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sobelsaint Samba Member
Joined: May 29, 2011 Posts: 83 Location: San Diego
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Posted: Tue Feb 06, 2018 3:32 pm Post subject: Intake Manifold Gasket Leak |
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I changed the intake manifold gasket twice and it still has a leak. First I sanded the manifold flat and used a new gasket and had no luck. I also used some Curil T on the second try and still had no luck. I need to know what kind of gaskets you guys are using that work best before I try this again. Thanks for the help. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Feb 06, 2018 3:36 pm Post subject: Re: Intake Manifold Gasket Leak |
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What are you using?
I use Berg paper gaskets and never had a leak.
_________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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sobelsaint Samba Member
Joined: May 29, 2011 Posts: 83 Location: San Diego
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Posted: Tue Feb 06, 2018 3:40 pm Post subject: Re: Intake Manifold Gasket Leak |
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I used the empi pack that my local shop sells. One thing i noticed is the first time I did it the leak was coming from the cylinder 3 and the second time the leak was coming from cylinder 4. I noticed because the idle mixture was not working properly. Should they be tightened down really hard or just enough? wondering if the head needs to be sanded or smoothed out somehow. I wonder if the berg gaskets are thicker than empi. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Feb 06, 2018 4:02 pm Post subject: Re: Intake Manifold Gasket Leak |
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The nuts should be snug... not "animal tight".
You can stack 2 gaskets if needed. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Tue Feb 06, 2018 7:07 pm Post subject: Re: Intake Manifold Gasket Leak |
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Make sure the manifold will sit in place with no gasket.
If it isn't sealing then the manifold must be hanging up on some edge, or mating surface on the head is FAR from flat. |
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sobelsaint Samba Member
Joined: May 29, 2011 Posts: 83 Location: San Diego
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Posted: Wed Feb 07, 2018 10:11 am Post subject: Re: Intake Manifold Gasket Leak |
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Is there a way to flatten the surface on the head? |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Wed Feb 07, 2018 10:14 am Post subject: Re: Intake Manifold Gasket Leak |
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Yes, but you'd have to remove it. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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74 Thing Samba Member
Joined: September 02, 2004 Posts: 7369
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Posted: Wed Feb 07, 2018 10:38 am Post subject: Re: Intake Manifold Gasket Leak |
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Get a small straight edge and place it on the head mating surface.
I am betting it is not your head surface that is causing the problem. I am assuming that either the manifold is interfering with engine tin or the carb is hitting the shroud, or you are not getting enough torque on the wrench when tightening the manifolds. What kind of nuts are you using and what tools are you using to tighten the nuts.
These nuts are nice to use since the socket size required is only 10mm instead of 13mm. Using these with some long extensions and a swivel socket make it a lot easier to install.
http://vwparts.aircooled.net/ACN-Flanged-Racing-Intake-and-Exhaust-Nut-8-x-10mm-p/acn-nuts.htm |
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mcmscott Samba Member
Joined: March 12, 2010 Posts: 4848 Location: sanger ca
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2714 Location: Hamble, Hampshire, UK
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Posted: Wed Feb 07, 2018 1:13 pm Post subject: Re: Intake Manifold Gasket Leak |
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Try making sure you tighten the nuts down at the same rate so the manifold does not lean over to one side or the other on the way down.
If you are using the metal gaskets you can manage to crush one side of the gasket, then have the manifold rock away from the crushed area as you torque up the other nut, leaving a gap.
Been there done that , have the T-shirt.
Also check it is not trapping tinware under the manifold on the way down. _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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fivelugshortaxle Samba Member
Joined: May 13, 2011 Posts: 4254 Location: Aumsville, Oregon
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Posted: Wed Feb 07, 2018 6:55 pm Post subject: Re: Intake Manifold Gasket Leak |
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What heads? I was running CB's Super pros and the ports are very big....which left a very thin ara between the ports. Needless to say I kept developing vacuum leaks. Spoke with David at CB and he recommended Loctite 518 flange sealant and no gasket....just metal to metal. He said most of the guys he knew did that with big port heads. I did it and zero intake leaks. _________________ Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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fivelugshortaxle Samba Member
Joined: May 13, 2011 Posts: 4254 Location: Aumsville, Oregon
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Posted: Wed Feb 07, 2018 6:56 pm Post subject: Re: Intake Manifold Gasket Leak |
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oops...just saw mcmscott's post to you. Ditto to that. 518 works great. _________________ Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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chrisflstf Samba Member
Joined: February 10, 2004 Posts: 3412 Location: San Diego
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Posted: Wed Feb 07, 2018 7:00 pm Post subject: Re: Intake Manifold Gasket Leak |
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Loctite 518 is only good to 300f. Heads run hotter than that. |
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jbbugs Samba Member
Joined: September 16, 2002 Posts: 2150 Location: Behind the wheel
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Posted: Wed Feb 07, 2018 8:32 pm Post subject: Re: Intake Manifold Gasket Leak |
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I assume it's Probably not much fun scraping it off the head when needed . _________________ Drag bus! http://www.youtube.com/watch?v=s2MOVmKdhX4
69 OG paint Transporter
73' Super Beetle Champcar Endurance Roadracer
Patina my ass, that's a Rust Bucket! |
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jason Samba Member
Joined: August 07, 2002 Posts: 3443 Location: Garage
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Posted: Wed Feb 07, 2018 8:38 pm Post subject: Re: Intake Manifold Gasket Leak |
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Comes off with spirits. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Wed Feb 07, 2018 9:39 pm Post subject: Re: Intake Manifold Gasket Leak |
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chrisflstf wrote: |
Loctite 518 is only good to 300f. Heads run hotter than that. |
yes and no. It does lose a lot of strength at 300f but, it will survive that continuously without really any change for a very long time.
A lot of epoxys or sealants that say they are "good" to 400 or 500F will turn to cheeze eventually if they live at 300f in the presence of gasoline or oil vapor. Loses 60% of it's strength yes, but still stronger than silicone, and it's only sealing air pressure not hundreds of PSI or something.
How "STRONG" is silicone?
Also, the intake flange won't be as hot as the spark plug.
300 is possible but 250 would be normal.
The 515 sealant has a higher temp rating, but really the only difference is the 518 has something in it to make it more flexible.........and, ah, maybe the ability to flex is figured into the temp rating somehow...because it seems to me they both work the same if you use them for the same job.
So, the 300F rating is an ok guideline but in this case, it's OK. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Wed Feb 07, 2018 10:56 pm Post subject: Re: Intake Manifold Gasket Leak |
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modok wrote: |
chrisflstf wrote: |
Loctite 518 is only good to 300f. Heads run hotter than that. |
yes and no. It does lose a lot of strength at 300f but, it will survive that continuously without really any change for a very long time.
A lot of epoxys or sealants that say they are "good" to 400 or 500F will turn to cheeze eventually if they live at 300f in the presence of gasoline or oil vapor. Loses 60% of it's strength yes, but still stronger than silicone, and it's only sealing air pressure not hundreds of PSI or something.
How "STRONG" is silicone?
Also, the intake flange won't be as hot as the spark plug.
300 is possible but 250 would be normal.
The 515 sealant has a higher temp rating, but really the only difference is the 518 has something in it to make it more flexible.........and, ah, maybe the ability to flex is figured into the temp rating somehow...because it seems to me they both work the same if you use them for the same job.
So, the 300F rating is an ok guideline but in this case, it's OK. |
How strong is silicone?......VERY.
It also depends on the silicone. With several thousand formulations.....silicone is not just silicone.
Also....it depends on how thick you apply it. Thicker is weaker with any sealant. Too thin is just too thin.
A thin film of silicone on gaskets.....only has maybe .001" of its thickness or face ....actually accessible to the inside of the manifold where fuel vapor is. Even though most good silicones have only intermittent resistance to fuels.....that resistance is also at around 500+ F.... and it takes many hundreds of hours of fuel contact to seep laterally through the silicone film.
It also depends on the durometer/hardness of the silicone you use. Some are quite hard....some are quite soft. Ray |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Wed Feb 07, 2018 11:21 pm Post subject: Re: Intake Manifold Gasket Leak |
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But in what way? It has a strong smell?
In this case.... it would be some combination of compressive modulus compared to sheer strength, which isn't so easy to imagine.
It's far easier to just say that it works, because it does.
Chances are under the hood of his car is an example of it working right now. The loctite family of sealants is used more often in situations that benefit from being more rigid, I think this counts as one of them. |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Thu Feb 08, 2018 2:45 am Post subject: Re: Intake Manifold Gasket Leak |
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chrisflstf wrote: |
Loctite 518 is only good to 300f. Heads run hotter than that. |
But the intake tract runs quite a bit cooler, constant outside air running through it. |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31266 Location: Hot Arizona
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Posted: Thu Feb 08, 2018 8:47 am Post subject: Re: Intake Manifold Gasket Leak |
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Glenn wrote: |
What are you using?
I use Berg paper gaskets and never had a leak. |
I use the metal dual-port gaskets. These were included in my engine gasket set.
_________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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