Difference between fire ring and o ring?

cliff-1972

cliff-1972

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Guys I didn't look this one up yet,but if some would like to answer it that would be nice.I am a drag racer (gas engine) I know when I o-ring a BBC I have to use a copper head gasket with a SS wire ring in the receiver grove.I bought a fire ring kit and was told some folks have had problems with them sealing or (I guess)poor machine work done.So,is the o-ring better?Or if I got a good machinist just stay with the fire rings.But,do I really need them if I keep boost down?If I use studs and stock head gaskets what will would be my limit on boost?I read that Garmon has a way of torquing a head that works great.I am sure timing also comes into play here also.So if boost was keep below 75 psi., would studs only be fine??
 
o-rings are a groove cut into your cylinder head and you use a piece of wire to put in the groove. It usually protrudes around .11 i believe

fire rings are usually cut into your block and head and you use an actual "ring" and set it into the groove. O rings are recommended for daily drivers and fire rings are more for competition because they wear out over several heat cycles
 
FWIW, I have fire rings in my daily driver/tow rig. Scheid did the machine work for me, and they were the ones who recommended fire rings based on my application and goals for the truck. I have read alot on here about fire rings being only for competition motors because of their tendency to not deal well with heat cycles but so far I have had no problems.

I had my head off a few months ago (after 60k+ miles) to fix a broken ARP head stud, and yes, one of my fire rings was cracked. Right next to the ARP stud that broke. The other 5 were in good shape, with no signs of cracking, or head gasket failure. My truck is mildly built by most standards on this board, so that may affect fire ring life span.

What are you wanting to use the truck for?
 
Thanks for the replys guys!I plan to use the truck as a part time daily driver.I may want to drive it a 1000 miles up the road from time to time,Michigan.But for the most part just a play/light tow (-8K) truck.I want 700 rwhp or darn close to it.Going back to the grove cutting.On my fire ring kit it says I can either cut the head or the block or both.Of course both is the best for high boost levels.On the o-ring who sells it and what gasket does it use?I give you some more info of planned engine set up if this will help:

98 12V stock bottom (this may change though??)
CDS or Garmon pump (12mm maxed out)
DDP comp injectors
Girdled bottom end.
Fluidamper
62 over S480
60lbs springs w/TI retainers & locks
Moly push rods
Ported head

I don't know timing yet.If I do rebuild bottom end I will get it balanced,but no lowered comp or anything in that line.
 
IMO I would run the o ring for the simple fact that you use a stock head gasket and with fire rings you use a after market gasket. I have heard bad thing about fire rings on daily drivers, because of heat cycles but that could be from bad machine or a bad torque job. I drive enough place that are in BFE that it is easier for me to get a stock head gasket that get a fire ring gasket from haisley machine.
 
the fire ring gasket is not custom, it is a stock gasket with the stock crush ring cut out. i would reccomend the oring setup for what your are wanting to do. i am one of those who tried fire rings, and i had two sets fail on me within 25K miles combine dof both sets. went with orings this time around, hopefully no more problems.

Wes
 
I have fire rings on my daily driver and have 30K on them, I had orings on my puller and had 4 years and 100+ hooks on them with no issues.
 
my truck is fireringed. 40,000 miles and no issues. o and it is my DD.
 
Well you all have been a great help.So,if my machine is up to par and head is torqued right then I should be fine.One other thing.Those who run fire rings on the street.Do you have the block and head cut or just one of them?

Also where do you get head o-ring kits?
 
Below 80psi you can cut just the head or block. Above it is recommended to cut both.
 
You have to be very careful cutting the groove for the fire rings and make sure there is no deviation on the cut depth. A buddy of mine cut his own into the block using the hand tool and ended up blowing the head gasket 3 times . After the third time we took it to Schieds and had them fix it. He could not get the depth consistent. They ended up cutting the groove bigger and had to have special rings made up for it. Needless to say it turned out to be pretty expensive.

For me unless you are running a ton of boost I would go with the o ring set up, the head gaskets are cheaper because you are using a stock gasket. And if it you are running enough boost that the o ring wouldn't hold you could always cut it deeper and make it into a fire ring. Pure Diesel Power.com has the gasket kits and fire rings
 
I have about 400 miles on my fire-rings and I don't have any problems... :D
 
cliff-1972 said:
Well you all have been a great help.So,if my machine is up to par and head is torqued right then I should be fine.One other thing.Those who run fire rings on the street.Do you have the block and head cut or just one of them?

Also where do you get head o-ring kits?
Click to expand...

Scheid cut the fire ring grooves in my block. They said cutting in the block, when possible, is always better because there is less chance of warping anywhere down the line.

Some argue that with 12mm studs you can't get enough crush on the fire rings to make them seal properly. I am running 12mm ARPs, and aside from breaking one a while back, I have had no problems with this setup. Scheid recommended both the fire rings and 12mm studs so that's what I went with.
 
I have 100+K on the same head, same o-Ring setup, installed it in the spring of 03' with 2 head gasket changes, one for a new short block and one for a broken cam that bend valves. I'm running a .010 over gasket with a .051 wire and .018 protrusion which is allot, new motor for the 01' 12V has the same wire with .014 protrusion.

To date I have had zero failures!

Jim
 
So if you had the choice to cut into the block or head (since both are out of the truck). Which would you guys choose? I'm talkin o rings here.. not fire.
 
Lucky Jeff said:
So if you had the choice to cut into the block or head (since both are out of the truck). Which would you guys choose? I'm talkin o rings here.. not fire.
Click to expand...

Personally, I've always heard head but thats because the block is still in the truck, but in this case I could see Scheid's argument that the block is less prone to warping. Plus, its easier to lay the o-rings on the block then put the head on instead of making sure the o-rings don't fall out of the head when you set it down.
 
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