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post #1 of 12 Old 11-14-2019, 01:14 PM Thread Starter
windsock
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Advise on two upgrades

I have a stock 1979 Jeep CJ7 304 and a 4 speed. I am wanting to do two upgrades to a basically stock vehicle. Currently it has dual exhaust and Urethane bushings throughout. Truck is just a runabout it sees no serious off roading and only the occasional freeway drive. It is used around my cabin on country and logging roads.
It currently has power brakes but I am looking to upgrade to four wheel discs any advise on kits?
Second upgrade is freshen the engine. Considering just pulling the stock 304 which runs ok. building a mild 360 with a throttle body fuel injection and installing that. Hoping for roughly 280-300 hp. Any suggestions from those that have been down this road already would be appreciated.


Mark
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post #2 of 12 Old 11-14-2019, 01:33 PM
Matt1981CJ7
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I can't help you on the disc brakes, but I did rebuild and swap in a 360 into my CJ.

Overall, the 360 has been wonderful upgrade over the 258. Mine dyno-ed at 325 HP, which is plenty for a little CJ. I think any more HP than that would require additional upgrades to the drivetrain/axles. I also upgraded my worn out SR4 trans to a rebuilt T-19. It's a completely different Jeep, now, and a LOT of fun.

Having said that, the cost of rebuilding the 360 was more than I was expecting. I did the disassembly, bought all the parts, and did the reassembly. With machining costs, I'm into it for around $6K, but heck, it's only money.

Good luck, and keep us posted.

Matt


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post #3 of 12 Old 11-14-2019, 08:44 PM
BagusJeep
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I have not done it, because it is quite pricey and the drum brakes are good for most applications until you get really big tyres on there, and you would be upgrading your axle before you got that big.

The Jeep Guy does not list the kit but I would drop him a line, seems very knowledgable about Jeeps brakes. 999offroad makes an AMC 20 disc brake upgrade that works with the e-brake and everything else but so do many others. You can have US or foreign brake parts, new or reman, the only new part the suppliers need to make is the bracket which holds the caliper to the axle but do check they are ensuring the e-brake cable will bolt back up. There are DIY lists on this forum and elsewhere as to what you could buy.

None of the kits I have seen, despite charging $500 to $600, include the other parts that you need to change to make a functioning brake system:
  • Master cylinder (disc/disc, not disc/drum which could have residual pressure valves for the drums)
  • Proportioning valve/ Combination Valve (discs require different amounts of fluid, so the old valve cannot be reused (actually they can but the braking is a bit iffy))

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post #4 of 12 Old 11-14-2019, 11:48 PM
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I don't see any advantage to rear disks in your application.


What part of the engine isn't performing to your expectations?

Low end?
mid range?
Top end?

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post #5 of 12 Old 11-15-2019, 10:56 AM Thread Starter
windsock
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Its just very tired overall and these only had 125 hp when new and operating at their best.

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post #6 of 12 Old 11-15-2019, 11:45 AM
Fourtrail
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It looks like SSBC is no longer offering their disc brake conversion kit for the AMC 20. OP, do you already have 1 piece axle shafts? That is a requirement for most conversion to disc brakes. If you aren't afraid of a bit of fab work, the conversion isn't that hard. Multiple companies make both the weld on brake bracket and new parking/ebrake calipers. RuffStuff and Speedway motors offer both parts. The biggest hurdle is cutting down the factory backing plate so you retain the axle retainer function and get enough clearance for the caliper and mount. We used the CJ thin front rotor for the conversion that we did. The master/proportioning valve is just one for a corvette from the early 80's. You will also want to shorten/replace the rear hard lines to install the new flex lines for the calipers. When we did this 13 years ago the e-brake calipers were very expensive and hard to find, we will eventually go to them. IIRC we put the rotor behind the axle flange because the flange wouldn't seat in the rotor and we didn't feel like spending the time to grind down the flange to fit. Used standard CJ font wheel studs.
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post #7 of 12 Old 11-15-2019, 12:43 PM
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Just a though... I am thinking of a similar conversion for a Dana 44 axel. if you need to grind the inside of the rotor to make it clear the axel flange, you can mount the rotor to the axle reversed and bold it down. You can then use a die grinder and stone to clearance the rotor with the engne ideling and the transmission in gear. It would be a poor mans lathe with a hand held toolpost grinder. You would want both sides of the axel on good jackstands and I would remove both tires in the rear and blcok the front ones well. Your conversion looks great.

Why did you decide to use the thin Jeep rotors? When I converted my front to the Chevy calipers (one of the best improvements I made to my Jeep), part of the requirements was to source the thicker 1-1/8" rotors as I was told by The Jeep Guy that the 7/8" rotors were too thin and would not work.

Quote:
Originally Posted by Fourtrail View Post
It looks like SSBC is no longer offering their disc brake conversion kit for the AMC 20. OP, do you already have 1 piece axle shafts? That is a requirement for most conversion to disc brakes. If you aren't afraid of a bit of fab work, the conversion isn't that hard. Multiple companies make both the weld on brake bracket and new parking/ebrake calipers. RuffStuff and Speedway motors offer both parts. The biggest hurdle is cutting down the factory backing plate so you retain the axle retainer function and get enough clearance for the caliper and mount. We used the CJ thin front rotor for the conversion that we did. The master/proportioning valve is just one for a corvette from the early 80's. You will also want to shorten/replace the rear hard lines to install the new flex lines for the calipers. When we did this 13 years ago the e-brake calipers were very expensive and hard to find, we will eventually go to them. IIRC we put the rotor behind the axle flange because the flange wouldn't seat in the rotor and we didn't feel like spending the time to grind down the flange to fit. Used standard CJ font wheel studs.
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post #8 of 12 Old 11-15-2019, 12:49 PM
Fourtrail
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Quote:
Originally Posted by StoneTower View Post
Just a though... I am thinking of a similar conversion for a Dana 44 axel. if you need to grind the inside of the rotor to make it clear the axel flange, you can mount the rotor to the axle reversed and bold it down. You can then use a die grinder and stone to clearance the rotor with the engne ideling and the transmission in gear. It would be a poor mans lathe with a hand held toolpost grinder. You would want both sides of the axel on good jackstands and I would remove both tires in the rear and blcok the front ones well. Your conversion looks great.

I would grind the axle flange before I would grind out the inside of the rotor, I wouldn't want to remove any material that wasn't casting flash and weaken the rotor hat to rotor material. This is only if it doesn't fit. I would test fit it before doing any major grinding, with the rotor on the outside of the axle flange, you will be real close to the weld for the bearing cup, moving the rotor to the inside of the flange gives you a bit more room to be on the smooth part of the axle tube.

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post #9 of 12 Old 11-15-2019, 12:54 PM
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Quote:
Originally Posted by StoneTower View Post
Why did you decide to use the thin Jeep rotors? When I converted my front to the Chevy calipers (one of the best improvements I made to my Jeep), part of the requirements was to source the thicker 1-1/8" rotors as I was told by The Jeep Guy that the 7/8" rotors were too thin and would not work.

For the AMC 20, we used GM metric calipers which are for a 1" wide rotor, went with the thinner rotor instead of grinding down the pads to fit the 1-1/8" rotors. Caliper pricing was quite a bit cheaper and I figured that the 79-88 availability would be better than the truck/early calipers.



When I did the conversion on the Dana 60 in the '6, I used the early mount for the larger caliper and used the thicker 3/4 ton 8 lug Dana 44 front rotor.

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post #10 of 12 Old 11-15-2019, 09:42 PM
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I got my rear disk from TSM and hope to get them put on next week along with 1 pc axles
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post #11 of 12 Old 11-17-2019, 11:49 AM
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TBI'd 360 yes. Do it.

Brakes. I remember when I first bought my CJ-5 it would stop about 10 feet beyond where I wanted to stop. Lots of fun I remember. It had 33" tires at that time. Come to find out the rear brake shoes were wet with gear lube from axle seal leakage. You might have something similar going on. Investigate that before committing to 4 wheel disc brake upgrade, unless you just can't stand maintenance on rear drum brakes. I understand if that's the case.

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post #12 of 12 Old 11-17-2019, 09:30 PM
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As noted above, unless you have bigger tires, disc's in the rear are not going to do much for you.
With that said....I'm doing the disc brake conversion to my CJ7. I have all the parts, just trying to find the brackets.

As for the engine. For the cost of rebuilding the 304, you could likely find a 4.3L V6 with the auto.....it's actually a pretty easy swap. It's about 100 lbs lighter....and gives you 225 HP....and a LOT better gas mileage. That is the route I would have gone had I not gotten such a good price on my SBC TBI and 4L60 tranny ($500 for the set).

About the only way I'd have a jeep now with a carb is if it was an old WWII Willis....


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