What is under there?
if you just want to see the pictures, click here
It's the good old AMC 360 V8
When I first got my '77 Wagoneer it had the original 360 with a Motorcraft 2bbl carb and everything else original. This setup had rambled under the hood for years and was not impressing to drive. I don't really think a 175hp engine in a car of this size could ever impress anyone even without the mileage my engine had.
So I decided to build myself a new engine and bought a used 360 out of a '79 Cherokee. Up too this day I regret not getting a 401 instead, but the majority of FSJ's in this part of the world was sold with the I6. There were some with the 360 but 401 equipped trucks were less common than a snowball in hell.
I used one year rebuilding the 360 because I wanted to do it right and I am not made out of money:-) When I finally finished I ended up with a strong running' engine that will serve me and the D'WAG for years (If I don't happens to stumble across a 401 block in the future).
Building a engine other than a Ch*vy 350 in Norway are very pricey and it's hard to find parts off the shelf. I did not want a Chevy in my Jeep for several reasons so I was glad to see that the '79 block was in good shape when I dissembled it. That convinced me once more that the AMC engines where very decent machines in the first place.
I was going to blueprint it anyway so after cleaning, the block went to a machine shop for boring, honing and installing new cam bearing's. The maximum recommended overbore for the 360 is .040 so I decided to do a .030 overbore to be on the safe side. Also AMC engines should always be machined using honing plates to simulate the clamp down forces of the installed head so I manufactured those and sent them along to the shop.
When the block returned from the machine shop I chamfered every oil return holes and filed off every rough spots where cracks could build before I painted it and set it aside for now.
CRANK, RODS and PISTONS
The crankshaft and rods where in good shape so I decided to re-use them. I had the shop do a .010 and polish the crank and when I got it back I cross-drilled and chamfered the oil-passages. I then took the rods, removed all rough spots and weight-matched so they where all in a 0,5g +/- range.
When it was time to buy pistons I used a long time deciding what kind of piston I wanted. The stock replacement piston was cast with a compression of 8,25:1. I wanted slightly higher compression but wasn't at that time ready for a custom built set of forged pistons mainly because of the price involved and the fact that I wasn't going too build a race car engine or add nitrous to my Jeep. I finally found a set of Speed-Pro cast pistons with a 9:1 compression. I also weight-matched the pistons.
When all this was done I had the setup balanced.
HEADS and CAMSHAFT
The head from the '79 where slightly ported and the chambers where cc'ed and matched. I then had the shop do a three angle valve job and machined to have o-ringed oil seals instead of the umbrellas that where original. They also shaved them for free. Back home I installed new valves and springs.
I ordered a hydraulic camshaft from PAW along with new lifters. The cam have an advertised duration of 272int/282exh, 214int/224exh at .050 lift. The gross valve lift is .472int/.496exh and lobe separation is 112 degrees. This is maybe a slight bit on the big side but the engine turned out fine and pulls very strong from around 2700 rpm. The torque is good from 1000 rpm so I have no problem lurking around the terrain.
INTAKE MANIFOLD and CARBURETOR
I ended up with a non-EGR Edelbrock Performer manifold which I did some modifications too. First I port-matched it to the heads then I machined off a bit off the plenum separation at the back. I did this because a had an idea of combining the pros from both the single- and the double-plane design. I have never had the chance to do a dyno comparison between my intake and a stock Performer so I really don't know if I made my goal. Later I've seen that Edelbrock themselves marketing so-called Air-Gap manifold for ch*vys so I guess I just was a little ahead of time..
I was going to use fuel injection on this engine(still am) but the bank account said different so I ended up with a standard Holley 1850 600cfm vacuum secondaries. This is good carb for strong runs in the streets but in off-cambered situations it's flooding like the Ganges. I know they can be fine-tuned for off-road use, but I still want EFI for my engine so I don't bother spending time on the carb.
It's topped up with a K&N 14" air cleaner.
The biggest problem with AMC engines is the oil system. The oilpump housing is the same as the timing cover so when your oil pressure starts to drop when a oilpump rebuild kit will in most cases do you no good at all. You will need a new timing cover and they are expensive. ($230 and up). Don't go to the Jeep dealer, they will charge $400. This design is also used by Buick AFAIK.
The camshaft bearings also plays an important role in getting good oil
pressure, so when rebuilding it's a cheap insurence to have the shop
install new cam bearings. Another thing is that the rear crank bearings
tends to get too little oil because of the directions the oil travels
through the block. A rear oiling kit from
American Performance Products can cure this. While you're at
it order a oil line kit for the timing cover as well. Together the are
$50 and your engine will love you.
Together with the above I installed an Autometer mechanical oil pressure gauge and a pressure switch that kills the engine when the pressure drops below 7psi. With this I can be sure that low oil pressure will not destroy my engine by accident. It isn't always easy to monitor the gauges when your in the middle of bottomless mud.
The ignition are Jacobs. I bought a Jacobs UltraTeam which came with new wires, ignition module and a new coil. My original ignition was not in a very good shape and I got a good deal on the Jacobs, so I went for it. The best thing about the Jacobs is the wires. They are very good quality and I think they are the main reason I've experienced good performance from the Jacobs setup. The coil is also good but the "magic box" I have doubts about.
Jacobs claims that it reads the sparks and adjust the voltage according to the needs of every single cylinder. They also says that it's capable of "refiring" if thats what the cylinder needs. My opinion on that is if your engine needs a separate type of spark for every cylinder and every rotation, then something is wrong and you need to look for another solution than your ignition module.
A cheaper solution for a very strong ignition for the AMC 360 would be a Standard Products LX 101 Chrysler-style ignition module together with any kind of good coil and the best wires you can afford. Or a conversion to GM HEI.
I must say that I have not been let down by the Jacobs, easier cold starts, more torque and more stable idle, I just think I could have made this with other (and cheaper) products.
I did not want to use the original exhaust on my new engine. I feel that the stock exhaust manifold and single 2" tubing is robbing the engine for way too much power. Besides I like the sound of my V8 too much to strangle it. The stock AMC exhaust manifold isn't the worst flowing in the industri so with a good double exhaust with free-flowing mufflers instead of the single system, it can be used without loosing too much power. But I wanted headers.
If I was to go with the best (and most expensive) a set off Thorley Tri-Y headers would be the answer. But as income dictates some of my investments I had to find a cheaper solution. So I ordered a set off BlackJack headers and some turbo-style mufflers. The tubing was regular 2 1/2" exhaust tubing. The BlackJacks have medium thick flanges so they tends to leak from warping over time, but I discovered that if the flanges are cut so that each port have their own flange it seems to last a bit longer between each time I have to re-tighten.
As I have relocated my fuel tank I have no problem running dual exhaust. I just run one pipe at each side of the tranfer into the mufflers. Then I turn the pipes over the frame and they exits in front of the rear wheels. As I have a 3" bodylift on the Wag I have no problem running the pipes over the frame.
I also added a cross-over pipe just in front off the tranny crossmember. This should also gain some power because it's supposed to equalize the left and right side of the engine. Don't know but it did something nice to the sound:-)
ASSEMBLING and INSTALLING
Time for the fun part! The first assembly I did was just the measure everything up for the last time. Everything turned out to be right on spot so I teared it down and cleaned everything one last time before I did the final assemble.
Then one night it was done, everything was finished and I got myself a brand new engine. What a feeling !
My garage at the time was too small for the Jeep (not to mention, my engine bay soon being to small for my engine and extras) so I borrowed a huge garage from a friend of mine to install the engine. Nothing unexpected did occur when installing the engine so after three nights work it was time to do the first start
What a moment of excitement and truth. After I filled it up with engine oil, connected everything electrical and set initial timing at 14 deg. BTDC, I prelubed the engine using an old distributor until I had pressure at my gauge. I had the support of a friend to turn the key while I looked under the hood for leaks or sign of other problems.
It fired right up and no leaks or other problems did show up, so I set the idle speed to 2000 rpm and let it run for 20 minutes just like the book says. I had no fans on the radiator so additional cooling was by a garden hose spraying water onto the radiator all the time. No signs of overheating.
I think I drove the Jeep home at around 5 in the morning that last night of changing the engine, but I was way to excited to feel tired at all.
Well, I have not had the chance to do an actual dyno test. I did however do several computer simulated test that showed me a peak Hp of 364 at 5500rpm and a peak torque of 400 at 4000 rpm. The torque was 361 at 2000rpm. This is the bare engine so I suspect different numbers at the wheels :-)) I also simulated a run down the 1/4 and ended at 13.91/102.3mph with my 35" mudders. I suppose the day I'll try the Wagoneer on the strip will never come, but it's nice to know :-))
I also did a compare with the original setup