Stroker decision

[saltilloxj]

Ok I have searched and searched and I need to know does anyone have a concrete decision on the best BUDGET stroker and the cost of it? MY old 90' is tired (non-HO) and it is time to do the stroker I have always wanted. Heres what I am thinking...
Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Jeep 4.0L 3.875" standard bore pistons
9.7:1 CR
CompCams #68-231-4 206/214 degree camshaft
Ported non-HO 1.91"/1.50" cylinder head
Stock 0.051" head gasket
0.081" quench height
Ford 24lb/hr injectors with adjustable MAP adjuster
should give this... 260hp @ 4850rpm, 321lbft @ 3500rpm
Maybe a bored throttle body as well...
But what will this cost will this CR be OK with regular fuel?
Let me know I know there have been a lot of questions on this but I want to do this RIGHT the first time and I am just trying to get as much info as possible before I start collecting parts.

 

[bajacalal]

CR may need premium fuel, I'll let the stroker owners comment.

Oh wait, youre in México.

My regular 4.0 runs like crap on "regular" gasolina (la verde). I don't think its going to work in a stroker unless you use the 92 octane, thats probably ok. The roja seems a lot better than the regular.

The crank/rods don't need to be Jeep, other AMC vehicles (passenger cars) you find lying around with the same 4.2 engine can be used.

Edit: Anyone have experience running strokers on PEMEX gasoline? The premium will probably be fine, right.

 

[saltilloxj]

Well then I need a different fomula becuase I don´t want to be paying for premium gas here or anywhere else. What is the Compresion on a stock 4.0? And can I build a stroker that will run oin regular?

 

[Dr. Dyno]

You obviously found that recipe on my performance website. The CR is definitely too high if you're gonna be running catpee for gas so perhaps you should consider my "rockcrawler" recipe instead.
_________________________________
Dino's "Mean Green Machine"
1992 XJ Laredo 4-dr - 14k miles on 4.6L HO Stroker AX15, NP231, D35c, D30

265hp@4900/325lbft@3500, 1/4 mile = [email protected], 0-60 = 5.5secs
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

 

[saltilloxj]

What do you think the TOTAL cost of parts will be for the rockcrawler? I need to know all the parts and I mean ALL the parts I will need because. I am living outside of the US right now and I only want to make one trip up to get everything. And what about just using the poor man recipe is the CR still to high for 87 octane gas?

 

[old_man]

I am running a stroker I built using the heavy crank and stock 4.2 rods. I am using the H802cp pistons, and decked the block .020 and I am using the Mopar performance head gasket (thin). My cam is a Crane, but I don't have the number handy. It is the low rpm cam. I say all this to let you know the quench height is more important than the compression ratio. I run the crappiest gas and have no ping whatsoever, even at high altitude, 12,000ft.

 

[saltilloxj]

What exactly is quench height?

 

[Dr. Dyno]

I am running a stroker I built using the heavy crank and stock 4.2 rods. I am using the H802cp pistons, and decked the block .020 and I am using the Mopar performance head gasket (thin). My cam is a Crane, but I don't have the number handy. It is the low rpm cam. I say all this to let you know the quench height is more important than the compression ratio. I run the crappiest gas and have no ping whatsoever, even at high altitude, 12,000ft.

Tom, the air is thinner at 12000ft so cylinder pressures are much lower and your engine definitely shouldn't ping. At sea level it'll be a different story though because the air density is much higher. That's why engines that need 89 octane at sea level can run happily on 85 octane at higher elevations.
For saltilloxj's benefit, your Crane cam part no. is 750501 and that's the same one in my "rockcrawler" recipe. Cost is ~$200 from Summit Racing. I have a comprehensive list of all the parts that I used in my stroker together with cost so that can be used as a reference to price the parts for other strokers.

http://www.angelfire.com/my/fan/parts.html

 

[3XJFamily]

SaltilloXJ

Chiming in since I was thinking of going the same route a few months ago. . .

Thinking stroker but wanted an engine that would run on the cheapest regular gas and pull a heavily loaded XJ up from sea level at the Rio Grande in 115 degree weather (with the A/C blasting). I was also planning a some cooling improvements, knowing that the XJ cooling system is already marginal, and the stroker would generate extra heat.

For what it's worth, I've had several stock vehicles that pinged on PEMEX gas, and now always carry octane booster if I know I have to fill up with it.

I ended up finding a stock replacement long block and with what I saved, I'll have enough to regear appropriately for my oversize tires. It's not the "look under my hood" kind of cool upgrade I was dreaming about but, it will get the job done.

 

[old_man]

I understand about the altitude, but here at 12K you are pulling REAL hard, I'm normally loaded with 4 adults and a full load of gear pulling a 6% grade and holding 80mph. If you are ever going to push an engine for all its worth, that stretch of highway will do it.

 

[saltilloxj]

I am at about 7000ft here in the mountains and regularly cruising with 4 adults and up large mountains. But then I drive back to texas at times and run 75-85 the whole way. I need a recipe for a stroker that will give that kind of power and run cheap gas. Right now I can't even maintain 80 on flat land... something needs to be done. But of course money is an object to overcome. So what will Dr. Dyno's "rockcrawler" really cost me to do. I will probably try to find a junk block and build on that. Other things I plan on doing is converting from closed to open cooling and a MAP adjuster, and a bored throttle body. But that right there is $300 bucks all said and done. So how can I build a low cost low CR stroker? Oh yeah and my header is shot too...:repair:

 

[3XJFamily]

SaltilloXJ,
Dr Dyno's recipe's are a great place to start. For me, I was looking at $2300 to have a stroker longblock built, and a $1,000 in bolt on performance options. I know it can be done cheaper but, I hate to admit, I don't have the tools or experience, to get into a complete rebuild without a lot of help.

I've got a number of XJ's, so I was swapping between my "$800 trasher" and my dying DD/Trail rig (now down for a new long block). The "Trasher" is at 250,000 miles, suspension sags about 1", stock tires, I can't say when it last had a tune-up but, it runs good. It will maintain 75 - 80 loaded down with no problem, My DD/Trail Rig was having trouble maintaining 65 and downshifted on even a slight grade. The "Trasher" launches from a stop like "holy $hit batman" where as my DD/Trail Rig was a gutless wonder. Switching back and forth between the 2 convinced me that a "properly geared" rig with a stock engine would do everything I needed (including running on regular gas). If that means pulling 65 on a steep grade when loaded down (without pinging, overheating, or puking a 2 quarts of oil into the air filter) - I'd love it - I was down to 45mph last time. . .

From your profile and posts, I see you have a 4" lift (so I'd guess bigger than stock tires), and 220,000+ on an engine suffering from blow-by and a broken header. It's probably time to replace the engine, and I can see the "While I'm at It" bug has bitten (it usually gets me too). But as you say, money is an issue. . . I had to look up "quench height" too, so I'd guess we've got similar engine experience, for me (us?), a stroker isn't a cheap or risk-free solution.

Converting from an open to closed cooling system won't get you any better cooling. I was looking at a heat shield on the intake, hood vents, Modine 2 core Radiator and possibly a high volume water pump.

 

[saltilloxj]

3xjfamily, I have some experience but have never rebuilt an engine like you said. But I have a very good friend that rebuilds transmissions for a living and has rebuilt a few engines for himself that wants to help me out. Your assumptions are right on though, so I am trying to learn as much as possible. Its good to know about the cooling system upgrade. I have already been thinking that I would add a heat shield and wrap the headers all at the same time. My big debate has been what exact recipe for a stroker to go with. A lot of my problem is lack of experience with engine internals. My friend as I mentioned wants to help me and has offered to step me through it for pizza and beer but I need to get the parts and decide exactly what to do. Thats why I keep hunting for the right balance of everyday reliability and power all while keeping costs down to a minumum. Or should I just buy a kit. But will a kit really have everything I need in it? Because of my limited knowledge I am worried I will end up with a half baked project. Have you been to this site?

http://www.bc4x4.com/tech/bryce/stroker/stroker.cfm

 

[3XJFamily]

SaltilloXJ,
Yeah, been to that site, every site that came up on a Google search, and read every thread on . Lacking a knowledge of engine internals, not wanting to rely on friends (their priorities change and the best intentions won't get the job done), and as you said, wanting "the right balance of everyday reliability and power all while keeping costs down to a minimum" is why I chose NOT to do a stroker.

No matter how much I prepare, every big project I've undertaken that was near the edge of my skill set has left me at some point scurrying for parts, and thinking it was a half-baked idea. But with more time, and an hour or two of help from a friend at the right moment, it came together. Knowing that nothing ever goes as planned, and there may not be a second chance to get it right, keeps me from rebuilding engines.

Dr Dyno, and old_man know their stuff. My "simple" understanding is that the strokers we are talking about are "just" 4.0 pistons with a 4.2 crank and rods. . . But then consider: compression ratio, quench height, cam ratio, and combustion chamber polishing are all factors that will affect ability to run "regular" gas. If the friend helping you can't look at Dyno's recipe page, and resolve the complexities necessary to put together a plan and a shopping list, then I'm VERY concerned your end result won't have the reliability and power you want. I have NO concerns in the ability of a stock engine to be reliable and burn regular gas, and I have NO concerns that a properly geared vehicle will provide "adequate" power.

It's unlikely most kits were designed to run "sub-regular" grade gas (I used to joke that PEMEX was kerosene), if you are dead set on a stroker, and don't have the bucks to spend for a stroker long block, I'd probably follow (or start with) Dyno's low CR RockCrawler recipe.

Don't get me wrong, I think a stroker would be great, I just don't think they are the most cost effective solution for everyone.

 

[saltilloxj]

I guess I would like to add some real horsepower to the engine since its due for a rebuild anyway. I have done all the regular things to add power but to no avail... intake, exhust, tune ups, heat shielding, and so on, but nothing has given me any ´seat of the pants´ gain. I think I am going to go to my friend with the ´rockcrawler´ recipe and see what he thinks. My question is has anyone ever actually built this stroker and if so what did it really cost them to do it? Regearing is not out of the question but I still then need to rebuild my motor.