TD5 Manifold Modification

[tombraider]

Guys... I mentioned the modifications to the TD5 manifold.

This tip was given to me from a guy Overseas... And it works well....

Here you go:

https://www.aulro.com/afvb/images/imported/2008/01/203.jpg
This is the original manifold warped after use....

https://www.aulro.com/afvb/images/imported/2008/02/306.jpg
You can see the webbing between the ports making it one rigid structure without the ability to expand/contract/flex...

This is what breaks the studs and/or warps the head...

https://www.aulro.com/afvb/images/imported/2008/02/309.jpg
Heres a new manifold that has been modified.
The holes in the end ports are slotted (elongated) to allow movement better too...

Result...
No more leaking manifold...

[ladas]

That's a logical fix.

Thanks

[LandyAndy]

Very good.
I will put it on my to do list!!!!
Andrew

[duff]

:confused: But it is the expansion of the manifold that applies shear load to the studs and snaps them, thats why we enlarge all but the centre holes to allow the slight expansion without contacting the studs. I understood that the warp sets in after the studs have sheared allowing the manifold to lift (curl)

The webbing was actually put in there to try and stop the expansion. to avoid the actual manifolds cracking like in days gone bye (series landys, early valiants, etc).

But hey if it works , there go's more theory:cool:

[Sandtoyz]

We could always go like the Ricer boys do...
and get a custom tuned length exhaust manifold fabricated.
Now that would look sweet :cool:

[duff]

:) .



We could always go like the Ricer boys do...
and get a custom tuned length exhaust manifold fabricated.
Now that would look sweet :cool:

[rjhjstr]

I'd be concerned that without the webbing the expansion/contraction process will actually cause the outlets to flex where they all join and cause cracking at that point. It is a casting after all and not designed to be flexible as it would be if it was fabricated.

Russell

[davros]

Did the later discos two td5s have larger studs or have some just been modified?
Dave

[tombraider]

We could always go like the Ricer boys do...
and get a custom tuned length exhaust manifold fabricated.
Now that would look sweet :cool:

Been done by a guy in Germany who also owns a 2.8L stroker version of a TD5 that he built himself.

[tombraider]

I'd be concerned that without the webbing the expansion/contraction process will actually cause the outlets to flex where they all join and cause cracking at that point. It is a casting after all and not designed to be flexible as it would be if it was fabricated.

Russell

I looked at that... And asked the guy...

But his words were, after 5 manifold removals in 2 years he had to try something!

It's since ran 2 years without incident.

I'm guessing smooth radius in the removal process would be critical to reducing stress points....

[tombraider]

Actually.... Come to think of it...
The modified manifold looks exactly like a ford crossflow manifold!

[rick130]

Been done by a guy in Germany who also owns a 2.8L stroker version of a TD5 that he built himself.

Lara ?
He's in Belgium, isn't he ?

BTW, that TD5 of his snaps Maxi Axles like twigs apparently. His axles are now made by a mob that make a few F1 half shafts out of something pretty exotic.

[Redback]

Your a lifesaver Mike:thumbsup:

Baz.

[tombraider]

Lara ?
He's in Belgium, isn't he ?

BTW, that TD5 of his snaps Maxi Axles like twigs apparently. His axles are now made by a mob that make a few F1 half shafts out of something pretty exotic.

Sorry! Yes, Belgium.....

Yes, he's built a tube manifold and using a different turbo.

I am however puzzled by his comment on snapping maxidrive axles....
He's not making "that" much torque really..... It's a nice project he's done but he's spent more than 2 new TD5 engines doing it...
I'm guessing he's a rev head by his job/company and that his driving style snaps axles.

Even a maxi cant take a slip/grip scenario at 4000rpm in a fully locked, aggressive tyred vehicle in low first.
Interestingly too, the tail shafts would screw apart before maxi axles in 95% of situations.

I asked him for the specs/data on the 2.8l a while ago. Overall I fail to see how its "so much better" - When I emailed JE Engineering who helped him their comment was "A chipped and intercooled td5 makes close to the same output - We wouldnt recommend the stroked engine" I left the idea at that....

[discowhite]

ive been looking at that enging build for ages!
lets just say he must be loaded!

i'll keep my TD5 thanks!


cheers phil

[akelly]

Another option for the exhaust manifold is to drill the holes larger and fit longer bolts/studs with compression springs and flat washers - this allows the manifold some movement. I got the tip from my father who used to do it on large Cats (from memory), but when I did mine I was very short on time so just drilled out the holes - that's been working for about 10,000km now without sign of leaking again.

When my manifold went it sounded like a buggered alternator bearing (squealing) - anyone else get this effect? It had me stuffed after I replaced all the bearings (idlers et al,) and it was still there!

[catch-22]

I was of the understanding that the nuts first came loose 'then' the manifold warped....

[rjhjstr]

When my manifold started leaking I was convinced the squeal was actually the belt slipping. Messed around with all sorts of things to try and stop the belt slipping (so I thought) until i finally realised that the squeal only occurred when I was going uphill and was putting more boot into the throttle. Took the heat shield off the turbo and black soot around no. 5 port.

Russell

[Bush65]

...The webbing was actually put in there to try and stop the expansion. to avoid the actual manifolds cracking like in days gone bye (series landys, early valiants, etc)...
The webbing can't stop thermal expansion.

I have no idea whether removing the webbing will help prevent warping or increase the risk of cracking. Real world testing will tell more than guesswork.

Expansion and stresses due to differential temperatures can be difficult to determine with complex shapes like a cast exhaust manifold.

Years ago I looked into a problem with cracking in crucibles that hold 60 tonnes of molten metal. Finite element analysis showed that the surface area of webs between stiffening rings was loosing more heat than surrounding parts (when exposed to light wind) and the temperature differential caused stress levels in the welds that lead to cracking.

Increasing the thickness of the webs reduced the temperature differentials and reduced the stress in the welds.

[duff]

Of course, I must learn to be more specific,, my day to day involvement takes your point for granted,, target audience etc etc. I forget,

Yes ,, you cant alter basic physics, the engine will submit the manifold to a wide range of temperatures, and with a 4wd you might even get shock loading, rapid coolings, etc.

My statement should have been that the webs have been included into the manifold to try and combat the effects of variant temps. The webbing will attempt to fight tension load being applied to the studs, but may actually induce shear load. Historically, in service results achieved by many brands, showed that the theory of casting a web into the manifold did limit warping and manifold circumferential cracking, especially on inline engines, but it is also employed on "V" engine manifolds in a similar but more specific manner. A negative to this addition was stud shearing. to alleviate this they altered the tolerance of the stud holes.

This is why I found it interesting and am surprised by the success of removing the web. My manifold cracked studs twice, I enlarged the holes on 1, 2, 4, and 5. and have not had any further problems. But I will be pleased to remove the webs if guys get good results from this and I get further probs.

BUT it would be a shame if a heap of guys go down this path and it proves to be an expensive mistake. Webs out easy, webs in, not as easy. my concern would be that a bloke somewhere has done it, one bloke, and a bloke with a record of snapping things,,, if I read previous posts correctly ? I would be interested to see some guys only remove the webs without enlarging the stud holes. it would give a good indication of the method.