cracking turbo manifold

drake21 · Post by **drake21** » Sun Aug 11, 2013 8:39 pm

hey there guys
first il put it out there that I'm new to the forum and i have recently brought coles old car also known as user sprsta

i have owned the car for nearly 2 months now and the manifold has cracked 3 times now the first time it cracked the engineer didn't penetrate the weld enough so this time round i got it done properly with a slight re route done on the down pipe to take some stress off it.it lasted 5days before i noticed it had cracked again (today)

now I'm sure it hasn't cracked before up until now that its in my hands i have been talking to sprsta and he said by the sounds of it the tune has been played around with so that may play a part in the mani getting to hot from running lean,I'm just having problems trying to connect my laptop to the link to see whats going on via data log.

long story short the manifold is made out of schedule 40 mild steel and is pretty much rubbish now.i just need some advice on what road to go down regards who does good custom manifolds or i have come across a flying miata cast manifold i can't post a link as I'm to new, it is found on flyin miatas webpage but going down that track i would have to change my down pipe.i just want to drive it and not be worried every time i lift the bonnet up :/ lol

your opinion would be greatly appreciated
il post up some photos of the manifold asap

marcus

Snapfrozen · Post by **Snapfrozen** » Sun Aug 11, 2013 9:27 pm

I'm assuming its turbo? Go with a nice simple custom log manifold.

2low2c · Post by **2low2c** » Mon Aug 12, 2013 7:23 am

my first question is what have you done to the car in the time you have owned it ?

built4speed · Post by **built4speed** » Mon Aug 12, 2013 8:30 am

If its mild steel you have done something wrong to crack it..
Do you have a flexi as close to the turbo as possible and if the wastegate is seperate and then joins the exhaust it will need a flexi too. Do you have a brace off your block to support the weight of the turbo? Also check the flanges for flatness as cranking them up to seal a gap puts a lot of unnecessary stress on the welds.
When the cracks were welded up did he drill the ends out? Or just poo over it?
Don't get a log manifold, they are horrible. Just spend money on a nice shaped, good quality mild steel one.
Mine has been glowing red hot after back to back dyno runs and 8 lap races and has cracked only once when a bolt vibrated loose.

sprsta · Post by **sprsta** » Mon Aug 12, 2013 8:50 am

There is a bracket on the down pipe to the gear box to take the weight of the turbo,
There is a flexi just behind that,

I'm at a loss, it never cracked in the four years i had it turbo.

drake21 · Post by **drake21** » Mon Aug 12, 2013 9:30 am

That's what I'm trying to understand ,I put a rubber mount on the bracket that bolts to the gearbox and got a slight re route done on the down pipe so evything lined up:bolted up nice with no stress. And like cole said its been running fine for the 4+ years he had it turbo..

Snapfrozen · Post by **Snapfrozen** » Mon Aug 12, 2013 8:42 pm

Unless you are chasing big numbers or are seriously concerned about spool times log manifolds aren't a bad choice to be honest.

Sure they won't be as good as other stuff on the market, but theyre cheap and effective

2low2c · Post by **2low2c** » Mon Aug 12, 2013 9:40 pm

first of all putting a rubber mount at the gearbox is defeating the purpose of the brace as it will move around .
secondly looking at your face book posts you have lowered the a lot more than when Cole owned it if it is hitting on the bump stops all the time the jaring will make the manifold crack as it is along manifold.
thirdly if you dont want to redo the down pipe and intercooler piping then you would have to find someone near you to copy the one you have.

drake21 · Post by **drake21** » Mon Aug 12, 2013 10:20 pm

Hi Paul it's not as low as what cole had it at and isn't anywhere near hitting the bump stops .can anyone suggest come good fabricators that they have has good experience with? Has anyone delt with sinco customs?

SLYDIT · Post by **SLYDIT** » Mon Aug 12, 2013 10:20 pm

My schedule 40 manifold has been in for seven years and I haven't touched a thing on it. Where is it cracking? There's nothing wrong with a log manifold for a street car. There's on point spending big bucks on a custom equal length manifold when you can spend it better else where like coil on plugs or ev14 injectors

drake21 · Post by **drake21** » Mon Aug 12, 2013 10:38 pm

Il post photos up tomorrow .having trouble with photo sizes for the forum

drake21 · Post by **drake21** » Wed Aug 14, 2013 6:30 pm

Here's some photos I'm sorry if its hard to see but the new crack is about an inch from the latest weld .the colour is a bit off for some reason the photos ce out with a bit of rainbow in them .
Marcus

sprsta · Post by **sprsta** » Wed Aug 14, 2013 8:58 pm

weird, that crack is right in the middle of a schedual40 bend, it really shouldn't crack there

drake21 · Post by **drake21** » Wed Aug 14, 2013 9:44 pm

I thought it was a very weird place to crack?

Growler · Post by **Growler** » Thu Aug 15, 2013 2:29 pm

Re-welding it could have heat treated the metal slightly - hence the crack above it...

SLYDIT · Post by **SLYDIT** » Sat Aug 17, 2013 6:42 pm

thats a classic example of overheating the work. you need to do a root run, then let it cool , then do filler runs. if you try to weld it/fill it all in one go you are going to stress the surrounding area.that bit is now toast. youll have to replace it.

Mad Kiwi · Post by **Mad Kiwi** » Thu Nov 07, 2013 2:41 pm

I am having the same issue with my manifold. When Keith had the motor he had zero issues. It cracks on me during/after every race meeting.

We have put in a flexi joint, re made the gearbox brace, repaired it, braced it you name it.

I am about to send it to Sinco for a replacement copy. Over it!!!

WideOpenThrottle · Post by **WideOpenThrottle** » Thu Nov 07, 2013 3:27 pm

I have a top mounted bracket...no issues with cracks...its the best way to support/brace the turbo.Completes the triangle just like anything that needs a brace you must have three sides to the equation...no good just having lower braces when all the weight is at the top.

Re-weld it,put a top brace on it and see how it goes!...cheapest option for now by far!

SLYDIT · Post by **SLYDIT** » Thu Nov 07, 2013 6:43 pm

my brace comes down from the turbine housing to near the engine mount

2low2c · Post by **2low2c** » Thu Nov 07, 2013 8:39 pm

just remember guys that a tube manifold needs to expand and contract with heat,to much braceing or to stiff can actually cause cracking.
i don't have any braceing on mine and i don't have any flex joints and have never cracked my manifold.

2old4this · Post by **2old4this** » Sun Nov 17, 2013 9:18 pm

Sometimes with the continuous heating and cooling of long term use and welding would not help being extreme localised heat. This causes the pipe to build up internal localised stress. . To stress releave the manifold I would crank up the Barby and cook the manifold till the whole thing is glowing red hot !!! Evenly - then let it cool slowly..... This and braces should help. :-)