Semi-Conventional E85 4.7 Build

[LRSimons]

Hi all, getting finished with the planning stage for my first stroker. Want to get some opinions and have more sets of eyes review my plans so far.


Jeep is a 95 XJ, 5 speed, 4wd, stockish. No crazy anything yet. Formerly my daily until blowing it up a couple months ago, was actually driving to buy a honda. Think the Jeep committed suicide.

Once completed it will see ~95% street use, I'll take it to work (not my daily), drive it around town, it will be revved to redline, taken to the track, etc. Think mild street motor over low end monster. I would love to wheel it more but the nearest trails are 2.5 hours, the nearest 1/4 mile track is 1 hour. A mix of both should be fun.

I would like for the stroker build to not be the end of fun projects for this engine. If time and budget allows, I'd like to do a megasquirt setup as the next big thing, and a turbo setup after that. Planning to leave some room for boost in this engine (see where the E85 comes in? )

By the way, budget is somewhat tight- but the jeep can sit and wait as I save and scavenge parts. I have another (far more comfortable) daily.

My 4.0 block, rods, and head will be kept. Planning on taking the bore out .060 because I can't really think of a good reason not to. It's getting bored anyway and won't cost more to take it .060 than .030. Therefore, free power? 4.0 blocks currently are cheap enough to be somewhat disposable in my mind. Block will be decked to zero. Going to have the rods shotpeened and port the head myself. I've done 2 strokes before and have seen how easily things can go downhill, so not planning on anything beyond a cleanup and polish on the exhaust ports.

Picking up a mostly complete 258 this weekend for $50. Score! I'll pull the crank and should end up ahead after selling everything else. (Anything worth keeping?) Also picked up a 99+ intake at the JY for like $20.

Piston choice is what has somewhat confirmed the idea of running E85. Initially, the goal was to be able to run 87 during normal driving and bump the octane once boost was added. After looking at the available pistons (and pricing out custom work) that kinda went out the window. KB944's might have worked, but spending $500 on a set of pistons isn't really palatable. I'm not good enough with a mill or CNC software to dish pistons myself (consistently...) and not interested in paying someone to do it for me. I'm planning on going with the silvolite hyperetectics for a more manageable $170 or so. This gives about 10.5:1 static and 9:1 dynamic compression with zero deck, 13.7cc dish, .043 HG, cam listed below. Totally manageable on E85 with room for boost, less room for error with straight gas.

Keep in mind when I say boost I mean a low boost setup on a smallish turbo, I have no interest in blowing up my nice and expensive engine.

E85 is very affordable and available locally, so I have no real issues with running it. The difference in price per gallon should offset the increased consumption. The added torque from compression should help with consumption if I baby it. In the end I'm not going to be that concerned with gas mileage, that's what the honda is for

My question here would be if anyone has ran or is running these pistons, with what results? Also, I'm fairly sure they will be strong enough for what I have planned, assuming detonation/ running lean/ general garbage tune is what blows holes in pistons- let's assume I have everything under control. Obviously forged would be the best choice but hyperetectics are supposed to stronger than cast.

Prospective cam choice is the comp 68-232-4. Looks to be well suited for the mildly street oriented goals I have without too bad of an idle or off idle torque. Again, experiences running this?


Wow, this turned out longer than expected. Have quite a bit more in my head still. I'll cough it up next time.

Thanks

Logan

[LRSimons]

Fueling considerations for E85-

Assuming 24# injectors would be appropriate for gasoline, I'm seeing that somewhere around 36# should be what I'm looking for.

Factory XJ fuel pump is reportedly adequate for a stroker, but not much beyond. This engine is going to require far more fuel than a gas stroker, so looks like this will need to be upgraded. I've heard (anecdotally) that the dakota/durango pump from the same era is rated for 190 lph (stock xj reportedly rated for 90lph) and the whole assembly bolts in. Can anyone confirm or deny? Seems like a cheap and ideal solution.

Are people running fuel pressure regulators simply to accommodate for different/better injectors from stock, or as a tuning device of sorts?



I have no idea how the stock computer will react to the corn juice. Here's what I'm thinking- assuming the ecu runs appropriately sized injectors exactly the same as is does when stock, all the sensor values should be within normal ranges except for the o2 sensor. From what I understand, the stock o2 sensor is a narrowband o2, only capable of reading rich and lean, in the normal range for gasoline. I know a wideband o2 and a proper gauge will be critical for reference, but not sure if a wideband could be made to play nice with the ecu. I'm guessing the sensor values when reading e85 would have to line up with the values the ecu associates with rich/lean somehow, to fool the ecu into thinking it's still running gas.

If this were unsolved and the ecu tried to bring the afr back to gasoline levels, a dangerously lean condition could occur. But here's where my lack of knowledge kicks in. What sensors does the ecu place priority on? If the TPS and MAP say full throttle and full airflow, would the o2 sensor value even be cared about or would the ecu go straight to open loop and full rich? I'm thinking it would go to full rich under this condition.

What about part throttle/cruising around conditions? From my (limited) understanding, this is where the (narrowband) o2 sensor shines as a fine tuning and emmisions control device. So just unplugging the o2, running in open loop and tuning with a map adjuster and the afr gauge may or may not be a good idea.



This could all be solved with the aforementioned megasqirt setup, but that's a whole different rabbit hole. I'd prefer to not break the stroker in on a completely untested ecu. Having played with MS before, the only thing I can say for certain is that it never works right the first time!

[Russ Pottenger]

In my opinion I would never set out to build a stroker engine with a cast piston especially in a potential boosted application when you have a choice of of a forged piston made out of 4032 high silicon aluminum alloy. They offer great wear and scuff resistance, a low expansion rate and are much more durable than any cast or hypereutectic piston. One of the advantages of my Pistons that I put in my Stroker kits is for the same price of a shelf KB piston I can supply you with a piston with any piston dish or compression height for the same price.

If you're looking for a cost-conscious piston, my custom spec piston
could be made allowing you to have a zero deck piston without necessarily having to get the block decked. That would help bridge the financial gap between the cast Silvolite and forged piston.

Lastly I think you should consider some of the disadvantages of running a blended type fuel such as E 85.
In the long run it's not any cheaper to run, and creates another turning challenge if you're going to switch back-and-forth between it and conventional gasoline.

Just something to think about.

Feel free to shoot me an email and we could go over some possible tweaks to your recipe. ; )
Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Cell (626) 673-2203
Email/PayPal: [email protected]

[LRSimons]

Thanks Russ. Your pistons seem like a logical option for greater margin for error and longevity. Let me crunch some numbers and see what sort of specs I come up with using full custom parts.

Seems like I have an easy way out to build a more conventional stroker with the option of a larger dish for off the shelf prices...

Or an easy way to even more impractical ideas!


I'll think about it and get back to you.

How are your pistons in terms of overall manners? I know some forged pistons can be noisy on cold starts, etc.


Logan

[Russ Pottenger]

Hi Logan,

At engines operating temperature range there's minimal differences in piston to cylinder wall clearances.

Additional piston noise shouldn't be a concern, but the increase in strength and reliability is a big benefit.

[Cheromaniac]

How are your pistons in terms of overall manners? I know some forged pistons can be noisy on cold starts, etc.

The alloy used in modern forged pistons allows a tighter piston-to-bore clearance than was previously required, thus cold start piston slap is a non-issue.

[LRSimons]

Update- Got lots done last night. Engine is out of the jeep and ready to be torn down.

The day started by picking up an engine stand that turned out to be uh, somewhat larger than I expected. Should come in handy if I ever need to move a horse or a small house. Pretty good deal considering I paid less than half of a harbor freight unit.

Anyway, we ripped the engine out the rest of the way in about 3 hours, not rushing. Also a new shop light is in order, my harbor freight special got close to lighting a couple things on fire and trips the breaker whenever it and the toaster are turned on.



Not really anything that got in the way too much, we were able to leave the trans in place so that was a plus. Exhaust got bashed a little and new motor mounts are certainly in order. Clutch was toast and nearly gone. More parts added to the list...

Another picture for scale of the hoist-



Big thanks to my very patient friend!


This was the first time I've cleaned jeep grime out of my ear.





Less immediate plans for the build-

A/C is going. I was on the fence about keeping or pitching it, and made the decision earlier to get rid of it. Too much clutter in the engine bay and it didn't work. If I want OBA later I'll just do an electric compressor mounted somewhere hidden.

Found a list of junkyard cars with desirable fuel pumps and injectors. Apparently some 90s mercedes came with the bosch 044 fuel pump which would be more than adequate. However, I have heard about E85 being rougher on in-tank pumps where fuel flows through the pump to keep it cool due to reduced lubricating properties. This probably won't be an issue but something worth considering. I've heard inline pumps are mainly used to boost line pressure as a secondary pump or need to be mounted below the tank if used as a primary pump. One of these could be a solution if a standard pump setup proved to be problematic.

Not sure what tank I'm going to use, something a little larger than stock would be nice and I have no problem chopping out the rear floor pan to lift the tank up higher. (A chop top will happen after it's running)

I won't be switching between fuels. Can't think of a good reason to do it.



Thinking about having static compression somewhere around 12:1. Should be good for roughly 30 hp more than a stock CR stroker. Should have no problem with fuel, but at this point clearances will be a consideration. Anyone know what the piston to valve clearance is? Piston dish will be very small or nonexistent at this level. Prospective cam has .476 exh. lift.

On that note, would it be better to have a flatter piston with no or a very small dish at zero deck, or have it sticking out of the hole a little with more dish? Quench could be tightened that way but I'm not sure if there would be any added advantage.



I'm questioning the viability of a turbo setup. A built motor can be dropped into a nicer jeep without too much trouble, should my XJ rip in half from living 23 years in the rust belt. All the turbo components may or may not. This also probably is not a cheap endeavor by any means, even with my mad junkyard scavenging skills

There are other ways to make more power should I feel the need to hit a specific number or something.

[Hedworx]

Very interested to see how this build turns out. I am thinking of building my stroker to run on E85 also, as a street strip use car (I have another XJ for wheeling)

Russ is building an edelbrock head for mine and as I want to run a high comp (12 or 13s) N/A setup, but I was thinking of using a carb in lieu of the efi.

I will keep a watch on this post and follow your trials and tribula.. I mean progress.

Good luck.

[LRSimons]

Thanks for feedback. Seems like we have similar plans.

A carb setup would be cool. It seems the general consensus (for carbs on the 4.0) is that it's kind of a step backwards (for gas), but for running E85 it might be a better option than trying to use the stock computer.

A carb could be a cost effective solution if you had the knowhow to set it up right.

I don't think I would run one on my build, with how cheaply and easily a fully tunable ecu can be set up.

I'd be excited to see a carb setup on one of these, keep us posted!



On that note, the current plan is to implement a megasquirt setup as soon as possible. I'm not going to try and fool around with the existing ecu. I think it will be a good move, should be really easy to control things like the fans and rev limit that are off limits stock. Not sure about the spark control conundrum, will probably just use the distributor until I figure out how to set up spark on the MS.

The main concern I have is the engine control during the break in period. I want it to be running GREAT with no issues so I can focus solely on the mechanical aspects. The best solution I've thought of is to keep the stock ecu hooked up for break in and run race gas. The MS can then be installed and tuned later without so much risk.

Other potential solutions are to install and bench tune MS and pour in E85 right away, turn the key and pray (sketchier than I'd like)

or

Trade my work truck for another jeep (not a big deal) and get the MS tuned and running E85 on that, then swap the works over. This would be a huge PITA though and I don't want to do it.




In the real world where I have far less money than all this requires, the 4.0 has been mostly torn down and old parts are getting sold/tossed. My garage is getting cleaner in anticipation of new shiny parts (exciting I know).

[GreenYJ]

I thought Ms3 had capability to use fuel sensor and determine ethanol % of fuel and alter tune accordingly. Sloppy Mechanics has a bunch of info on megasquirt.

[LRSimons]

Progress-

Hit the junkyard last friday. Things I needed- Power steering bracket, battery cable, injectors, and another dozen things

Things that I needed and got- Power steering bracket

What I didnt need and got anyway-




HX35 from a school bus. Yes, a school bus! Had the 5.9 cummins in it with this turbo.

Super crusty and dirty, but including lines and a rebuild kit I can have a very capable turbo for about $100. It should be about the right size, DSM guys use them on 2 liter engines so I think the 4.7 should spool it fine.



Picked up a $20 sandblaster from tractor supply over the weekend and blasted the new intake and the valve cover today. Turned out pretty good for low expectations, and I recovered about 3/4 of the media by blasting on a tarp. I got a little nervous going through half a 50# bag in one sitting until I got the stuff off the tarp. Not sure if going the polish and clear coat or ceramic coating route on the intake. Probably polished and coated. With the turbo I can't imagine ceramic coating the intake would do anything besides waste money better spent on a better intercooler.



Motor is 100% torn down. Jeep still needs some love in preparation for the mad power coming its way.


I've been thinking about dropping in a $300 craigslist 4.0 for the time being so I could have the jeep driving around for the time being, and get rid of the work truck. Swapping in another engine would be a pain, but in the end its only another saturday.

Anyone take this approach of building an engine off to the side while keeping the jeep running?





Looks like MS3 can use a flex fuel sensor. D'oh. Thanks for that. Good for the variation between winter and summer blend E85.

[SkylinesSuck]

I ran an HX35/40 hybrid then a full on HX40 with a 19cm exhaust housing on my Skyline. Those are not small turbos. Should be fun. Don't get too caught up on the displacement of the engines they are on though. That HX35 should be good for north of 450-500hp depending on the version.

[LRSimons]

Cool. What did you think of the hybrid setup? Single or twin scroll exhaust housing?

[krom]

IMHO :
I woudn't go to .060" over, power gain doesn't amount to squat.
I would also get the engine together and running NA, with a fuel system built for boost on e85, first once the bugs are sorted out, add boost and a megasqurit.

If you are going turbo, and have E85 available, you would be crazy not to use it.
Megasquirt can use a cheaply available fuel content sensor, and automatically adjust for the amount of corn juice in the fuel tank.

[SkylinesSuck]

Cool. What did you think of the hybrid setup? Single or twin scroll exhaust housing?

The 35/40 hybrid was single scroll IIRC but the spool was amazing. Came on super quick; almost too quick and hard. It was not very linear, but I learned to drive around that light switch aspect of it. It was probably the must fun the car ever was. The straight 40 was twin scroll and the boost came on mitre gradually as you would imagine. Thing pulled like a freakin freight train up to. It was probably a little north of 600hp at 3.2 bar of boost.