Rebuild Parts Questions

[crazydog]

I am in the process of gathering parts to rebuild a 401 if it passes muster for being rebuilt. In looking at Bulltears store and reading this forum, other perusing of the internet, and some dicussions with a couple of engine builders that have not really done much with AMC's I have a few questions. Please preface your answers based on a street driven Cherokee that will see nothing more than some occaisional rough roads. No rocks and minimal mud.

1. Is there a difinitive point when the oiling mods "need" to be made? RPM, HP..?

2. When would the decreased oiling cam bearings and push rods "need" to be used?

3. There are a bunch of different options on the oil pumps. What adds to the functionality, duribility, or performance and what is more visual? Like the nickel plating?

4. Stock iron heads vs. Edelbrock aluminum heads, what are the recommended maximum compression ratios for each using 90 octane?

5. Has anyone used Rhoads lifters? I have been looking at the new V-Max ones. In reading how lift and duration are decreased at lower RPM's, would one still run the same cam they were considering with normal lifters and in theory pick up some extra torque down low, or go one step larger on the cam and have more top end when needed?

Also, if you have any extra tips or advice, please feel free to throw some in. Thanks for your time.

[Wrench Man]

It sounds like the guys you've been talking to build RACE! engines, for the intended use you state I'd do nothing more than make certain that the oil passage in the front of the cam and timing gear are open to provide proper oiling to the distributor drive, and simple deburring and flash removal.
Any of the available dish pistons will provide a good street compression ratio.
"RHOADS" lifters are for race applications where the have "vacuum" restrictions, they're very noisy and you'll get tired of listening to them in a hurry! and most any cam that they'd be good with has no place in a street driven Jeep.

[tufcj]

1. Is there a difinitive point when the oiling mods "need" to be made? RPM, HP..?

2. When would the decreased oiling cam bearings and push rods "need" to be used?

3. There are a bunch of different options on the oil pumps. What adds to the functionality, duribility, or performance and what is more visual? Like the nickel plating?

4. Stock iron heads vs. Edelbrock aluminum heads, what are the recommended maximum compression ratios for each using 90 octane?

5. Has anyone used Rhoads lifters? I have been looking at the new V-Max ones. In reading how lift and duration are decreased at lower RPM's, would one still run the same cam they were considering with normal lifters and in theory pick up some extra torque down low, or go one step larger on the cam and have more top end when needed?

Also, if you have any extra tips or advice, please feel free to throw some in. Thanks for your time.

1 + 2) OEM AMC engines ran for 100K+ miles from the factory. A good quality rebuild is all you need unless you're running it up to red line (about 5500 RPM) for any extended periods.. The oil restricting cam bearings don't hurt anything, just depends on what you want to spend.

3) An oil pump within factory spec is critical for proper pressure/volume. If your factory cover is within clearance specs, and has no excessive scoring or wear in the walls, you can use it. I'd replace the pump gears as part of the rebuild. The filter adapter should also be replaced for a new style one without the filter bypass. The nickel coating on the Bulltear covers increases the hardness of the walls of the pump housing, making them less vulnerable to scoring than just aluminum. A Bulltear mid plate is cheap insurance, I have one in both my AMX and CJ.

4) For street use, stick with a set of steel heads. A good 3 angle valve job and mild porting, and you'll still have money left over for other mods. Replace the springs and have positive seals added as part of the rebuild. With 90 octane, keep it around 9:1, no more than 9.5:1. With aluminum heads, you need to raise compression about 1 point over steel just to compensate for thermal loss in the cylinder.

5) Rhodes lifters are noisy. I had a set in my CJ, and ended up taking them out. I saw no performance change after going back to standard lifters. The oil bleed that the Rhodes lifters do drops pressure some, so you have to have a good oiling system.

Stick to a good RV cam. A lot of people here are running the Summit 8600, and like it a lot. Stick with something with lift in the .480-.490 range, duration around 270 and a 112 LSA. Don't over cam, a lot of people do. Bigger is not better. Look at the cam specs, and find one that makes it's peak torque in the RPM range you run in. If you don't have a tach, get one and watch it a while before building your motor.

Bob
tufcj

[crazydog]

Thank you for all of the input. I will stay away from the Rhoads. The 401 did not come with a timing cover, and I plan on leaving the one on the 360 on the 360. Do Bulltear's covers come eith the midplate? I like the idea of a remote mount filter, but I will have to check for real estate to mount it.

If I go with the Edelbrock heads, and you are saying shoot for what 10 to 10.5, it appears that there are no off the shelf pistons that will land in that area that I have found. Should I shoot for the high end or low end? I guess cam selection will play a role in that decision. Or does someone know of a off the shelf piston to go with? It seems to be pretty easy to hit the 9 to 9.5 range off the shelf for the stock heads, but I won't know if they can be rebuilt until the machine shop gets them. From what I have read, the AMC heads handle more compression than the SBC heads I am used to, is this correct?

Like you said, I have narrowed it down to either the Summit, a Reed TM264H/TM272H/110a2, or a Engle K-52/K-54. The Summit and the Engle both have a 112 LSA, and the Reed has a 110 LSA. This engine will have a NV4500/Dana 300 with 3.54 gears and 35" tall tires. Once I swap in the Dana 60 rear, I will be going to 4.10 gears.

Once again, thanks for your assistance.

[tufcj]

I'm running a mild 360 (about 300HP) in my CJ. Stock cast pistons, 291C heads that have been ported/polished/gasket matched for around 9:1 compression, Edelbrock cam, roller rockers, and Howell EFI. I have a T-18/Dana 300 combo. I rock crawl a lot, running 4.27 gears (Dana 44s in both ends, Dana 60 rear coming) with 35" BFGs (locked in both ends). Sometimes that just wasn't enough gear. I have 37" MT/Rs on it now and it's downright doggy. I have a set of 4.88s waiting to go in with the 60.

3.54 gears with 35s aren't going to perform well, 4.10s will still be a little less than stock. I'd think about going 4.56 or 4.88 when the new axle goes in.

Bob
tufcj

[Mudrat]

Echo what Bob said (TuffCJ).

I've got a 360 pushing 400HP, but have 'other parts' installed. A stock 401 rebuild will be fine and keep the CR between 9-10 for regular pump gas. A mild cam and a GOOD head rebuild )match spring weights, with mostly stock parts will keep you well within your HP range with no problems at all. AMCs like to BREATHE so if you go with a bigger carb (dump the BBD) and some good headers (and that depends on if you want shorty's & 1.5-1.58" for the torq or long in-rame 2" for higher RPM) either way you'll really wake the engine up for cheap!! :t:

No mater what you do make sure your timing gears, oil pump and pick-up are up to speed. I've got BT oil pump in all 3 of my 'race' engines and do not have the mid-plate (yet) (budget was an issue with five 4WD trucks in the yard :oops: the oiling mods and push rods are really for when you push the envelope. Not needed if your basically stock.

Keep us up-to-date on your build, all info is welcome!!!! :t: