442olds

Ok, here is a picture of my oil filter pad on a Mark VI big block 454 block. Now there are two pressure relief valves, one on the supply side of the filter base (the one on top next to the oil supply hole from the pump), then another on the outlet of the filter (down in the hole where the threaded nipple for the filter should be). Now here's the next part. There are two pipe thread holes to the right of the oil filter base. They are both connected to the same passageway and go back to the oulet hole of the oil filter base. I figured the two pipe thread holes were for an external oil cooler but they are connected so the oil will flow to both holes at the same time and won't really return like I would think it should. Can anyone shed any light on what does what. Also, do I need a filter adapter like the old small block and big blocks used or do I just put in a threaded nipple to screw on the oil filter. And why is there two pressure relief valves in this setup?



Thanks.....

ORVette

Hope this helps. It's out of an HP Books Gen V/VI rebuild book. I'm trying to locate some more specific info on your questions, but I thought I'd throw this up for now.

442olds

That helps a lot, but I still don't understand the use of two bypasses. I would also like to force the oil to continously flow through the fileter, so I guess I would tap out the top bypass.

It just doesn't make sense to have oil flow through an oil cooler if the oil comes and goes from the same oil feed from the block. Maybe there's another galley running into those to ports but As far as I can tell theres only one.

Where did you get that book?

ORVette

I bought it from TISQUICK. It's ISBN # 1-55788-357-2. "Rebuilding Gen V/Gen VI Big Block Chevy Engines" by Mike Mavrigian. Pretty handy, I needed it for the torque specs to some of the roller cam exclusive parts(ie.: not Gen IV). I looked through it and it doesn't have anything to say about why there are 2 bypasses. Maybe in case one fails?? Also doesn't say any more about the oil cooler holes, and I don't understand it either. Could you shine a flashlight into one and see if they are in fact both plumbed to the same passage? If they are, it seems it would be like hooking both battery cables to the same terminal :confused:

clem zahrobsky

those 2 holes in the pan rail are not in the same oilpassage. the rear hole is the output to the cooler and the front hole is the return. the oil filter adapter you need is part# 3853870

442olds

I stuck a piece of thin solder down the front hole, and i could see it through the rear hole. Also if I blow air through the front hole and hold my hand over the rear hole I get air out of the outlet part of the oil filter. Could there maybe be some kind of restrictor that is supposed to be there that isn't if you do infact utilize the oil cooler. Currently I my oil cooler lines are supplied and returned to the same oil galley.

It would make sense that they are different passeges but they don't seem to be.

clem zahrobsky

some thing does not sound right because i have the GM blue print of the oil passages and there should be 2 parallel drillings but no connection at the area between the 2 oil cooler holes. :chevy

ORVette

You must have a defective block! :skep:
Just kidding, although on my block the fuel pump pushrod would not go all the way into the hole. Had to do a little back yard "machining" to get it right. We'll see how well that worked when I get it started. Could be a very short break in run???

442olds

Clem,

Is there anyway you might be able to scan that portion of the print of the block showing those drilled holes so I can do some comparisons. The only thing I can think of is that there should be something threaded in there to seperate the two holes.

Thanks

clem zahrobsky

it will not scan very good because it is a very small print but if you can get a "chevrolet power" 7 th edition it is in there on page 112. i have build several 510 mark V supercharged boat engines with oil coolers and all we ever did was connect the coolers to the 2 holes in the pan rail. :chevy

442olds

Cool thanks, I think I may try to find both of those books for future refrence.

As far as the mystery goes, I looked around it some more. Here's the scoop. The top bypass is the bypass for if the filter clogs, the second is if the oil cooler circuit clogs. Now, as for the mystery of the oil cooler ports. The oil cooler supply is connected to a top galley and the hole is drilled stright through into the galley that comes from the oil cooler return. What I believe is the idea her is that some of the oil will in fact travel to the cooler and some will flow down into the return, this way the engine doesn't suffer from a lack of oil on start up or if the engine is empty of oil, like an oil change. Makes sense I think. I bet that no one has ever really checked into it this much and that's why I have questions about it. I was just trying to figure out which was the supply and which was the return, but as far as the cooler goes it doesn't really care but it would be nice if it flowed downhill in the cooler.

Thanks for all the help guys. I hope this will help you out in the future as well.