More Wide-Axle Answers
Question: I have an '83 CJ-7. I have swapped in a GM 350 and a Turbo 400 tranny. I want to swap in a set of 3/4-ton Chevrolet axles, but I'm concerned about the caster camber angles on the front axle. I would like to know what I would need to fix these angles.
Dakota
via 4wheeloffroad.com
Answer: This is a great followup to last month's Tech Question of the Month about putting full-width axles under a Jeep YJ. GM 3/4- and 1-ton front axles have the passenger-side spring perch machined into the cast part of the axlehousing. Because of this, the pinion angle and caster angle are set towards each other from the factory, between 2 1/2 and 7 1/2 degrees up for pinion and about 6 degrees back for caster.
As for camber, it can be slightly adjusted at an alignment shop with shims if needed but isn't as detrimental and most likely is set from the factory.
When going to the GM axles under your Jeep, you'll need a full-width kit like the versions we mentioned last month from either Blue Torch Fabworks (334.673.2755, www.bluetorchfab.com) or Poison Spyder Customs (303.777.4820, www.spydercustoms.com). By simply going spring-over you will gain a fair bit of lift, and if you go up to a 2-inch lift spring I am told you can often squeeze a 40-inch-tall tire under a Jeep with some body trimming or a high clearance hood like those sold by 4-Wheelers Supply (602.273.7195, www.4wheelers.com). Also it seems that with a 2-inch lift spring or less you can usually make the factory pinion angle work and not have terrible caster as long as the mounting points are similar to those on a GM truck. Most of my trucks have about 3-6 degrees of caster.
If you go to a taller lift you'll need to crank up the pinion angle, and this would reduce your caster, at which point you need to look into getting your axletubes pressed out and reset for your desired caster and pinion angle. Some folks use front axle shims that can compensate for misaligned pinion angle and caster. Bolted to the front leaf spring with the center pin, they are usually OK, but I am not a huge fan of front axle shims and especially not front lift blocks because of the possibility that they can come out during hard braking.
Swapping Answers
Question: I have a '70 350 Chevy with a Comp cam, AFR aluminum heads, and an Edelbrock fuel-injection system. I wanted to put it in a YJ Jeep but can't find anything on emissions and how to install it in a newer Jeep from an emissions perspective. Do you have any information? Thank you.
Anonymous
via 4wheeloffroad.com
Answer: I have looked into the engine swap laws in California, and though laws vary across the nation it seems that the rule of thumb is the engine must come from a vehicle that is the same year or newer than the vehicle it is going into, and it should have with it the factory-installed emissions systems. Also, the engine must come from the same class of vehicle as it is going into, such that a passenger car cannot get an engine from an industrial truck, though most pickup engines from up to 1-tons can be swapped into smaller vehicles like Jeeps. Since you say you want to put this V-8 into a Jeep YJ and they were only made from 1987 to 1996 and the engine is a '70, this swap is probably not legal. Your state may be different, but you need to check with your local emissions or inspection laws first. Some regions of the country don't have emissions testing, but that doesn't mean you can legally stuff whatever you want under the hood; it just means you may be a little harder for the authorities to catch.