Jeep Strokers

Well as promised i am reporting the stroker came to life on April 1st at around 330 pm.cst. I got it all buttoned up yesterday and got my first test drive. The engine seems to rev quicker than the old 258. There is a little piston rattle on start up due to the .005 piston clearance. I have just a little valve, rocker, lifter noise that may or may not quieten down. No oil or water leaks. I used Brad Penn 30w break-in oil. It has 75 psi cold on start then drops to 40 psi when warm and idling, anything above an idle it goes back to 75 psi. I'm not to impressed with the power, Although all i have done is set the timing, I haven't put the wide band on yet to see where the fuel is at. But i don't think it very bad off. It would take alot to make up for what i was expecting. Maybe my old 4.2 wasn't as wheezy as i once thought ( you got to remember i build Blown Fords). But all in all i guess at least i got a new engine to replace the old 4.2 that had 160000 miles. Now I'm either going to put a aluminum head on or go forced induction. But gonna drive for awhile to see how all goes. If i can help anyone feel free to ask.

I just wanted all to know the stroker is doing better in the power department, This morning i took it out and joined the triple digit club. Maybe since it was so tight it just needed some time to get everthing settled in.

Good--didn't want to call you a debbie-downer.

Just got off my first road trip, Power is doing OK. (not what i expected). But on the up side, The motor runs good, No leaks, Temp is actually cooler than the old 4.2. I went about 150+ miles. Checked the mileage and it still getting in the lower 20s. So with a little tuning i may actually get better than the old motor. I haven't tuned any I'm waiting till full break in. I did get up to 95 mph on the 4 lane coming home, So it does have more power. The cam comes on at about 1500 rpm and it is still pulling at 3G.( haven't went much higher than this) so I'm really impressed with the cam.

What cam are you running? I'm building a stroker for my 1936 Dodge sedan and looking for something with good mid to upper range for the HP

2k mileage update, All is still well with the engine. I had to add 1/2 quart of oil at about 1200 miles, But hasn't used any since. I made my first interstate drive yesterday and was very pleased. I could run with the traffic (75-85 mph) And still had power if i needed it. And this was with the air on too. The gas mileage didn't suffer as bad as i expected. It still got 19.3 mpg. So all in all i am very pleased with the engine. It does still have the piston noise as stated earlier, But most of the valve noise is gone. The oil pressure is still about the same as stated earlier.

You said you were running with traffic on the interstate. what model jeep is this stroker in? how much lift? tire size? gears?

tigerShark wrote:You said you were running with traffic on the interstate. what model jeep is this stroker in? how much lift? tire size? gears?

A 1987 model, Stock ride height, 30-9.50-15 tires. Factory 3.07 gears.Its my traveling Jeep. Got a 1955 for wheeling.

5k+ mile update:
The motor has been running fine, I have some piston noise on cold start, But this was expected with .005 clearance. I take a trip every year to Bowling Green Kentucky on the first of October, I have always had to get in the truck lane on some of the hills. NOT this year, I could pass trucks and cars with ease going up those hills. I also had another Wrangler "try me out" on one open stretch of the interstate. He obviously didn't have a stroker, Because at about 90 mph he was fading fast. Although i didn't get the fuel mileage i was expecting i did get 23 on the interstate. I retuned the carb the other day so maybe this will help a little, Although it may make it worse as i had to rich-en both primary and secondary as well as making the power valve come in quicker. I haven't tried any 89 octane fuel yet as the weather hasn't been cool for very long, I did have to return the water running Thur the manifold because it wouldn't run on the cooler mornings. My next step is to try some lower gears, as i still have the 3.07 gears. I think I'm going to go with some 3.55 so i can keep my highway speeds. But to sum it up, I am mildly impressed with the engine. I think with some gearing and the rite amount of boost the engine could be what i want in my Jeep. Ill be back with more news as time progresses.

Because 23 mpg is horrible! My XJ didn't even get that stock

bbarrett: Hey, I was wondering why you built a motor with .005" piston to wall clearance ? And your 23mpg sounds outstanding ! This a CJ7 ? I would say that lower gearing will give you better pull at hwy speeds.. you could look into a OD transmission and gear even lower than 3.55's.

JeepsAreBuilt wrote:bbarrett: Hey, I was wondering why you built a motor with .005" piston to wall clearance ? And your 23mpg sounds outstanding ! This a CJ7 ? I would say that lower gearing will give you better pull at hwy speeds.. you could look into a OD transmission and gear even lower than 3.55's.

Actually it's 5 1/2 thousands, that's the reccomendation from Diamond. It is a 87 Wrangler, already has od. 3.55 would put my rpm on " The cam" so to speak.

JeepsAreBuilt wrote:I was wondering why you built a motor with .005" piston to wall clearance ?

The extra clearance is necessary to accommodate the faster expansion rate of forged pistons (Diamond pistons are also used by Hesco). The downside is that forged pistons shrink when they're cold and rock in the bores (piston slap) at BDC and TDC, causing the engine to sound a bit like a diesel until it's warmed up.

11K MILE UPDATE
As i promised i would here is another update, Not much has changed with the stroker, I been thru two oil changes since i last posted, it doesnt use but very little if any between the 3k oil changes. It may show it has used a pint on the stick at 3k miles. I have faitfully used the comp cam lifter oil additive, use a k&n filter or motorcraft. I have had no kind of lifter or cam problems (stock Springs).It still sounds like a diesel on cold start up, But has gotten no worse than when it was new:)
I still have the 3;07 gears, I havent tried any gas lower than 93 octane, But i have noticed this summer that it doesnt rattle quite as easy as it did when it was new. Usually i have to take the water heater loose from the manifold in the summer mounths and reroute so it wont heat the manifold (pain in the butt, cause i get sticky antifreeze all over the motor). But this summer i forgot, I had my boat (1800 pounds)behind it one day and was pulling a decent hill and i heard it rattle just a little, It dawned on me i hadnt unhooked the water. But since then when i have the boat behind it i just go back to 4th ( remember 3.07 gears, it will do 70 + in 4th) and all has been good. It still gets 23 on the highway, 17 with the boat and around town, and this is with the air on. I wish i had the time and the want to to build one more as i know where i made my mistakes with this one! My only advice to anyone building one is to have the crank indexed ground before you order your pistons, that way you can get the deck height correct on all your cylinders. Use a cam that doesnt dump a lot of your low end cylinder pressure . And go with the least spring pressure that you can safely get away with. I very seldom wind mine past 4 grand so stock springs has suited me fine. I know this recipe doesnt suit every one but it suits me fine, it all depends what you are gonna do with your jeep! But i made a couple of mistakes and would like to keep others from making the ones i did.