Hairline cracks on exh. turbo housings?

[MidnightGTR]

I purchased 2 turbos off Doughboy recently that had been rebuilt by Precision turbos in Sydney.

When I got the turbos to me they looked fine, booked it in down at the workshop and my mechanic rang me a few hours later and said he had some bad news. Said both turbos had a hairline crack on the exhaust side where the actuator lid open/closes, on the surface and also down into it.

I asked for my money back but later got an email saying he had rang both Precision and GCG turbos and both workshops apparently said that is normal and they wont get any bigger, and wont affect the performance of the turbos as the lid seals the flow.

My mechanic also said he rang 4 people and 2 said its normal and will be ok, and 2 said they wouldnt go near em.

My mechanic said he could weld the break and grind it back etc, but being cast iron and always moving/changing temps he said it would just cause a crack next to the weld anyway.

End of the day DoughBoy wasnt going to give me my money back so I have no choice to fit them anyway, but what i want to know is will they be ok and will they be ok for a long time, or will the cracks eventually split too big and be forced to fix them up?

I thought it was strange a turbo workshop that apparently charged $2000 to rebuild the turbos didnt even bother fixing the cracks in the first place...

Has anyone had any experience with this sort of shit happening on turbos?

[Roy]

If 4 out of 6 people say they will be all right? Unless your mechanic is a ticketed welder then id say do not weld them.

If your mechanic has experience with welding housings, then he is your mechanic. But id be worried about the type of welding he is doing, the wire/ he is going to use, will be gouge the welds, how will he know what is sufficient penetration etc etc???

Having fair a amount of experience with boilers/burners and all the cast items used in these, its not unusual for castings to have what appears to be hairline cracks on the surface of their bodies. If you have to look twice to see the cracks then i think you are in the clear.

Sure the things get hot, but they are not under any mechanical load or under pressure. So the cracks will stop and grain boundaries and not propogate thru the whole casting...that would be considered catastrophic failure...and according to the calcs you can punch for cyclic heat loads would be akin to winning lottery ... not going to happen in this life time.

If you rang a place like AMEC, (materials science/testing experts) i reckon they will tell you what i have told you, but charge you coinage for the test to verify what they would be pretty sure of. Hell if you want it tested but dont require any NATA certificates for it, they will be able to confirm what 4 out of 6 people have told you, and what i suspect based on experience in the pressure piping/vessel industry.

Hope that helps?!?!?!

[666DAN]

NATA

Pffft non-profit organization, you pay a lot for those four letters grrrrr!

[ylwgtr2]

its normal...i have seen it heaps on VL turbos....dont weld them....just runs them...they will be fine.....doughboy wouldnt stitch you up on purpose...i have dealt with him and found him great to deal with

[MidnightGTR]

well the turbos are on now and everything seems to be fine, just hope it lasts and the cracks dont get any bigger.

Id like to believe they will be ok but I thought id just ask anyway, I ended up not getting it welded and just left it as is.

[600hp]

I've seeen a lot of turbos with with hair line cracks but non of those i have seen have caused a problem.

let us know how the car goes with the new turbo's!