Jeep Strokers

What kind of reliability can I expect from a 4.5/4.6 stroker motor that I have built. I know it's all about the quality of the build and having an experienced machine shop put it together. But I've heard a lot of negativity regarding the reliability of stoker motors no matter how good the build.
Any thoughts from actual owners of stroker motors?

I can't see why there would be any problems that stand out as long as there is regular maintenance like oil changes etc done. I haven't heard of any straight 6s that aren't reliable so I would be inclined to think the same for a stroked 4.0

I've just heard from a few peeps that once the stroker motor was built and installed, it never ran the same again. One problem after another.

flexin91xj wrote:I've just heard from a few peeps that once the stroker motor was built and installed, it never ran the same again. One problem after another.

I thought I did everything right the first time around, and my motor made it barely 10K before having to come out again. That was Jan 3, 2012- since then, it´s been back in and out two more times with issues, and is still out again at the machine shop for a complete rebuild. My stroker, despite all of my diligence, patience, and care, has been one nightmare after another. It doesn´t go that way for everyone, but it goes that way for enough people that it should make you think twice. Fortunately, I have another vehicle- knowing what I know now, if my jeep were my only vehicle, I would not even CONSIDER building a stroker unless i used a separate junkyard motor to do it, and preserved my old motor, fully assembled, as a drop-in emergency engine because the stroker will most likely be coming back out sooner than you´d like.

# of times my original factory-built 4.0L engine had to come out in 186,000 miles: 0
# of times my carefully-built stroker engine had to come out in 11,000 miles: 3

showtime3492 wrote:I can't see why there would be any problems that stand out as long as there is regular maintenance like oil changes etc done. I haven't heard of any straight 6s that aren't reliable so I would be inclined to think the same for a stroked 4.0

Do you have a running stroker in your rig? If so, how many miles do you have on it?

Technically there should be no difference in reliablity between a stock engine and a stroker. If anything, the stroker would be more reliable.

That being said there are plenty of failures.. but most of the time they are revolving around the CAM. Its probably best practice now a days that if your using higher than stock spring pressure (which alot do because they want to run high lift cams) then you should go with a solid cam button instead of the spring / button stock set-up. This appears to be the fix for the cam issues people are seeing.

FWIW, my stroker has had 0 reliablity issues. I retained the stock cam button / spring setup, but im using new stock springs on a Mopar Performance Cam.

Also keep in mind that you are going to here way WAY more about failures than success stories.. just as you would anything else positive/negative.

We've got 5k or so on ours. Only problems we seem to be having is related to parts failures. Specifically the Cam Position Sensor.

theres also been ALOT of people who go from posting regularly during their build to dropping off and not coming back after its done. go to the member list and sort by either join date or post count and see how many are still active....

i have over 20,000 miles on my $300 4.5 stroker and no problems(all done in my garage and no machine work). other that the few parts related, one injector worked when it wanted and the coil, cap, rotor, plugs, wires, had to be changed but that happens to stock 4.0. and thats after taking it to silver lake(sand dunes) and putting it the mud, countless times.

flexin91xj wrote:What kind of reliability can I expect from a 4.5/4.6 stroker motor that I have built. I know it's all about the quality of the build and having an experienced machine shop put it together.

I've noticed that the probability of a problem occurring in a stroker increases as the spec deviates further away from a stock 4.0. Aftermarket cam/lifter failures combined with the use of stiffer valve springs and low ZDDP oil seem to be a common issue. I originally built my stroker with a Crane cam/lifters and Mopar Performance valve springs, and it ran perfectly for the first 30k miles with no problems. I'd been using Mobil 1 oil the whole time except for the first 3k miles. It then developed a lifter tick that gradually became worse over the next 4k miles until I began to notice a slight loss of power. The no.6 exhaust lifter had completely collapsed with no sign of wear but the no.6 intake lifter was cupped and had wiped out the corresponding cam lobe. I decided to cut my losses and threw my old stock cam/valve springs back in with new lifters. It turned out to be a very good decision 'cause the engine ran just as strongly as it did with the Crane cam but without the valvetrain noise. After 68k miles my stroker's still as strong as an ox, sounds sweet as honey, and I love it to bits.

Mine had 18,000 miles on it when my Jeep got totalled. I had a few bugs to work out, due to roller rockers, and larger diameter valve springs hitting my valve cover baffle. After that was resolved, I had no problems. I used a custom ground Engle cam, Mopar performance springs, and crower roller rockers. I used a solid pin to retain the cam.

doublins wrote:

showtime3492 wrote:I can't see why there would be any problems that stand out as long as there is regular maintenance like oil changes etc done. I haven't heard of any straight 6s that aren't reliable so I would be inclined to think the same for a stroked 4.0

Do you have a running stroker in your rig? If so, how many miles do you have on it?

Mine is being built by a race shop presently

showtime3492 wrote:

doublins wrote:

showtime3492 wrote:I can't see why there would be any problems that stand out as long as there is regular maintenance like oil changes etc done. I haven't heard of any straight 6s that aren't reliable so I would be inclined to think the same for a stroked 4.0

Do you have a running stroker in your rig? If so, how many miles do you have on it?

Mine is being built by a race shop presently

Well, I wish you the best of luck with it- Mine has been an absolute nightmare, despite being professionally built. It's been an exercise in the acceptance of Murphy's Law as fact.

doublins wrote:

showtime3492 wrote:

doublins wrote:

showtime3492 wrote:I can't see why there would be any problems that stand out as long as there is regular maintenance like oil changes etc done. I haven't heard of any straight 6s that aren't reliable so I would be inclined to think the same for a stroked 4.0

Do you have a running stroker in your rig? If so, how many miles do you have on it?

Mine is being built by a race shop presently

Well, I wish you the best of luck with it- Mine has been an absolute nightmare, despite being professionally built. It's been an exercise in the acceptance of Murphy's Law as fact.

Case in point- shop called yesterday- the cam they had sent out to be nitrided- came back to them in two pieces- broken in shipping by UPS. So now we start all over again with another new cam, + sending it out to be hardened, before we can bolt the thing back together again- it just goes on and on and on. Of course this has absolutely NOTHING to do with the reliability of a stroker- just more murphy´s law in action with respect to mine.

This is cam #3.

There is no way for me to tell how many miles I have on mine since I was running w/ the wrong speedo gear for a long while. I also changed the stock gauges out for the 125mph Import cluster and have the mileage written down on a paper somewhere. The stroker specific problems I've had over the past 4 years is one stock timing chain disintegration. Issues that would've happened regardless of stroker: letting the o2 sensor harness melt to the Borla header and blowing a PCM, three blown coils(Accel, MSD, and BWD), 1 blown Auburn LSD(was driving my 2wd every day in that 2-week Snowcopalypse), 1 broken Hurst(they couldn't believe it), and maybe one CKP. I have the Mopar 30ab cam with the bigger Mopar springs(yes, they clearanced the valve cover without my help) and retainers and reused the old cam button and spring(shoulda replaced them when I put the Rollmaster set in). I've been using Brad Penn 10w30 racing oil since day one to keep one variable constant. All said and done, I'd build and will build another $2K stroker, but this time use long forged rods(already have the Eagle 6.150s) and custom forged pistons. I recommend the 4.0 rods and IC944s instead of 4.2 rods and off-the-shelf 4.0 pistons.