TD5 broken manifold stud - is to deferring repair an option?

Hi All!
I am pretty handy with stuff being a tradie come engineer, but I ruined a good head trying to remove a broken stud!
I will pay a man if I need to do it again!

FWIW, everything I tried made it worse, to the point that when drilling the stud for a second time, to enlarge the hole for a bigger extractor, the bit engaged suddenly into the stud, which rotated clockwise, stripping the thread and before I realised had scarfed through to the water jacket :(
I thought about having the entire hole welded, and the stud hole re-machined, but had another head. Project I'll never get too.

Don’t see the point of ceramic coating. It’s so thin that there would be no insulative properties surely?

I noticed no difference in performance after most of mind flaked off!

But yes, better performance with no exhaust manifold leaks I noticed 😊

Quote:

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Originally Posted by simonmelb

Don’t see the point of ceramic coating. It’s so thin that there would be no insulative properties surely?

I noticed no difference in performance after most of mind flaked off!

But yes, better performance with no exhaust manifold leaks I noticed 😊

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I think some of us were convinced that ceramic coating would lower under bonnet temps... On reflection I'm not so sure. Mine had the 2nd batt over there, but it was right next to the turbo and nobody suggested coating that.

Fixing the leak? Yep, worth the trouble.

I did the following about 6years and about 80+k ago.

1 cut fillets between pipes out. Used a reciprocating saw then bent the bits until broke then ground down remnants.
2 opened out the 1 and 5 holes by slotting them outwards and inwards. 2 and 4 slotted also to lesser degree.
3 then had manifold ground flat. Interesting that warp increased when fillets removed.
4 bought set of Mercedes studs from UK with brass plated nuts.
5 had manifold powder coated inside and out . Coater commented that he was happy that the inside was pretty well covered which is a difficult task.
6 fitted a number of Belleville washers (3?) to all studs to maintain pressure during heat and cool cycles.

I think that the broken stud issue is not from warp as AFAIR the warp was concave. The stud breakage is from the lengthways expansion of the manifold when it gets extremely hot. Toyota deal with this in their 6 cylinder diesels by having a slip joint in the middle of the manifold. Ie the manifold is in 2 parts. so it can expand and contract independently. I think the elongation of the end and near end holes is an important step.
So far no leaks I can see or hear.
Regards PhilipA

Quote:

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Originally Posted by PhilipA

I think that the broken stud issue is not from warp as AFAIR the warp was concave. The stud breakage is from the lengthways expansion of the manifold when it gets extremely hot. Toyota deal with this in their 6 cylinder diesels by having a slip joint in the middle of the manifold. Ie the manifold is in 2 parts. so it can expand and contract independently. I think the elongation of the end and near end holes is an important step.
So far no leaks I can see or hear.
Regards PhilipA

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I totally agree with this, when I had to replace the studs on mine I noticed the studs had rubbed on the manifold outer edges, not the inners, to me this indicated that the ali head had expanded more than the cast manifold (this is just boiler maker logic so use at your own risk...) I de-webbed mine, installed longer studs with spacers (same as on Toyota D4D engines) and drilled out the end couple of holes a size or 2. I didn't have time to get it surfaced but did use some wet and dry on a large sheet of glass, sort of holding up so far. I also painted it with some pot belly black paint, just to stop the rust, so far that is also holding quite well

To the OP they can run a long time with broken studs (mine had 3) will make a bit of noise and may have peak boost issues but nothing that is a real show stopper

cheers

Redd

cheers

Redd

Quote:

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Originally Posted by PhilipA

I did the following about 6years and about 80+k ago.

1 cut fillets between pipes out. Used a reciprocating saw then bent the bits until broke then ground down remnants.
2 opened out the 1 and 5 holes by slotting them outwards and inwards. 2 and 4 slotted also to lesser degree.
3 then had manifold ground flat. Interesting that warp increased when fillets removed.
4 bought set of Mercedes studs from UK with brass plated nuts.
5 had manifold powder coated inside and out . Coater commented that he was happy that the inside was pretty well covered which is a difficult task.
6 fitted a number of Belleville washers (3?) to all studs to maintain pressure during heat and cool cycles.

I think that the broken stud issue is not from warp as AFAIR the warp was concave. The stud breakage is from the lengthways expansion of the manifold when it gets extremely hot. Toyota deal with this in their 6 cylinder diesels by having a slip joint in the middle of the manifold. Ie the manifold is in 2 parts. so it can expand and contract independently. I think the elongation of the end and near end holes is an important step.
So far no leaks I can see or hear.
Regards PhilipA

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Quote:

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Originally Posted by Reddirt204

I totally agree with this, when I had to replace the studs on mine I noticed the studs had rubbed on the manifold outer edges, not the inners, to me this indicated that the ali head had expanded more than the cast manifold (this is just boiler maker logic so use at your own risk...) I de-webbed mine, installed longer studs with spacers (same as on Toyota D4D engines) and drilled out the end couple of holes a size or 2. I didn't have time to get it surfaced but did use some wet and dry on a large sheet of glass, sort of holding up so far. I also painted it with some pot belly black paint, just to stop the rust, so far that is also holding quite well

To the OP they can run a long time with broken studs (mine had 3) will make a bit of noise and may have peak boost issues but nothing that is a real show stopper

cheers

Redd

cheers

Redd

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Very true, I'd forgotten I'd drilled the end holes a number of drill sizes larger, stepping them down as they approached the centre studs to remediate this.

Engines such as the Tdi use slip joints for expansion/contraction. And plenty of other modern TD's snap studs and warp manifolds too. the machine shop that surfaced mine has done plenty of Toyota and Nissan TD's with the same problem.