Hi all Ater pulling the heads from my 71 Centurion I noticed 2 things. One there appears to be a plug of sorts in what looks like an oil passage just next to the upper left head bolt hole (drivers side). The passenger side is plugged but it looks like it was done properly. The drivers side looks like a ball was pushed into it. It does not look "professionally' plugged off like the passenger side one. The other thing I noticed is when I pulled the drivers side head a small "ball" seemed to drop out of it. It almost looks like I could press this "ball" into the space over the other "ball" plug and it would probably seal pretty well. Is this the oil passage that is plugged up on the post 70 455 block due to the use of hollow push rods? After wrestling the heads off I DO NOT want to have to pull them again once I get it back together. Thanks in adavnce!
Glen, You mean pre 455, like 400-430's. They oiled the rockers through the heads via that passage that was blocked off.
Quite possible. I tried several searches on the forums and maybe I suffered info overload. I just want to make sure I don't miss anything putting the head back on. The one side is troubling me because of that passage with the ball thingy in it and the ball thingy that came out as I lifted the head off. It just looks different than the passenger side.
Glenn, What are the numbers on your heads, are they correct for a 71 455, or could they be earlier heads?
Casting # is 1237661. They are correct for the year/engine (the engine is original and I'm pretty sure the reason I have to do head gaskets is that they are 34 years old!)
After looking at both sides again it looks like that one side must have had the "plug" blown out of it or blown loose and that is why it looks so warn. Both sides of the passenger side and the rear of the drivers side have the port plugged up so I'll cross my fingers and drive the plug back in and see what happens (unless someone can shed some light on it before I put the heads abck on on Thursday PM)
PLEASE, don't take my word for this because I'm almost blind but I think what you are talking about is just the dial pins that line the head up when you set it on the block???? :bglasses: You said there are two in place on one side and one on the other side? Could be that one just fell out?? Hopefully everyone on this thread will go back and look at the pics again and post again!! Ken
What you will find is that some 455's still had the drivers side drilled for the overhead oiling. I have a 70 455 that is drilled on that one side, but not on the passenger side. Look at your casting number on the block and you may find it is the 70 casting number. It would be correct for an early 71 car. I would have to look as some 71 blocks I have to see if they are drilled or not, but I don't think they are. Why the 70 blocks were drilled is anyones guess. Also, looking at your pictures, the passenger side does not seem to be drilled. If you had head gaskets that had the oil hole in them, the block may just be stained from oil residue and give the appearance of a hole existing. Don't know what the deal is with the ball plugs. Are there holes in the heads? 71 heads should not have oil holes in them, but could have been drilled as well. If you do have holes in the heads, and use head gaskets with holes in them, you will have oil leakage if the hole in the block is not plugged. I have seen that on some motors before and you DON'T want to loose any oil pressure. What works nicely is to tap the block (5/16-18 I think) and then use an allen set screw to plug the hole. Just make sure file down any burrs on the block surface after you tap the threads and install the set screw. I have done this and it works fine. Good Luck, Mark
Here is a picture of my 71 when the head gasket went to the crapper.. You can see a faint outline of a hole in the gasket. The heads are not drilled.. The last picture is of the new head gasket laying on the block - I wish I had a pic of the bare block, but it looks like there is a hole there!
Adam, I have a set of the blue Felpro gaskets for my 430 (long story) and they have the hole as they are to fit all 67-76 big blocks. Your block does not look like it has the hole drilled. Buick made some red gaskets for the 455 (have a set of them too) that do not have the oil hole as they were only for the 455. My guess is you have the 71 casting on your block (1388861 I think or something close) which should not have the oil hole drilled. Years ago a NE member had problems as the block/gasket/head all had the hole and he wound up with oil squirting out of the rocker shaft. If he had the valve cover cap off, it shot right out of the valve cover. :shock: Even if there are no holes in the head, it would be a good idea to plug the hole in the block so that it doesn't force oil into the lifter galley or combustion chamber. With no pressure outlet through the rocker shaft and the high oil pressure a Buick has, it is my opinion that a leak could eventually happen. Mark
