Mystery Bolt

A while back, the engine builder fastened the valley tray with these unusual bolt heads (capscrews). They have a sunburst head -- like a kind of inverse torx head. I'm having trouble finding the right tool that removes them. Is there a name for these? Thanks in advance.

[img]https://lh3.googleusercontent.com/4mX7tk...2g=w825-h485-no[/img]

Looks like a simple 12 point to me....

Yeah, the correct term is "12-point Flange Bolt" yours appears to be Grade 8.

A 12 point wrench or socket will remove them. Looks like you'll need a 5/16 wrench.

Many header bolts are like that. The idea is lighter weight and more clearance.

They are 1/4-20 12 point bolts

!2 point socket. Useful for tight clearances, trans pans, intakes, headers, even head bolts.

They may be 12 point 11/32 head size
The 12 point nuts on 1/4 inch studs I use for valve covers use that size

Every bolt and nut on my brad hemis are 12 point. Actually there are no bolts on my hemis, all studs except for the 12 point rod bolts. Every bolt and nut are 12 points on my dragster chassis, some are titanium. Many racing/aircraft fasteners are cut down for clearance and mostly light weight.

Many are aircraft grade like some in this picture and are a one time use. I got a buddy who works at GE aircraft engines and gave me piles of trick fasteners.

All Indy valley trays and intake tops use only 1/4-20 12 point bolts

Not mine. lol. I make my stuff easy to work on so for applications like that hex head bolts work great.

I have that socket..I never used it before so I assumed this was something exotic. I can see how these would be ideal for headers. Thanks.