Stroker vs Stock

[89 MJ]

I have a choice. A friend of mine has a new Stroker kit he would sell me cheap, or I can buy a new stock crank for my MJ, or find a different motor completely (I would most likely buy another Jeep with a good motor). What are your thoughts on this?

[omega_rugal]

get the stroker only if you know how to do it...

[89 MJ]

2 hours ago, omega_rugal said:

get the stroker only if you know how to do it...

I feel confident in being able to do it. Thank you for your input. 

[Eagle]

2 hours ago, 89 MJ said:

I feel confident in being able to do it. Thank you for your input. 

 

Do what? Bolt it in? Or deal with all the issues arising from the fact that the deck heights are different between the 4.2L and the 4.0L, meaning that to NOT have super high compression you have to take into account cam overlap, quench, combustion chamber volume, whether you run 4.2L rods (wimpy) or 4.0L rods with custom pistons ... yada, yada.

 

There's a LOT that goes into making a good-running stroker. I love the concept, but I've never seriously thought about doing one because I don't have the time or the $$$$$$$$$$ t make it work.

[89 MJ]

7 hours ago, Eagle said:

 

Do what? Bolt it in? Or deal with all the issues arising from the fact that the deck heights are different between the 4.2L and the 4.0L, meaning that to NOT have super high compression you have to take into account cam overlap, quench, combustion chamber volume, whether you run 4.2L rods (wimpy) or 4.0L rods with custom pistons ... yada, yada.

 

There's a LOT that goes into making a good-running stroker. I love the concept, but I've never seriously thought about doing one because I don't have the time or the $$$$$$$$$$ t make it work.

I feel confident in dealing with the issues. 

[ghetdjc320]

We have no info on what stroker kit it is. There are supporting mods as eagle mentioned but they Vary depending on what kit you are talking about. Ideally, use 4.0 rods with the correct pistons. The 4.0 rods also offer better rod angle. Several piston manufacturers have made sets that work with the 4.0 rods and stroker crank. You can find forged, cast and hypereutectic with the correct compression height. Have built a few strokers now. My favorite is the 232 crank based stroker. Stock 4.0 rods and a good set of stock compression heigh pistons and you have a 4.2. No decking of the block either. 

[89 MJ]

39 minutes ago, ghetdjc320 said:

We have no info on what stroker kit it is. There are supporting mods as eagle mentioned but they Vary depending on what kit you are talking about. Ideally, use 4.0 rods with the correct pistons. The 4.0 rods also offer better rod angle. Several piston manufacturers have made sets that work with the 4.0 rods and stroker crank. You can find forged, cast and hypereutectic with the correct compression height. Have built a few strokers now. My favorite is the 232 crank based stroker. Stock 4.0 rods and a good set of stock compression heigh pistons and you have a 4.2. No decking of the block either. 

Interesting. Good info. Thanks. 

[Jeep Driver]

1 hour ago, 89 MJ said:

Interesting. Good info. Thanks. 

 

Have a big-world view, gather as much information as you can, learn all you can before you make a decision. 

 

As mentioned, rod angle, Engine Masters just did a long vs short rod comparison, you need to understand basic theory. 

 

I'm not going to post vids here but there are a number of good engine builders on youtube, discern and watch, learn. Theory and knowledge applies to all engines. 

 

Free and Cheap are very very expensive. 

 

Choose parts/materials/machine shop wisely. There is a guy on NAXJA who is currently tearing down a 1 year/5000 mile stroker he built. You'll find him on page two of modified. I believe he's got a material problem, he may have lost his crank. He's so busy telling everyone else what-for that he can't solve his own problem. 

Don't be a guy who creates his own problem. 

Just an observation of mine- Jeep people suffer tunnel vision, just because everyone else is doing X does not mean you should be doing X. 

 

You've mentioned in other threads that you are considering selling the MJ...........that weighs on this decision also. 

 

You are a young guy, I know you have help (dad), however, my suggestion-

Get one basic rebuild under your belt. 

Crank, pistons, machining, head work, gaskets......etc..........will cost you $2000. 

The experience will be priceless. 

 

Basic first, learn.............then...............

[Eagle]

2 hours ago, 89 MJ said:

I feel confident in dealing with the issues. 

 

I wish I had your confidence. I'm in my 70s, I've been working on cars since my teens, crewed on a friend's stock car for a number of years, and I built the engines for my own race car and a street car. For all that, after I had researched what it took to make a stroker run reliably without getting into detonation problems I decided it was more than I was willing to undertake. My pockets aren't deep enough to get it wrong and start over.

[omega_rugal]

10 hours ago, Eagle said:

deck heights are different between the 4.2L and the 4.0L, meaning that to NOT have super high compression you have to take into account cam overlap, quench, combustion chamber volume, whether you run 4.2L rods (wimpy) or 4.0L rods with custom pistons ...

 

and the fuel related problems: higher flow inyectors, higher flow pump, higher or adjustable fuel regulator, more displacememnt means more air so more fuel is required to feed the beast

[ghetdjc320]

The stroker kits now available have made it easier to a degree. As mentioned above. do plenty of research and built it right. If you’ve never done an engine rebuild before then perhaps take it to a reputable, competent machine shop instead of tryin to diy. I do recommend that you have a look at jeepstrokers.com and check out the builds over there. Learn all the specs on the base 4.0 so you know exactly what you want to have done with your stroker. There is a nice stroker calculator there as well to help you get started. (Not trying time promote another site by the way, just helping the OP find more resources to make an informed decision). Also, let us know what kit you have available to you. 

[ghetdjc320]

5 hours ago, omega_rugal said:

 

and the fuel related problems: higher flow inyectors, higher flow pump, higher or adjustable fuel regulator, more displacememnt means more air so more fuel is required to feed the beast

 

if your talking obd1 HO models then you are working with a 39psi system. Calculate injector need accordingly based on HP, engine size, VE, and max rpm. Typically something in the 24-30 range works for most strokers. Adjustable fpr helps to get your afr’s where you need them (afr gauge is a bit of a must for tuning). Most of the strokers I see built don’t do anything to tune them other than new injectors. That being said, I think they are leaving a lot of power on the table by not getting it tuned. Personally, I’d say stand alone efi systems are the way to go if you want to get the most power from any setup. However, to the OP: at a minimum you will need different injectors but to get the fueling just right, add an adjustable fpr from hesco and an afr gauge to tune it. 

 

 

 

 

[89 MJ]

Thanks everyone for the input so far!

[75sv1]

In the grand real of things, quality being equal, a stroker is probably not that much more.  I would base your decision on whose stroker kit it is. HESCO or Russ Pottenger,  then grab it. The guy on NAXJA knows what he is doing, (not me). There was a fitment issue on the timing gear. Caused the crank thrust bearing to wear. I would try and find out if the kit in question is a 'budget' kit (242 rod) or a 'long' rod (4.0 rods) . Also, what brand of pistons. That might clue us into who's kit.

[89 MJ]

47 minutes ago, 75sv1 said:

In the grand real of things, quality being equal, a stroker is probably not that much more.  I would base your decision on whose stroker kit it is. HESCO or Russ Pottenger,  then grab it. The guy on NAXJA knows what he is doing, (not me). There was a fitment issue on the timing gear. Caused the crank thrust bearing to wear. I would try and find out if the kit in question is a 'budget' kit (242 rod) or a 'long' rod (4.0 rods) . Also, what brand of pistons. That might clue us into who's kit.

Thanks. I’ll check on that. 

[Jeep Driver]

1 hour ago, 75sv1 said:

There was a fitment issue on the timing gear. Caused the crank thrust bearing to wear.

 

Back in '14 I had one long conversation with one of the guys at Hesco regarding the last of the custom grind 2.5 cams. That phone call stopped me dead in my tracks. 

 

The fact that anyone at Hesco suggested the timing gear to be the cause........does not surprise me, but it should. 

[75sv1]

89 MJ,

       One point will be cost. With a stroker, you will need to do a complete rebuild. I cost me $400 to have my block prepped and machined. I did replace the crank in another motor. I used a used crank. I actually reused the crank bearings from the other motor. I did get new rod bearings.  I don't know what is wrong with your present crank. Or what cranks will interchange between the years. Also, what time frame you need this running. Also, I'd factor in a new harmonic balancer and possible a timing chain set. Also, there is a rubber tensioner for the timing chain that should be replaced.

[89 MJ]

8 hours ago, 75sv1 said:

89 MJ,

       One point will be cost. With a stroker, you will need to do a complete rebuild. I cost me $400 to have my block prepped and machined. I did replace the crank in another motor. I used a used crank. I actually reused the crank bearings from the other motor. I did get new rod bearings.  I don't know what is wrong with your present crank. Or what cranks will interchange between the years. Also, what time frame you need this running. Also, I'd factor in a new harmonic balancer and possible a timing chain set. Also, there is a rubber tensioner for the timing chain that should be replaced.

Thank you. I will factor that stuff in. 

[ghetdjc320]

     The “rubber tensioner” is just a chain guide and does not tension the timing chain. Aside from a few one-off parts from Hesco (e.g. thermostat housing spacer, locked dampener)  I try to stay away from them. Most of their parts are simply repackaged oem parts that are sold as “specialty” with significant markup (like their “custom” vss for adding mpfi to vehicles with a cable driven speedo (it’s just an oem 91 YJ vss for twice the cost and there are many other examples). Dealing with Hesco reminds me of dealing with Clifford Performance. It’s their way or the highway and the customer is always wrong. That has been my experience at least.
     Personally I would just piece together a stroker “kit” myself. However, we still want to know what kit your friend is offering you. Please let us know what it includes

[75sv1]

      I am in the process of building a stroker, myself.  I have followed stroker builds from the early days, say 2001. Brice was still posting on CC, as I remember. I think he did the first budget stroker. I am not an expert by any means. Also, the 'negative' post on strokers do have some weight. It would depend on what level of stroker you are planning. In this case, what the kit is. For my kit, I went with Bishop-Buell (Russ Pottenger). I wanted a mild stroker to run on 87 octane. That was mainly what piston to use vs head.  So, I should be able to get by with the 12 hole Bosch injectors I already have.  The minimum piston I could go with was a .030 over bore. So a 4.6L stroker. Also, I have a mild cam for it. It would be interesting as to what parts are in the kit. 

[89 MJ]

1 hour ago, ghetdjc320 said:

     The “rubber tensioner” is just a chain guide and does not tension the timing chain. Aside from a few one-off parts from Hesco (e.g. thermostat housing spacer, locked dampener)  I try to stay away from them. Most of their parts are simply repackaged oem parts that are sold as “specialty” with significant markup (like their “custom” vss for adding mpfi to vehicles with a cable driven speedo (it’s just an oem 91 YJ vss for twice the cost and there are many other examples). Dealing with Hesco reminds me of dealing with Clifford Performance. It’s their way or the highway and the customer is always wrong. That has been my experience at least.
     Personally I would just piece together a stroker “kit” myself. However, we still want to know what kit your friend is offering you. Please let us know what it includes

I will as soon as I see him again and get more info!

[89 MJ]

1 hour ago, 75sv1 said:

      I am in the process of building a stroker, myself.  I have followed stroker builds from the early days, say 2001. Brice was still posting on CC, as I remember. I think he did the first budget stroker. I am not an expert by any means. Also, the 'negative' post on strokers do have some weight. It would depend on what level of stroker you are planning. In this case, what the kit is. For my kit, I went with Bishop-Buell (Russ Pottenger). I wanted a mild stroker to run on 87 octane. That was mainly what piston to use vs head.  So, I should be able to get by with the 12 hole Bosch injectors I already have.  The minimum piston I could go with was a .030 over bore. So a 4.6L stroker. Also, I have a mild cam for it. It would be interesting as to what parts are in the kit. 

I was told it would make a 4.6. I'll post what it entails when I know more.

[benjy_26]

IIRC, you can *buy* a stroker engine from Oreilley's with a 3 year warranty. That may be an option. 

[89 MJ]

1 hour ago, benjy_26 said:

IIRC, you can *buy* a stroker engine from Oreilley's with a 3 year warranty. That may be an option. 

At that point, it would be cheaper to go with an LS and wouldn't be much of a learning experience, as I have completed engine swaps in the past.

[benjy_26]

Would it really be cheaper?