99 4.0 rebuild: Stroker or no stroker?

[Hook_62]

Picked up a spare 4.0 for $275, 180K mi. on teardown after removing the head I noticed I could still see the crosshatch hone marks on the cylinder walls, figured someone had had already rebuilt or at least re-ringed the engine. after I mic'd the cylinders I found they are all standard 3.875 +/- .002 within the stock bore. Anyway making a long story short, thinking that I may just go with a stage 1 performance cam and a high performance head instead of going full stroker (thinking budget), so the question is. Has anyone out there done a build like this? will there be a drop in low end torque with a stroker head and performance cam but no stoke upgrade? I've done many engine builds but never a 4.0. Don't want to kill the off road capability, at the same time I want more highway power as this is also a daily driver. Any advise would be highly appreciated.

 

[Alex0413]

Gap the rings, MLS head gasket, and a chinese turbo at 12 PSI. Then have it dyno tuned: smile every time you drive it and pass people on the interstate! This would cost less than a stroker and yield much better results.

 

[Chris]

Gap the rings, MLS head gasket, and a chinese turbo at 12 PSI. Then have it dyno tuned: smile every time you drive it and pass people on the interstate! This would cost less than a stroker and yield much better results.

X2. I agree with this 100%.

Just my opinion of course having gone the forced induction route on my previous TJ.

 

[Hook_62]

Gap the rings, MLS head gasket, and a chinese turbo at 12 PSI. Then have it dyno tuned: smile every time you drive it and pass people on the interstate! This would cost less than a stroker and yield much better results.

Do you have a link to Chinese turbo your talking about?

 

[Alex0413]

Do you have a link to Chinese turbo your talking about?

You want the GT3582R turbo:

https://rover.ebay.com/rover/1/711-...0001&campid=5337789113&icep_item=253986136990
Most 4.0 turbo setups generally go under the engine and 90 the exhaust back up on the passenger side and put the turbo there, then run it into an air/water intercooler and into your throttle body.

 

[dbbd1]

Forgive my ignorance- what is "gap the rings?"

 

[Alex0413]

Forgive my ignorance- what is "gap the rings?"

A boosted engine needs a larger piston ring gap due to the increased heat and pressures seen in the cylinder that cause the piston rings to expand more and could result in the ring ends touching eachother. This isn't a problem typically in a 4.0 or other engines when you're running less that 10PSI, but if you have the engine out, set the gaps larger for boost so you can exploit the benefits of more boost! Here's an article with a better explanation:

http://blog.wiseco.com/everything-you-need-to-know-about-ring-gap

 

[astjp2]

.002 taper/oversize on a hypereutetic piston is a lot, they dont like a lot of big tolerance. Tim

 

[dbbd1]

Here's an article with a better explanation:

http://blog.wiseco.com/everything-you-need-to-know-about-ring-gap

Thanks.
I knew rings had a gap, I just wasn't familiar with the usage in that sentence.

 

[Lan117]

Gap the rings, MLS head gasket, and a chinese turbo at 12 PSI. Then have it dyno tuned: smile every time you drive it and pass people on the interstate! This would cost less than a stroker and yield much better results.

What rings, gap or spec do the rings need to be!