Are the fwd and rwd pentastar the same minus accessories and intake/exhaust?
Actually the only revision appears to be to the front casting where the alternator mounts to the front of the block on top of the 2012 Wrangler, and looking at a recent minivan it had the holes and flat places in that front casting already for attaching the alternator where the Wrangler attaches it. So the engine itself appears identical across all Chryslers that use it, with the only difference being accessory mounting (the Wrangler putting the alternator up top). Well, and the computer is tuned slightly differently due to the Wrangler's different exhaust and different operational requirements (a Wrangler needs low-end torque more than it needs top-end power), but if there is a problem it should affect all Pentastars, not just Wranglers. In particular, the driver's side/left side head is the same on all Pentastars.the only different one is the wrangler so far, parts were revised when the 2012 wrangler started with the 3.6.
Looking at the Wrangler forums, the issue has affected people with 3,000 miles, and people with 35,000 miles, so it isn't as if there's a magic number where your engine suddenly just disintegrates. The Wrangler has had the Pentastar only since August and there's already a number of Wranglers affected (not a huge number, maybe one or two per dealership out of the several dozen that each dealership has sold of this amazingly popular upgrade to the Wrangler platform) so clearly the mileage stated is an average (since most of these Wranglers don't have 20,000 miles on them yet), not a fixed number. As with everything dealing with this problem, the mileage at which it crops up seems fairly random and likely related to driving patterns, exhaust design, and random brownian motion of aluminum molecules during head casting.better be offering loaners to people affected. I still have ~8k miles left before I get there.
It appears to be the timing chain cover (that's that the front casting is called? Hard for me to to tell, since Chrysler won't give access to mere mortals to their electronic service manuals unless we fork over $$$$ for access to *ALL* service manuals, hopefully next year they'll let AlldataDIY do the 2012 Wrangler) is the only difference. There may have been a block change to add reinforcement for the cover mount bolt holes that were repurposed for the alternator mount, but looking at the preproduction Pentastar photos on the main site, the bolts appear to have already been there to hold on the timing chain cover, just without the flattened surfaces needed to mate with the alternator housing. See, e.g., this photo on the main site from last year:what i meant to say is a revision in the castings were made for 2012 to accommodate the JK's accessory drive. new special tools were released for holding the timing chain tension while servicing the cam sprockets. the old ones wont fit with the new bolt hole boss in the timing cover and head configuration.
how many heads in the last 10-15 years have been made or of iron? other than some truck v8's I can't think of any cars since the early to mid 90's that had factory cast iron headsThis is why I got my Challenger with a 3.5. Let them get the bugs worked out.
Seriously though, how long have we been making cylinder heads? Didn't we learn in the 80s this aluminum head garbage doesn't work?