Father/Son Project - CJ7 258 to 4.6
Posted: May 3rd, 2018, 7:21 am
Hi all,
I'm a relative newbie to Jeeps - I've owned Gertrude (my CJ7) for almost three years but still feel like a newbie. I have rebuilt engines and vehicles in the past, but never built a performance engine of any consequence.
So in the process of putting a new head on the 258 (due to a stuck valve) I went ahead and dropped the pan when I found a ton of sludge in the oil galley/lifter area of the block. I need to replace the gasket and RMS anyway and to see how much sludge and debris was in there. While I was pleasantly surprised that there wasn't any sludge in there I was not pleasantly surprised at the condition of the mains. Not *terrible* but my guess would be another 25k miles tops. I didn't check the rods at all. Replaced the oil pan, RMS, and gasket and moved on.
While cleaning out the oil galley/lifter area with a modified attachment for my shop vac, I began to wonder about the lifters so I started pulling them. All were perfectly flat (and the cam lobes looked perfect) but each lifter had a healthy coating of carbon around the bottom 1/3. So I spent $50 on a cheap set from Summit and am installing them with installation lube and adding ZDDP to the new oil. I have new pushrods, new rockers, and rocker pivot kits as well.
Anyway - In the middle of all this I began to think about the future and the fact that I was going to have to spring for a new motor eventually. No two ways about it. Two days ago, my seventeen-year-old video gaming son tells me he's not going to college. He wants to go to tech school instead and learn to be a mechanic and engine builder. This came as a surprise to me because he's never even shown the first bit of interest in the Jeep or any of the work I do on it, but I figured I would play along and began asking him a few basic questions about engines and I presented him with the idea of helping me build a new motor. Turns out he'd been reading up a bit and was clearly enthusiastic about the prospects.
At this point, I hadn't thought of building a stroker. It wasn't until I did a Google search and came across Dino's page, which led me to Robert Bryce which eventually led me here. Now the idea alone has me hooked.
Yesterday I decided to do a Craigslist search just to see what might be around locally. The first thing that popped up was a 4.0 block - it doesn't *look* great, but it is complete and the guy wants it off his lawn and is selling to me for $50. The next thing I found was a 4.2 12 weight crank and 707 rods for $175. I am picking the block up tomorrow and the crank and rods on Saturday. Funny note: Both of those ads were put on Craigslist within two hours *after* my discussion with my son. And both are within 20 miles of me. The guy with the crank is about three miles away... Funny how the world works sometimes.
So I figured I would add yet another project to the list and introduce myself.
The plan is to build a "Poor Man's Stroker" with the shorter 707 rods. I've read up on everything as much as I could and believe that the shorter rod version will work fine for our purposes. My CJ is a daily driver (for the most part, LOL) that hardly sees the freeway. It's also a weekend trail rig but nothing outrageous. I've weighed the pros and cons and I am okay without the added expense of the longer rods/custom pistons. I have a T176 in a box in the garage that needs rebuilding and we will mate it with that instead of the T4 that's in her now. We're also going to buy a used head and port/polish it ourselves and probably go with a stock cam and valve springs. I can build out the wiring harness as well so a computer with plugs and ends off eBay should do nicely. I also found a few 91 - 95 Cherokees in the local Pull-a-Part yards so we are going to spend a Saturday scavenging for anything useful.
Other than that, he and I will discuss the rest of our choices as we move along in the process.
See you around the board!
Tim
I'm a relative newbie to Jeeps - I've owned Gertrude (my CJ7) for almost three years but still feel like a newbie. I have rebuilt engines and vehicles in the past, but never built a performance engine of any consequence.
So in the process of putting a new head on the 258 (due to a stuck valve) I went ahead and dropped the pan when I found a ton of sludge in the oil galley/lifter area of the block. I need to replace the gasket and RMS anyway and to see how much sludge and debris was in there. While I was pleasantly surprised that there wasn't any sludge in there I was not pleasantly surprised at the condition of the mains. Not *terrible* but my guess would be another 25k miles tops. I didn't check the rods at all. Replaced the oil pan, RMS, and gasket and moved on.
While cleaning out the oil galley/lifter area with a modified attachment for my shop vac, I began to wonder about the lifters so I started pulling them. All were perfectly flat (and the cam lobes looked perfect) but each lifter had a healthy coating of carbon around the bottom 1/3. So I spent $50 on a cheap set from Summit and am installing them with installation lube and adding ZDDP to the new oil. I have new pushrods, new rockers, and rocker pivot kits as well.
Anyway - In the middle of all this I began to think about the future and the fact that I was going to have to spring for a new motor eventually. No two ways about it. Two days ago, my seventeen-year-old video gaming son tells me he's not going to college. He wants to go to tech school instead and learn to be a mechanic and engine builder. This came as a surprise to me because he's never even shown the first bit of interest in the Jeep or any of the work I do on it, but I figured I would play along and began asking him a few basic questions about engines and I presented him with the idea of helping me build a new motor. Turns out he'd been reading up a bit and was clearly enthusiastic about the prospects.
At this point, I hadn't thought of building a stroker. It wasn't until I did a Google search and came across Dino's page, which led me to Robert Bryce which eventually led me here. Now the idea alone has me hooked.
Yesterday I decided to do a Craigslist search just to see what might be around locally. The first thing that popped up was a 4.0 block - it doesn't *look* great, but it is complete and the guy wants it off his lawn and is selling to me for $50. The next thing I found was a 4.2 12 weight crank and 707 rods for $175. I am picking the block up tomorrow and the crank and rods on Saturday. Funny note: Both of those ads were put on Craigslist within two hours *after* my discussion with my son. And both are within 20 miles of me. The guy with the crank is about three miles away... Funny how the world works sometimes.
So I figured I would add yet another project to the list and introduce myself.
The plan is to build a "Poor Man's Stroker" with the shorter 707 rods. I've read up on everything as much as I could and believe that the shorter rod version will work fine for our purposes. My CJ is a daily driver (for the most part, LOL) that hardly sees the freeway. It's also a weekend trail rig but nothing outrageous. I've weighed the pros and cons and I am okay without the added expense of the longer rods/custom pistons. I have a T176 in a box in the garage that needs rebuilding and we will mate it with that instead of the T4 that's in her now. We're also going to buy a used head and port/polish it ourselves and probably go with a stock cam and valve springs. I can build out the wiring harness as well so a computer with plugs and ends off eBay should do nicely. I also found a few 91 - 95 Cherokees in the local Pull-a-Part yards so we are going to spend a Saturday scavenging for anything useful.
Other than that, he and I will discuss the rest of our choices as we move along in the process.
See you around the board!
Tim