Head gasket question

thethee

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Once again looking for some advice.

One of the items still on my list is replacing the valve stem seals on my 440. Not sure if they are that bad but if they are like the rest of the seals on the engine they are most likely rock solid by now and the new seals came in the engine kit so might as well.

This had me thinking, as the head gaskets were also in my Fel Pro kit, would it be wise to also change those? I'm fairly certain the ones in there now are original to the engine. I have little experience with head gaskets so I'm curious, do these deteriorate over time or are they good up until they fail? Right now the engine shows no signs of head gasket problems.
 

MEV

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They are not re-usable. Some mls designs are reusable, yours are not mls.
 

thethee

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Heads are still on the engine so no harm done yet. But should I replace them or just leave em be?
 

mikedrini

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I agree with @MEV and when I changed mine out, I went with Cometic MLS head gaskets and they are fantastic. No leaks, reusable and in my opinion worth the price. With that being said, if you aren't looking to impact compression from what you have currently, the Fel Pro's will do the job.
 

detmatt

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If you are not pulling your heads for any other reason I would just leave them.
 

thethee

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For future reference, are the stock cylinder head bolts reusable or are they torque to yield?
 

68PK21 440.6bbl

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Without pictures we have no overall idea at the condition of your engine, but with a little Colombo work I see "She is in pretty rough shape but I love it. They are a pretty rare sight this side of the Atlantic" soo... do a compression test and if all is level/good for the mileage leave it be and cruise with it, opening the heads on a "pretty rough shape" car/motor is just opening a can of worms.

Hey but heck it's your car go for it, then it will be bore/cam/headers/sidepipes/EFI... the sky's the limit WooHoo!


.
 

Big_John

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Once again looking for some advice.

One of the items still on my list is replacing the valve stem seals on my 440. Not sure if they are that bad but if they are like the rest of the seals on the engine they are most likely rock solid by now and the new seals came in the engine kit so might as well.

This had me thinking, as the head gaskets were also in my Fel Pro kit, would it be wise to also change those? I'm fairly certain the ones in there now are original to the engine. I have little experience with head gaskets so I'm curious, do these deteriorate over time or are they good up until they fail? Right now the engine shows no signs of head gasket problems.
This is a "If it ain't broke, don't fix it" scenario.

Unless you are either losing compression, or leaking antifreeze into the combustion chamber, there's no reason to change head gaskets. If that's happening, there's a real good chance it's more than just a bad gasket, but we won't talk about that if it's not a problem.

To change it for the sake of changing it might even bring on new issues.

In other words, leave it alone.
 

mikedrini

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This is a "If it ain't broke, don't fix it" scenario.

Unless you are either losing compression, or leaking antifreeze into the combustion chamber, there's no reason to change head gaskets. If that's happening, there's a real good chance it's more than just a bad gasket, but we won't talk about that if it's not a problem.

To change it for the sake of changing it might even bring on new issues.

In other words, leave it alone.

It's like scraping off the caked-on mud and gunk from the undercarriage to clean it up-when in reality it was protecting the frame and all you did was expose aged metal to rust. Or when someone adds an oil additive and it dissolves the barrier that was built up preventing leaks.
 

thethee

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Thanks guys, much appreciated. I'm basically using this car to learn my way around an engine and what not. Your advice sure helps a lot with that. I will leave the head gaskets well enough alone.
 

bigmoparjeff

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One big reason not to change the head gaskets is that it will lower your compression from the already too low 8.2:1, down into the high 7's. It's very, very rare for original big block Mopar head gaskets to fail.

You are likely due for valve stem seals. They are a bit of a pain to do on that engine, but I wouldn't call it horrible to do. I did the ones on my parent's '78 NYB decades ago, outside in the driveway.

Jeff
 

thethee

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Thanks Jeff, I hadn't even thought about the compression ratio, now I will definitely leave it be.

About the stem seals, just looking for a connector for my compressor that bolts into the spark plug hole and I should be good to go. Probably won't start with this for another couple weeks though.
 

65CopCar

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Head bolts can be reused, but they need to be inspected. Never sand/bead blast or use a rotary wire wheel on the threads. Big no-no. A good solvent and/or ultrasonic clean with a very light hand wire brush is ok. If any deficiencies are found , they need to be replaced.

Remember that proper torque is generally 70% of proof yield. That means theoretically if the bolt is 30% overtorqued, it would be stretched to the point that it begins to lose elasticity and therefore no longer have proper clamping force. You don't have a large torque margin to work with. And lubrication on the threads and under the bolt head has a huge impact on proper bolt torquing. I believe that the specs in the FSM are with a light amount of oil on thread and under the head bolt.
 

rapidtrans

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If valve seals are bad you’ll know. You’ll notice puff of blue smoke at start up and you will loose oil at highway speeds. If these conditions don’t exist I wouldn’t bother till I pullin engine apart till necessary.
 

Mr C

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I did my valve guide seals without removing the heads...takes an afternoon.
That's what I'd do.
 

70bigblockdodge

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If the cooling system was very rusty (took a lot of flushing to clean it out) the original steel shim gaskets could have some potential weak spots. If cooling system is or always was in decent shape I would just leave them alone. There is a lot of clamping and stability in the 5 bolts around each cylinder/17 head bolt arrangement.
 

69PHOENIX

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G'Day,
In My Humble Opinion, Unless There is a Problem Leave it Alone.
In My Many Years of Experience, I have Found that Whenever I Open a Can of Worms it Can Often Turn Out to Be Full of Snakes!
LOL
Regards Tony.M
 

thethee

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G'Day,
In My Humble Opinion, Unless There is a Problem Leave it Alone.
In My Many Years of Experience, I have Found that Whenever I Open a Can of Worms it Can Often Turn Out to Be Full of Snakes!
LOL
Regards Tony.M
That's how I went from "fixing an oil leak" to "changing the timing chain" just a couple of weeks ago. Glad that I did though.
 
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