PRODUCT FITTING INSTRUCTIONS  

 200-8530 ARP HARDENED STEEL WASHER SET FOR a-SERIES MAIN CAP BOLTS.  

200-8530 ARP HARDENED STEEL WASHER SET FOR a-SERIES MAIN CAP BOLTS. 

ARP hardened steel washers for the A-series main cap bolts. Using these eliminates the need for the cheap and badly made off-the-shelf centre main straps many believe is essential for up-rated A-series engines. The centre main strap came about in the early 1960s when it was believed that the only way to high performance was monumental rpm. The A-series 3-main bearing crank was not best disposed to that. Sustained high rpm caused the main cap bolt heads to chew in to the main cap lands, effectively reducing the torque clamping load. The caps start jumping about, and eventually break. These steel washers prevent that from happening. A far more cost and mechanically effective solution. The standard existing bolts can be retained. 
 
Because of manufacturing tolerances, it is necessary to check the fit and clearance of the washers once fitted. 
Check for clearance between the washer part that over-hangs the inside face of the end main caps and the outer face of the crankshaft end webs. If the washer catches, simply grind a small flat to give the clearance required. Do not forget to allow for end float movement. To hold in place while torquing the bolts down, position the crank so the adjacent web is out of the way, then use vice-grips/Molegrips to locate the washer in the required position.