Double O-rings

Drothgeb

Drothgeb

Almost Fast-N-Loud
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Sep 18, 2010
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Well, I finally got the truck on the track with the new engine last weekend. Unfortunately, despite my wife's recommendation to "not blow it up on the first pass". I blew the head gasket at around the 1000' mark.

I'm running a single O-ring in the block, Extreme Studs@155lbs, 85psi of boost and it makes mid 900hp. Looking back, I probably should have just fire ringed it, but it's mainly just a street truck with just occasional trips to the track. Anyway, it's too late for fire rings now, and it's obvious I need to do something. In addition to bumping the torque up some, I'm also thinking about adding another O-ring in the head. Just can't decide exactly where to do it.

So let's hear some opinions on whether I should do it exactly opposite the one in the block, or whether I should offset it some. With my last head I actually had double rings in the head, and it worked well. So I'm also thinking about the doing the same thing and have the one in the block centered between the two in the head.

Plans for torque to compress the rings into the gasket will likely be 160lbs. And just as a side note on studs... I was giving thought to dumping the Extremes and going to 625s. But before I did, I wanted to do some testing with a couple of extra Extreme Studs I have. I torqued them suckers down to 180lbs last night using an old block and head. I know some have had problems with Extreme Studs breaking. But after testing them last night, I gotta say I'm impressed.
 
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I would torque them and let them sit for a while, few days, maybe more. I had a block on the stand with A1 studs and had one pop and imbed itself in my ceiling after a month.


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Did you do a hot and then cold retorques before jumping on it?
 
Probably been re-torqued a half dozen times since I got it together last fall. Had it running for a while to bring it up to temp before the pass too.
 
It was 6.8@103.?

I was actually taking my wife's advice and made a pretty soft start at 15psi. I think my 60' was only 1.67
 
Normally something is not flat or oring is not dead center of fire ring .. I ran over 90 psi for 2 seasons with twins.. .010 protrusion arp 425 .. Check wire location and also see if head is flat and wire is .010 the hole diameter.. I found using a milling machine is best way but it's slow .. The jig leaves a room for problems if not really careful ..
 
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I hot retorque single orings at 160 with 625's and never blew the gasket, even cracked a cylinder before blowing one. I was only around 750-800 tho> I'm planning on giving it the beans in a few weeks so we'll see if it holds
 
I'm surprised that you cracked a cylinder at 800, I wasn't going to worry about that until I pushed it over a 1000.

I do think the power level had a lot to do with blowing the gasket though. Throw in that I was running fueling based on water injection, and the water pump didn't kick on. EGTs were up close to 2000. Did I mention I'm running over 18:1 compression too?

I'm not surprised that I blew a gasket, just a little surprised I didn't get in one full pass on it.

Biggest question is, how to beef it up so it last longer. I'm running the thick gasket, so it should be able handle a being sandwiched between 2 O-rings shouldn't. Seems like I've heard it being done before?
 
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I’ve done the double o-ring in past. Using the 3283339 gasket is ideal. Going to come down to figuring out if your block o-ring is dead center of fire ring of gasket or offset some. If dead center, I suggest cutting your head o-ring closest to cyl so you have .020” clearance of wire to outer wire of block o-ring for squish/seal (distance between outer and inner of wires). If block o-ring is closer to cyl, then you have no choice but to cut head o-ring to outside of gasket fire ring.
 
Drothgeb said:
I'm surprised that you cracked a cylinder at 800, I wasn't going to worry about that until I pushed it over a 1000.
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I think it was just a freak deal, idk. Stock block with many years of abuse and insane egts. My new block is .040 over so hope it holds lol.
 
Might not be the easiest to do now but I have been running a half and half fire ring in the block and head with a copper gasket. Has never let me down in years. Ran it on puller and my new engine for a street truck will run same setup. Our machinest has been doing this setup for years on the tractors and has never had a head gasket failure since.
 
I have the oring in the block and a mating groove in the head
.015 protrusion
Works awesome
No retorques, just 425's at 150 lb ft

80 psi
 
Nascar said:
I’ve done the double o-ring in past. Using the 3283339 gasket is ideal. Going to come down to figuring out if your block o-ring is dead center of fire ring of gasket or offset some. If dead center, I suggest cutting your head o-ring closest to cyl so you have .020” clearance of wire to outer wire of block o-ring for squish/seal (distance between outer and inner of wires). If block o-ring is closer to cyl, then you have no choice but to cut head o-ring to outside of gasket fire ring.
Click to expand...

I'd have to install the head the head O-ring as the outer. How much protrusion were you running?

dieselpolaris said:
Might not be the easiest to do now but I have been running a half and half fire ring in the block and head with a copper gasket. Has never let me down in years. Ran it on puller and my new engine for a street truck will run same setup. Our machinest has been doing this setup for years on the tractors and has never had a head gasket failure since.
Click to expand...

Kinda too late for this engine. But I actually have two engines in the works. This was the first, that was supposed to be the lower HP engine that I'm using in the street truck. Was trying get away with stock rods, block and etc. But got carried away using the pump and some other goodies destined to eventually go in the higher hp engine that will be fire-ringed, Carrilo, 625s and etc. Seems that I mis-overestimated how well O-rings will hold 900hp and 18:1 compression.

pushlar84 said:
I have the oring in the block and a mating groove in the head
.015 protrusion
Works awesome
No retorques, just 425's at 150 lb ft

80 psi
Click to expand...

I was giving a lot of thought to this too. After seeing that someone else has had success with it, I'm leaning in this direction.

jedeka said:
I would get some ARP 625 head studs.
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I have been totally happy with the Extremes, and honestly believe that it won't make a difference, but I probably will get a set of 625s, just for peace of mind that I did all I could.

Probably what was worst than my wife saying not blow it up on the first run, then doing so. Was when I popped the hood, and had oil and water all over the place. Then my wife says sarcastically says "isn't there a $4000 set of bolts or something that could have prevented this?" and I had to answer, maybe...
 
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LOLLOLLOLProbably what was worst than my wife saying not blow it up on the first run, then doing so. Was when I popped the hood, and had oil and water all over the place. Then my wife says sarcastically says "isn't there a $4000 set of bolts or something that could have prevented this?" and I had to answer, maybe...
:hehe::hehe:
 
Just curious what are your shift points at rpm wise? not sure what turbo setup your running but I imagine with that high of compression it spools pretty dang good. It seems high rpms are easier are parts, I think I blew my cylinder wall right when I locked the converter in first gear under full load according to my buddies in the truck..:hehe:
 
First to second to third are around 3300. TC locks in second. Third to OD 3700-3800.

I'm running a 366 over a 491. Spools decent, start seeing boost 1700-1800, 20psi by 2000. Works well with the 2500 converter. Starts really well too, just takes a quick flip of the key with no pedal.

I like the crispness of the higher compression. But considering it blew the head gasket in 5 different places, it obviously does put a lot more strain on parts.
 
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