Taking the plunge! Newbie Mini-Stroker

[Toy_Truck]

For starters I am amazed (overwhelmed) by the plethora of information available on the forums. It was this forum that inspired my delusions of grandeur which shall hopefully become a running Mini-Stroker in the next couple of weeks. So on to the nitty gritty...

I am starting with my 211k mile 4.0L H.O. out of my 1992 Wrangler. It had leaky valve stem seals and plenty of blow by and piles of charred oil clogging the works (I think it may have been the original oil, I purchased the Jeep 1k miles ago and I won't express my feelings about the PO .) It also had a large crack in the exhaust manifold resulting in an unpleasant odor in the cab. Did I mention it ran well? No really... it did.

The Plan Based on the "Revised Milder Mini Stroker" recipe:

Stock 7120 HO 1.91"/1.50" cylinder head. (Factory Valvetrain.)
Block bored +0.060 and possibly 0.00 decked
Stock Jeep 4.0L 6.125" rods w/ARP bolts
AMC 232 3.500" stroke crank (72-79)
Silvolite UEM-2229 +0.060" bore pistons
CompCams 68-115-4 192/200 degree camshaft

Reuse:
Block, Con Rods, Head, Push Rods, Rockers, Springs, Valves, Head Bolts

Questions:
To deck or not to deck? I'd like to use 89 octane, what is an ideal DCR for that (8.7:1?)? What quench height should I be aiming for? Have a Fel-Pro head gasket (0.051?)
To dish or not to dish? What is the need or purpose in the recipe for dishing (in relation to changing other factors like deck height)? and 15cc or 23cc?
ARP rod bolts, use 258 rod bolts? ARP doesn't have a part number for 4.0 rods (according to their catalog and tech support).
Crank spacer and balancer? I assume I'll need the spacer and can reuse my 4.0 balancer?

I've been reading (and hopefully absorbing) a lot but these are the things I haven't been able to pin down. Thank you in advance for the pointers and help. I know I'll be asking more questions in the near future but I'll keep reading to try and keep them to a dull roar.

Cheers,

Matt

[Dezertxj88]

While there isn't much info out yet about the 4.2L..I have asked tons of questions and got tones of useful answers and opinions from the vets here!
No decking the block, you pistons will be at the deck height..maybe .005 over or .005 under the deck..DO NOT DECK. Consider it 0 decked already lol.

Honestly, I'd leave the OEM cam in it, less cost, and it'll make great power with that added displacemnt and compression ratio! On a stock cam you'd be shooting around 9.2:1 SCR roughly..but it also depends on sea level ect ect ect...Tones of factors. Really build it up, don't worry about octane, run whatever you have to! Back in the day when premium was 50+ cents more than regular it was stupid, but now the difference is pennys..no need to worry bout that extra 5 bucks it cost you to fill up..the added performance and less headaches worth it!

I kind of kicked up the whole 4.2L thing again..I was shooting for a stock 4.0 with boost when I came across the 232 cranks..asked Dino and here we are lol.
I have since kicked the boost idea, I'll need a different fuel controller and thats even more cash into it for no good reason! I'm really jumping into the ExPo world head first, so a good healthy, torquey N/a setup will do me just fine!
Anyway my set is, .60 over, 2229 silvolites- stock 11cc, stock 87-95 cam, ported 7120 head with ls1 valve train, using a .043 Mopar head gasket, my quench is .038, pistons sit .004-.005 above deck at the highest point. Speced out I'm at 9.85:1 SCR & 7.18 DCR, this will drop slightly because I didn't add in the extra cc's for the piston ring depth..so I'm around 9.7:1, or slightly less I want to say...which should be fine for 87 during winter months and 91 during summer heat! If not then 91 year round, no biggy.
I really wanted to do a diesel swap..the Mer Om617..bio fuel is awsome, diesel is awsome! But idk, just didn't seem to smart to do.

Basics are with the 232 crank and a 1.581 pin height pistons, you'll be above ever so slightly, or below ever so slightly...so no need for decking which is wonderful! Don't mind octane, just run 91, it pennys more! If you have any other question I didn't answer, shoot away!

I think my setups a very cheap option..not paying to dish pistons, not paying for a cam ect ect..decent compression, 91 octane, should make decent torque & power. I upgraded the weak links, running a dual roller, good lifters, and possibly roller rockers since I'll be spending less from not going turbo lol. We will see..

[Cheromaniac]

Questions:
To deck or not to deck? I'd like to use 89 octane, what is an ideal DCR for that (8.7:1?)? What quench height should I be aiming for? Have a Fel-Pro head gasket (0.051?)
To dish or not to dish? What is the need or purpose in the recipe for dishing (in relation to changing other factors like deck height)? and 15cc or 23cc?
ARP rod bolts, use 258 rod bolts? ARP doesn't have a part number for 4.0 rods (according to their catalog and tech support).
Crank spacer and balancer? I assume I'll need the spacer and can reuse my 4.0 balancer?

1. You won't need to deck the block. With the 232 crank, 4.0 rods, and Silvolite 2229 pistons, deck clearance will already be near zero or even slightly above the deck. Use the Mopar Performance 0.043" multi-layer steel head gasket (part no. 4529242, available at Summit Racing).

2. The Silvolite 2229 pistons have an 11.5cc dish and if you leave them as they are, your mini-stroker will have a SCR of ~10.0:1 and it'll need to run on 93 octane. Increasing the dish volume will lower the SCR and allow you to run lower octane fuel but if you don't want to take that route, maybe you should consider the wilder mini-stroker instead.

3. The 4.0 rods and the 258 rods use the same ARP bolts (part no. 112-6001, available at Summit Racing).

4. If you have a long nose 258 crank, you'll need a harmonic balancer spacer. Buy a new HB, have the rearmost 1cm cut off the old HB on a lathe, and use that as a spacer.

[Toy_Truck]

Awesome guys thank you! Well the head and block are off to the machine shop. I'm waiting on the crank and pistons to be delivered. Also sending the TB to be bored if I can find that web site again...

[Cheromaniac]

This one by any chance?

http://www.strokedjeep.com/tbody.html

The same guy can also dish your 2229 pistons:

http://www.strokedjeep.com/piston.html

[Toy_Truck]

Yup that would be the one! Unfortunately, Jeff said he won't have any stock until the end of April. Any suggestions on the sizing of the T-Body? I'll be having a local shop dish the pistons.

Mailman has been good to me! So far I have the 232 Crank, 2229 Pistons and rings, Cam, RAM Clutch, Rod bolts, and Mopar head gasket. Ive ordered Ford 24lb injectors and will pick them up on Monday. Unfortunately my machinist has fallen ill and the machine work is behind.

How far shall I go with the dish? I really would like to take the minimum out.

[Toy_Truck]

One other question I just remembered: Head bolts? Are the 96-Later head bolts ok? I've found the earlier ones hard to come by.

[SilverXJ]

Yes, the later bolts will work fine.

[Cheromaniac]

How far shall I go with the dish? I really would like to take the minimum out.

It depends on what static CR you're aiming for. Polishing the piston dishes and the combustion chambers might gain you enough cc to reduce the SCR to the mid-9's.

[Toy_Truck]

Well I wasn't going to port the head but I decided to give it a whirl. So I took out the grinder and set to work. Lets just hope I don't royally mess it up.

[Dezertxj88]

Well I wasn't going to port the head but I decided to give it a whirl. So I took out the grinder and set to work. Lets just hope I don't royally mess it up.

Go slow and remember, your just cleaning things up..don't use cardbite bits lol, just some paper rolls & some stones.
On the intake do a 80grit finish, on the exhaust you want them glass smooth, also the combustion chambers, do them glass smooth as well.


Dino, how does one polish the piston tops?

[SilverXJ]

For the piston tops I would knock down the sharp edges with some sand paper then polish them with a cross buff.

[Cheromaniac]

For the piston tops I would knock down the sharp edges with some sand paper then polish them with a cross buff.

What he said.

[Toy_Truck]

Thanks for the tips guys! I am taking it slowly seeing as how this is my first attempt at porting. I am also trying to figure out the best way to deal with the iron dust. Even though I wore a par of safety goggles I still ended up with particles of iron stuck to my contacts. So now I am going to switch to a full face shield and stick a vacuum hose at the other end of the port to hopefully contain the majority of it.

[SilverXJ]

I used the kind of goggles that seal to my face. The safety glass that don't seal aren't worth a damn for anything.