jbc426
Well-Known Member
I built a 408ci stroker to replace a junkyard motor that had 145 to 150 psi in all cylinders except #2. The new motor is a stock Magnum block with a Hughes bottom end and their CNC Super Prep heads with a few extra hours of hand blending in the bowls etc. I'm running one of their Dave recommended smallish hydraulic roller with less than .245 at .050. and 260 'ish lift with 1.6 to ones. Compression is 10.2 to 1.
Back to the junkyard motor, when I pulled the # 2 cylinder's piston the cylinder had no cross hatch marks left, but there was barely enough ridge at the top to catch a fingernail. The rings looked fine, but the top and second ring had the gaps in the same place near the piston pin facing the front of the engine.
Is that enough to let that much compression blow by? Or, did the thing just have a lot higher mileage than I was told it had when I bought it?.
It's EFI and all the plugs were perfect light tan color. it ran great, but it just had low compression in that one cylinder. and it smoked out the right side on deceleration something fierce.
Here's a picture of it all cleaned up and painted. I was bummed when it turned up with only 90 psi in the # 2 hole, but I tool a gamble and didn't pull the heads. I do have a nice smaller Hughes roller cam with like 2000 miles on it that will work with the stock valve guides, the matching Hughes 1100 springs and a modified beer keg manifold that raises the torque peak about 500 rpm I will let go for cheap. I 'll throw an add in the for sale section too.
Back to the junkyard motor, when I pulled the # 2 cylinder's piston the cylinder had no cross hatch marks left, but there was barely enough ridge at the top to catch a fingernail. The rings looked fine, but the top and second ring had the gaps in the same place near the piston pin facing the front of the engine.
Is that enough to let that much compression blow by? Or, did the thing just have a lot higher mileage than I was told it had when I bought it?.
It's EFI and all the plugs were perfect light tan color. it ran great, but it just had low compression in that one cylinder. and it smoked out the right side on deceleration something fierce.
Here's a picture of it all cleaned up and painted. I was bummed when it turned up with only 90 psi in the # 2 hole, but I tool a gamble and didn't pull the heads. I do have a nice smaller Hughes roller cam with like 2000 miles on it that will work with the stock valve guides, the matching Hughes 1100 springs and a modified beer keg manifold that raises the torque peak about 500 rpm I will let go for cheap. I 'll throw an add in the for sale section too.
