1 Head bolt question & 1 Aluminum head question. [Archive] - FSB Forums

: 1 Head bolt question & 1 Aluminum head question.


Gacknar
08-17-2005, 02:34 PM
1. 302s have lower head bolts that penetrate a water jacket. I am told that the lower head bolts on a 351w are blind (i.e. they do not penetrate a water jacket). A 302s lower head bolts need thread sealer, a 351w's do not.

Is this information correct?

2. Do you need to use anti sieze lubricant on bolts/studs going into an aluminim head. I'm talking about rocker bolt, header bolts, accesory bracket bolts, ect, ect, or is it just on Spark plugs?

JahWarrior
08-17-2005, 03:37 PM
On #2, you should apply anti-seize to any steel bolts going into an aluminum head for sure. Torque them down carefully. Good luck :thumbup

stangmata
08-17-2005, 03:50 PM
2. Do you need to use anti sieze lubricant on bolts/studs going into an aluminim head. I'm talking about rocker bolt, header bolts, accesory bracket bolts, ect, ect, or is it just on Spark plugs?

When I did the 350's heads (AFR), I just put assembly lube on all the bolts. However, the motor will probably never see rain etc.

JahWarrior
08-17-2005, 04:46 PM
The chemical reaction of steel against aluminum is what causes the bolts to seize, not water per say.

Kamster
08-17-2005, 06:56 PM
I reccomend using some type of stuff on any bolt I touch. What I mean by stuff is either loctite or antisieze. I always lube my stud ( that did not come out right, anyway).

The issue JahWarrior speaks of is called Galvanic Corrosion. It is really bad if you mix stainless steels and aluminum. They trade electrons and join themselves together. Not Good. It is also known as "cold welding".

I work in the dairy industry (meaning stainless steel as far as you can see) and we swear by the stuff. I have used it liberally for years on my rigs and have not seen any repercussions from doing so.

If you want to remove it again someday, lube it up!

My 2 cents

81Bronk36
08-17-2005, 11:55 PM
We call it dissimiliar metal corrosion. I would put anti seize on the bolts.




I hope your 350 doesnt get rain on the rocker arm bolts :twak I think thats what valve covers are for. :rofl:

Gacknar
08-18-2005, 10:10 AM
Let me make the question a little more specific.

I'v already installed my rockers, I didnt use any anti seize on the rocker pedistal bolts. Should I remove the bolts, put anti seize on them and reinstall, or is it not worth worying about. Yes I will probably need to remove the rockers at some time and I dont want it to ruin the heads.
http://www.supermotors.org/getfile/218787/fullsize/rockerson.jpg
I'm proply going to remove them and put anti seize on them this weekend anyway, I just want to know that i'm not wasting my time.

Chuck
08-18-2005, 10:18 AM
Every bolt (in general, not just in this case) should be assembled with oil, anti-sieze, threadlocker, or sealant. Most internal engine bolts prefer oil (main and rod studs/bolts). In the case of the rocker bolts, I'd be more likely to use anti-sieze or a low-strength threadlocker (depends on the type of valvetrain you use, and whether or not it can be adjusted at the rocker bolt).

I believe the information you have on the sealant and coolant passages is correct, but couldn't verify for certain until I check my roommate's bare 351W at home. Since that's a nice, pretty 351W you're building, I assume that you're mostly concerned with the 351W bolts, and the 302 information is just for reference/comparison?

Gacknar
08-18-2005, 11:27 AM
(depends on the type of valvetrain you use, and whether or not it can be adjusted at the rocker bolt)They are pedistal mount, the only way to adjust them is to ad shims undere there fulcrums when you first install them.

(I assume that you're mostly concerned with the 351W bolts, and the 302 information is just for reference/comparison?Correct

RLKBOB
08-18-2005, 12:14 PM
Correct, no coolant passages are penetrated on the 351W, just the 302. The instructions that came with my Aluminum heads(Trick Flow) said not to use anti-sieze on any threads, it said just to use a thin coat of motor oil. The guy at the machine shop confirmed this. Apparently anti-sieze on the threads will give you inaccurate torque readings. I did use anti-sieze on the bolt shank to keep that part of the bolt from siezing to the bolt hole.

Gacknar
08-18-2005, 02:19 PM
The instructions that came with my Aluminum heads(Trick Flow) said not to use anti-sieze on any threads, it said just to use a thin coat of motor oil. The guy at the machine shop confirmed this.Should I be woried enuff about it to pull the bolts out and put oil on them now (before the engine is installed)?

If I need to remove the rockers sometime in the future, I dont want the bolts to pull the threads out with them.

The bolts had a verry light coat of machine oil on them when they where installed.
(the kind of light oil that is on all internal engine parts when you buy them.)
Would that be enuff oil to keep them from destroying the threads if I ever need to remove the rocker bolts?

stangmata
08-18-2005, 02:26 PM
I hope your 350 doesnt get rain on the rocker arm bolts :twak I think thats what valve covers are for. :rofl:

:doh0715: :thumbup :drinkbud

Chuck
08-19-2005, 10:05 AM
Should I be woried enuff about it to pull the bolts out and put oil on them now (before the engine is installed)?

If I need to remove the rockers sometime in the future, I dont want the bolts to pull the threads out with them.

The bolts had a verry light coat of machine oil on them when they where installed.
(the kind of light oil that is on all internal engine parts when you buy them.)
Would that be enuff oil to keep them from destroying the threads if I ever need to remove the rocker bolts?
It's not just a matter of corrosion prevention -- the lubrication on the bolt threads has a big effect on the bolt preload. If the threads aren't lubed, then the same torque will not get the amount of preload required on the bolt (takes more friction to turn to the same point, so the torque wrench will read the desired torque sooner). It would be worth doing it to me just to be certain I had the torque right. :duh :thumbup