Third time’s a charm. Always read, follow, know, and love your instructions. To err is human. That feller is dumber than 40 chickens. We could keep going, but these sayings ought to give you an idea of roughly what happened and how we feel about it. We (and by that, we means me) screwed up royally and rounded a few lobes off the Edelbrock cam we installed in Part 1 of The Hunt For Power. We like doing things ourselves—that’s because we feel like it makes us better prepared to write about the ups and downs of aftermarket modifications.
We usually like spinning wrenches (less so after tearing down this 360ci V-8 for a third time in as many weeks). After all, anyone with a credit card could pay a professional to do something to their Jeep (in hindsight that’s probably what we should have done), but where is the learning, exploration, or reward in doing that? Occasionally, our flaws as simple-minded humans take over. Simons will happily admit that he is not much of an engine guy. Here’s proof. We were in over our heads—just slightly, but still. Changing cam, heads, timing chain, distributor, rockers and so on and so forth was apparently just a little more than we could handle all at once. It started when we installed the wrong rockers on our beautiful Edelbrock heads. Don’t do what we told you in Part 1 and install Comp Cams PN 1231-16. They won’t work. We got some bad advice on that and tried to run them despite what the instructions say. Someone with more engine experience might have figured that out before hurting expensive engine parts. Luckily for us, not much was hurt.
Ugh. Cracking into this engine again was tough. We already had to tear it halfway apart after the first build because of a leaky timing chain cover. That meant this was the third time we were going to crack deep into this (Piggy) in just a few weeks’ time.
Add to that the new distributor. We spent way too much time trying to time the AMC 360 with our new distributor from Davis Unified Ignition. As a result of this and the rockers that didn’t open the valves all the way, we never really broke the cam in properly. The incorrect rockers we got pressed down on the valve spring hat rather than the valve stem. All in all, we’re lucky we didn’t drop a valve. That would have been very bad. These rookie moves resulted in a ruined cam, some pretty messed up lifters, and a bunch more work for us.
Somewhere during this debacle, we drove the unknowingly hurt Pig truck to Big Jim’s exhaust shop in Phoenix for a clean dual exhaust. Once the duals were in place and we got a hundred miles or so on the truck, we knew things were not right. A little advice from a mechanic friend (thanks, Doug) helped us realize the horrible truth that we had screwed up—royally. So, the lesson to be learned here is: In the future, try to follow the directions, even if it hurts.
Getting the correct rockers would have been as easy as reading the instructions that came with our heads. Also, it turns out cam break-in is important. Again, that was in the instructions that came with the cam. We blame the many nights assembling Swedish furniture while scoffing at the strange instructions. Oh well. The reality is, if this is the last time we screw something up, it’s going to be a miracle. Anyway, time to move on and fix what we ruined. Hopefully this time the cam will take, the Pig will be healthier and happier, and maybe you will learn from our big old screw-up. Here’s what we did.
Step By Step
Here are the lifters and the cam that lived a short, sad life because of our mistakes. The lifter on the far left is still pretty good, and the one up top is only a little worn. The other three are doing their best impersonation of an ice cream scoop.
The rounded-off cam lobes mean our valves were just barely opening. The engine had a distinct backfire that made it clear that, somewhere in there, an intake valve was not doing its job. Oh well. Time to move on and quit beating ourselves up over this.
Once the engine was torn down as far as we needed to go, we knew we had to clean up the block as good as we could.
Down in the lifter galley was evidence of the metal that used to be part of either the cam or those messed up lifters. We pulled the drain plug and drained the oil and then hosed the block down with a few cans of parts cleaner in hopes of getting as much metal out of the engine as possible.
With the engine pretty well cleaned up, we lubed up the new cam and began to install it into its new home. Here ya go, little buddy. Hopefully, you will live long here and, it’s nothing personal, but we hope to never see you again.
Once we got the cam almost all the way installed, our friend, Doug (who is a full-time mechanic that tolerates our foolishness), said we could make an impromptu cam installation tool with a long stud or bold, a socket that fit over the stud (or bolt), and an extension. This “tool” helps you get the leverage on the cam to get it that last few inches into the cam bearings.
After our last experience, we slathered the assembly lube on each lifter. That’s not to say we did not do that last time but still better safe than sorry—again.
Here are the new rockers that we should have used from the get-go. These are Comp Cams PN 1442-16 that we got from Summit Racing. The rollers actually hit the valve stems. The rockers we used before did not and actually hit the valve spring hats. That’s bad and probably meant the valves were never opening all the way. That could explain why we kept thinking the timing was off. We got some bad advice and were told the other rockers would work. That sucks, but we should have realized they were not right. As a result, the cam was never properly broken-in.
After pulling the harmonic dampener three times and installing it twice, we had the technique pretty well mastered. Because the crank pulleys are so deep on our AMC 360, we used a short length of tubing to help the installer tool push the harmonic dampener back on the crankshaft. We used plenty of anti-seize on the threads of the installer tool. We also like to add a little grease to the bearing surface on the dampener so it doesn’t hurt the seal.
Now that we are back to reading instructions, adjusting the valves is pretty easy. The details of how this is done were laid out in the instructions that came with our heads and the new rocker arms. Our only complaint is that adjusting the valves on Piggy requires a step stool, and afterwards, our back hurt. Maybe we are getting too old for this stuff, maybe not.
So, not all that happened with the first cam was bad. Sure, we wish it would have worked out fine without all this work, but by god, we now know just how to stab the Davis Unified Ignition distributor in this engine. Also remember to use a manifold vacuum (rather than ported vacuum) source for the distributor’s vacuum advance, and don’t forget to disconnect and cap this manifold vacuum when setting the initial timing. Edelbrock recommends 10-14 degrees advanced timing with the cam. That’s a touch higher than our Howell TBI system recommends, but we will play with it as we put miles on the Jeep.
Since we were gun-shy after ruining our first cam and lifters, we went ahead and added some engine break-in oil additive before firing the Pig. Also after break-in, during which the 30 minutes varying the rpms between 2000-2500 seemed to take hours, we promptly drained the engine oil and replaced it with a new filter and a second bottle of engine brake-in oil additive. Why? Well, that extra zinc won’t hurt our old-school pushrod V-8 and might just help that new cam live even longer than it might without it. Honestly, we will probably keep adding a zinc break-in additive with every oil change from here on out.
So, we know we are going to catch flack from all the hot-rod Jeep folks about running exhaust manifolds on a performance build, but hey, we also went with a milder cam ’cause this thing is a truck with a truck transmission in it. The fact is, we just don’t want to deal with headers on this truck, but we have always wanted to run dual exhaust, so that’s just what we did. To save ourselves some time and headache, we took the pig truck down to Big Jim’s Custom Exhaust. Once there, Ted hooked us up with a sexy system that isn’t too loud or too quiet—just what we wanted. Next time, we’ll toss the Pig back on AIRAID’s dyno and see what she can do.