Our Readers Write Back
I thought that black Rubicon TJ on 37s that you covered was a very cool rig. It was really one of my favorites. It was great to see that it was wheeled and showed the part. That’s what we build them for, to have fun. Thanks again for another great issue.
via jpmagazine.com forums
Road Trip Regearing Tires
Your article “Road Trip Regearing,” (Nov. ’12) gave us lots of good details, but nothing about the tires. Tire diameter was the reason for all this effort in the first place. Your only photo shows the Jeep hangin’ there without the wheels and tires.
I’m interested in all the details because my present project is a 2001 XJ Sport.
Little Rock, AR
Technically, since we didn’t monkey with anything else, the results were based on the percentage change gained by the gears. And we did say in one of the photo captions that we regeared the speedo to read accurately with our 33-inch tires. But you’re right, we should’ve stated the type and size tire clearly in that story since many people like to emulate our buildups.
For the record, Trasborg’s ’98 XJ used in that story runs 33x12.50R15 Goodyear Duratrac tires mounted on 15x8 MB Model 72 wheels from Discount Tire. At freeway speeds under 70 mph, the swap from 3.55s to 4.56s resulted in an improvement of about 2.5 mpg. Above 70 mph, economy tanked into the 14s.
I’ve never seen this mentioned in Jp before, but if you have a two-door JK (in my case a ’12 Rubicon), you can order the heaviest duty OEM JK Unlimited springs (PN 52126319AC, front and PN 68004460AA, rear) from the dealership and get a 2- to 23⁄8-inch lift in front and a 11⁄4- to 11⁄2-inch lift in the rear. It varies a bit from Jeep to Jeep depending on weight.
I did this to my Rubicon and got 21⁄4 inches of lift in the front and 13⁄8 inches of lift in the rear. On the front of my Jeep I also run a 11⁄4-inch spacer. These springs are not only a bit taller, but are made of larger diameter wire. They improve the handling on-road and soften the ride off-road. The springs can frequently be found online used for about $50 to $75, or they can be had for about $190 to just over $200 from the dealer.
For someone wanting a small amount of lift and the ability to fit up to 35-inch tires, this is an inexpensive option. One word of warning: It would help to get some shocks with a little more travel. The red paint showing was under the shock cover when I painted it black before adding the new Unlimited Wrangler springs. The red doesn’t show all of the lift, as some of the black paint got up under the cover.
Tech Talk Smack
Verne, you got that one wrong! (Editor’s note: He’s speaking about a tech question and answer from our monthly column, Your Jeep (Nov. ’12), about a drop-in CJ V-8 swap for a 258-powered ’83 CJ-5). If you recall, ’72-’81 CJs were equipped with the AMC 304 V-8. To say there is no V-8 that will directly bolt in a CJ is a gross error on your part. Any 304, 360, or 401 is a straight bolt-in operation in place of the 258 six. I’ve been reading the column for quite some time and have found you people don’t quite really know your Jeeps at times. It’s unfortunate that readers are being misinformed, and you people are not the Jeep aficionados you pose to be.
Rohnert Park, CA
We’re more enthusiasts than aficionados, but “potatow,” “potatoh.” It’s funny to me that often times those who lambast us the most are often guilty of not actually reading the story they seem to have a problem with. I sat down to really roast you in response, but you know what? You’re not entirely wrong. But then again, you’re not entirely right, either.
The question that was asked is, “Can you tell me what would fit without going through a lot of trouble or expense and will bolt up to my transmission?” Verne was correct when he said, “There is no V-8 that will bolt directly to your motor mounts and transmission.” And you’re correct when you point out that Jeep CJs came with 304s and that other AMC V-8s of the era could work. But they are by no means as you say “a straight bolt-in operation in place of the 258 six.”
The passenger-side frame-to-engine brackets are different between I-6 and V-8 CJs. You need to replace the passenger-side CJ frame engine bracket with one for a V-8 application. You’ll also need new CJ engine motor mount brackets. Obviously,you’ll need new isolators. The AMC V-8s are externally balanced, so you’ll need to make sure the new engine comes with a flywheel or flexplate that will work with the CJ tranny since you can’t reuse the 258 flexplate or flywheel. The power steering pressure hose needs to be swapped out, the fuel line is on the wrong side of the chassis, some electronics need monkeying with, as does the fan shroud, exhaust, and so on.
In all, it’s not a hard swap, and technically there is no welding involved with an AMC I-6-to-V-8 swap in a ’72-’86 CJ. The six-cylinder radiator can be retained, and the AMC I-6 and V-8 bellhousing bolt patterns are the same. But it’s not a swap that’ll just plunk into place without a fair share of trouble and expense—which was the point of the original question.