Probably one of the most troubling discoveries was this casting defect that I found on one of the crank main journals. Luckily after speaking with the vendor, they agreed to send me a fresh crank under the parts warranty.
After about a week, the new crank came in - much cleaner than the original. The journals didn't have any of the streakiness that the original crank did.
I also installed my ARP rod bolts and measured the big end bores for out-of-round, finding that they did indeed need honed back into shape. To torque the bolts down I used an improvised vice since I don't have a real one - ended up using the clamping fixture I had used for the wooden frame laminates from a previous blog post.
Measuring the bore
Also punched the rods and caps with a machinists punch to make sure I didn't accidentally mix any of them up.
Also discovered a slight distortion to the cap on the #1 rod - notice the visible seam, which you could also feel. It was curious that you could only see/feel the split on one side of the rod, and that none of the other rods had this problem. I separated the cap from the rod and tried re-aligning it, but it only goes on one way due to the texture of the mating surfaces. At the very least - it looked as though I'd be replacing this rod at a minimum.
I also brought my pistons in to work to measure them since I don't have a 3-4" mic. I measured each piston in the "meat" of the skirt, about 1.5" below the oil ring and found that they were all at the low end of my spec window. Meaning that any cleanup of the cylinder bores would likely bring about the need for a new oversized piston set.
With my piston measurements, I now needed to take bore measurements. But to do this accurately, I needed to bring the block as close to running condition as I could. So I bought ARP head studs, head gaskets, and torqued the heads and mains down. The clamp load distorts the bores from how they are at rest, and could result in problems if you don't take this into account. For that reason, most performance oriented engines nowadays are honed with torque plates to simulate this effect.
Also got a thread chaser to clean out the head mounting threads. Important since the oem bolts used a threadsealer that can cause cross-threading and stripping if left unaddressed prior to reassembly.
Heads and mains torqued down:
With the oil pan off, you can measure the bores from the bottom with careful setup and manipulation of the dial bore gauge. I bought a Mitutoyo 0.0001" dial indicator for improved resolution over the supplied Jegs indicator. The extra resolution was critical when you're working with tolerances that are this small.
And here are the results:
All cylinders are beyond the allowable taper, and all of my piston clearances are beyond the allowable spec.
New pistons it would be.
After much research and playing with compression calculators, I ended up with a tentative build list that looked something like this:
Shooting for an 11:1 static compression, ~8.5:1 dynamic compression with 0.035" quench.
Stock crankshaft (may polish journals as necessary but they are really clean)
Diamond LS1 Street/Strip Flat Top Pistons - #11502, 3.905" bore
Compstar LS1 4340 H-Beam Connecting Rods PN# CSC6125DS2A2AH, 6.125" length
241 ported heads milled for 62 cc chambers (~0.040")
0.045" gaskets for 0.034" quench
TSP 228R cam
It turned out there wasn't much in the way of aftermarket pistons available that used the stock style press-fit 0.945" wrist pins. Most use a superior 0.927" floating style pin that increases the load bearing area and increases the life of the components. So instead of putting money into having the big ends of the stock rods honed back into round, and having the small end bushed and honed to accept a floating style pin, I decided to put that few hundred towards a set of forged H-beam rods. Ended up going with the Callies Compstar rods. 4340 forging, H-beam design, ARP 7/16" 2000 bolts.
Should be getting here tomorrow:
More to come shortly, I hope.
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