Need help with a 4.6 build

[jbain]

Hello eveyone, I've been lurking around for a few months and now I'm out of time (gotta drop the block off at the Machine Shop 5/20 and I need your help). My 1998 XJ with stock 4.0 has 262.XXX on the clock and carries about 2 pounds of Oil Pressure at hot idle. Recently it has started making unpleasant noises above 3k RPMs so it's time to pull the trigger. I'll be using it for trail riding mostly but will compete in an occasional Mud Bogg as well (about 2K per year), so I've decided to build a 4.6 Poor Mans. I've been reading everything and understanding very little, add in a Dial-Up connection and you get the picture so I apologize in advance if the question has already been asked and answered. I'm starting with a standard 4.6 "poor man's" recipe.

Jeep 4.2L 3.895" stroke crank - I already have this (.10/.10) with very little wear, my only question is how much do I need to have milled off the nose? I read somewhere you can use a washer?

Jeep 4.2L 5.875" rods - I have these from the same donor motor above (707's) - I plan to have the machine shop hone them and add ARP rod bolts.

Sealed Power 677CP +0.020" bore pistons - This is where I need help...can I run a +0.030 bore piston without changing my quench? (I'm not smart enough to use the calculator) Also I read somewhere that I need to make sure I get the correct rings because they are different between years? Were these hard to get (I saw on Summit they ship in like 2 weeks but you know how that is) and is there a non-KB alternative?

Stock 4.0 HO camshaft - I have this from the 1999 4.0 Donor Motor with no wear, but what about a Comp 68-231-4? Not counting the Cam how much additional cost is associated with using an aftermarket Cam?

Ported HO 1.91"/1.50" cylinder head - I plan to Port and Polish the Head (0630) and have the Machine Shop do a 3 angle and lap(?) my existing valves. What springs... ect.... are you guy's who are running the 68-231-4 using?

Stock injectors with stock 49psi FPR for '96 and later engines - Since I have the 96+ setup will a bigger injector be worth the money? I love the Pick and Pull and I've read some about possible donors..... anyone using JY Ford or Dodge injectors?

Machine Shop Questions: (I've never had any machine work done before so I'm trying to keep from making any extra trips, it's an hour drive)
1. I have the Block stripped and ready to go, I don't plan to have the mains journals line honed so should I send the Main caps and stabilizer rail? Also do I need to buy new bolts for the Main Caps or is it ok to use the old ones?
2. Should I bring Freeze Plugs or is that something most Machine Shops do or does it matter either way?
3. Same question for Cam Bearings.

Machine Shop Work:
1. Hot Tank the block
2. Press on new pistons, install ARP Rod Bolts and verify Rod Journal and hone (if required).
3. Turn Crank, mill nose.
4. Press in new Cam Bearings.
5. Press in new Freeze Plugs.
6. 3 angle valve job on head
7. Lap existing valves.

Ok guy's I know this is long but I figured it was better to put it all out there at once. Again this is only a Mud Jeep so it's going to be beat real hard and once broken in this new engine will resemble the rest of the engine compartment... brown. Thanks in advance for any help / criticism you can give me. Oh and by the way I have $1000.00 left for parts and Machine work.

[Cheromaniac]

Jeep 4.2L 3.895" stroke crank - I already have this (.10/.10) with very little wear, my only question is how much do I need to have milled off the nose? I read somewhere you can use a washer?

Yup. Just take your old harmonic balancer to a lathe shop and ask them to cut the rearmost 10mm from it, and use that piece as a spacer in front of the new balancer. There's no need to cut the crank nose.

Jeep 4.2L 5.875" rods - I have these from the same donor motor above (707's) - I plan to have the machine shop hone them and add ARP rod bolts.

Good.

Sealed Power 677CP +0.020" bore pistons - This is where I need help...can I run a +0.030 bore piston without changing my quench? (I'm not smart enough to use the calculator) Also I read somewhere that I need to make sure I get the correct rings because they are different between years? Were these hard to get (I saw on Summit they ship in like 2 weeks but you know how that is) and is there a non-KB alternative?

You can use 30 thou overbore pistons. It won't matter. Just make sure you get matching rings. The 677CP use standard size rings (not metric) and these are the ones you'll need:

http://www.summitracing.com/parts/SLP-E-234K030/

Stock 4.0 HO camshaft - I have this from the 1999 4.0 Donor Motor with no wear, but what about a Comp 68-231-4? Not counting the Cam how much additional cost is associated with using an aftermarket Cam?

You'll need new lifters either way but if you go with an aftermarket cam you'll need to factor in the additional cost of Mopar Performance 5249464 valve springs ($131.40), 4452032 spring retainers ($119.40), and 4529218 valve keepers ($39.90). Add the cost of the cam ($139.39) and the total extra cost comes to nearly $430. Now you see why the poor man's route with the stock cam is attractive.

Ported HO 1.91"/1.50" cylinder head - I plan to Port and Polish the Head (0630) and have the Machine Shop do a 3 angle and lap(?) my existing valves.

Good eye deer.

Stock injectors with stock 49psi FPR for '96 and later engines - Since I have the 96+ setup will a bigger injector be worth the money? I love the Pick and Pull and I've read some about possible donors..... anyone using JY Ford or Dodge injectors?

Chevy LT1 24lb/hr injectors (Part no. 17124248) would be a good swap.

Machine Shop Questions: (I've never had any machine work done before so I'm trying to keep from making any extra trips, it's an hour drive)
1. I have the Block stripped and ready to go, I don't plan to have the mains journals line honed so should I send the Main caps and stabilizer rail? No need. Also do I need to buy new bolts for the Main Caps or is it ok to use the old ones? Reuse the old ones.
2. Should I bring Freeze Plugs or is that something most Machine Shops do or does it matter either way? Take them with you.
3. Same question for Cam Bearings. Take those as well so that the machine shop can press them in.

You'll also need to take the pistons with you so that the machine shop can measure them and bore/hone the cylinders accordingly.

[jbain]

Thanks alot and without this site and the excellent (Flame Free) help I would have never considered attempting this build. So I now need to call Summit and get those pistons ordered.

[Cheromaniac]

Thanks alot and without this site and the excellent (Flame Free) help

Nah, we just keep the flame throwers hidden in our tailpipes and only let them loose on stupid ass ricers after they're left trailing in the rear veiw mirror.

[SilverXJ]

Machine Shop Questions: (I've never had any machine work done before so I'm trying to keep from making any extra trips, it's an hour drive)
1. I have the Block stripped and ready to go, I don't plan to have the mains journals line honed so should I send the Main caps and stabilizer rail? No need.

I would ask the machine shop about that. Some shops will need the caps to setup the block on the machine.

[jbain]

Ricers?...... .....What Ricer? Thanks SilverXJ I'll ask the Shop if they require them for setup. Oh and here's "Chief" my pride and Joy...

[jbain]

Ok a couple more questions?
1. If I went with the H802CP instead of the 677AP would that help or hurt my quench? They seem easier to get and have a bigger dish.
2. If I re-use the stock cam and I marked the lifters when I pulled them out do I have to buy new ones?
3. With the 4.6L will enlarging the TB be worth the associated costs? any idea of gains?

[amcinstaller]

id bring the main caps with you, and if you use the cam in your jeep NOW, and the lifters in your jeep NOW, mark them and you should be ok. lifters wont be happy on a different cam, stock or not.

[4.whoa]

If I went with the H802CP instead of the 677AP would that help or hurt my quench? They seem easier to get and have a bigger dish.

The dish size does not affect quench, just compression. the quench is the difference from the top of the outer edge of the piston to the head surface.

[Cheromaniac]

Ok a couple more questions?
1. If I went with the H802CP instead of the 677CP would that help or hurt my quench? They seem easier to get and have a bigger dish. The H802CP's are 0.007" taller than the 677CP's so the quench would be reduced by the same amount. The dish is slightly smaller in the H802CP's (~15cc).
2. If I re-use the stock cam and I marked the lifters when I pulled them out do I have to buy new ones? No. You can reuse the old ones as long as each lifter is placed in the same lifter bore that it came from, so mark them all when you take them out.
3. With the 4.6L will enlarging the TB be worth the associated costs? any idea of gains? A 62mm TB is optimal for a mild 4.6 stroker so you can either search for a cheap one in ebay or alternatively, have your existing TB bored out to 62mm at a lathe shop and make an oversize throttle plate 2mm bigger in diameter than the stock one (use the stock one as a template). Been there, done that, and it works great.

[jbain]

So the quench is reduced a little and the CR is increase a little..... Win .....Win.....?

[jbain]

Thanks everyone, I've ordered the 802's, ARP rod bolts and was able to find freeze plugs and cam bearings locally. Hopefully I'll get it done in time for Fair Season and the Mud Boggs.... Last year I schooled alot of Fullsize trucks with thousands in their rigs with only my stock 4.0L "Tractor Motor". Hopefully this stroker motor will give me the two or three tenths required to beat the rest of them...... It's priceless to overhear them complaining about us "cheating Jeeps"........

[jbain]

Dropped the Block, Crank, Pistons, Cam Bearings and Freeze Plugs off at the Machine Shope last night..... I felt violated when I walked out with the estimate.... Thanks again for everyones help.

[jbain]

Finally finished the stroker and was able to drive it home last night and to work this morning. First impressions is more torque in lower RPM's then before and much better throttle response. The only issues I've experienced is the oil pressure is only 15 psi hot and my low beams no longer work (obviously not related). The machine shop only polished the crank and with standard bearings all the tolerance's were on the big side so I guess that's expected. I'll probably just drop the pan and throw in a HV oil pump. So far so good and the engine is quite as a mouse, I'm keeping my fingers crossed. I plan to change the oil at about 100 miles and drive it like I stole it, does anyone have any "Oh by the ways" that may help me in my quest to break in the stroker?

[hflmike21]

Ive always heard that the motor break in period was 500 miles.... I could be wrong though congrats on finishing it