Milling radius grooves

Don’t need whole head , just around where the radius goes.
It wouldn't matter if he zoomed in close or out as wide as possible because it has nothing to do with the pictures actual image. It has to do with pixel size being larger then the sites limits setbin place to conserve memory space.
 
Back in the day, we would call these "o-rings" and use .015 stainless wire. Grooving was cut with a boring bar or a facing tool with a shop-made radiused groove cutter, and only the block was done because a deck job was cheap and many builds could survive a .015 decking compared to decking the heads. Nobody cut two o-rings and opposed (mated) them on the block and heads. So with these diesels, the minimum wire is .049 and it is run on both sides of the gasket. That's quite a bit different than the nitrous and blower motors of the 80s and 90s. What's changed to require two fat o-rings?
 
Back in the day, we would call these "o-rings" and use .015 stainless wire. Grooving was cut with a boring bar or a facing tool with a shop-made radiused groove cutter, and only the block was done because a deck job was cheap and many builds could survive a .015 decking compared to decking the heads. Nobody cut two o-rings and opposed (mated) them on the block and heads. So with these diesels, the minimum wire is .049 and it is run on both sides of the gasket. That's quite a bit different than the nitrous and blower motors of the 80s and 90s. What's changed to require two fat o-rings?


Hey Pontiac! That is correct. And O rings still are alive and well, and are still used. O rings are just a more street friendly version of a firering, firerings beings really for competition use only. In an O ring application, the o ring in the head helps clamp down on the firering inside the headgasket to help seal. In a "Firering " application, an aftermarket headgasket with the firering removed from the gasket is used, and .105"x4.550 rings provided, and instead the receiver grooves are cut and firerings are recessed into the head/block. It's fairly old technology I believe, same old school rules apply, but is more commonly found in diesels due to extreme exhaust gas temperatures and boost pressures. Comp diesels using multi-turbo applications can see 2000* egt, and boost pressures of 100psi +, this is where the firerings come in, aiding the headgasket, and clamped down using 26- 14mm fine thread head studs. Also these engines have comp ratios of 16.5:1, some newer engines 19:1, and in a performance scenario can use all the clamping/sealing available
 
I could see why competition diesel is on the extreme end of cylinder pressures. So is the fire ring a one piece deal that sits in recesses in both the head and block, or are you using two rings and butting them together? The one piece ring might require more precision than you can get with a boring bar indexed off of the stud bosses. Hitting a tight tolerance on both mating halves would require a skill level more like die making than old school performance shop machining. I suppose that's why people buy those very expensive tools and alignment plates to do the job. I wouldn't hesitate to do an o-ring job in my home shop, but this seems to be something different. I could grind a custom radiused bit for you if you get to that point.
 
Back
Top