4.7 recipes

[Cheromaniac]

is this what you did?

No. I started collecting parts for my stroker 8 years ago and had it running in July 2004. Back then IC944 pistons weren't available so my original build was a "poor man's" with a Crane 753905 cam, but I had to go back to the stock cam 5 years ago after two lifters failed and one of them took out a cam lobe at 34k miles. My stroker now has 67k miles and it still runs great.
I'm sure you'll like the low buck recipe that I recommended to you and it should run fine on 91 octane gas. If I had to do it all again I'd probably build the same one.

[95_xj_country]

is this what you did?

No. I started collecting parts for my stroker 8 years ago and had it running in July 2004. Back then IC944 pistons weren't available so my original build was a "poor man's" with a Crane 753905 cam, but I had to go back to the stock cam 5 years ago after two lifters failed and one of them took out a cam lobe at 34k miles. My stroker now has 67k miles and it still runs great.
I'm sure you'll like the low buck recipe that I recommended to you and it should run fine on 91 octane gas. If I had to do it all again I'd probably build the same one.

this is so much to think about lol. and how do you know what octane to run at it seems the higher the compression the higher the octane. i could do this one too:
4.7L medium-buck stroker

Jeep 4.2L crank offset-ground to 3.915" stroke
Jeep 4.0L 6.125" rods
Keith-Black UEM-IC944-060 pistons
10.0:1 CR
CompCams 68-235-4 210/218 degree camshaft
CNC ported HO 1.91"/1.50" cylinder head
Mill block deck 0.018"
Mopar/Victor 0.043" head gasket
0.043" quench height
Flometrics F&B 68mm billet TB
Accel 26lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Accel 26lb/hr injectors with stock 49psi FPR for '96 and later engines.
281hp @ 5000rpm, 337lbft @ 3700rpm

[GoMopar440]

Cheromaniac is Dino. One of the resident stroker Guru's around here and a source of a lot of the info you'll see referenced on this forum. I'd highly suggest you check out the links in his siganture and take the time to read through them completely. It's a great starting point to get the big picture about what you're about to get yourself into. Links-> http://www.angelfire.com/my/fan/stroker.html and http://www.jeep4.0performance.4mg.com/stroker.html

As far as the compression ratios, there's Static Compression Ratio (SCR) and Dynamic Compression Ratio (DCR). It's one of the key points you'll need to understand in order to build a stroker that can make power where and when you want it without eating itself alive. Basicly SCR is how much compression is measured from the top of the piston travel to the bottom. With DCR there's the cam to take into account. It will hold the valves open part way during the pistons travel, so you only measure the compression during the time that the valves are completely closed. The FAQ explains this a lot better than I can, but you basicly want about 8:1 or less DCR to run on pump gas. If you can get an aluminum cylinder head ($$$) or have access to E85 fuel you can usually run a bit more compression than that.

[95_xj_country]

whats the most performance 4.7 recipe i could do? looking to start building a stroker and have been searching. found all kinds of different recipes. never done any type of internal engine work. going to do a learn as i go kinda thing.

I think you'll like this one:

4.6L low-buck stroker

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith Black IC944-030 pistons
9.6:1 CR
CompCams #68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.050" quench height
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines
264hp @ 4900rpm, 324lbft @ 3500rpm

Easy to build, lots of torque, and a good all-rounder for daily driver and offroad use.
You'll find nearly all of the aftermarket parts you'll need for the build from Summit Racing.

so you think this will be better for what my driving ways are compared to the 4.7?

[Cheromaniac]

so you think this will be better for what my driving ways are compared to the 4.7?

My 4.7 medium buck stroker combo is also great for a daily driver. It's just more involved to build mainly 'cause of the offset grinding of the rod journals of the crank and the need to use 0.040" undersize rod bearings. Jsawduste did a similar build but with Diamond +0.080" pistons and the Hesco H274 cam, and he loves it.
Don't be put off by a high static compression ratio (SCR). It's the dynamic compression ratio (DCR) that determines what octane fuel your engine will require, and the DCR is largely dependent on the intake valve timing events of the cam so the cam selection is important. A tight quench space (0.040-0.050") also helps to reduce the likelihood of detonation and allows you to run a lower grade of fuel despite a high SCR.

[95_xj_country]

what does the offset do? with the research ive been doing it looks like ill be living in the machine shop.

[Cheromaniac]

what does the offset do?

It increases the stroke length; in this case from 3.895" to 3.915".

[95_xj_country]

what does the offset do?

It increases the stroke length; in this case from 3.895" to 3.915".

so if i use one of the recipes above i dont have to mess around with scr and dcr to much right? unless when its done it pinging

[Cheromaniac]

Correct. If the engine does ping, either try a higher grade of fuel or a colder set of plugs. Pinging could also be a sign of the engine running lean so the color of the plug deposits will give a clue.

[95_xj_country]

So if I used a fuel/air gauge it would be easier to figure out if it would be running lean or rich. And would it be easier if I rebuilt a 4.0 first with all stock parts then later do the Stroker. I'm kind of leaning more in that direction I think. So I could put most of the stuff in myself when I do the Stroker. I want to research and basically know every thing before I start to build a stroker

[Muad'Dib]

My opinion is that if your going to have the motor out then why do a rebuild when your just going to pull it again to do a stroker? Seems like a waste of time and money to me. Additionally, your going to want a Wideband 02 and AFR Gauge no matter what. This is going to be the best way to see what the engine is doing. You can try the read plugs thing which works for some people... but i would recommend a Wideband.

There are many considerations to evaluate when building a stroker.

1.) How much money do you have to spend
2.) How will the Jeep be used (ie offroad or street 60/40 etc)
3.) Octane of fuel you want to run
4.) Your own skill level
5.) Kind of performance you want from the vehicle.

1. Money:
Some would say this is the biggest determining factor.... My opinion would be to set a dollar amount you want to spend and try to stick with it the best you can.

2. Vehicle Use
Knowing this will help you build / design the engine to run at a specific RPM range. Generally you want your peak power lower for offroad use, and higher for Street. This will be the determining factor of your cam choice.

3. Fuel Octane
I personally don't see the point in worrying about octane level.. although it seems most people here want to build something that will run on regular gas. I build my stroker to run premium... but again i just don't see the need to worry about the extra ~$5 per fill up just to run a lower octane gas. Once you make a decision on what octane you wish to run, then you can decide on what DCR (Dynamic Compression Ratio) your engine design is tailored to. Its been said that anything between 8-8.5 DCR is considered Premium Range. Anything over 8.5 will probably ping with premium at sea level (Altitude Matters).

4. Skill Level
Its been suggested that if you have never built an engine before then you should have your machinist do the assembly. I wouldn't say this is true in all cases, but it might be for some. Everyone is different and only you will know what your comfortable with. I found the assembly fairly easy... although i am self taught in every area of my life and i am a super quick learner. Plus i usually research the shit out of things. My current stroker is the first engine build i have done... I felt very comfortable before this engine build with any kind of maintenance / broken parts issues on my Jeep.

5. Performance
This will be the "compromise" factor. Obviously the more performance you want usually the more you have to spend. You may want the best performing vehicle you can possibly get, but you may have to spend 10,000 to get to that point. I personally spent a little over 5000 on my engine, but i bought mostly new parts and did a lot of extra things most don't do. Most here spend around 2500 or so.

I wanted the best performance i could get without getting to deep in custom stuff where fabrication might be involved etc. I built a fairly high compression engine (8.5 DCR) and i planned on running premium. I built the Engine to run mostly on the street.. It seems like these I6's in our Jeeps are torque monsters anyway, so building towards this didn't compromise low end torque. You could get crazy with cam selection and ruin the low end... but its not going to happen if you stick with the recommended cam selections.

My tips would be to read read read. Start in the FAQ section and then move into the "Projects" section.

I hope this helps!

[95_xj_country]

yes it did help what im going to do is get a engine from a junk yard then build it. not sure yet on the rebuild or stroker. but if i rebuild it i can take the one in my xj now and save it until i research mostly everything about a stroker.

[nasreenk088]

There's an FAQ section that should help you with basic information. Most people spend months or even years researching before they take the plunge. You may be able to collect parts over time, but putting it together requires quite a bit all at once. If you have never built an engine before, you should trust your machinist to do the assembly.

hmmm. this is a very much informative info thanks for sharing,

[Cheromaniac]

yes it did help what im going to do is get a engine from a junk yard then build it. not sure yet on the rebuild or stroker. but if i rebuild it i can take the one in my xj now and save it until i research mostly everything about a stroker.

Since you're going to rebuild a junkyard engine anyway, I suggest you build it as a stroker from the outset. It'll only cost you about $800 more (the cost of a 258 crank and IC944 pistons/rings) to build it into a stroker than doing a stock rebuild. Then when it's ready you can swap it into your Jeep and enjoy the benefits.
You'll be left with your old engine which you could sell to recoup some money. I sold my old 4.0 to another Jeeper and he gave it the fate that it deserved by also rebuilding into a 4.6 stroker.

So if I used a fuel/air gauge it would be easier to figure out if it would be running lean or rich.

Yes. No doubt about that. Use a wideband O2 sensor and AFR gauge for better accuracy.