Quote:
Originally Posted by Chipper Chapman
-Block is not poured,
-.005" piston to wall as per CP
-Plateau Honed with torque plate, cannot remember exact grit but we spoke to total seal and did what they said
-Bearing clearances .0025 rods, .0037 mains
-Broke in and dynoed with amsoil break in 30 weight
-now running amsoil dominator 5w20
-M55A pump with stock spring,
-Champ CP40 pan
Cam specs
Bullet CHS 307/315-06H duration @.050 262/270
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Okay, in my opinion, for whatever it is worth, what I have highlighted above is problem one. There is no production block that I know of that will stay round under stress at 0.065" over. I've never seen an 010 or other block thick enough to do that.
If you want to run that big a bore size, you need to pour the block with Hard Blok or Embeco 885. At a minimum. You really need a BowTie or Dart to make it work well.
Ring seal is the most critical and fundamental part of restricted engine performance. You simply do not have one single solitary cfm to waste, the engine is suffering pumping losses just to breath, you cannot waste what it breathes. The bores have to stay round and straight, period.
I do not know if you can salvage what you have by pouring that block. You could try it, and maybe open the clearance up to 0.006-0.0065. If you pour a block one side at a time with either cylinder heads or torque plates, it will sometimes get a little smaller. Not every time. And if you cannot get it back round and straight by 0.0065" clearance, you'll have to change blocks.
I run tighter oil clearances, and use a lighter oil ring with a Napier cut second ring. No more than 0.001" per 1.0" of journal size. Of course, the bearing bores have to be dead round and stay that way. But it allows around 10-12# oil ring tension with no oil consumption.
Next, with a cam ground on 106 and in at 103, you're going to have an early HP peak, especially considering low lift and relatively low compression. You might consider a cam ground on 108 and in at 104-105. You can try moving the cam you have around.
That's about all I can offer you on the forum. Take it for whatever you think it is worth. Good luck.