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258 head suggestions

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irish13jeff View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote irish13jeff Quote  Post ReplyReply Direct Link To This Post Topic: 258 head suggestions
    Posted: Dec/26/2018 at 2:36am
Changing the intake/manifold and head gaskets all stock 258 out of a 83 Cj7,stock aluminum intake 

Intake/Manifold gasket-

 I’ve noticed when looking some of the gasket kits come with two separate gaskets for each and other kits have one gasket for both. Any input on what’s the preferred ( best sealing) gasket kit, any tricks and explain the one or two gasket kit difference?

Head gasket-

Reason for changing-I believe my oil leak was coming from the head gasket. Changed out valve cover gasket and had no signs of oil leaks between the valve cover and head . Oil coming from back side of engine at the head gasket on down. I figured since the intake and manifolds are already off might as well take the head off and correct the suspected leak.

Currently have a felpro 8778pt head gasket on the 258. Any suggestions on a better quality gasket or things to look out for to insure the best seal ? I know the basic stuff , just looking for the out of norm or unique things regarding the 258 . For instance I noticed  one of the head bolts run through a water jacket, should I use thread sealer on that bolt?...that sort of stuff 
 
Thanks for any helpful input..



Edited by irish13jeff - Dec/26/2018 at 5:44am
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FSJunkie View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Dec/26/2018 at 3:23am
Whatever I apply to the threads of one head bolt gets applied to them all so the clamping force of each bolt is equal. AMC's fastener torque specifications say "All torque specifications are dry fits unless otherwise specified." and nowhere does AMC say to oil the threads or heads of the head bolts. That said, I still apply Rectorseal #5 thread sealant to all head bolt threads if any one of them threads into a through-hole (a hole not sealed at the end).

The Fel-Pro blue Permatorque head gaskets seal very well. I cannot say how well they work against extreme combustion pressures created by turbocharging, high compression, or nitrous, but I have personally used them up to 9.2:1 compression with perfect results and I drive my engines hard. It is thicker than the original steel shim gasket used by AMC, but the extra thickness is usually made up by head resurfacing during a rebuild. It is tolerant of imperfect sealing surfaces. Install them dry. No sealant on a Permatorque gasket.

AMC originally did not use an exhaust manifold gasket. I have seen NOS crate engines and engines with less than a couple thousand original miles to know this is true. Only the intake manifold had a gasket. If your engine's had a gasket installed before, you must use a gasket now as the surfaces are no longer flat enough to seal on their own. Few machine shops do a good enough job of resurfacing the head and manifold to provide a gasket-free seal and many will ruin your head or manifold trying. The Fel-Pro composite exhaust gasket will burn out if the engine is run hard, AKA driven above 70 MPH for extended periods of time. A Remflex gasket will seal extremely well so long as the bolt torque is reduced to 20 foot-pounds. Custom cutting a copper or steel shim gasket is an option if you have the means and ability. Regardless, an intake manifold gasket should always be used because it allows for proper spacing of the intake and exhaust manifolds to each other. Also regardless of the gaskets used, bolt torque should be periodically checked and the spefified tightening sequence followed. Those big, long manifolds have a nasty tendency to work bolts loose as they expand and contract a lot with heat cycles. They also like to crack if tightened improperly.

A tip: Less silicone, RTV, or Teflon. More Permatex #2, Copper Coat shellac, and Rectorseal #5, all used sparingly only where needed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Dec/26/2018 at 8:22am
100% agree with everything FSJunkie has said. Been down that path many times.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Dec/27/2018 at 10:38pm
ditto here.

the exhaust manifolds especially seem to warp. I had my local (not very skilled) auto machine shop resurface one on their big head belt sander. while it's not very good for precision head work is great for the exhaust manifold. it was nearly 1/16" curled up. problem solved.

the two-piece exhaust gasket set is aftermarket fix-up for an OEM problem. they are good. follow the instructions, which basically accommodate aligning things before you torque it down. but the gasket set can't perform magic; if it's too warped it will leak.

I had a manifold on a 1981 head that had shrunk so much it wouldn't fit over the studs at each end, in addition to being wildly non-flat! I had to rattail-file the bit ears at the end to fit then pay more care to the fitment. but when parts get this old all sorts of strange things happen.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Dec/28/2018 at 2:35am
I had the manifold for my 232 milled flat when I was fighting exhaust gasket failures. I got so tired of replacing burned out gaskets that I though by milling the manifold flat I could bolt it on with no gasket like AMC did originally.

The manifold only had a couple thouandths of warp yet the machine shop removed 1/8" of material from it. They also milled it at an angle so the manifold no longer bolted pependicular to the head, nor did it line up with the intake manifold where the two manifolds both together under the carbruetor heat riser.

So in other words I paid a guy $120 to ruin my original date coded exhaust manifold...and it still leaked.

I have a Chinese aftermarket new manifold with a Remflex gasket now. The casting was rough so I went to town on it with a grinder for some port and polish work but it works great. It has a metal flange for the exhaust pipe rather than using a doughnut gasket like the original manifold and I prefer that, because the doughnut gasket used to blow out all the time. I prefer the metal flange that never leaks.
'66 Marlin: 327/T10/3.54 Twin Grip
'72 Wagoneer: 360/TH400/3.31
'73 Ambassador: 360/TF727/3.15
'77 Hornet: 232/TF904/2.73
'84 Eagle: 258/TF998/2.35
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaemonForce Quote  Post ReplyReply Direct Link To This Post Posted: Dec/28/2018 at 2:42pm
$120 to obliterate a rare 258 manifold? I would have told him to pound sand. That's exactly the kind of work that I get from a local machine shop that has no business ever touching exhaust and they are $$$! Specialize in SBC but any time I bring anything AMC/Jeep, it's a joke. Whatever work you do, make sure you verify it yourself. There are WAY too many screwballs doing bottom quality work at top dollar price.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Dec/28/2018 at 5:13pm
Actually I think it was $75 to the machine shop, but the new manifold cost $200. So at the end of the day, their screw-up cost me close to $300.

That's nothing compared to some of the things I've paid machine shops to do that came back to me completely botched up that I had to redo myself.

Which is why I do everything myself that I can.
'66 Marlin: 327/T10/3.54 Twin Grip
'72 Wagoneer: 360/TH400/3.31
'73 Ambassador: 360/TF727/3.15
'77 Hornet: 232/TF904/2.73
'84 Eagle: 258/TF998/2.35
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Post Options Post Options   Thanks (0) Thanks(0)   Quote irish13jeff Quote  Post ReplyReply Direct Link To This Post Posted: Jan/04/2019 at 2:04am
What’s the thoughts on re-mounting both of the manifolds to the head before the reinstalling of the head? Going to use all thread to center up the gasket and head 

Edited by irish13jeff - Jan/04/2019 at 2:06am
Please don't tell my parents I'm a truck driver..... They think I'm a piano player in a whore house...

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: Jan/04/2019 at 6:57am
That's a whole lotta extra weight on an already heavy part. The head weighs 78lbs on it's own. I would only do it if I was using an engine crane.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pdok Quote  Post ReplyReply Direct Link To This Post Posted: Jan/04/2019 at 7:52am
It's just not that hard to put the head on, and keep the gasket lined up. I've done it by myself, no issues. Didn't even need anything to align, but you can just use a bolt from the top if you're worried about the gasket moving.

Just put the gasket down on the block, a bolt through the front corner of the head. Make sure the bolt finds the right hole, then just line the rear up with the head right before you set it down. If the holes are a tiny bit off, then you can just lift the head and nudge it a little.

I can't imagine having the extra off-center weight of either manifold to deal with.

The Remflex gaskets are simply outstanding. Before installation, they need careful handling not to bend them, but if you properly install them, they can easily handle two surfaces that are not perfectly flat. Then again, so can the metallic style exhaust gaskets. Mine are a little warped because it's a header, and no leaks on the Omix or Felpro silvery gasket, can't remember what it was. I do recheck bolt torque periodically though.

For my header collectors, I had to double up on Remflex gaskets because the angles were screwed up after I swapped to the 4.0 head.  Even with one side of the collector practically crushing the Remflex, it has stayed sealed up for the past 8 months when the performance parts store gasket lasted about a week.
76 Grem X 258/904,4.0 head/MPFI, Comp X250H cam, Hughes springs, Clifford header, serpentine swap.
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