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#1
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Water neck sealing -- what's the best way?
Hey tribe. Thanks again for the excellent help I got on my last issue, the alternator / wiring PITA. Very helpful. (All of you were right, it's not the alternator.)
I'm getting some leakage from the water neck base of my '71 Formula 400, so I'm replacing it. It's a paper gasket, not the o-ring kind. I know leaks on these necks can be both common and persistent... what's you guys' take on the best way to seal these? Should there be gasket sealant between the gasket and manifold, water neck and gasket, or both? Should I put silicone on the bolt threads? Finally -- is there a certain torque value for these bolts, or just get it good and tight? Again, my thanks for all the expertise on here.
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"A MAN IS ONLY AS OLD AS THE WOMAN HE FEELS." -- Groucho Marx |
#2
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Your best bet is to go to the parts store and get a can of a sealer called "The Right Stuff". It's the best there is, hands down. It is leaps and bounds better than any other RTV out there. I use it without a gasket, but you can use one if you like. If your water neck is pitted, I also recommend grabbing a new one. They've gotten cheap for new ones, I think RockAuto has them for $10-15 or so. Hope this helps!
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#3
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I had to have the mating surface milled a little on the intake itself. Just wouldn't seal even with new water neck. Right stuff is good product so try that 1st.
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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
#4
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if you ever have to change a thermostat DONT use the right stuff!There is better sealants.I use Hylomar on both sides of the gasket.Take the fixture and put a piece of sandpaper on a really flat surface and run it on the paper until flat.Try to clean the intake side real good.Should NOT take much.Good luck with your project.Tom
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The Following 2 Users Say Thank You to tom s For This Useful Post: | ||
#5
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i have used permatex ultra black or grey on most gaskets for these engine, never had a
stock water neck leak or other areas leak. i usually use the supplied gaskets too with just a thin coat of the permatex to help seal any pitting or imperfections. but i also use the chrome O-ring type water necks on 2 of my cars, they work great & have never leaked, beauty of that style neck is you can remove it multiple times without hassle of cleaning old gaskets or sealers & when the O ring gets too old & flat you just buy a new one for a dollar & its like new. torque rating for most 3/8 bolts like this is about 25-30ft/lbs. i snug them up after a few heat cycles & check every year or 2 for tightness. same with most other bolts, especially header bolts, cant just tighten them once & forget it then blame the headers or water neck etc for leaks. |
#6
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Okay, thanks. Yeah, I'm replacing the neck, should have specified that at the gitgo. Of course the rear bolt broke off at the head. Once I get it drilled out, what are good replacement bolts? Stainless steel?
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"A MAN IS ONLY AS OLD AS THE WOMAN HE FEELS." -- Groucho Marx |
#7
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#8
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I would not use stainless. They can gall quite easily.
If you don't have the factory bolts available, just use good zinc plated bolts from your local hardware store. You can also go all the way to cadmium plated grade 8 bolts, but they are not necessary for such a low torque situation. Hope that helps.
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Eric "Todd" Mitten '74 Bonneville 4dr Sedan (455/TH400/2.93 open) '72 LeMans GT (455/M-13/3.23 [8.5"] posi) '71 GTO Hardtop (400/TH400/3.07 12 bolt posi) ‘71 GTO Convertible (455HO/TH400/3.23 posi) '67 GTO Coupe (455/ST-10/2.93 posi) '67 Tempest Wagon (428/TH400/2.56 posi) Deuteronomy 8:3 |
#9
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Not saying it’s the best way but my water neck always seemed to seep eventually no matter what I did. Sometimes after a few years and sometimes not so long. Years ago my dad bought me a water neck like this….
https://www.jegs.com/i/JEGS/555/511301/10002/-1 …..thinking it would solve my issue. I left it in a box for years thinking I would have better luck with my original water neck. A couple years ago I think I decided to try it while replacing my thermostat and I’ve not had a single drop escape since. For what it’s worth.
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1977 Trans Am 400/4speed (swap) Brian |
#10
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Yes. If the mating surface on your manifold isn't all pitted up, it's hard to be an O-ring for sealing, IMO.
John
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70 TA RAIII M20 05D 70 TA RAIII M20 06B |
#11
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Flatten the sealing surface of the neck with a file. I've even rubbed them around in circles on concrete to do this. Then DO NOT over-tighten it when reinstalling. That's how they get warped in the first place.
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'69 GTO Convertible - Acquired October 2020. An all original project car. Restomod is underway PROJECT THREAD '83 Chevy Choo Choo SS El Camino - LT1 350/4L60e, Owned for 30 Years, completed 2nd restomod in 2018 PHOTO 2019 BMW 440ix - Twin turbo I6, 8spd auto. PHOTO '55 Chevy Bel Air Sport Coupe - Ram Jet 350 / T56 Magnum 6spd, Restomod Completed Sept. 2012, Sold Sept. 2021 PHOTO |
The Following User Says Thank You to roger1 For This Useful Post: | ||
#12
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I have pretty good luck lapping the bottom of the neck on a surface plate and using a file on the intake.
I did contemplate trying to figure out a way to mount the neck in the lathe and cut an o-ring groove but never came up with anything. If anyone has any ideas on fixturing a neck in a lathe or on a rotary table on a mill .. I'd like to hear it. I'd go the o-ring route in a heartbeat if they made one non-chrome and identical to the OEM piece.
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I'm World's Best Hyperbolist !! |
#13
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Quote:
if originality is not a concern, the O-ring necks are great & for $10-15 are well worth it, with all the aluminum & chrome parts people use on non original look engines, these look & work great. |
#14
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I'd use grade 5 because they would be less likely to twist off if they get any corrosion. Plus, I'm not aware of the factory ever using grade 3 bolts anywhere on automobiles.
__________________
'69 GTO Convertible - Acquired October 2020. An all original project car. Restomod is underway PROJECT THREAD '83 Chevy Choo Choo SS El Camino - LT1 350/4L60e, Owned for 30 Years, completed 2nd restomod in 2018 PHOTO 2019 BMW 440ix - Twin turbo I6, 8spd auto. PHOTO '55 Chevy Bel Air Sport Coupe - Ram Jet 350 / T56 Magnum 6spd, Restomod Completed Sept. 2012, Sold Sept. 2021 PHOTO |
#15
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sorry, meant grade 5. the bolts with 3 dashes on them... was early in the morning so confused the 3 dashes with grade 3.
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#16
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Okay thanks, one other thing please -- what's your preferred spray-on for loosening broken bolts? A couple car guys I know say WD-40 isn't that effective, one recommended PB Blaster aka B'laster. I'm going to use a bolt extractor on it but want to give it an overnight soak in something that will hopefully loosen it a little. It's the original manifold so of course it's pretty frozen in there.
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"A MAN IS ONLY AS OLD AS THE WOMAN HE FEELS." -- Groucho Marx |
#17
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As others have mentioned lapping the housing is important. The aluminum deforms over the years.
I have used an old truck mirror and a piece of 400 grit wet dry sandpaper for years. Get the sandpaper wet and make circles on the sandpaper. Be careful to always keep the gasket surface flat to the sandpaper.
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If it breaks. I didn't want it in the first place. _____________________________________________ 69 GTO \ 72 FIREBIRD \ 1/2 OF A 64 GTO \ 70 JAVELIN \ 52 FORD PU \ 51 GMC PU \ 29 FORD PU \ 85 ALFA ROMEO SPYDER \ A HANDFUL OF ODD DUCATI'S \ 88 S10 LT1 BLAZER & MY DAILY DRIVER 67 SUBURBAN. |
#18
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Quote:
for heavily corroded/rusted/seized bolts, none of those will do much good... heat is the best option & will get out almost any stuck bolt/nut if used right. the idea is to heat/expand the outer area the bolt goes in to, then loosen the bolt while that area is still hot. if that doesnt work or you cant get to the outer area to apply enough heat, the bolt itself can be heated, to red hot if possible, then let cool before removing, the bolt expands when hot breaking free the rust bond, then when everything has cooled it should come out easier. sometimes a few times are needed. |
#19
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Quote:
__________________
"A MAN IS ONLY AS OLD AS THE WOMAN HE FEELS." -- Groucho Marx |
#20
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if theres no leaks & the air cleaner is on, using a propane torch should not be an issue, just use common sense & direct the flame away from the carb & be sure theres adequate ventilation... always a good idea to have a fire extinguisher near by in the garage too regardless of using a torch.
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