An attempt at a tech post.



This is the Valve cover before any modification. I believe they are made by Blue Thunder. They match the Blue Thunder intake.







First I drill the hole using a 1 3/16 hole saw. This gets it close to the 1.220" diameter specified for the grommet I used. It actually comes out to about 1.200" with the hole saw - rather than 1.188. They aren't the most accurate.







Next, I use a 1 1/2 grinding stone to grind the fins down and provide a smooth surface for the grommet to mount.







I hand sanded the hole to get it to the 1.220" spec. I tried a brake cylinder hone but the stones wore quite fast. Too much pressure on a small surface area.



Here are some pics of the finished product.











The cover is about 1/8" thick after the fins are ground so there is plenty of meat. I chose the center of the valve cover so that they can be swapped if there is any reason to do so in the future. It falls right in the middle of the rocker shaft so there is no interference with the rocker arms. I am using baffled grommets to prevent oil from leaking through the breather. Hopefully they will work well. If not I'll have to have some baffles installed. I may enlarge the holes another .010" because it is a b!#@* to push the breahters in and I plan to use them as oil fillers.

I don't know if two breathers are necessary. I like symmetry and it seems that too many breathers is better than too few.

Now if I could find some nice cast breathers that sort of match the valve covers! I really don't like chrome. And billet stuff is usually too plain for my taste.



There we have it. It is amazing the things that can be accomplished with simple tools.


Lawrenceville, GA