Head install

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gumper

gumper

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Putting my freshly ported heads back on the 408 today. Using ARP bolts. Which bolts need sealant? Which ones should I use ARP lube on? I plan on torquing them 45-65-95 as well.
 
The head bolts to the block do not need sealant.

Only the end exhaust manifold bolts/studs need sealant to keep the coolant from leaking.
 
The edelbrock heads don't need the exhaust bolts sealed. Just lube the head bolts then?
 
I have put sealant on every head bolt I have ever put in an engine and never had issues. Whether they go into the water jacket or not. People will argue the point, but it is something I have always done. I have seen head bolts rust into the block.....whether blind holes or open to the water jacket and break when loosened. A small amount of RTV on head bolt threads will act the same as lubricant while torqueing, seal open holes into the water jacket and keep the head bolts from breaking upon removal. It's a win, win, win.....I don't really care who argues what. That's been my personal experience as a mechanic doing it well over thirty years. It WORKS. End of story.
 
I just lubed them all with ultra torque, so we'll see what happens. I also remember why I hate A body headers. Always in the way.
 
I've used thread sealant on studs on SBCs. The guy who assembled this 408 for me used sealer on most of the head bolts, so I figured I'd ask here what it needs. What I get for having a chevy guy put a mopar together.
 
How many of you guys go back and re torque the heads after a few heat cycles? I honestly never have. This especially would suck since the headers are always in the way as I'm sure you all know. Much profanity was utilized today while torquing them the 3 rounds.
 
I always retorque steel shim gaskets. Composition gaskets do not require it.
 
I always re-torque any head, especially with AL heads.

As for thread lube, something maybe a good idea for rust and sticking (that IS a crappy situation when you snap off a head bolt deep in the block hole), but realize that thread lubes modify the actually clamping pressure of the bolt relative to the torque on the bolt head. The torque is just an indirect way of measuring clamping force and if you modify it, then your clamping force may be too high; it may not matter so much on iron heads but I personally am leary on AL heads. It also does not so much matter on the newer torque-to-yield bolts, but it does on the older non-yield head bolts. That is the reason for some assembly instruction to be for clean, dry threads.

At least with the ARP lube, they give you info to modify the torque. What I don't know is how much something like RTV changes the torque-to-pressure relationship.
 
I cannot say I disagree, BUT how much are you really changing anything? I think that's getting pretty nit picky in the grand scheme of things......not YOU personally, just breaking it down that far. I just don't think it makes that BIG a difference.

That said, use what makes you comfortable and works for YOU.

Having been a line tech in LOTS of dealerships over the years, I can attest to how finikey stretch to yield head bolts are. They WILL break off very easily upon removal if everything has not gone well.......and under what circumstances would you be pulling a head if things are going well? Fact is, I've seen a ton of them break. They are bad about it. I adopted my method early on and it worked for ME a lot of years as an engine tech. Say what you will about it, but it WORKS.

nm9stheham said:
I always re-torque any head, especially with AL heads.

As for thread lube, something maybe a good idea for rust and sticking (that IS a crappy situation when you snap off a head bolt deep in the block hole), but realize that thread lubes modify the actually clamping pressure of the bolt relative to the torque on the bolt head. The torque is just an indirect way of measuring clamping force and if you modify it, then your clamping force may be too high; it may not matter so much on iron heads but I personally am leary on AL heads. It also does not so much matter on the newer torque-to-yield bolts, but it does on the older non-yield head bolts. That is the reason for some assembly instruction to be for clean, dry threads.

At least with the ARP lube, they give you info to modify the torque. What I don't know is how much something like RTV changes the torque-to-pressure relationship.
Click to expand...
 
RustyRatRod said:
Having been a line tech in LOTS of dealerships over the years, I can attest to how finikey stretch to yield head bolts are. They WILL break off very easily upon removal if everything has not gone well.......and under what circumstances would you be pulling a head if things are going well? Fact is, I've seen a ton of them break. They are bad about it. I adopted my method early on and it worked for ME a lot of years as an engine tech. Say what you will about it, but it WORKS.
Click to expand...
Yeah I know; I was trying to say how the thread lubes don't make much difference in the clamping pressure in torque-to-yield bolts, not that lubing those won' t make a difference in their removal. For THOSE, I don't see an issue with lubes; they are the only ones I have ever broken.
 
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