Jeep Strokers

i have some questions for you fellas and i hope you can help me figure out what my jeeps got under the hood.

side note: i write a lot

----history-----
traded lifted cherokee straight across for this jeep to college kid from houston. he wasn't a mechanic and this is an old wrangler, carb'd. he wanted fuel injection and the lifted look while i wanted a wrangler with 6 cylinder, auto, hardtop and full doors. it was a swap made in heaven . the wrangler had some little issues which i recognized as soon as i popped hte hood on it when we met to swap. the cherokee was perfect but i was ok with it because it was the carb and linkage system that was causing this guy's troubles. we swapped and i drove it home from victoria, roughly 2 hours with no trouble. the kid tells me afterwards "the jeep has had some work done on it. the previous owner swapped the block and did some work but i don't remember what it was." hmmm, i wonder what.

the carb was a crappy weber 34 two barrel. it ran ok but dieseled like crazy when you turned it off. no matter what i did, i couldn't get it to stop. and the jeep got terrible gas mileage, 10-11mpg. the dieseling really bothered me so onto craigslist i go and find a stock chrysler two barrel holley from a 68 something with a 340 or 360 v8 for 20 bucks, SCORE!!! i rebuild it and drop it on and what an improvement. the jeep is badass. can smoke a tire once in a while and runs down the highway up to 100mph like nothing. i am living the good life.

but, life moves on and the good life becomes normal and things i didn;t notice in my joy to have a non-dieseling jeep start to pop up. gas mileage has not improved one bit and hte jeep idles terribly rich. i learn about vacuum gauges at this point and tune up the carb. runs great but i realize i can do better so i start with the gauge and screwdriver and a mixture screw snaps off jaggedly.

dammit, what the heck?!

i pull the holley and throw on a motorcraft 2100 and it is back to running. not as good as with the holley but ok. dang it, for some reason, i have lost a huge amount of power and have to floor it to keep highway speeds. gas mileage has increased though. i cannot stand the lack of power so the motorcraft comes off and the intake comes off for an offenhauser intake i got off ebay cheap. motorcraft goes back on and nothing has changed. dammit!!

i start researching jeep mods and learn that the reason nothing fits when i buy 87 parts is i have a 99 block in my wrangler. why the hell would someone put a 4.0 block in a jeep under a 4.2 head? is something done to this jeep i don;t know of?

after the intake swap and reading a lot, and discussion with fellow jeepers on other forums, we have come to the possible conclusion my jeep has been stroked.

how you ask? well, let me list the ways.
4.0 block
4.2 head
old school distributor with 13/18 advance plate
jeep smokes the tires when i have 225/75/16 tires on it, larger then stock!!
previous previous owner mentioning to previous owner engine work and block swap
jeep smokes tires with oversized tires on it
jeep is a light to light dragster (for a jeep)
jeep smokes tires

i am running the offenhauser intake and a holley 4 barrel currently. i just put 31" tires on a few days ago. it cruises on the highway like nothing and can pass people with ease. i know the 4.2 isn't known for doing that kind of stuff.

what can i look at, without tearing the engine down, to see if i have a stroker or not. everyone tells me i do and i will happily believe them but i have this back of my mind voice saying "you cannot verify that so stop saying it is."

give me some ideas fellas.

here is the monster, on the previous rims and tires

easiest way would be to drop the oil pan and get the numbers off the crank to see what crank you have. all it'll cost you is an oil pan gasket, oil and about 30 minutes of your time. the faq section on the site here has all the block, crank, and head numbers so you can find out what everything is

That is the best way, the only other MAYBE????, that I know of that's not 100% by ANY! means is there might be a spacer on the front of the crank for the dampener, but there are short snout cranks that don't require them or the crank snout can be cut to length on a lathe, I trimmed my crank snout so it'll look stock!

ok, so only way to be 100% is visual and easiest way is to drop the pan. bummer. oh well, i guess i will get to it sometime. i am just glad this thing runs so good

ok, new question:


if it does happen to be just a 4.0 bottom end with a 4.2 head, i should have lower then normal horsepower it would not run as well?

you could try this
http://www.fordfe.info/FEStrokeCheck.htm

using the AMC stroke measurements.
3.895" 258
3.414" 4.0

If it works great if not you're out a coat hanger and the 2 minutes to pull a spark plug.

it seems REALLY backwards to put a 4.2 head on a 4.0. somethin doesnt seem right to me here. have you checked the obvious things, like port alignment, fuel pump spot in the block, etc? do you have pictures of the engine? the more likely scenario would be the 4.0 head on a 4.2 block. also, if it was originally a 4.2, swapping in the 4.0 block with a 4.0 crank would destroke it, and to change only the block just leads back to the original idea that the 4.2 head is really just terrible. does it have the siamesed (sp? but i dont care) 3 and 4 exhaust ports?

yuppiexj, good idea.

amcinstaller: you and i are thinking along the same lines, why in the hell would you put a 4.2 head on something, especially a 4.0 block? thats going opposite the normal direction and makes the engine even more inefficient.

this is for sure a 4.0 block. its got no fuel pump mount on it and the numbers came out to a 99 or 98 block (i don't remember exactly which year). the head is a 4.2, as far as i can tell. my offenhauser intake bolted on properly and its from a 4.2 so i really think the head is a 4.2. the hoes matched up. plus, it did have the original intake and vacuum set up on it when i got it but it had a weber carb on it.

yuppiexj wrote:you could try this
http://www.fordfe.info/FEStrokeCheck.htm

Don't know how well that would work considering the coat hanger may move around on the piston top and the spark plug will put it in at an angle.

Unless you see a spacer on the front of the harmonic balancer you will need to drop the pan.

not good enough to see. i am trying to go through pics i can find while i am at work to see the end of the crank. nothing so far though

Higher than stock static compression will tell you something.
You could look up casting numbers on the head?
The tabs might be cut off of the dist. hold down, as an indicator of it might be a stroker.(not difinitive)
Hope i helped some.
M

ok guys, what does the nut and washer that hold the harmonic balance on look like? this one doesn;t look like bmw or volkswagon ones, which are the only engines i have ever taken apart that far. anyone got a pic of it or can tell me how thick the washer is? this one is the nut and then an umbrella-ish shaped washer that is about 1/8 or 1/6th in thick and then there is another washer underneath it of the same thickness, maybe a little more

tequila mike wrote:Higher than stock static compression will tell you something.
You could look up casting numbers on the head?
The tabs might be cut off of the dist. hold down, as an indicator of it might be a stroker.(not difinitive)
Hope i helped some.
M

the head is a 4.2 head. its not a 4.0. i have a 4.0 in the shed and they are not the same looking. what tabs are you talking about?

The bolt looks like a bolt, with a large washer behind that. There may be another piece right behind the washer sticking out. If there is no ring the washer would be flush with the balancer.

so this has the spacer on it then? its not just a bolt and washer, there is something between the washer and harmonic balance. i can take a picture later