Thread: Exhaust Manifold

thanks all for the info , its giving me a lot to work on

cheers

FWIW I'm slotting the end and second bolt holes, leaving the webbing, surface grinding both faces and ceramic coating the manifold and using standard studs.

My feeling is de-webbing isn't necessary if the bolt holes are slotted to allow for expansion/contraction.
Most 4cyl manifolds are two/three piece with slip joints to allow for expansion/contraction. We have a 5cyl engine with a one piece manifold and hopefully slotted stud holes, while not quite as elegant as a slip joint will suffice.

its probably not a pretty fix but couldnt you just put a new gasket on and use some off that expanding exhaust sealant/gasket goop. I have use it a few times on other cars and had great success, but none of them were diesel. But it i has warped once what is the chance of it warping anymore

But it i has warped once what is the chance of it warping anymore

Mine has now done about 40KK after deweb, flattening, elongation of holes, ceramic coat in and out and stronger studs.
So AFAIK no further warping.
I keep under 700C when possible with sensor on manifold at turbo mouth.
I sometimes wonder what temps some can get to even with stock map.
Regards PhilipA

Originally Posted by rick130

FWIW I'm slotting the end and second bolt holes, leaving the webbing, surface grinding both faces and ceramic coating the manifold and using standard studs.

On my third exhaust manifold (in 120,000km) that I've owned the vehicle but I know the previous owner did it once before as well. Again used a second hand manifold that had previously warped and had the face redone. This time I've left the webbing etc untouched but had it ceramic coated (which made a big difference to EGT - up to 100*C lower at peak stress points), I fitted the extended studs and spacers to the centre three ports only - couldn't do the outters as the threads in the head have already been redone to suit larger size studs. I drilled the the holes for ports 2 and 4 approximately 1mm larger and the outter ports (1 and 5) approximately 2mm larger to give some movement room. So far this is the longest lasting manifold on my vehicle - it's been on running for a few years now without an issue.

Originally Posted by Noisy

its probably not a pretty fix but couldnt you just put a new gasket on and use some off that expanding exhaust sealant/gasket goop. I have use it a few times on other cars and had great success, but none of them were diesel. But it i has warped once what is the chance of it warping anymore

The problem is it's warped - it's no longer flat - it's now curving away from the head. The gasket goo etc. won't last filling such large gaps. You need to fit have the manifold face dealt with so that it's back to flat.

Each to their own on what method they want to use, de-webbing, larger holes, larger studs, stronger studs etc etc etc.

BUT.. I do get all my TD5 manifolds ceramic coated now for customer jobs and I'm happy with the no returns a few years later.

BUT ALSO, if you are going to flog your TD5 you are going to warp the manifold. Although saying that ceramic coated seems to be more flog proof.

What about allisport manifold? I run that will high boost and 600c egt and not had an problem

Originally Posted by DazzaTD5

Each to their own on what method they want to use, de-webbing, larger holes, larger studs, stronger studs etc etc etc.

BUT.. I do get all my TD5 manifolds ceramic coated now for customer jobs and I'm happy with the no returns a few years later.

BUT ALSO, if you are going to flog your TD5 you are going to warp the manifold. Although saying that ceramic coated seems to be more flog proof.

Originally Posted by twr7cx

The problem is it's warped - it's no longer flat - it's now curving away from the head. The gasket goo etc. won't last filling such large gaps. You need to fit have the manifold face dealt with so that it's back to flat.

Fair enough but i guess it also depends on the amount it has warped too, some seem to warp more than others. I have also seen cases of them returning to almost flat, after dewebbing. Not sure yet how i am going to fix mine, whether i get a replacement one or just machine mine.