# Finally doing my heads. Have some questions.



## diabolical1 (Mar 26, 2005)

I've finally started working on my heads and I've got a few questions for any of you that will share. For now, most of it is exhaust side because that's where I am, but I'll use this thread to ask whatever questions come up along the way.

1. With the combustion chambers turned up and the exhaust side away from you, there is a port next to the valve guides in the LEFT ports only. I'm curious what those ports are for.

2. I've seen some people do heads where they shave the valve guides flush with the port bowl and others where the guide are left alone. I doubt if any testing has been done, so I'll ask for opinions here. I can guess what the presumed benefit is, but what are the drawbacks of shaving the guide flush? 

3. Has anyone ever tried to alter the combustion chamber on one of these heads to de-shroud the valves - particularly the exhaust valves?

4. In this thread: http://www.audizine.com/forum/showt...alves-before?p=7207879&viewfull=1#post7207879 - the final post talks about Inconel being brittle. In his defense, he also said that he was drumming up a worst-case-scenario, so I get that. I also understand that a broken valve - ANY broken valve - is shrapnel and can cause collateral damage. However, until now I had pretty much decided to go with Inconel. I just want to hear thoughts on using stainless versus Inconel.

5. Retainers ... I just wanted to know what upgrade options are out there beside Titanium. Has anyone here used OEM retainers with upgraded springs with good, LONG-TERM results? I am leaning toward going with upgraded springs (I'd say 75/25 right now), but I get mixed advice on Titanium in long-term use. I just want to know what options are available and OEM can remain an option for these engines.



Thanks for any information, advice or references.


*Non-Technical question* - Considering all my exhaust valves were FUBAR'd, does anyone have any straight ones laying around gathering dust? If I can get 6 that would be great, but I can make 2 work just as easily. I basically need some to do the combustion chamber work when I get to it.


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## diabolical1 (Mar 26, 2005)

I've got a few answers along the way, so I figure I'll post them just in case anyone ever has the same or similar questions ... doesn't seem likely, but .....

1. They are SAI (Secondary Air Injection) ports. They seem to be emissions-related for automatic cars. The manual cars have the external paths to the ports capped from the factory. I will investigate further.

2. As I figured, shaving them has no realistic effect. Some people do. Some people don't. Increased wear (due to possible side-to-side valve movement) might result though.

3. Still no response from anyone who has tried or thought about trying.

4. There doesn't seem to be any head-and-shoulders advantage to using Inconel over stainless steel. So it pretty much comes down to personal preference and (I guess in some cases) budget.

5. There does not seem to be any significant incidence of retainer-related failures in the Audi 2.7T community, at least none that I have seen reported thus far. I am therefore open to using them now.


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## PernellGTI (Jan 1, 2010)

seems like the 2.7T section is dead


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