Loc-wire/o-ringed heads?

gtsr515 · 02-12-2002, 10:30 PM

What is the difference between "Loc-wire" machined heads and "O-ring" machined heads?

DZEE'S LX · 02-12-2002, 10:36 PM

Maybe this is a trick question.

They are the same.

Oringed heads have grooves machined in them to allow use of the Fel Pro "Lock Wire" gaskets.

gtsr515 · 02-12-2002, 10:40 PM

Whew!!!!!, thought i was loosing it, thats what i thought, there is a post describing them as different here, and thought i'd ask before answering, thank-you.

StangFlyer · 02-13-2002, 01:34 AM

DZEE'S LX - That's not really true. There is, in fact, a difference. A head that has been machined for "loc-wire" gaskets has a circular groove cut around each camber. You must use specialized gaskets from Fel-Pro or TFS that have a metal ring designed into them that protrudes from the head gasket o-ring for each cylinder. That o-ring inserts into the head groove that has been cut to receive it.

O-ringed heads on the other hand are cut with grooves into the head in the same type of manner, yes, but also have a metal wire already pressed into the head. This type of set-up does not use a specialized gasket. You use a standard gasket and the ring that has been placed around each chamber in the head then pinches the metal o-ring for each chamber on the gasket. This gives the gasket extra sealing.

The Loc-wire set-up is known to be a pain in the rear because it can be hard to get the rings in the special gaskets to seat properly into the receiving grooves in the head. And, if not done right or if the groove tolerances are wrong the gasket can fail. So, a lot of folks prefer the o-ringing method verus the loc-wire method - including me.

However, the most ideal method for o-ringing a motor is not to do this to the heads at all, but instead, o-ring the deck surface of the block. This tends to yield the most effective improvement for sealing. Also, with aluminum heads, I've been told the metal is so soft that it is possible for the heat to cause the metal o-ring to "push" up into the metal and loose it's sealing effectiveness.

DZEE'S LX · 02-13-2002, 01:44 AM

Oops, just when I thought I had the quick answer...

I always thought of the lock wire grooves as being O-ringed cause,..... well.... cause they looked like O's.

I stand educated.

gtsr515 · 02-14-2002, 07:19 PM

Thank-you both, I stand "educated".

Thats how i like to see replies, educational, not, argumentative.

02-12-2002, 10:30 PM	#1
gtsr515 Registered Member Join Date: Nov 2001 Location: Sunny, Hot, Sebring, Florida Posts: 725	Loc-wire/o-ringed heads? What is the difference between "Loc-wire" machined heads and "O-ring" machined heads? __________________ Remember...2nd place is 1st place for losers!

02-12-2002, 10:36 PM	#2
DZEE'S LX Registered Member Join Date: Jan 2001 Location: Salt Lake City Posts: 117	Maybe this is a trick question. They are the same. Oringed heads have grooves machined in them to allow use of the Fel Pro "Lock Wire" gaskets. __________________ Spec Service (UHP), BFG G-Force KDW's, Turbo Coupe 3.55 rear w/disks, 73mm calipers, Stg 1 Twisted Wedges, TFS Street Intake, 70mm TB, E cam, Crane 1.7's, Aeromotive FPR, BBK 1 5/8 shorties, elec fan, FMS Al Radiator, Moroso Wires, Kenne Bell Ramair, March pulleys, Race Magnums, 190 lph Walbro, FMS Al Dshaft, D/S loop, MM 4point rollbar, FMS C spngs, strut tower brace, Tokico Illuminas, Prothane bushings, MM Lwr Conrol Arms, KB welded subs, Cervini Mach 1 hood/valence/side skirts/wing/airdam.

02-12-2002, 10:40 PM	#3
gtsr515 Registered Member Join Date: Nov 2001 Location: Sunny, Hot, Sebring, Florida Posts: 725	Whew!!!!!, thought i was loosing it, thats what i thought, there is a post describing them as different here, and thought i'd ask before answering, thank-you. __________________ Remember...2nd place is 1st place for losers!

02-13-2002, 01:34 AM	#4
StangFlyer Founder Join Date: Jun 1995 Location: Michigan Posts: 19,326	DZEE'S LX - That's not really true. There is, in fact, a difference. A head that has been machined for "loc-wire" gaskets has a circular groove cut around each camber. You must use specialized gaskets from Fel-Pro or TFS that have a metal ring designed into them that protrudes from the head gasket o-ring for each cylinder. That o-ring inserts into the head groove that has been cut to receive it. O-ringed heads on the other hand are cut with grooves into the head in the same type of manner, yes, but also have a metal wire already pressed into the head. This type of set-up does not use a specialized gasket. You use a standard gasket and the ring that has been placed around each chamber in the head then pinches the metal o-ring for each chamber on the gasket. This gives the gasket extra sealing. The Loc-wire set-up is known to be a pain in the rear because it can be hard to get the rings in the special gaskets to seat properly into the receiving grooves in the head. And, if not done right or if the groove tolerances are wrong the gasket can fail. So, a lot of folks prefer the o-ringing method verus the loc-wire method - including me. However, the most ideal method for o-ringing a motor is not to do this to the heads at all, but instead, o-ring the deck surface of the block. This tends to yield the most effective improvement for sealing. Also, with aluminum heads, I've been told the metal is so soft that it is possible for the heat to cause the metal o-ring to "push" up into the metal and loose it's sealing effectiveness. __________________ StangFlyer 1991 Mustang GT - Supercharged 377 Stroker 2000 Ford Lightning - Project Lightning Hauler Media Center Gallery - View my member photos

02-13-2002, 01:44 AM	#5
DZEE'S LX Registered Member Join Date: Jan 2001 Location: Salt Lake City Posts: 117	Oops, just when I thought I had the quick answer... I always thought of the lock wire grooves as being O-ringed cause,..... well.... cause they looked like O's. I stand educated. __________________ Spec Service (UHP), BFG G-Force KDW's, Turbo Coupe 3.55 rear w/disks, 73mm calipers, Stg 1 Twisted Wedges, TFS Street Intake, 70mm TB, E cam, Crane 1.7's, Aeromotive FPR, BBK 1 5/8 shorties, elec fan, FMS Al Radiator, Moroso Wires, Kenne Bell Ramair, March pulleys, Race Magnums, 190 lph Walbro, FMS Al Dshaft, D/S loop, MM 4point rollbar, FMS C spngs, strut tower brace, Tokico Illuminas, Prothane bushings, MM Lwr Conrol Arms, KB welded subs, Cervini Mach 1 hood/valence/side skirts/wing/airdam.

02-14-2002, 07:19 PM	#6
gtsr515 Registered Member Join Date: Nov 2001 Location: Sunny, Hot, Sebring, Florida Posts: 725	Thank-you both, I stand "educated". Thats how i like to see replies, educational, not, argumentative. __________________ Remember...2nd place is 1st place for losers!

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