Jeep Stroker Inline Six 4.6L and 4.7L thread

[Rescue Diver]

I decided to pull the trigger on starting my stroker motor project. I'm picking up a good 1995 4.0 donor motor today or tomorrow, and over time I will pick up new Sealed Power dished pistons that should give me roughly 9.25 to 1 compression, getting the block bored either 30 or 60 over, and I'll be using the crank out of my AMC 258 i6 / 4.2l machined 10 under to clean it up.

My plan is to do a cheap but solid build using my AMC 258 i6 / 4.2l crank and rods, the 4.0 block and new pistons, and the stock 4.0 high output cam and lifters. I already have a killer 4.0 head that I'm using on my AMC 258 i6 / 4.2l , but I also plan to continue using my HEI distributor and MC2100 carb instead of going the fuel injection rout that most do. Unless it shows signs of wear, I think I'll also be re-using the tru roller timing chan I already have in the AMC 258 i6 / 4.2l . It only has 25k on it, so I expect to find it still in good shape. I guess I better check to make sure the 4.0 and the AMC 258 i6 / 4.2l take the same chain and gears?

What I've confirmed so far is that the bell housing bolt pattern is the same between the AMC 258 i6 / 4.2l and 4.0. The distributor will also fit. There is a little question on the motor mounts though. From what I gather, the later model 4.0's (TJ's maybe) require a little grinding on the block to get the CJ mounts to clear, but I don't know for sure what year in the 4.0 production that this change occurred. Any input on this would be welcome!

I also discovered that there's a slightly different part number for the oil pump. The 4.0 pump is the same number as the AMC 258 i6 / 4.2l pump but with an "A" on the end. Does anyone know if they're interchangeable? The motor I'm buying is complete, so I'll probably switch to the serpentine belt settup. I've read that I'll need to use some kind of spacer to mount the 4.0 serpentine's harmonic balancer to the AMC 258 i6 / 4.2l crank.

The last issue that I can think of to tackle is the fuel pump. Since the 4.0 was built for fuel injection, it won't take a mechanical pump, so I'll have to switch to electric. That goes against my "Keep it simple stupid" philosophy, but I have no other choice. I'm thinking of using a Mr. Gasket Micro electric 4-7 PSI pump with no regulator, and mounting on the inside of the right rear bump stop extention to keep it level with the bottom of the gas tank. Does anyone on here have any experience with these pumps? Should I carry a spare so I don't get stranded???

I think I covered all the bases. Did I miss anything????

Thanks for any input!
David

 

[Incommando]

Just curious:

Why build a stroker 4.0L ( which many claim have longevity and cooling issues as well as a premium fuel requirement) for a rig like our CJ's? A V8 swap is easy to do and would probably be cheaper and/or yield better results, wouldn't it? I understand doing it may be appealing for later rigs that never had a factory V8 option and therefore the swap is more involved and expensive but a swap to an AMC V8 or (gasp) SBC in a CJ is relatively cheap even if you upgrade the engine first. I have less than a grand in my 360 with a comp cam, HEI distributor, performer intake, Q-jet carb, and MORE motor mounts. Other V8's aren't very hard, either.

 

[Rescue Diver]

Just curious:

Why build a stroker 4.0L ( which many claim have longevity and cooling issues as well as a premium fuel requirement) for a rig like our CJ's? A V8 swap is easy to do and would probably be cheaper and/or yield better results, wouldn't it? I understand doing it may be appealing for later rigs that never had a factory V8 option and therefore the swap is more involved and expensive but a swap to an AMC V8 or (gasp) SBC in a CJ is relatively cheap even if you upgrade the engine first. I have less than a grand in my 360 with a comp cam, HEI distributor, performer intake, Q-jet carb, and MORE motor mounts. Other V8's aren't very hard, either.

I've gone the V8 AMC rout in the past. They're good motors as long as you do the oil bypass trick under the intake to keep from destroying your rear rod bearings, but I want the Inline six stroker this time around for the weight and fuel economy advantages. I don't expect my already good mileage to go down much if any from what I'm currently getting with my AMC 258 i6 / 4.2l and 4.0 head(19mpg highway). My mileage may even improve with the more efficient 4.0 cam?

The Inline six AMC 258 i6 / 4.2l with its long stroke is a low RPM stump pulling torque monster that is perfect for rock crawling. Building a stroked 4.0 keeps that low RPM torque and gives more HP at highway RPM's. It's the perfect all around CJ motor. That's why they're so popular!

 

[Rescue Diver]

This is what I'm building because it's what I want after doing a lot of research. I started this thread to get input from those with experience with this build, not to answer questions about why I'm not building a totally different engine.

And before anyone asks why I don't go with fuel injection, please don't ask. I've answered that question in countless threads. I am going for simplicity, plain and simple.

 

[coldair]

I think it's great keep us updated. I've got a spare AMC 258 i6 / 4.2l crank and set of connecting rods I've thought about building one myself but think i will see how my AMC 258 i6 / 4.2l build turns out.

 

[Incommando]

I've gone the V8 AMC rout in the past. They're good motors as long as you do the oil bypass trick under the intake to keep from destroying your rear rod bearings(Yeah because every AMC V8 gets that mod and without them the all blew up as soon as they left the dealer's lot...I have abused several AMC V8's without such mods and without issue. Sustained high RPM racing? Maybe then you need that..., but I want the Inline six stroker this time around for the weight and fuel economy advantages. AMC 360 is listed at 540 pounds versus 500 for the AMC 258 i6 / 4.2l ... Swap to an aftermarket intake and the 360 weighs slightly less than a stock AMC 258 i6 / 4.2l ... add headers and it is about 50 #'s less.... Without EFI I am not sure what MPG gains you are really getting

I don't expect my already good mileage to go down much if any from what I'm currently getting with my AMC 258 i6 / 4.2l and 4.0 head(19mpg highway). My mileage may even improve with the more efficient 4.0 cam?

The Inline six AMC 258 i6 / 4.2l with its long stroke is a low RPM stump pulling torque monster that is perfect for rock crawling. (Actually for any given year even the low AMC 304 had more horsepower and more torque over a broader RPM range than a AMC 258 i6 / 4.2l . Look at the first year of AMC's ownership of Jeep for an example: 360 245hp/365 TQ bone stock. The AMC 258 i6 / 4.2l ? AMC 150 /240! Even if the 360 only has 2/3's available tq at idle where does that put it against even the full tq if the I6? Your average 4.0 stroker cost thousands to build to equal the stock 360 and that is with the superior attributes of EFI. For far less than stroking an I6 you can add a cam/intake/carb to a V8 and get numbers unattainable for the I6. Any dollar spent on the I6 being spent on the V8 will give you even higher numbers.Building a stroked 4.0 keeps that low RPM torque and gives more HP at highway RPM's. It's the perfect all around CJ motor. That's why they're so popular!They are popular in later years because of the need to keep an engine that came in the vehicle for street legality and emissions. It is also much much harder to swap a V8 into an YJ/XJ/MJ/TJ than a CJ. For a CJ they really aren't nearly as popular as swapping a V8 of any type into one.

There is no replacement for displacement...that is the purpose for stroking the I6 to gain displacement. So by starting with much more displacement to begin with....

 

[Incommando]

This is what I'm building because it's what I want after doing a lot of research. I started this thread to get input from those with experience with this build, not to answer questions about why I'm not building a totally different engine.

And before anyone asks why I don't go with fuel injection, please don't ask. I've answered that question in countless threads. I am going for simplicity, plain and simple.

Why didn't you go with FI? This seems to be the thread to exert the minimum effort to copy/paste that info as it is about the build of stroked 4.0's and it would seem to be worthy of inclusion for others deciding on this swap.

By the title this is not a thread about your build but a thread about putting a stroked 4.0 in a CJ. The WHY to do this mod versus a V8 swap seems like a logical discussion in a thread about putting a stroked 4.0 in a CJ instead of a V8.

 

[Rescue Diver]

CJ PLEASE CLOSE THIS THREAD or delete the posts that are OFF TOPIC!!!!!!



I'm sick and tired of SOME people on this site not being happy unless everyone else uses exactly the same stuff they do.

 

[Incommando]

As I stated in my response to your pm this was not labeled as your build thread but laid out as a general discussion. SOME people post incorrect info regarding weight and power and consider it off topic when they get called on it. Choosing a fairly bizarre induction over the superior EFI is also worthy of discussion in a discussion thread and I am sure most would agree. If you want to blog about your build there is certainly a process to do that. If you post an open Discussion in an open forum don't be shocked if maybe some of the discussion is not 100% to your liking especially if you imply things like the V8 was so much heavier than the AMC 258 i6 / 4.2l or that a stroked I6 is some power monster when in the grand scheme of things they are not. Yep keeping your info factual is a great way to avoid getting called on it.

My first post was to legitamately ask why go this route. It was a great opportunity for you to cheerlead this option but you chose not to. To paraphrase the advice that CJ gave me when I was concerned over responses to some of my early threads: don't post if you can't handle the response

 

[Rescue Diver]

I labeled this thread "Stroker Inline Six 4.6L and 4.7L thread" because I wanted to discuss building this engine, not to hear why everyone that builds them is wrong for not building something totally different. I guess that was too much to ask.

Anyone is welcome to start their own thread about the superiority of their settup. Why do some insist on hyjacking threads to promote their own settup when it has nothing to do with the clearly stated topic?

 

[CJ]

Wow...

My thoughts, you asked for any input. You got it. Not what you wanted but it was input.

Just make a post (in this thread) stating that this is not open for discussion as you are going to build the I6 and you are good to go!

I'm not going to close this thread, I DO hope you continue the build as I think it would be some good info.

BTW - if anyone ever wants to make a how to - we do have an Articles section...

 

[BajaEdition]

I have read the thread and will not delete it.
I will ask that Incommando refrain from upsetting Rescue Driver anymore as he does seem to be upset with your questions and answers
I will ask Rescue Driver to please continue with the thread and trust me when I say if you ask a question on line you will get a lot of answers, and many will not be what you want to hear.
Any other discussion between the 2 should be in PM

I am sure many will want to offer other information that will be as Recu Driver intended. I cannot delete info or discussion just because it was not to the personal likes of the OP.

good luck to everyone

 

[Rescue Diver]

Wow...

My thoughts, you asked for any input. You got it. Not what you wanted but it was input.

Just make a post (in this thread) stating that this is not open for discussion as you are going to build the I6 and you are good to go!

I tried that twice and someone persists with the argument. I give up.

 

[BusaDave9]

I understand your frustration. You're not asking if people recommend a stroker over a V8. You're picking up a stroker tomorrow and haven't yet received any advice on what you plan on doing. I am not against Incommando giving his opinion as long as he doesn't get argumentative.

That' just my 2¢

Now I hope I can give a little advice on the topic you are asking about.
I installed an electric fuel pump and was also reluctant. You really want that as low as possible. Preferably close to, and level with the bottom of your tank. I know that's not easy to do an an off-roader where ground clearance is important. The reasoning is if you ever run out of gas and the pump is higher than the bottom of the tank it very well will not fill with gas. Gas will not go through the tube up to the fuel pump. A dry electric pump will not be able to suck air to pull fuel (a mechanical pump is better at that). If you completely run out of gas you may need to prime the pump.
Since I installed my electric pump I have run out of gas and even though my pump is mounted on the tank down low I still had to prime my pump by removing the fuel line and pushing compressed CO2 into my tank. Only then could I get my CJ started.

The real moral of the story is if you have an electric fuel pump you need to be even more careful not to run out of gas. Unless it's an in-tank pump, but they are a pain to install and replace.

 

[coldair]

Build the stroker I really want to see what way you go with it.

 

[Rescue Diver]

I have read the thread and will not delete it.
I will ask that Incommando refrain from upsetting Rescue Driver anymore as he does seem to be upset with your questions and answers
I will ask Rescue Driver to please continue with the thread and trust me when I say if you ask a question on line you will get a lot of answers, and many will not be what you want to hear.
Any other discussion between the 2 should be in PM

I am sure many will want to offer other information that will be as Recu Driver intended. I cannot delete info or discussion just because it was not to the personal likes of the OP.

good luck to everyone

I appreciate your points Baja. I know I went a little over board. I guess I've just seen one too many posts on here by know it alls that take any oportunity to promote what they built instead of recognizing that there are countless ways of going about things, and no one answer is the only correct answer. I never really asked for "any input". I asked specific questions about motor mounts, oil pump, crank spacer, and electric fuel pumps. Most of the original replies were arguments about why I don't do what someone else feels is the only correct way to do things, even after I said that although they're nice engines, and I've even built one for an old Jeep I had in the past, I didn't want a V8 this time around and asked for this thread to stay on the topic of strokers. It just gets old. By the way, I did send a PM to the user aksing him to please stop pushing the V8 because that's not what my thread is about. His response was less than polite.

I plan to abandon this thread and stick to the new one I started where I was more specific about keeping it only to ways of building an I6 stroker. Hopefully that keeps it a little more on topic.

 

[Rescue Diver]

I understand your frustration. You're not asking if people recommend a stroker over a V8. You're picking up a stroker tomorrow and haven't yet received any advice on what you plan on doing. I am not against Incommando giving his opinion as long as he doesn't get argumentative.

That' just my 2¢

Now I hope I can give a little advice on the topic you are asking about.
I installed an electric fuel pump and was also reluctant. You really want that as low as possible. Preferably close to, and level with the bottom of your tank. I know that's not easy to do an an off-roader where ground clearance is important. The reasoning is if you ever run out of gas and the pump is higher than the bottom of the tank it very well will not fill with gas. Gas will not go through the tube up to the fuel pump. A dry electric pump will not be able to suck air to pull fuel (a mechanical pump is better at that). If you completely run out of gas you may need to prime the pump.
Since I installed my electric pump I have run out of gas and even though my pump is mounted on the tank down low I still had to prime my pump by removing the fuel line and pushing compressed CO2 into my tank. Only then could I get my CJ started.

The real moral of the story is if you have an electric fuel pump you need to be even more careful not to run out of gas. Unless it's an in-tank pump, but they are a pain to install and replace.

Thanks for the info Busa! I was eyeing the right rear bump stop extender I made out of 2x5" recangular steel tubing as a mounting location, but after reading your post, I might make a bracket that attaches to it and locates the pump a couple inches further down behind the axle to get the pump even with the bottom of the tank.

I'm leaving this thread alone so hopefully everything else on this topic will end up there without all the clutter at the beginning.

 

[Rescue Diver]

Build the stroker I really want to see what way you go with it.

I am. Should be fun!

 

[Rescue Diver]

Here's the new, unspoiled thread.

http://www.jeep-cj.com/forums/f2/th...best-ways-build-jeep-i6-stroker-motors-14864/

 

[Incommando]

Just read this as of now ( it was further down the new posts list then some others I have already responded to such as folks hijacking the hijack thread with off topic stuff)

The most important thing for an inline electric pump IMHO ( O for opinion which is not necessarily a proven fact) is to run a good filter between the tank and the pump. Heat kills these pumps so don't mount them any closer to another heat source than necessary. A cheap rotary pump that has a max output that is hopefully what you need is not as good of an investment as say a Holley Blue pump with a regulator to give it the correct pressure. Mounting the pump close to the tank so the "pull" length is as short as possible is aso said to make them last longer.