El Camino Central Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
After many hours of tinkering and freshening up she's looking pretty good. Now the pressing question is, is there a method to the madness of what's sae and what's metric? I spend half my time looking for the right tool.
 

·
Registered
Joined
·
1,183 Posts
Yes! There is a method to it. If it’s a part of or attached to something designed in the 50s, 60s or early 70s it’s standard (GM isn’t going to redesign cylinder head bolts or the like just because Jimmy Carter said ‘let’s go metric!’). If it’s a part or component initially designed after about 1977, it’s going to be metric (like the body bolts).
Patrick
 

·
Premium Member
Joined
·
864 Posts
Yes! There is a method to it. If it’s a part of or attached to something designed in the 50s, 60s or early 70s it’s standard (GM isn’t going to redesign cylinder head bolts or the like just because Jimmy Carter said ‘let’s go metric!’). If it’s a part or component initially designed after about 1977, it’s going to be metric (like the body bolts).
Patrick
I can remember working on some of the 78-80 cars that would have 1/4 screws on one side and 7mm on the other! Also, the color of the bolts made a difference during those years. The colors were thread pitch specific and some would work where the other was but not the other way around. I still have a thread tap I used to clean some threads up to use the newer bolts in some older parts. This is coming from an old body tech, used parts made life interesting back then!

Joe
 

·
Registered
Joined
·
939 Posts
Basically depending upon model redesign during the late seventies early eighties: Chassis and engine were SAE. Body was metric.
 

·
Registered
Joined
·
109 Posts
87 305 has 2 bolts on carburetor that are ½". Most of the interior trim is 9/32, or can be 1/4 or 5/16 although some of it is 7.5mm etc.

After doing a ton of car audio and some general fix-it's as a kid, I've yet to see any kind of rhyme or reason, I'm thinking many nuts/bolts were just ordered in bulk and the factory got rid of them when it could. With the car being built in Mexico, I'm not sure Jimmy's wishes actually held any real weight.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #6
Yes! There is a method to it. If it’s a part of or attached to something designed in the 50s, 60s or early 70s it’s standard (GM isn’t going to redesign cylinder head bolts or the like just because Jimmy Carter said ‘let’s go metric!’). If it’s a part or component initially designed after about 1977, it’s going to be metric (like the body bolts).
Patrick
Thanks to everyone for the feedback. Glad to know it's not just me.
 

·
Registered
Joined
·
109 Posts
Well that's also assuming mission critical nuts and bolts, like the afore mentioned head bolts. Tore into the gauges last night to paint for better lighting and replace the busted/zip-tied plastic headlight bracket with a metal one, and wouldn't you know all 12 or 13 of those screws were different. I'm talking flathead wood screws to Philips machine screws to 1/4, 9/32, 5/16 hex some course, some fine threads. No 2 the same, most variable lengths from 1/2 inch to 1inch. Welcome to Jim-bobs back yard, down home fixit in a pinch - shop.
 

·
Registered
Joined
·
109 Posts
Because of the different threads, sizes, lengths of screws, had to be careful to mark each screw or run the risk of stripping/breaking the already worn out plastic. So each screw had to go right back where it was, including the 2 bolts holding the shift needle, which used finishing washers (not flat washers) because the heads were smaller than the stressed out bracket slots.

Going through the trouble to ream out and retap the holes for something more uniform would be more dangerous to that already 34 year old plastic than just leaving well enough alone.
 
1 - 9 of 9 Posts
Top