Exhaust Manifold Cracks- What to do?

[Scott]

Hello, i am doing a total engine rebuild (well the whole car will be, engine first) and i have seen some cracks in the exhaust manifold. This is common as i know and i'd like someone to tell me what is best to do, rebuilding it by filling the cracks or built a new one to an exhaust specialist? I know that cast iron cannot be replaced and all extras are alluminum. So.. any opinion or experiences? Also do you still recommend the Piper Exhaust system?

[lotusflasherman]

Hello, i am doing a total engine rebuild (well the whole car will be, engine first) and i have seen some cracks in the exhaust manifold. This is common as i know and i'd like someone to tell me what is best to do, rebuilding it by filling the cracks or built a new one to an exhaust specialist? I know that cast iron cannot be replaced and all extras are alluminum. So.. any opinion or experiences? Also do you still recommend the Piper Exhaust system?

Cast iron can be repaired - I had to have the cast iron exhaust manifold on my Eclat welded many years ago and it's still in one piece - it was in two bits after the exhaust hit a raised drain cover and the manifold broke. I got an agricultural machinery firm to do mine but you can now find specialist firms via the internet. www.castironweldingrepairs.co.uk/classic-vintage-veteran-motor-vehicle-casting-repairs.php

If they are only hairline cracks filling them might be easiest... or this article says just let them rust up - www.lincolnelectric.com/en-gb/support/welding-how-to/Pages/welding-cast-iron-detail.aspx

[dapinky]

I had this problem a long time ago, and on my first repair I used 'Chemical Metal' filler - it seemed to last well, and didn't leak.

Then i got hold of a spare manifold which i had welded, so swapped them over. The repaired one was still holding at that time.

Welding cast iron is a fairly simple process, but required some knowledge and regulated heating/cooling of the item - best left to someone who knows what they're doing (I got mine done by the development department at Jaguar motors, so can't give any idea of commercial prices).

[simonbuk]

I had an exhaust manifold repaired by a company like the one suggested above. Don't really weld it, they heat it up to a few hundred degrees and add more metal into it. Then they run it through a few heat cycles to see if it shows any sign of cracking.

Did a good job and were impressed.

I've got no idea if a new one can be purchased for our vehichles or not, but by the sounds of it probably not or they are very expensive ?

[HJ2]

On the NA there is room to fabricate a custom (and expensive!) spaghetti system.
I don't think there is enough room on the Turbo Charged engine though. It would never fit...
If this is wrong then please educate me as I foresee possibilities for another group buy

[cliff]

My manifold was very badly cracked so I approached a couple of cast iron repair specialists, the quotes I received were astronomical.

I got lucky and managed to find one on ebay for a very good price.

[Scott]

On the NA there is room to fabricate a custom (and expensive!) spaghetti system.
I don't think there is enough room on the Turbo Charged engine though. It would never fit...
If this is wrong then please educate me as I foresee possibilities for another group buy

Well, if it comes for a custom made system, for turbo version seem more important and despite the space (there is always enough space), talking with my mechanic he told me that me there is nothing better than cast iron but in case of performance etc everybody go for the ''spaghetti'' alluminum system you called (here in Greece we call it Octapus because of it's looks) if they are planning to go 400+ bhp.
On the other hand, a friend of mine who owns an EVO X, when his manifold cracked (entirely) he replaced it with a new one even if many were telling him to go for a custom system as he already had a full new big exhaust (75mm). Of course they were people saying the opposite.
I think at first, as the price goes really high to what I'm doing, I will begin by filling it..
But we have to discuss a lot here..

[HJ2]

(there is always enough space)

I very much doubt it, but would love to be proven wrong here!

[Scott]

(there is always enough space)

I very much doubt it, but would love to be proven wrong here!

It ok mate! We're not having an argument! Just saying that custom made is custom because someone does serious job, besides don't forget that Shark had a custom manifold I think

[HJ2]

Haha! No argument here! I am just genuinly interested if it is possible!
I stared at the exhaust manifold many times wondering what could be done without relocating the turbo. (which would mean adapting the downpipe as well) The result of this staring... well, see above

[Grampy]

Look at this on eBay:

https://www.ebay.co.uk/itm/201613035433

LOTUS ELAN M100 SE TURBO EXHAUST MANIFOLD

[Grampy]

Look at this on eBay:

https://www.ebay.co.uk/itm/201612954108

LOTUS ELAN M100 SE TURBO EXHAUST MANIFOLD - UPPER SECTION of

[Grampy]

Look at this on eBay:

https://www.ebay.co.uk/itm/201603358217

LOTUS ELAN M100 SE TURBO EXHAUST MANIFOLD - LOWER 'BOWL' SECTION

[Scott]

Yeah I have seen them, I should buy for a replace after time. Now I will fulfilled it. But I will get those parts for later use

[chrisP]

I would not bother with the last two ebay items, just get a replacement pipe from Piper more horses and lots of weight saved

[dapinky]

Those 2 items rarely fail/break on our cars, and are likely to not be any different to what you already have......

..... but if you want to 'upgrade', then there are options of the complete Piper downpipe (replaces both parts) or the Pre Cat Eliminjator (PCE) which replaces just the lower section - either will join to a suitable exhaust system - not just the Piper one (Which is excellent, anyway!).

[Scott]

:agree:

Those 2 items rarely fail/break on our cars, and are likely to not be any different to what you already have......

..... but if you want to 'upgrade', then there are options of the complete Piper downpipe (replaces both parts) or the Pre Cat Eliminjator (PCE) which replaces just the lower section - either will join to a suitable exhaust system - not just the Piper one (Which is excellent, anyway!).

I know, Piper system is already in my to do list with the downpipe too! Only the manifold is our really common problem