Originally Posted by ICDEDPPL (Post 4067604)

Well I`m glad I put the post up this has been very informative! Thanx Bob for explaining it so well, I`m going to pick up a couple sets.

As far as my "preoilers" going to have to check the plumbing , it picks up from the pan and moves the oil before the stat in my oil adaptor. Not really sure what that acccomplishes.

Originally Posted by rmbuilder (Post 4067522)

IC,

The valve spring is potentially one of the most significant contributors of thermal transfer into engine oil, in some cases more so than even the combustion process. Valve springs generate heat as a byproduct of both internal and external friction. As the spring cycles through extension and compression, internal friction of the wire becomes the primary source of heat. As the cycle rate increases, the greater the heat generated per unit of time. The second is external and is developed as the spring moves against another surface. Inner and outer springs, dampers, retainers, and spring seats are the primary sources. Friction heat is the primary source of wire fatigue and resulting spring sag.

This is compounded by the fact that as the spring fatigues, the ability of the spring to maintain dynamic stability of the valve train diminishes, generating more heat. As this downward spiral progresses the spring will become increasingly unstable resulting in failure. This can manifest itself in collateral component failure within in the system such as pushrods, rocker arms, and very likely, the lifter.

On examination, a typical valve spring for a BBC marine application (Isky 9905 Tool Room) is surprisingly long. The unwound wire length of the outer, .207” dia. wire is ~ 24.5”. The inner .148” dia. wire length is ~17.5”. That totals 42” of wire per spring x 16 equals ~ 56 feet of spring wire per engine. The springs operate at temperatures varying from 200º F to 400º F under high stress conditions. Above 400º the wire color begins alter color. At 475º chrome silicon will lose temper. 56 feet of wire @ 350º F generates a massive amount of heat to dissipate with oil being the primary method of transfer.

There are numerous methods available to assist the thermal transfer from the spring with oil. Bottom line, anything you can do too promote the reduction of spring temps will benefit long term durability and valve train stability.

Bob

Originally Posted by rmbuilder (Post 4067619)

T&D integrated spring oiling rocker arm.

Originally Posted by mike tkach (Post 4090320)

i dont know if you were asking bob or anyones but il give you my opinion,the500 merc engine does not need that elaborate rocker system unless you have an unlimited budget but some under the valve cover oilers might extend the life of your new springs.