I just got a used set of type 4 bolt-on valve covers, for an engine I'm slowly working on. They came without hardware, and I was wondering if any of you could please tell me which hardware kit I need to get for these -- it looks like Empi has a few different versions available, and I'm not sure which one is correct for these covers, or if the T1 & T4 bolt-on covers share the same hardware.
Here's a pic:
I had originally planned on just buying some metric coupling nuts, bols & o-rings from a hardware store & cutting the nuts to the necessary length, but was surprised to find that the rocker shaft studs in the heads I've got seem to be M7x1.0, which is an oddball size that's not available in my area. Even McMaster-Carr doesn't carry much in M7 fasteners. So it looks like I've got to buy one of the kits. I was surprised that the studs were that small -- I expected at least an M8 for rocker studs. They seem like a pretty high-stress and important fastener, that you wouldn't want to fail.
And just out of curiosity -- I assume that the coupling-type nuts in the kits replace the stock rocker shaft nuts & do double duty in anchoring the arms & providing threads for the cover bolts. Is that correct? If so, are the original stock nuts some type of high-strength steel, and are the nuts in the kits of comparable strength? I ask because I've never seen a high-strength coupling nut -- they always appear to me to be around Grade 2 or the metric equivalent.
Do the kit nuts have a different thread size in each end, or are the covers actually held on by little M7 bolts?
Also -- I've seen these particular covers sometimes referred to as "Mr. Bug/Empi" covers. Was Mr. Bug some company that originally made them that later got bought out by Empi? Or always paart of Empi? Just curious.
Thank you for any advice or info anyone can offer. And Happy New Year!
Thank you!
Drew J.