Another rattle

MR-S Turbo · July 28, 2006, 15:18

Quote from: "spit"
Quote from: "MR-S Turbo"I think the welds only held for about an hour of driving as the noise is back s:cry: :cry: s:cry:
Will have to pull it apart again and investigate s:cry: :cry: s:cry:

How you getting on with yours?

I'm taking mine in Monday to a new firm. This guy is reputed to be one of the best stainless steel welders in the North of England....perhaps a custom equal-length manifold in the offing. We'll see!

Now that sounds interesting. I havent had chance to look at it yet. Maybe I will get some time tommorow to strip it down again.

MR-S Turbo · July 29, 2006, 12:00

I have stripped it down and no signs of any cracks. But is still making the noise s:cry: :cry: s:cry:

spit · July 29, 2006, 12:06

Quote from: "MR-S Turbo"I have stripped it down and no signs of any cracks. But is still making the noise s:cry: :cry: s:cry:

s:shock: :shock: s:shock:

Turbo inlet gasket is a possible, but the distinctive noise is more likely to be closer to the head than that....and you renewed that one.

s:? :? s:? confused.

Do you get a single and very brief "chirp" on start-up? Thats what mine is doing now. The stress point has moved since the last repair and its the tiniest of cracks between the manifold plate and pipe on Cyl 4.

Washing up liquid bubble test?

kanujunkie · July 29, 2006, 12:07

strange, whats your next plan then Ian?

MR-S Turbo · July 29, 2006, 12:31

I have cleaned up all the flanges and now reassembling it. I only get the noise when the oil is over 90 Deg C ie the engine is warmed up and inbetween 2 and 3k on light load.

Anonymous · July 30, 2006, 07:54

Just seen those photo's of your cracked manifold, I would say you are wasteing your time trying to reweld it, it's cracked along the HAZ (heat affected zone) of the weld, this area has become brittle so no amount of rewelding will correct the problem it will just keep coming back, it's like chasing the draggon s:shock: :shock: s:shock:

Thanks
Rob

kanujunkie · July 30, 2006, 13:18

you could always use it as a model to get one cast

MR-S Turbo · July 30, 2006, 19:51

It all got put back together and I have been to York today for TOTB in it and all seems fine s:D

s:D And is boosting much better. I may of not got the seal right on the manifold gasket right the first time, thats all I can think it could of been.

kanujunkie · July 31, 2006, 19:19

my fingers are crossed mate s:wink: :wink: s:wink:

spit · July 31, 2006, 19:33

Thats good news.

Found out today that one M-T bolt was loose and a nut missing too - even after being nutlocked and nordlocked s:shock: :shock: s:shock: . Made it easy to get the manifold off though s:lol: :lol: s:lol:

Its with the stainless welders tonight. He's taking off all of the old mig from the last repair, fixing the new cracks s:roll: :roll: s:roll: and giving it a general patch-up where it looks to be weakening.

He reckons the Mig fix is way too heavy-handed and too rigid to cope with the temperature and vibration stresses, and it seems to be lifting away in parts.

We'll see what sort of fix he comes up with tomorrow. I've limited him to about an hour's labour - which he says will be ample to get it fettled.

MR-S Turbo · July 31, 2006, 20:27

I got mine TIG welded with just a little bit of filler. The welder did say that it probably wont last long.

Anonymous · July 31, 2006, 21:48

Quote from: "MR-S Turbo"The welder did say that it probably wont last long.

s:wink: :wink: s:wink:

normanh · August 1, 2006, 10:29

I think MIG is by far to heavy a weld on the manifold, and will crack much more easily. Never liked MIG on stainless, TIG is much more refined and more controllable in welding. I would think you need to add just sufficient filler to make a good weld. I have known guys weld 25 thou filler gauges as a test on TIG skills and these guys rebuild jet engine cases in stainless so provided the stresses are controlled theres every chance a repair should last. Its the welders skill!!!! Something I dont have I know.

normanh

kanujunkie · August 1, 2006, 10:32

look out for a welder who's Civil Aviation Authority(CAA) or Joint Airworthiness Authority(JAA) or Joint Airworthiness Requirements(JAR) approved, you'll be fine then

spit · August 1, 2006, 20:12

(I've a feeling this thread will become an ongoing thing between the pair of us)

With happy face on - Yay I'm running again at a cost of 20 quid and some knuckle flesh s:lol: :lol: s:lol: The manifold was pooping gases out everywhere, including the old 'fix' s:? :? s:? .

Mr Tig has done a great job in saving it, & the spool-up is seriously serious now s:wink: :wink: s:wink:

Less happy face - Its clear from putting everything back together that there are some serious stresses in the pipework....and thats without the engine running.

*Ste theorises....* I think it goes back to the timeline of the build, where exhaust alignment shenannigans came before the turbo brace had arrived from Hungary. The two have never sat together well s:roll: :roll: s:roll:

I need to de-stress the setup and beef the bracing. I'm thinking a 3-point bracing of turbo to block, so the manifold is effectively just sitting on top. This'll be a cheaper option that'll drain every last bit of life out of the old manifold. What thinks you?

Also, I'm wondering if we're limited to the pressed metal gaskets at the manifold and turbo inlet. Anyone know of a flexible "liquid gasket" option thats up to the task?

MR-S Turbo · August 1, 2006, 20:36

Im on with some serious bracing to take some of the stresses out of the manifold. And also looking into alternatives.

spit · August 5, 2006, 00:05

Well, a bizarre downturn since the last repair is that I'm not peaking at 0.8 bar any more. Its down to 0.7 bar.

Why would this be? I don't have the cyl4 and turbo manifold leaks that I had at JAE s:? :? s:?

The only other material difference is that I'd say about 15% of the outer ceramic coating was removed to facilitate the TIG welding. Is ceramic coating really that good s:?: :?: s:?:

kanujunkie · August 5, 2006, 10:07

they didn't decrease the interior bore of the pipe when they did the welding did they Ste?

spit · August 5, 2006, 10:25

Nope. The repair has affected the smoothness of the bore a little though, but I doubt thats enough for such a big change s:? :? s:? Confused.

Anonymous · August 5, 2006, 10:37

The only way you can confirm that you have no further cracks in your manifold is to get the welder / company to do a dye pen test on all your new and existing welds, then you can be sure. Sorry mate as I've said before it's like chasing the dragon.

spit · August 5, 2006, 11:38

sphericals s:cry: :cry: s:cry:

kanujunkie · August 5, 2006, 12:48

Quote from: "FGRob"The only way you can confirm that you have no further cracks in your manifold is to get the welder / company to do a dye pen test on all your new and existing welds, then you can be sure. Sorry mate as I've said before it's like chasing the dragon.

really doubtful that a crack thats so small that it requires dye pen testing or any other ndt testing is going to make a .1bar diff, i could be wrong and if you were talking HP fluids then i'd agree, but seeing as its a gas then i doubt it has the power to open up any crack to a large enough size to make a difference.

Ste, if you want though i can grab some dye pen stuff from work. Give us a buzz before bed on Sunday night if you do want some

Anonymous · August 5, 2006, 13:28

I'm not talking HP fluids or gases, I'm talking metal and how it reacts when heated especially welding. It's all about using the right base material and the suitablity of that materail for the use intended, so for the sake of "peace of mind" it's worth doing. Remember from little acorns grow some very large trees - now theres an old saying s:wink: :wink: s:wink:

The best solution to eliminate the manifold from future problems either to have one cast in steel or have one made by a professional company - not an exhaust company - someone who does it for a living, the downside to this is the cost, you have to be talking over a £1000+ for decent job.

Tem · August 5, 2006, 14:35

WTS (at least I think it was him) just gave a good advice how to find out leaks. Just block your exhaust and put compressed air in the intake. Then listen to hisses.

spit · August 5, 2006, 18:53

Slightly more technical than the fart/sniff method then s:wink: :wink: s:wink: s:lol: :lol: s:lol:

Thanks Tem. I think I'll just run the manifold to destruction now .... we're in talks to get an equal-length tubular made up. It won't be £1000+ but it will be the work of a time-served stainless weldererer.