and pray?
Written by WhiteMonster
Jun 30 2009
Great pics, I look forward to the continuing progress of this motor ...
Written by mike343sharpstick
Jun 29 2009
[quote author=Brian Lohnes link=topic=13266.msg260808#msg260808 date=1246113306]
Yeah it would require rods and pistons because the rod journals of the 401 crank are larger than the 360's and the pin height issue would be a problem.
Why does my imaginery bank account never run dry like the real one? :)
Thanks for the reality check Jim.
Brian
[/quote]
Bingo!
I have been considering the same option for a future modification for my Javelin every time I see a used 401 crank on eBay.
Note that a 401 block has thicker webbing around the crank to support the stronger forged crank. I am honestly not sure if a stronger forged crank with the weaker 360 block would provide any benefit ???. Also a quick FYI, there is a few AMC guys using cheap SBC rods and offset grinding to stroke a 401 crank to something like 425ci, unfortunately none of this can be paid for with an imaginary bank account..... Dammit! >:(
Written by DanStokes Jun 29 2009
For a plow truck motor it actually looks really good. Evidently somebody didn't know the rule that you never change the oil until the motor blows. A lot of plow trucks get really abused because they sit until somebody notices that the snow is piling up, then is get out the jumpers, fire that sucker up (on skunky gas) and shove it's guts out. So I'd say you done goooood.
Hope everything measures OK.
Dan
Written by realsteelfreak
Jun 28 2009
Thanks for the pics , cant wait to see the build up and what kind of power this thing makes after some tuning.
You betcha...I'm going to have to wipe the drool off.
I'll slap 'em up tomorrow.
Brian