Jump to content
SAU Community

What caused this to happen - cracked exhaust manifold??


Recommended Posts

Hey Guys,

After the really hot track day at Phillip Island my car was sounding like it had a gasket leak on the exhaust side. Stripped her down this week only to find a cracked & severely warped exhaust manifold :)

There was a 2 inch split/crack in cyl 3's manifold pipe and the metal was tinted blue suggesting some major heat.

Anyone know if the heat was the major factor in this -or- is it more likely that the crack had been developing over time and the heat just made it worse??

hahaha.........I would have thought so Nark but its not the only thing that would cause it. Maybe if a lot of people had this happen it could be an inherent fault in the design or something......All I know is it was an absolute b@stard of a thing to pull off the block 'cause it had warped sooooo much (and warped the heat shield 2). As for the shiney S/S one, if I had more time before the next track day I would have hunted an aftermarket one down but unfortunately I had to have the car back together ready for winton. Anyway managed to get my hands on a ported std item so should flow pretty well anyway.

Ash....thanks for the suggestion but my car has an a'market ecu etc etc and only got dyno'd recently so I know shes not running lean. Do have the req'd free flowing exhaust which helps but I'm thinking maybe when my manifold was match ported they could've shaved too much off in that area which led it to crack.

Did it snap and studs?

Looking at the designm they will always want to warp as the heat form all 6 cylinders is focussed int he centre.

But one thing i have noticed at a few Voc track days, you boys hok straight into full throttl work once leaving pit lane. I always do a lap of light throttle / med revs stuff to get a bit of heat into not old tyres, brakes, gearbox, diff etc, but also because i have a stainless steel manifold and i dont want to hit it with a bucket load of heat straight away.

So maybe a slighlty slower out lap may help reduce the heat shock/distortion?!?!?!

Troy.......Man it was a b@stard. Luckily it only snapped one bolt so not much drilling out to be done. B@stard part of it was that it was warped so that the studs were forced up against the edges of the holes in the manifold preventing it from being taken off the block. The diff was really apparent when I went to put the new one on....fitted straight up with the studs right in the centre of the holes.

You are right about the warping happening at the centre of the manifold as the crack was in the pipe off cyl 3 and once the manifold was off the block it had warped in a concave shape.

I usually do a slow lap outta the pits mainly putting heat into brakes etc - never thought about things like the exhaust manifold. Going against that is the fact that I'm running street rubber (more heat=less grip) so I tend to hit the gas straight after the out lap.

Will go easier for the first couple of laps at Winton and see how I go....

Where is the crack?

right neat the plate?And troy, en EX man will get most the heat-up done just idling before you hit the track man.

Yeah it'll rise somewhat more... but most if its already done.

Its the mechanical bits after the motor that need the warmup more-so

Ash.....Nah mate the crack was no where near the flange plates that connect to the block or the flange plate that connects to the turbo. The crack was close to where the pipe off cyl 3 mates into the common runner that lead to the turbo - but the crack actually ran along cyl3's exhuast pipe.

check the crappy attached pic......

I personally think it was some type of failure in the flux capacitor or possibly the Mr. Fusion......:D

Nah but really, could be simply a defect in manufacturing? What about timing and cams? Have you had diff cams put in? I'm not expert but you know how they play with timing (or is is exhaust cams) and it draws more heat away from the engine, perpahs it's caused the manifold to get super hot. Could be combination of both! If there was an impurity in the metal could be a probelm...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Pressure when IDLING, is meant to be 51PSi... So that amperage value needs to go up a fair chunk... I'd personally be factoring for more like 12amp at least on those runs, and at that point you need to hope the already there wiring doesn't drop you a volt or two, as that's a lot of fuel pressure flow drop off from 13.5 to 12V! Taking idle pressure of 51psi, means the pump will be drawing a MINIMUM of 9amps all the time based on your reading of the graph (3bar base, then allowing an extra 0.5bar for boost = roughly 51psi)
    • Hi all,  I am in the market for an R200 longnose diff out of a Z31 300ZX, or S12 RSX, DR30 skyline, or similar, in a 3.9 ratio.  Preferably a late model one with the M12 crownwheel bolts.  The only easy to find advert for one of these was my ad back in 2007 when I sold it on this forum.  I sold the diff as I had sold the car it goes to, but as it turns out, after 18 years I got the car back late last year, so now I'm looking for the diff !  If anyone knows where to find a longnose R200 LSD with the M12 crownwheel bolts, drop me a line at [email protected] - Bonus paid if soomeone comes up with the original diff (stranger things have happened !).  Cheers   Ben D    
    • Hi everyone, I used to post here a bit from 2004-2013, when I owned various Nissans, in particular my S12 RSX gazelle, which was sold in 2007.  As luck would have it, after an 18 year hiatus, the car found its way back to me last year, and over the past 11 months I have had the pleasure of restoring it with my kids.  One thing that I am after in particular is a 3.9 ratio R200 LSD for it.  I actually sold the one out of the car here back in 2007 , and it would be incredible if I could track down who I sold it to, so I can see how they have progressed over the years (and to be honest, to see whether I can get the diff back !).  Anyways, hi all and let me know "where are the R200 Longnose diffs all at these days ?  Cheers Ben D  
    • Arms will be the same as the G35 or 350Z, but as above, there was a change in the lower control arm where it connects to the ball joint.  That said, you can remove the ball joint cone from your old ball joints and fit them to the new ball joints.  To be honest, I didn't think the ball joints themselves were different. The main ball joint is a bit awkward to replace, you really need to remove the steering knuckle to press out the old one.  Some people have used tools to remove it in place, but it just seemed too hard to get to. If you are going to press out/in that ball joint, then you may as well just replace the bushings in the LCA and the compression rod.  You can buy the compression rod bushing from Nissan, but the LCA bushes, you will need to go aftermarket. Much cheaper than buying the whole arm.
    • Ha, well, it's been.... a bit of a journey. Things have taken much longer than I'd hoped. I'll probably put up a thread at some stage. Hopefully soon. The car's not done any kms since my update in June though, put it that way.
×
×
  • Create New...