I was going through some of the junk I have laying around last week. I found my stash of timing covers and decided to clean them up cause I will need to use one on my 70 motor. I cleaned up the one from that 70 motor and repaired it the best I could (some gorilla tightened the lower rad hose to much and cracked it). I then cleaned up one from a 67 430. My question is about the timing marks. The 70 goes from 0 to 4 to 8 then to +. I know the later ones go the same way but instead of a + there's a 12. The 67 cover goes from 0 to 5 to 10 to 15. This is the only cover I've seen like this. My buddy had a 430 cover from a 69 and it was like the 70. Another Question: Regarding the wear of the oil pump gears. I wondered if its OK to clean up the machined side of the oil pump cover with a file, or do I have to get a new one? Will this screw up the clearances? New ones cost well over $100...ouch!!!
I don't know the answer to whether you can use the file to clean it up but I can answer the other question about timing marks. I have a 67 GS 400 and it is marked 0, 5, 10, 15. :grin:
Joe, The later covers have timing tabs that go to 12*. As far as the oil pump pocket goes They wear at the bottom and sides of the pocket. If you want to check them, get a oil pump rebuild kit with new gears. Install the gears in the pocket. Check for wear between the sides of the pocket and the gear teeth. Anything over .004 and the cover is junk. Use a good set of feeler gauges. Then, with the gears installed, place a straight edge across the gear faces, and measure between the straight edge and the aluminum gasket surface. The gears should actually protrude beyond the gasket surface by .002-.006. Anything less than .002, and the bottom of the pocket is worn. You can mill the gasket surface down to get the correct clearance as long as the side of the pocket is not worn and the pocket in general isn't scored too much. As far as the oil pump cover is concerned, you can resurface that to get rid of the scoring. I wouldn't use a file to do it. I've seen guys use a sharpening stone and some oil, and remove material that way. There are no critical dimensions for the cover. Or you could simply use a booster plate and that will give you a new surface and reroute the oil in the cover for better pressure. Hope that helps.
You can clean up the oil filter housing, Or better yet, just add the gear thrust plate, this gives you a new surface and also fills in some unecessary voids in the stock housing. Jim Burek
Buick's initial timing spec for most '67 400-430 motors was 2-1/2 degrees BTDC. My guess is that by marking the cover in 2-1/2 degree increments it was possible to accurately time the motors without having to guess where to set the timing mark between the lines. The timing specs for the '68 and '69 motors were also multiples of 2-1/2. In '68 and '69 it was TDC. Some '69s were 2-1/2 degrees ATDC. And for the '69 Stage 1 motors it was 10 degrees BTDC. So they were able to use the same cover all three years. If I remember right, starting in '70 Buick no longer used fractional timing specs and they changed the covers accordingly. Larry
Thanks guys!! The timing mark differences make sense now. I checked my clearances on the covers, all are within spec. I was considering a booster plate before but figured I could file the grooves out (trying to save a buck). I'll opt for a booster plate after hearing your opinions.
