TrollTuner

Those of you familiar with the later model 4cyl engines issues with head bolts will understand what a problem they have been. On stock vehicles the head bolts after 50K miles are usually only finger tight! This poor clamping of the head gasket can lead to simple oil seepage cured with re-torque and in worst cases complete failure needing gasket replacement. Most of the problem cars are 1997 through 2001, these had the worst bolt design. For most stock applications one of the latest bolts and a proper re-torque will be fine. However for high output applications where the cylinder pressures are much higher better fasteners are justified. I the pursuit of high output durability on my project Viggen I chose to use ARP studs giving better clamping and long term durability. The studs have a 5 mm hex socket in the top for easy install and are a direct fit. The new fasteners have a finer pitch nut and therefore require less torque to generate the same preload. The materials used are also much stronger (190,000 psi) allowing them to better keep the specified preload. Basically this is not upgrade to add power but will make the power more reliable. This is the most important part of any upgrade plan that is missed completely most of the time. You have to keep it all balanced.