Leaky manifold gasket - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 10-01-2006, 12:28 AM   #1
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default Leaky manifold gasket

My exhaust manifold had a small pinhole leak near the dipstick when I installed my kit. Now after 2 weeks it has grown so large under acceleration it sounds like a misfire. I've been meaning to replace it, but I just haven't had the time. On to my questions.

1. My boost gauge only reads 2-3 psi. I'm pretty sure the cause is the air rushing out the leak instead of going threw the turbo. Am I correct?

2. How hard is it to replace the gasket now that I have my whole kit installed? I'm assuming it will be easy, just difficult to get to all the bolts. Anyone recommend a method?

3. My vacuum read a solid 20 on my gauge before I put on the turbo. After the turbo its around 18-19. Is this caused by the exhaust manifold leak or is it just a small leak i'm missing? I used soapy water to check EVERYTHING, but its always possible I missed one.
miataspeed1point6 is offline   Reply With Quote
Old 10-01-2006, 12:39 AM   #2
Senior Member
 
Join Date: May 2005
Location: San Francisco
Posts: 547
Total Cats: 0
Default

1. Probably. What's your car's vacuum level @ idle? It might be a combination of both.

2. You'll have to remove the obvious bits. Might want to soak the bolts in something like PB blaster so they come out easier. Which Gasket? The head/manifold gasket or the manifold/turbo gasket? You might try running without the gasket between the manifold and turbo. It probably won't leak, and you probably won't have a problem of blowing out the gasket

3. I had to remove a bunch of stuff on my turbo, and after I reassembled everything it went from about 20 to 16. I spent an evening tightening all my clamps, and zip tied and replaced all vaccum lines, and vacuum went to 21.

You're probably missing a small leak somewhere. The exhaust manifold leak won't cause less vaccum.
turbored is offline   Reply With Quote
Old 10-01-2006, 12:53 AM   #3
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

Cars vacuum at idle is 18-19. The gasket is head to manifold. And I will triple check for vacuum leaks. Thanks!
miataspeed1point6 is offline   Reply With Quote
Old 10-01-2006, 02:00 PM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

get a large hose that you can listen through. Say a length of gardening hose. hold it up to the edge of the manifold while the car is running and try to listening for the leak. It should sound like clicking, like you're low on oil or the lifters are ticking. If there is a leak at the manifold try tightening the manifold bolts at the problem area.

Did you install the heater hose bracket above or below the manifold?
Braineack is offline   Reply With Quote
Old 10-02-2006, 01:05 AM   #5
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

I sprayed soapy water on the manifold and had splatter from all over the rear of it, so manifold gasket is for sure the culprit.

The heater bracket actually doesn't fit the greddy manifold, so I just used some wire wrapped around the manifold to hold it.

I will be fixing this on saturday, I'm hoping I can just remove the downpipe bolts and intake hoses and just unbolt the manifold.
miataspeed1point6 is offline   Reply With Quote
Old 10-02-2006, 01:13 AM   #6
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

I'd make sure you can't tighten it down first.

When it is off make sure you true the manifold surface. Did you make the relief cuts? If not do them and then true the surface.

you need to trim the bracket so it looks like this:

Braineack is offline   Reply With Quote
Old 10-02-2006, 01:27 AM   #7
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

I had a machine shop true the manifold. Then I made relief cuts. Is it possible doing it that way let the manifold somehow untrue itself? And eventually I will trim the bracket, I have NO metal working tools at my house so things like that take me a while to get done. Thanks for the help.
miataspeed1point6 is offline   Reply With Quote
Old 10-02-2006, 02:08 AM   #8
Elite Member
iTrader: (14)
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,921
Total Cats: 0
Default

Make sure the leak is at the head to manifold and not the turbo manifold flange. When I had a sizable leak at the turbo->manifold flange (caused by a broken stud) I swore it was at the head. Using a 2ft length of vacuum hose in my ear I could easily tell that the leak was coming from the turbo flange, in fact I could tell exactly where on the flange it was leaking. It'll sounds like a put-put-put sound, VERY obvious.

I'd be surprised if it was a leak at the head, unless you didn't use the gasket or didn't torque things down enough.

For what it's worth other than the noise coming from under the hood and the smell of exhaust I could barely boost over 5psi, where previously I was able to get to 9psi.
jayc72 is offline   Reply With Quote
Old 10-02-2006, 09:58 AM   #9
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

the manifold could have come untrue once the cuts were made. Just double check the torque on the studs before ripping the system out. I know the GReddy would kill my 15min. teardown record.
Braineack is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
Moroso Air Oil Separator Catch Can Aroundcorner Miata parts for sale/trade 2 10-01-2015 04:20 PM
ISO 1.6 turbo cast iron manifold cale saurage DIY Turbo Discussion 16 10-01-2015 12:25 PM


Thread Tools

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



All times are GMT -4. The time now is 11:41 PM.