All new and re-built engines by FSRC have had all fasteners properly torqued. All of them are assembled with a very small amount of Loctite 290, the green stuff. Should you need to disassemble any engine, be careful with any Loctite flaking residue. All OS 3.5mm SFN / SX cylinder head bolts should be tightened to 13 in-lbs to 14 in-lbs. This is just slightly over one foot pound, not very much. If you tighten an SX head & the piston sticks hard at TDC with oil in the cylinder, you have over tightened the head bolts & should start over. Always use a good cross pattern several times around to fully tighten. You will FEEL the fastener though end of the allen wrench take a hard set at full torque. In other words, after getting all the fasteners just touching down evenly & taking one good cross pattern around, you will feel it on the next path as the fasteners reach full torque. Don't go any further - just make sure they are all equally firm.
All new FSRC ABC / AAC liner & piston assemblies should have a tight fit at the last quarter of the stroke coming up to / going down from TDC. This is why it is important to gently tighten the bolts in a good cross pattern to achieve proper liner taper. Also, all new ABC/ AAC engines assembled by FSRC have been broken in by hand using ATF oil with the engine fully assembled & everything tightened, ready to run. The engine is turned over about 200 times with the glow plug removed & oil liberally applied. Once complete, the oil is cleaned from the internal parts & they are reassembled using automobile crankcase oil, such as Mobil 1.

During the ATF break in procedure, the squish clearance is checked by inserting a thin piece of hollow, rosin core electronics solder, no more than 0.032" - 0.035" thick. Insert it when all of the ports are just closed when turning the cranks shaft up to TDC. Make sure the solder reaches the OD of the chamber and is in line front to back with the piston wrist pin / crank shaft for an accurate reading. Rock the crank back & forth a few times, & then measure the resultant flattened solder with a micrometer or vernier calipers. FSRC has provided an additional 0.003" shim with all SFN billet heads (two 0.005 installed) and an additional 0.002" shim with the SX. Install this shim only if the glow plug indicates greying or ashing of the element (overheating / too lean) or bending deformation (pinging). Retorque the head bolts as above.

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