Best way to repair cracked exhaust manifold? - Rennlist Discussion Forums
Rennlist Discussion Forums   classifieds | membership | rennlist | photo album    
sponsors | upload photo | chat    
 
Go Back   Rennlist Discussion Forums > Water Cooled Technical Discussion Areas > 924/931/944/951/968 Forum
Sign in using an external account
Register Forgot Password?
Search

Reply
 
Thread Tools Search this Thread
Old 06-04-2010, 12:08 AM   #1
Dryslick13
User
 
Dryslick13's Avatar
 
Join Date: Apr 2010
Location: Western Slope of CO
Posts: 325
Default Best way to repair cracked exhaust manifold?

I have a bad crack on the header that goes to cyl 1 and 4. It is right were the two pipes merge to the collector. What is the best way to repair this so it will hold? Looks like it is cracked under the plate that braces the pipes at the Y. Guess I'll need to cut this off to fully repair the crack? Is there any way to better brace the pipes? I am missing the hanger that goes in front of the cat. I have the parts to put that back in, but need to weld on a flange to the pipe to bolt the hanger to. Tried buying a used set from e-bay but they ended up being cracked just like mine. Hope he gives me a refund since he said they had no cracks!
To remove this ad, register today or login if you already are registered!

Dryslick13 is offline   Reply With Quote
Old 06-04-2010, 12:21 AM   #2
Strike-Force
User
 
Strike-Force's Avatar
 
Join Date: Sep 2004
Location: York PA
Posts: 472
Default

If you patch it it will crack again. The only way to get rid of the problem is to replace the manifold.
Strike-Force is offline   Reply With Quote
Old 06-04-2010, 12:24 AM   #3
Wipeout
Not Special
Rennlist Member
 
Wipeout's Avatar
 
Join Date: Dec 2006
Location: Rosaria, Cascadia
Posts: 2,604
Default

Agreed - replacing it is the only way. I have the headers from my early '85 (don't recall any leaks/cracks, but I think mine are cast. They should fit an '86, but not sure if you'd want them. Yours for shipping if you need 'em.
Wipeout is offline   Reply With Quote
Old 06-04-2010, 01:22 AM   #4
m73m95
Addict
Rennlist Member
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,100
[RENN]m73m95
Default

Wrong..... it can be welded.

It takes special rod..... and its one of the rare cases that arc (stick) welding is the preferred method. Arc welding rod remains flexible, and will expand and contract with the heating/cooling of the manifold.

Take it to a good welding shop for the fix..... or send it to me. I have welded MANY exhaust manifolds on big diesel engines. They crack all the time. Nickel rod is $$$$, but it will never crack in the same location again.

(EDIT .. I read "manifold" as you having the early cars cast iron manifold..... if you have a late car header, that can be repaired as well, just a different process.

Never trust anyone that tells you something can't be welded, and have it be strong. Everything made of metal in the world has been welded at some point, and many times, the weld is stronger than the surrounding metal.)
__________________
85.5 944, now in multicolor
09' Audi A4 Avant
m73m95 is offline   Reply With Quote
Old 06-04-2010, 01:32 AM   #5
Tom M'Guinn
Addict
Rennlist Member

 
Tom M'Guinn's Avatar
 
Join Date: Jan 2002
Location: Just CA Now :)
Posts: 8,411
Default

Quote:
Originally Posted by m73m95 View Post
Wrong..... it can be welded.

It takes special rod..... and its one of the rare cases that arc (stick) welding is the preferred method. Arc welding rod remains flexible, and will expand and contract with the heating/cooling of the manifold.

Take it to a good welding shop for the fix..... or send it to me. I have welded MANY exhaust manifolds on big diesel engines. They crack all the time. Nickel rod is $$$$, but it will never crack in the same location again.

How about the heat shields on the 951 manifolds? Any tips for MIG welding those back on after removal?
Tom M'Guinn is offline   Reply With Quote
Old 06-04-2010, 01:38 AM   #6
m73m95
Addict
Rennlist Member
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,100
[RENN]m73m95
Default

Those are filled with some kind of black beads.... I haven't seen them, but I have read posts about them. They absorb the heat I guess.

If they (heat shields) are whole, just removed, they should just be spot welded back on, then "refilled" with whatever that stuff is.
__________________
85.5 944, now in multicolor
09' Audi A4 Avant
m73m95 is offline   Reply With Quote
Old 06-04-2010, 01:53 AM   #7
m73m95
Addict
Rennlist Member
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,100
[RENN]m73m95
Default

Also ..... never trust anyone that says something can't be welded and be strong. Everything that is metal in the world has been welded at some point... And most times, the weld is stronger than the surrounding metal.

Every kind of metal, and every use for that metal takes a different welding process. Meaning, there are THOUSANDS of ways to weld "correctly".

Just because somebody tried welding a cast iron manifold in their garage with a torch and coat hanger, which of course failed, doesn't mean they know WTF they are talking about.

Some metals require processes that cannot be done in a garage (titanium can only be welded "correctly" in a vacuum). Take your stuff to a good/certified weldor.
__________________
85.5 944, now in multicolor
09' Audi A4 Avant
m73m95 is offline   Reply With Quote
Old 06-04-2010, 01:28 PM   #8
kombatrok
User
 
Join Date: Feb 2010
Location: Portsmouth VA
Posts: 440
Default

Why not replace with MSDS headers? Cheap and easy. Replace the cat with a modern high flow imo while you are at it.
kombatrok is offline   Reply With Quote
Old 06-04-2010, 02:47 PM   #9
dme
Addict
Rennlist Member

 
dme's Avatar
 
Join Date: Mar 2004
Location: Grapevine, Texas
Posts: 1,108
Default

I had Marcus (in Canada) weld my 2-3 header. He added an expansion joint to relieve the stress and keep it from cracking again. He also welded it while installed on a head to keep the alignment correct. The first (local) guy who did it, welded it free standing and it would not fit back on the head.
dme is offline   Reply With Quote
Old 06-04-2010, 10:56 PM   #10
elzergone
User
 
elzergone's Avatar
 
Join Date: Jun 2005
Location: Around Lake Tahoe, California
Posts: 523
Send a message via MSN to elzergone
Default

Quote:
Originally Posted by kombatrok View Post
Why not replace with MSDS headers? Cheap and easy. Replace the cat with a modern high flow imo while you are at it.
Does that have any noticeable effect on an NA? I was under the impression it was kind of a lost cause. Or are you just suggesting it as a cheap fix.
elzergone is offline   Reply With Quote
Old 06-04-2010, 11:04 PM   #11
JimV8
Addict
Rennlist Member
 
JimV8's Avatar
 
Join Date: Nov 2002
Location: Upper Canada
Posts: 17,578
Default

It can be welded without a lot of trouble. I'd gas weld it. Oxy/Acetelene is great for doing that kind of stuff.
__________________
Formerly known as Jim7

"Frankly, we need a lot less of the passive tolerance of recent years and much more active, muscular liberalism...." Rt Hon. D. Cameron.

'When the ocean of time is at low tide you must wade in further to get the fish". unknown

Chimera or fusion protein, a hybrid protein made by the splicing of two genes
93 black 968 coupe Chimera Project
95 Jeep YJ
01 GMC Savana
07 Gardena electric
JimV8 is offline   Reply With Quote
Old 06-05-2010, 12:41 AM   #12
Dryslick13
User
 
Dryslick13's Avatar
 
Join Date: Apr 2010
Location: Western Slope of CO
Posts: 325
Default

I've got the late headers. Guess I'll take them to a muffler shop since I only have a MIG welder. Have a shop nearby that does good work on the cheap. What are the MSDS headers? Would be interested in them if they are not too much coin.
Dryslick13 is offline   Reply With Quote
Old 06-05-2010, 12:42 AM   #13
Dryslick13
User
 
Dryslick13's Avatar
 
Join Date: Apr 2010
Location: Western Slope of CO
Posts: 325
Default

Wipeout, I might take those cast manifolds off your hands if the muffler shop can't fix the cracked one I have.
Dryslick13 is offline   Reply With Quote
Old 06-05-2010, 02:17 AM   #14
kombatrok
User
 
Join Date: Feb 2010
Location: Portsmouth VA
Posts: 440
Default

Quote:
Originally Posted by elzergone View Post
Does that have any noticeable effect on an NA? I was under the impression it was kind of a lost cause. Or are you just suggesting it as a cheap fix.
I didn't really notice much difference, but it was a little louder. It's just an inexpensive, well made one piece header.
kombatrok is offline   Reply With Quote
Old 06-05-2010, 03:57 AM   #15
m73m95
Addict
Rennlist Member
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,100
[RENN]m73m95
Default

Quote:
Originally Posted by Dryslick13 View Post
I've got the late headers. Guess I'll take them to a muffler shop since I only have a MIG welder. Have a shop nearby that does good work on the cheap. What are the MSDS headers? Would be interested in them if they are not too much coin.
If you were on the other side of the divide, I would suggest a great weldor for you to take your headers too.

You should be fine MIG welding it, as long as you are using gas (not inner shield), and can purge the inside of the headers as well.

If you do take them somewhere, I would not suggest a muffler shop. Take it to a professional weldor.... maybe even a fab or machine shop. The fix should only take 15-30min to do right, so you can probably find someone to do it on their lunch break for a 12 pack
__________________
85.5 944, now in multicolor
09' Audi A4 Avant
m73m95 is offline   Reply With Quote
Old 06-05-2010, 03:57 AM
Rennlist



Paid Advertisement
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
exhaust manifold crack....options? johnu 928 Forum 3 05-27-2014 11:34 AM
997 PSE Question mabf355 997 Forum 7 05-13-2014 12:36 PM
Steering shaft flex coupling repair ideas ammonman 928 Forum 10 08-18-2013 02:31 PM
Flex pipes cracked what to do? Hamlet Porsche Cayenne Forum 5 07-30-2013 07:17 PM
Say No To Dashboard Crack aaddpp 928 Forum 24 04-12-2011 02:45 PM


Tags
1998, arc, cast, crack, cracked, exhaust, f150, fix, ford, iron, manifold, nickel, patch, plymouth, repair, voyager, weld

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Join rennlist.com

All times are GMT -3. The time now is 02:50 AM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.6.1
Copyright ę 1998 - 2007 Rennlist.com

Advertise on Rennlist - Privacy Statement - Terms of Service - Jobs