Is a stroker the right option for me?

[mveltre123]

Hello everyone,

New to the forums here, after all the research I have done so far I figured this would be the best place to come. I'm sure this topic has been covered a bunch but I was looking for some insight on my specific scenario.

Basically, my 01 XJ needs an engine rebuild and I'm super conflicted on my best option moving forward: Rebuild a stock 4.0 or build a 4.6L. This jeep was my daily driver and I never intend to use it off-road however I ride dirt bikes and frequently used the jeep to haul my bikes around. The added power of the stroker was appealing to me as it would add versatility to my jeep in regards to hauling and all around highway performance. The stock 4.0 did decent on the highway but once I got up to speed it was a little sluggish to accelerate further. I am running 31" tires though so maybe I just need to re-gear?

Having priced everything out it looks like the stroker build will be about double the cost of a stock rebuild. My math came out to $900 for a stock build (Clegg master rebuild kit) vs $1700 for a stroker (Clegg Stage 1 stroker kit plus all addition parts for full rebuild). I'm still new to this but the stroker configuration I have in mind is obviously the 4.2L crank reusing my 4.0 rods, the associated pistons from the clegg kit with a 0.030 cylinder bore, and a stage 1 clegg camshaft. The stage 1 stroker kit from clegg is advertised to have a 8.8:1 compression ratio. The CR thing is something I'm still trying to understand but from what I gathered it seems like with a lower CR I can run pump gas with no problems. I would like to avoid having to run premium at all costs. Clegg kits are also available in 9.3:1 and 9.5:1 CRs.

I apologize for all the questions but I would like to get this build right the first time. Buy once, cry once I guess. I've attached links to all the kits I mentioned below for anyone who might be interested. Thank you in advance!

Clegg Stage 1 Stroker kit: https://www.cleggengine.com/jeep-4-0-stroker-kits.html
Clegg Stage 1 Camshaft Kit: https://www.cleggengine.com/engine-rebu ... -cam1.html
Clegg 4.0 Master Rebuild Kit: https://www.cleggengine.com/engine-rebu ... -2006.html

[Cheromaniac]

If you want to run 87 octane, you could still go for a 9.3:1 compression ratio but I'd suggest you opt for Russ Pottenger's custom pistons. The ICON pistons in Clegg's kit have a pin height of only 1.353", leaving them 0.027" below the block deck at TDC. This would necessitate milling 0.020" from the block to reduce the deck clearance, adding to the cost of the build.
OTOH, Russ' pistons have a pin height of 1.385" which actually leaves them 0.005" above the deck at TDC, avoiding the need to mill the block. With a 0.043" head gasket, the quench height will be a nice and tight 0.038", reducing the risk of pinging when running low octane gas. A 27cc piston dish combined with a 57cc combustion chamber and the aforementioned head gasket would yield a low octane friendly 9.3:1 compression ratio.

[Krat0s]

In hindsight if I had done a stock 4.0 rebuild instead of the 4.6 I would have regretted it. I think any hesitancy you have towards a 4.6 build would be quashed on the first drive

[mveltre123]

Hey thanks for the replies guys I appreciate it! Apologies for my late response I never actually realized that my post got approved by the mods.

I am very interested in purchasing a kit from Russ, however if I did end up using the clegg kit and decked the block to achieve proper clearance, would this require use of different length pushrods? I read on other threads that failure to swap pushrods could negative affect valve train geometry.

Second question, how do the stock camshafts perform in strokers? This would be the oem cam from my 2001 4.0l. From my research cam failures are the most common failure points in strokers and was considering using the stock cam for reliability. I'm not overly concerned with squeezing every ounce of available power out of this engine especially since I won't be porting my head either. Just looking for some noticable gains while maintaining this engine as reliable as possible.

[amcinstaller]

If you deck the block or head you will likely need new pushrods, which you can measure after it's assembled to be sure. If you plan to reuse the cam, make sure the lifters go to the love they were mated with, they wear as a set

[mveltre123]

If you want to run 87 octane, you could still go for a 9.3:1 compression ratio but I'd suggest you opt for Russ Pottenger's custom pistons. The ICON pistons in Clegg's kit have a pin height of only 1.353", leaving them 0.027" below the block deck at TDC. This would necessitate milling 0.020" from the block to reduce the deck clearance, adding to the cost of the build.

Just out of curiosity, would it be realistic for me to have the block decked to zero using clegg's kit 8.8:1 kit to increase compression and reduce quench height? If I understand this correctly decking the block to zero means that the top of the piston and the surface of the block would be exactly equal at TDC.

I put the above combo into the compression calculator on this site using the OEM 99-04 cam specs and got a SCR of 9.1:1, DCR of 7.86:1, and quench of 0.043". I read on a different thread that in stock from the 99-04 4.0's had a SCR of 8.7:1 and DCR of 7.47:1. If that's true, the numbers I got for my possible combo look good and close to stock, especially the quench with it being less than 0.050. However, I'm too inexperienced to know if these numbers are desirable or not, what do you all think? As always any feedback is greatly appreciated!

[Cheromaniac]

Just out of curiosity, would it be realistic for me to have the block decked to zero using clegg's kit 8.8:1 kit to increase compression and reduce quench height? If I understand this correctly decking the block to zero means that the top of the piston and the surface of the block would be exactly equal at TDC.

Correct.

I put the above combo into the compression calculator on this site using the OEM 99-04 cam specs and got a SCR of 9.1:1, DCR of 7.86:1, and quench of 0.043".

Those numbers are absolutely fine for low octane pump gas.

[mveltre123]

After additional research it appears that the KB424C that come in clegg's stage 1 kit are actually undesirable because they're full dish pistons. This would prevent them from utilizing the "quench pads" or "squish pads" that are machined into the head from my understanding. Should I avoid full dish pistons for this reason? If so, would anyone be able to recommend a different/more desirable piston? I am still looking to purchase pistons from Russ but haven't been able to get in contact with him just yet. Just looking for piston recommendations as a backup plan in case I need to go a different route.

[Russ Pottenger]

I would definitely avoid using a full circular dish piston in a normally aspirated engine (non boosted)

Two weeks ago I had a double bypass open heart surgery and just now getting caught up on my emails and calls.

Feel free to shoot me an email or call I’d be happy to set you up with a piston and connecting rod combination along with anything else that you might need.

Thanks,
Russ Pottenger
Cell (626) 673-2203
Email: [email protected]

[Cheromaniac]

Two weeks ago I had a double bypass open heart surgery and just now getting caught up on my emails and calls.

I wish you a speedy recovery Russ.

[Russ Pottenger]

Two weeks ago I had a double bypass open heart surgery and just now getting caught up on my emails and calls.

I wish you a speedy recovery Russ.

Thanks So Much Dino!

Everything is looking good in recovery is going well.

It’s humbling to see the tremendous amount of outreach support and prayers that I have received.

God has blessed me with the greatest friends and customers I could’ve ever imagined.

Love Ya All!
Russ

[mveltre123]

Feel free to shoot me an email or call I’d be happy to set you up with a piston and connecting rod combination along with anything else that you might need.

Thanks Russ. I sent you an email with some more information whenever you get a chance to see it.

[Hellfrekke80]

Hello everyone,

New to the forums here, after all the research I have done so far I figured this would be the best place to come. I'm sure this topic has been covered a bunch but I was looking for some insight on my specific scenario.

Basically, my 01 XJ needs an engine rebuild and I'm super conflicted on my best option moving forward: Rebuild a stock 4.0 or build a 4.6L. This jeep was my daily driver and I never intend to use it off-road however I ride dirt bikes and frequently used the jeep to haul my bikes around. The added power of the stroker was appealing to me as it would add versatility to my jeep in regards to hauling and all around highway performance. The stock 4.0 did decent on the highway but once I got up to speed it was a little sluggish to accelerate further. I am running 31" tires though so maybe I just need to re-gear?

Having priced everything out it looks like the stroker build will be about double the cost of a stock rebuild. My math came out to $900 for a stock build (Clegg master rebuild kit) vs $1700 for a stroker (Clegg Stage 1 stroker kit plus all addition parts for full rebuild). I'm still new to this but the stroker configuration I have in mind is obviously the 4.2L crank reusing my 4.0 rods, the associated pistons from the clegg kit with a 0.030 cylinder bore, and a stage 1 clegg camshaft. The stage 1 stroker kit from clegg is advertised to have a 8.8:1 compression ratio. The CR thing is something I'm still trying to understand but from what I gathered it seems like with a lower CR I can run pump gas with no problems. I would like to avoid having to run premium at all costs. Clegg kits are also available in 9.3:1 and 9.5:1 CRs.

I apologize for all the questions but I would like to get this build right the first time. Buy once, cry once I guess. I've attached links to all the kits I mentioned below for anyone who might be interested. Thank you in advance!

Clegg Stage 1 Stroker kit: https://www.cleggengine.com/jeep-4-0-stroker-kits.html
Clegg Stage 1 Camshaft Kit: https://www.cleggengine.com/engine-rebu ... -cam1.html
Clegg 4.0 Master Rebuild Kit: https://www.cleggengine.com/engine-rebu ... -1999-2006.html

In hindsight, if I had done a stock 4.0 rebuild instead of the 4.6, I would have regretted it. I think any hesitancy you have towards a 4.6 build would be quashed on the first drive.