Stroker tips for dummies

[marmotoffroad]

Hi,

great info here! Hats off to all contributors

I am new member and have already done some intensive reading how to build my first stroker. Since I have lots of suspension work to do, I do not plan to start soon, so I will continue to read and learn and hopefully one day I will be ready

I would like to collect information about the steps I have to perform in order to complete the modified poor man's stroker. Looking at the recipies I wonder is this all I need? This is not much...and if I order the custom pistons from Russ Pottenger, I even can skip one machining operation.

So here is my plan:
1. Disassemble the engine
2. Overbore block +30
3. Machine block flat
4. 4.2L crank, 4.0 rods (stock), Russ Pottenger pistons, +30 piston rings, new bearings etc.
5. stock 4.0 camshaft, valves, springs
6. DIY head porting job
7. 0.043 head gasket
8. Fuel injectors

Do I miss an operation?
Thanks

[Randy Bobandi]

What model Jeep is this for and what is the power/overall goal for the engine?

[marmotoffroad]

It's a 1990 YJ with 4.0 swaped from 96' XJ. This is my one ton project - HP Ford Dana 60 front, GM 14 bolt rear. I still have lots of work and after the Jeep is running again, I will drive the stock 4.0 for a while until everything is ok. Now it has 4.56 gears, but I may opt for lower. Tire size will be 40.

It is not a racing machine (but may become one later). I want to start with some basic stuff, say 250ps or so. If I get the stroker desease...who knows.

[Cheromaniac]

You've basically got the gist of it.
I started out with the Crane 753905 cam in my stroker until it failed after 34k miles. Fortunately I still had my '92 OEM cam as a spare so I reused it and my stroker became a proper poor man's. In that configuration it ran reliably for another 52k miles until I sold the Jeep to a happy new owner.
On the dyno it put down 200rwhp & 258rwtq (246hp & 311lbft at the crank) with at least 90% of maximum torque available from 1500-4500rpm (great for pulling up highway inclines in 5th gear), delivered good gas mileage, and had cleaner emissions than my original and very healthy 4.0.
You could go one step above the poor man's by adding a mild performance cam e.g. Russ' custom modified 68-232-4 and running a higher CR e.g. 9.5-9.6 to eke out another ~15hp.

[marmotoffroad]

Cheromaniac, I have read many of your posts and you were my motivation that I would dare to start a stroker job by myself.

Are there any stock engine parts that are mandatory to be replaced, for example valve springs, engine bolts...?

[Cheromaniac]

I'd recommend that you use ARP 112-6001 rod bolts. You can reuse the head bolts once if the head hasn't been pulled before, but otherwise I'd recommend new head bolts too.
The original valve springs would be 25 years old so I suggest you replace those. Russ' mild performance cam allows you to use stock valve springs so you could get those together with the new cam/lifters.

[marmotoffroad]

Does the poor man's stroker recipe require a new exhaust header and larger throttle body?

My exhaust is cut right now (just behind the header) because it is in the way of the 4 link suspension. I do plan fabrication of new exhaust with 2.5" diameter pipes, but I am uncertain if this will make sense if I reuse the stock header.

Regarding the throttle body - can I bore ot to 62mm or do I have to consider replacing it with larger unit?

Thanks for your help!

[Cheromaniac]

My dyno numbers were with a ported head (stock valves), port matched '01 intake manifold, 65mmTB with tapered 65>62mm spacer, Borla header, 2.5" exhaust, and dual electric fans (no clutch fan to suck up HP).
A 62mm TB on a poor man's is probably adequate.