Mystery Stroker Motor

Newbies, and basic Stroker Recipes... Get started with your first stroker here!!
DillyFPV
Posts: 8
Joined: November 8th, 2022, 6:58 am
Stroker Displacement: 4.7
Vehicle Year: 2001
Vehicle Make: jeep
Vehicle Model: cherokee

Re: Mystery Stroker Motor

Post by DillyFPV »

Got the head back, they said its good to go. Also started tearing the motor down. I'm gonna have the machine shop clean, hone, and measure the bores and pistons to order rings. I was able to rock the piston a tiny bit by pushing on the thrust sides, and the coating on the skirts is pretty much gone. Hopefully nothing is too out of whack and everything can go back together. The shop said they could stretch the pistons if they are undersized. We will see. Also, anybody know what cam this is?
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DillyFPV
Posts: 8
Joined: November 8th, 2022, 6:58 am
Stroker Displacement: 4.7
Vehicle Year: 2001
Vehicle Make: jeep
Vehicle Model: cherokee

Re: Mystery Stroker Motor

Post by DillyFPV »

Well, further down the rabbit hole I go(and money hole). The machine shop said that my pistons were collapsed and unusable. They also claimed that my pistons were stock and that they could get the exact same ones. I said "great, if you can get the same pistons, go ahead". I picked up my engine yesterday and my new pistons are not the silvolite 2229 pistons that came out of the engine, but DNJ P1123 pistons, and they are already hung on the rods with knurled skirts. Furthermore, I can clearly see that the dome volume is much smaller than my 2229 pistons. WFT right? I told them that these pistons weren't going to work because the compression ratio was going to be too high for 87 and they insisted that I will be fine. They couldn't even tell me what the dish volume was and they didn't agree with me that these supposed "9.2-1" pistons (for a stock 4.0 application) would have much higher compression in a stroker. :doh:

I spoke with Russ about the whole ordeal, and he recommended that I start over and only reuse my 4.2 crank and rods. He thinks that the fact that they had to knurle the skirts on a .060 over block is a good indication that my bores are all out of whack and that the block is unusable. Maybe he is right, but I am not ready to give up on this one yet.

I could just assemble it as is and have a high compression, 91 octane motor. I don't know exactly how high yet because I cant find the dish volume anywhere and I don't even know where my deck clearance is yet. After messing around with a compression calc and trying to reverse-engineer these piston according to a supposed 9.2-1 compression ratio, it looks like they could be 11cc which in my stroker application and assuming worst case scenario of zero deck clearance, I'm might be at 11.1-1. I could maybe polish the dishes, get a .060 HG, and hope that my deck is at stock height, which might get me down to 9.6-1... And Im obviously just speculating on a lot of this because of the unknowns and my lack of ability to accurately measure a lot of this stuff.

Or I could throw more money at it and find some other pistons. What stock +0.060 pistons have the largest dish volume? Or where could I get some 2229's machined like my old pistons?

oh also, my cam is a comp 68-231-4
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