I've started assembling my 1961, 235 engine. #3 main bearing cap has what appears to be an 1/8th inch pipe threaded hole. What is this threaded hole for? I do not remember if there was an oil line connected to this or if anything for that matter.
Interesting. This looks like a 216 I worked on several years ago. I'm wondering if the 235 used the same bearing cap as the 216 but the threaded hole is not used on the 1961 235 engine. The attachment of the oil pickup assembly is quite different between the 216 and 235. I'll take a closer look at the size and threads tomorrow. Your thoughts?
The pic I posted is of a freshly rebuilt 1954 235. It's been too long since I dropped a pan on a 216 so I don't recall how the pickup screen was secured. Heres a Pic of the same 235 engine as I tore it down. The engine still had the stock pistons and shims under the main bearing caps and it's overall condition indicated it hadn't been rebuilt before. Chevy made changes to the 235 through the years so it's hard to say if the pickup screen mounting changed. Good luck Dave
I have two 59 261 motors, one has the drilled hole on the main cap, the other has the pad but not the hole. The photo is one of the 59 261 motors without the hole but has a 55-57 pick up (car). The pick up for 58 looks similar but is slightly different, and the 59-62 also looks similar but is shaped slightly different. None use a hold down bracket or bolt so it must be an early 55 and prior thing, and maybe even a later thing for accommodating a later fitted block into an earlier model truck or car.
I dropped the pan on a 216 to see how the oil pickup screen was mounted. The 216 main bearing cap where the oil pickup screen mounts is much different than the 235 pictured above. I measured the threaded hole in #3 main bearing cap on my 1961 235. I turns out it is not the 1/8" NPT I thought but it is a 3/8"-24. From Mike's and Dave's responses and pictures, I'm convinced the threaded hole in #3 main bearing cap on my 1961 235 is not used. I thank you both for your kind and informative responses.
