JS Manifold cracked

[phil_m]

I am in the process of changing the turbo and noticed that the JS manifold has a dirty great crack

What are my options repair or replace and what effect will the crack have on performance, i cant say that i have heard it blowing but as you can see from the pic it obviously has been.

Cheers

Phil

 

[ibizacupra]

different location crack to mine. mine was on the collector top.
it could possibly be welded as a racer i race against had his JS mani welded to allow for an external wastegate.
small cack would'nt effect performance much, nor blow aside from when cold if like mine was.

 

[tashacupra]

That will weld up no problem if you take it to a good welder, just make sure that they do a full pen repair because if its not it will just crack again.

Best bet for cast is pre heat the crap out of it weld it up heat it again then put it in a stress oven to cool over at least 24 hrs, if this is not availiable heat some blast sand up as hot as you can (or building sand will do) then cover the manifold completly in as much sand as you can and leave it to cool, uncover it clean it out and it should be crack free.

One last thing that will help would be to call JS and see if they will tell you the make up of the material used for the manifold fabrication (although i suspect they may not) it will defo be high nickel but there may be other stuff in it. The reason for this is to help the welder assertain the best suited welding consumable in relation to the perent metal to complet the repair.

 

[Wilko]

Phil
Mine is cracked (like most of them) above the collector. It's been cracked for 30,000 miles or more. Had it welded, but the repair failed and it cracked again. Only blows when cold. Seals up when it gets hot.

Mine came off today to have the turbo/manifold flange ground flat. It goes through 2 gaskets a year, and I'm sick of it, so it's coming off to be ground.

 

[ibizacupra]

if you are able, counterbore the manifold and exhaust housing and insert a small spigot between them. No blowing after, no matter what shape the housing turns..

Thats how I run my IHI based units

 

[Wilko]

I was thinking along similar lines bill.
Laser cut high nickel content plate to match flange at 12mm, machine flat to 5mm thick leaving a 3.5mm spigot each side to enter into maniflod and turbo. Bore turbo and manifold to match. Gasket either side of plate for good luck. Alows for slightly bigger comp housing too.
Might try a blouch dominator II.

But with it all off, I'm tempted to just buy a full race or 034, with downpipe, and get a big garret. Top mount is definately the way forward.

I need to look at steve's MKIV with the full race on to se what fitment issues there are.

 

[pj1985]

As far as am aware with steves the only thing fitment wise was a little bit taken off the rocker cover to give the turbo more room when getting hot. The dp was easier to make than an ibiza IHI and I believe the mani bolted up fine as I havnt heard anything otherwise about it.

 

[HTC]

Wilko. Let me know if you want to sell your Blouch 18G.

 

[ibizacupra]

it need'nt be as much work as that john.

c'bore JS mani a few mm, and same on ex-housing. insert a tube spigot which is slightly shorter than the 2 c'bores combined and di it up.. make sure fits are nice and snug. I used 316L stainless tube machined for the stub. makes a nice socket joint.

giving away all my secrets here - lol

 

[Wilko]

Bill that would work, but I want to space the turbo away from the js manifold to give some comp housing clearence.
Have to ring blouch this afty to see if the dom II is physically bigger externally. Looks the same in their website pics.

HTC. Will do, but won't know for a couple of weeks.

 

[HTC]

No problem, whenever you are ready.

 

[phil_m]

Cheers guys and gals, i think i might leave it for the time being, like wilko says if it has to come of i will prob replace it with something better, if its only going to blow when its cold then i can live with it.

As for the turbo/manifold gasket i have left mine off this time, it seems pointless keep putting new ones on everytime only for them to go 2 months later.

 

[ibizacupra]

only time i ever ran a gasket before i made my own sealing method it blew the gasket first test day out.
rubbish.

says how much hotter 1.8t install is over scubaru

 

[HTC]

I run a gasket. Not had a problem with it yet. I use genuine Subaru if it makes any difference. Really like the leaving method. Saw this recently on a 1998 Rover Mini inlet manifold of all places.

Phil, so will you not be fitting the new charger just yet?

 

[Wilko]

My manifold flange is not flat. It blows like a mofo without a gasket.
Got the tuby off tonight, and the gasket has burnt through in 3 places.
Not surprisingly in exactly the 3 places that my manifold has hairline cracks through the flange.
Manifold is coming off, and will be counter bored as bill suggests and a sleeve put in. I've got a couple of weeks to get it repaired, re machined flat, and counterbored/sleve made.
Tuby should be back by then.

Anyone know how tight the exhaust manifold to head bolts are?

 

[DPJ]

Just 25Nm standard, John.

.....but ATP say 32lb/ft on theirs.

 

[HTC]

ElsaWin tech says 30Nm, but I've never been able to get a socket to all the nuts let alone a torque wrench.

 

[ibizacupra]

I run a gasket. Not had a problem with it yet. I use genuine Subaru if it makes any difference. Really like the leaving method. Saw this recently on a 1998 Rover Mini inlet manifold of all places.

Phil, so will you not be fitting the new charger just yet?

I only ever used original scooby gaskets.. blew just the same.
the manifold does not stay flat on high boosts/EGT's

 

[phil_m]

I run a gasket. Not had a problem with it yet. I use genuine Subaru if it makes any difference. Really like the leaving method. Saw this recently on a 1998 Rover Mini inlet manifold of all places.

Phil, so will you not be fitting the new charger just yet?

Kev new turbo is all fitted.

All my gaskets have come from Subaru to, i was told that Js dont use gaskets on there installs anymore because of this problem, i will run it without for a while and see how it goes.

 

[HTC]

Will be interested to see how you get on. So how did you approach the larger fittings for the water pipes? The turbo to block pipe on mine has the banjo welded or pushed on to the pipe. I guess I would have to cut this off and replace with a lager banjo?