Thread: Exhaust gasket zzp downpipe leak

Results 1 to 9 of 9
  1. #1 Exhaust gasket zzp downpipe leak 
    SE Level Member Tater85's Avatar
    Join Date
    Dec 2017
    Location
    Idaho
    Posts
    22
    Thanks (Received)
    1
    Likes (Received)
    4
    Dislikes (Received)
    0
    I have tried 3 different exhaust flange gaskets all new felpro metal design with a new 3" zzp catted down pipe. I still have a leak heard only under throttle. The last time I added some copper rtv on the crush part of both sides. Flanges look good no cracks. Seems like the gasket is just to small diameter to catch 3" flange.

    Any body have any experience with this and have any advice?
    Reply With Quote  
     

  2. #2 Re: Exhaust gasket zzp downpipe leak 
    GXP Level Member GTPpower's Avatar
    Join Date
    May 2008
    Location
    Schuyler, NE
    Posts
    2,972
    Thanks (Received)
    8
    Likes (Received)
    23
    Dislikes (Received)
    0
    A lot of the time, they do a bad job welding and warp the flange. So, you have to either straighten it, or apply a liberal amount of copper rtv to seal it.


    2001 GTP Drag Car - XPZ, Tischler heads, Upsidedown M90 IC'd, e85, Gen V, 2.3 w/ 5%OD
    2005 F350 6.0 - studded, deleted, tuned
    2001 GTP - cam, headers, nitrous, stock trans - 11.83 @ 116 <$2k in mods - sold
    Reply With Quote  
     

  3. #3 Re: Exhaust gasket zzp downpipe leak 
    SE Level Member Tater85's Avatar
    Join Date
    Dec 2017
    Location
    Idaho
    Posts
    22
    Thanks (Received)
    1
    Likes (Received)
    4
    Dislikes (Received)
    0
    I pulled it off again and used a mahle gasket, a bit different style. This time I checked the flanges for straightness. The pipe flange was warped so I set it on some wood and beat the ear back down until it was straight with no daylight on a straight edge. It still leaks but only at higher pressures. Gonna try some thin wire with same style gasket and some copper rtv and thin ss safety wire if it is warped again. Only torquing to 26 ft lbf according to gm manual. I still feel like there is very little surface width of the crush part of the gasket to seal it due to the 3" pipe size.
    Reply With Quote  
     

  4. #4 Re: Exhaust gasket zzp downpipe leak 
    GTP Level Member FriboRage's Avatar
    Join Date
    Jun 2009
    Location
    Pennsylvania
    Posts
    915
    Thanks (Received)
    8
    Likes (Received)
    13
    Dislikes (Received)
    0
    Hey I realize this thread is pretty old, but this is a problem I’ve been living with for years.

    Ever since I first put my zzp downpipe on uears ago it’s been ticking. I’ve tried different gaskets, I’ve tried rtv, I’ve taken it down and reseated it a few times. Always ticking, never gets any better.

    I can hear it when it’s at high idle on a cold start, and under medium or higher throttle. The last time I took it down I could see the thin little carbon trail.

    Zzp just always tells me it’s impossible, their pipes have no known defects, and I must be installing it wrong or using incorrect gaskets.

    I never heard anyone talk about warped flanges from welding before so that really interests me... you just used a straight edge to look for light, and actually found it was warped like that? Then hammered it back to shape? Almost 6 months later now, has it stayed fixed?

    I’ll have time to take the pipe again since I try to keep it garaged when there’s salt on the roads.
    Reply With Quote  
     

  5. #5 Re: Exhaust gasket zzp downpipe leak 
    GrandPrix Junkie SgtMarshal's Avatar
    Join Date
    Feb 2012
    Location
    Kemmerer, Wyoming
    Posts
    4,701
    Thanks (Received)
    10
    Likes (Received)
    25
    Dislikes (Received)
    0
    zzp doesn't tell the truth all the time. I know a guy who bought a downpipe from them and the mating surface wasn't completely flat so it wouldn't seal.

    are you sure you aren't getting lifter tick?
    Reply With Quote  
     

  6. #6 Re: Exhaust gasket zzp downpipe leak 
    GTP Level Member FriboRage's Avatar
    Join Date
    Jun 2009
    Location
    Pennsylvania
    Posts
    915
    Thanks (Received)
    8
    Likes (Received)
    13
    Dislikes (Received)
    0
    Yeah, that’s kinda what I was implying, that they’re just blowing me off. I’ve asked them a few times and they don’t even wanna talk about it. Just “nope they don’t leak, it’s you, okay bye” lol.

    But as for the lifter tick, I was thinking that too, so when I did my LIM gaskets last year I replaced all 12 lifters with new ls7 lifters from intense, and the tick is unchanged.. plus I can see carbon tracks on the flange when I take the pipe down.

    I never attempted to check the flange for straightness, though. The idea never really occurred to me until now, so I’ll put that on the to-do list.
    Reply With Quote  
     

  7. #7 Re: Exhaust gasket zzp downpipe leak 
    GrandPrix Junkie SgtMarshal's Avatar
    Join Date
    Feb 2012
    Location
    Kemmerer, Wyoming
    Posts
    4,701
    Thanks (Received)
    10
    Likes (Received)
    25
    Dislikes (Received)
    0
    with LS7 lifters I guarantee some of it is lifter tick
    Reply With Quote  
     

  8. #8 Re: Exhaust gasket zzp downpipe leak 
    SE Level Member Tater85's Avatar
    Join Date
    Dec 2017
    Location
    Idaho
    Posts
    22
    Thanks (Received)
    1
    Likes (Received)
    4
    Dislikes (Received)
    0
    Mine still leaks but its better than it has ever been. I am not happy about it at all just have too many other things going on to mess with it anymore. Last time I used thin wire rtv and new gasket. The wire seemed to make a difference.
    Reply With Quote  
     

  9. Likes superdev liked this post
  10. #9 Re: Exhaust gasket zzp downpipe leak 
    GT Level Member
    Join Date
    Mar 2018
    Location
    NY
    Posts
    172
    Thanks (Received)
    2
    Likes (Received)
    3
    Dislikes (Received)
    0
    Maybe its the flex section itself that's leaking. The flex on the SLP headers were known for having a ticking sound under throttle. I've heard the same for some of the ZZP flexpipes as well. The fix was to put some header wrap around it. Been living with mine wrapped up for well over 10 years lol. A good way to find exactly where your leak is coming from is to do the seafoam test.
    Reply With Quote  
     

Similar Threads

  1. Rear Exhaust manifold to downpipe gasket
    By bigdan002001 in forum 3.8L V6 Naturally Aspirated (L36)(L26)
    Replies: 2
    Last Post: 09-15-2016, 09:22 AM
  2. Exhaust gasket leak; which parts do I need?
    By Centauri in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 4
    Last Post: 10-23-2014, 05:27 PM
  3. Downpipe Gasket???
    By donkason in forum General Tech Discussion
    Replies: 5
    Last Post: 05-08-2011, 08:35 AM
  4. Is it safe to drive with an Header exhaust leak or any exhaust leak??
    By GOTIT4CHEAP16 in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 4
    Last Post: 01-11-2011, 05:45 PM
  5. Where to get a S&S header downpipe gasket?
    By Smokin2000gtp in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 12
    Last Post: 10-08-2008, 10:48 PM
Tags for this Thread

View Tag Cloud

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •