4.5 or 4.7?

[hot_rod_hooligans]

Ok, so I've got my fingers on a 4.0 with 11k on it. The only thing thats for sure wrong with it, is two of the bolt bosses that the motor mount bolts to the block on the passenger side of the engine, are broken off from the block, an easy fix with M.O.R.E. Bomb Proof engine brackets:

Even with the two thats broken off, I'm still gaining strength over stock.

So the major question is, do I bore it out and do a 4.7, or do I just throw the 258 rods and crank in, as well as the head work, and valve train? Or would the performance gains of .2 liters really be worth the cost? Now mind you, the machine work is not an issue, as I can have that done for free. there is a pretty good chance I'll send it to get checked for any yet unknown damages, and cleaned, even though, how dirty could a engine with 11k really be? But I'd kind of like to start with a clean canvas so to speak. I'm also thinking Fire Engine Red for the block color

I'm not really looking for this to be a super cheep build, but at the same time I don't want to spend money where it's not really necessary. Things like forged rods, pistons, and high dollar valves, aren't necessary, as I will not be pushing enough power to really need the strength, and the engine will probably never reach the kind of milage that would warrant the need for such durable parts.

[mendelmax]

To me the question is also what year that motor is?

I'm asking because making it 4.5 is beneficial only if you re-use the pistons, to cut down the costs. Now the pistons from 96 are hypereutectic, which I find pretty useful in a stroker application (more compression, more A/F mixture, more power = more heat = higher than stock thermal expansion).

If you have post 96 I would consider leaving old pistons in (the argument against is the tendency of piston skirt damage in these pistons). If you have pre 96 I would definitely get some different, hypereutectic or forged ones.


Also, if machine work is not a problem, I would most definitely get new, hypereutectic or forged pistons. Maybe even KB944?
But hey, that's just me

[hot_rod_hooligans]

To me the question is also what year that motor is?

I'm asking because making it 4.5 is beneficial only if you re-use the pistons, to cut down the costs. Now the pistons from 96 are hypereutectic, which I find pretty useful in a stroker application (more compression, more A/F mixture, more power = more heat = higher than stock thermal expansion).

If you have post 96 I would consider leaving old pistons in (the argument against is the tendency of piston skirt damage in these pistons). If you have pre 96 I would definitely get some different, hypereutectic or forged ones.


Also, if machine work is not a problem, I would most definitely get new, hypereutectic or forged pistons. Maybe even KB944?
But hey, that's just me

It's an 05, and yes I planed on reusing the pistons, though I didn't know the stockers were hypereutectic, so thats good news. I would think harder about boring it out and using the 4.0 rods, and Keith Blacks, but with only 11k in the motor I'm having a hard time getting into the block just yet. Then again I haven't opened up the engine yet, it's been setting in a garage for the last 2 or so years, and may hold a different story.

[1bolt]

I can't remember what the quench is for this style build but it's not good at all. The 4.5 is known as a "junk yard stroker" or Ultra low budget stroker. So called due to the fact that no overboring/machine work and stock 4.0 pistons on 258 rods is usually assumed to be a money saving choice, such as re-ringing a junk yard 4.0 that has decent bore wear -- unlike your scenario where it's just not necessarily needed.

If machine work is free and your budget is reasonable... you'd be missing out not to overbore, and go with a well matched piston and deck the block for "zero deck" (piston flush with deck at TDC) for sake of brevity I've been trying to get the term "GC" (Gasket Quench) to catch on around here so we can stop typing that long involved sentence... basically GC means zero deck and your head gasket thickness then determines your quench spec, a .043 gasket = .043 quench which is excellent, and will allow more compression before onset of ping, more power or lower octane fuel use for the same power (or more power with higher octane and a aftermarket engine management setup).

If you only deck the block to improve quench you'll put your compression ratio through the roof which will require deeply dishing the stock piston (which can take a fair bit of dishing it appears they are very thick in the crown) and/or enlarging the 4.0's combustion chambers which we have on good authority are too big already and not ideal for performance.

If money and machine work permit you'll be much happier with a more engineered thoughtful build... Just ask all the budget stroker owners (myself included) that have ping issues.

[hot_rod_hooligans]

I can't remember what the quench is for this style build but it's not good at all. The 4.5 is known as a "junk yard stroker" or Ultra low budget stroker. So called due to the fact that no overboring/machine work and stock 4.0 pistons on 258 rods is usually assumed to be a money saving choice, such as re-ringing a junk yard 4.0 that has decent bore wear -- unlike your scenario where it's just not necessarily needed.

If machine work is free and your budget is reasonable... you'd be missing out not to overbore, and go with a well matched piston and deck the block for "zero deck" (piston flush with deck at TDC) for sake of brevity I've been trying to get the term "GC" (Gasket Quench) to catch on around here so we can stop typing that long involved sentence... basically GC means zero deck and your head gasket thickness then determines your quench spec, a .043 gasket = .043 quench which is excellent, and will allow more compression before onset of ping, more power or lower octane fuel use for the same power (or more power with higher octane and a aftermarket engine management setup).

If you only deck the block to improve quench you'll put your compression ratio through the roof which will require deeply dishing the stock piston (which can take a fair bit of dishing it appears they are very thick in the crown) and/or enlarging the 4.0's combustion chambers which we have on good authority are too big already and not ideal for performance.

If money and machine work permit you'll be much happier with a more engineered thoughtful build... Just ask all the budget stroker owners (myself included) that have ping issues.

Thats one thing I am apprehensive about doing the 4.5, that I'll be giving up a lot of the ability to fine tune by not going with a bigger bore. I like the ability to play with dish volume, deck hight, and combustion chamber to play with the C/R a little. I'm not as much concerned about needing high octane fuel, by the time the stroker goes in, the Jeep won't be a DD.

I guess I'll have to start gathering parts that I know I'll need(crank, cam kit, etc), see where I sit budget wise at that time, and then start crunching numbers . 'Cause I really do like the idea of the Keith Blacks, since I would ultimately like to use the 4.0 rods instead of the 4.2, and would also help offset the cost of the pistons VS. rods and pistons. As it stands, I guess I'd be looking at about $200 more to go with the KBs, since the KBs come with rings, and I won't have to buy rods, it is a viable option I guess. Could probably do the whole thing for around $1500 or less.

I'm looking at Summit($$ rounded up)
$540 Keith Black/KB Pistons KB944KTM-040 - Keith Black/KB Pistons Pistons & Piston Rings
$340 COMP Cams K68-231-4 - COMP Cams Xtreme Energy 4x4 Cam and Lifter Kits
$45.00 Manley 10550-1 - Manley Budget Series Performance Valves - Intake, Stainless Steel, 2.020
$50.00 Manley 10551-1 - Manley Budget Series Performance Valves - Exhaust, Stainless Steel, 1.600

$975
I was looking at a crank from O'Reillys, but can't find it on their site now, I think it was about $180, making it almost $1200, and try to budget a little more in there for odds and ends like gaskets and such. I'd like to re-use as much as I can safely, but I'll probably set back another $500 for thing like bearings, wrist pins, push rods, and possibly a high volume oil pump.

[Plechtan]

By the way, the MORE mounts will not fit a 2005 block, i assume it is either a Wj or Wrangler block. They changed tie bosses on the block around the 2000 model year. The 3 holes for the mount are basically in the same place, but the height of the bosses on the block are different. Newer blocks use 10mm bolts the older blocks use 3/8. The additional holes used by the MORE mounts may have been moved around or removed, I don't know. Looks like you may have to do some of your own fabrication.

[hot_rod_hooligans]

Yeah, thats the one thing I was really iffy about, and have been told several times that I was wrong when I would quote 4 Wheeler Magazines artical "Inside the Inline"

We learned the hard way that there are significant external differences between the '00-and-later engines ('99-and-later for the WJ) and the earlier ones. Eye exams for all were ordered. It was as obvious as a garish Aloha shirt at a funeral. Water pumps, accessory mounting, engine mounts, induction systems, and more-all changed.

Telling me that the block was unchanged the entire time. I would really have loved to pull the but have no first hand experiance to back it up.

Well I guess the good news is, a fellow IndyORV member has his own fab shop, and is waiting for his new Gantry CNC plasma table to show up in the next couple of days. So I could probably talk to him about having the parts cut for me.

Although BrownDog says that their Super Kit w/ MM & Engine Brackets will fit up to 01 XJs, http://browndogindustries.com/su2572-0s ... ubber.aspx
I'm going to call both M.O.R.E. and Browm Dog and get the info first hand. Then figure out from there if I need to make custom ones or not.

[Plechtan]

I had an 02 Wj block and was able to use the brown dog mounts for the 00 and up wrangler. I had to throw the bolts away and go get metric ones. Those mounts only used the stock 3 holes per side. I was putting the motor into a 88 Comanche.

[hot_rod_hooligans]

I had an 02 Wj block and was able to use the brown dog mounts for the 00 and up wrangler. I had to throw the bolts away and go get metric ones. Those mounts only used the stock 3 holes per side. I was putting the motor into a 88 Comanche.

I know the brackets your talking about, just helped a buddy of mine put them on his 05 TJ, looked to be good quality, but not what I need, and the Brown Dog Super Kit isn't really what I need either

Left bracket features seven bolts, four more than the original. Right bracket features four bolts, one more than the original.

Where as M.O.R.E.:

We have come up with a replacement bracket that will bolt on using 7-8 existing threaded holes on the side of the block.

Since I'm already working two bolt holes short, I really like the idea of 4-5 more than stock, rather than 1-4.

Just got off the phone with M.O.R.E., and they do have brackets for the late model block, unfortunately it's going to run me about $400 for the engine brackets and motor mounts, I'll have to sick my buddy on them, he has an amazing ability to get killer deals out of a lot of venders.

Also, found this in the PDF file for the engine bracket instal instructions:

The BBXJ9101 Block Brackets are designed to fit the following Jeep® vehicles: 1991-2001 XJ Cherokees equipped with 6-cylinder engines (4.0L ). These Brackets will work with the OEM motor mounts along with most Aftermarket Motor Mounts.