13 replies to this topic

[speedster]

What over size valves options are there for the NA? What the best valve configuration when running itbs and wild cams?

Anybody done this work themselves?

 

 

[vocky]

I would only recommend the GM Racing +0.5mm valves or buy direct from SI Valves and purchase their +1mm valves.

 

My SI Valves did well over 20,000 miles (the head was fitted to three different cars), never had any problems, well until Joe melted the car

 

GM Racing are the best quality

 

ps: For SC the OEM Saab valves are the best option

[FLD]

Might be worth mentioning that the +0.5mm valves fit in the OEM seats (just).  It did concern me as I was just scraping into the alloy when I cut mine in.  Any bigger and you'll have to fit new seats.

[vocky]

the machine shop I use have a fancy valve seat cutting machine and they can do +1mm, but no more on a z22se / b207 head

 

That opens up the valve seat insert to maximum, but I have done quite a few +1mm and so far they are still all okay

[oakmere]

I have the allecotec 1mm over sized but not sure if it was one of the ones that failed on Vocky's. Get the machinist to open up the valve hole (not sure of it name) not just the seat to match. Most of the after market valves also have a waisted stem.

[FLD]

the machine shop I use have a fancy valve seat cutting machine and they can do +1mm, but no more on a z22se / b207 head

 

That opens up the valve seat insert to maximum, but I have done quite a few +1mm and so far they are still all okay

 Braver than me then!  I do tend to err on the side of caution though.

 

Get the machinist to open up the valve hole (not sure of it name) not just the seat to match.  

 Valve throat?

[oakmere]

Yes that's it. They opened up the valve throat up by 1mm as well. +1mm is the maximum size for this head.

[FLD]

I wonder if mine are +1mm, it was a while ago I ordered them.  It'd certainly explain why I felt it was on the edge of the OEM seats.  I got the supertech ones  BTW.

I cut in mine with three angle seats then opened up the throat.  Make sure whoever does it uses a single point cutter not one of those grinder things

[speedster]

What work can I do myself?  Can I manually grind in +.5mm or +1mm valves?

[FLD]

No.  You need a valve seat cutter.

[FLD]

You need one of these:

http://www.ebay.co.u...=item41771c9d90

 

[oakmere]

I think it only cost me £80-£90 to get the valves cut.

[NickB787]

Wouldn't mind +1mm valves in the Saab head

[speedster]

No.  You need a valve seat cutter.

 

 

I think it only cost me £80-£90 to get the valves cut.

 

 

OK, hopefully I can find a decent machine shop that can pressure test, skim and cut