Club G40 Forum

Technical => Engine and Transmission => Topic started by: breadman on December 12, 2009, 11:19:45 AM

Title: Big exhaust valves.
Post by: breadman on December 12, 2009, 11:19:45 AM
Does anyone know the exact spec. of the 2mm oversize exhaust valves used by Jabbasport etc? I'm assuming they're not a specially made valve for the Polo head but possibly an O.E. valve that happens to fit?
It's just that it seems that the £100 or whatever it is Jabba charge for them is quite expensive.
After all, they're not sodium filled or 214N valves, just the normal type which are usually pretty cheap.
Anyone shed any light on this?
Cheers,
Richard.   
Title: Re: Big exhaust valves.
Post by: Nick_S on December 12, 2009, 11:35:13 AM
Jabba ones are still bi-metallic though even if not sodium filled. Run a magnet up and down them and you see this. Chap who did my cylinder head said they were definately not OEM spec.
Title: Re: Big exhaust valves.
Post by: breadman on December 12, 2009, 12:16:51 PM
Thanks Nick, so they are a specific valve then?
Title: Re: Big exhaust valves.
Post by: Nick_S on December 12, 2009, 01:03:50 PM
I reckon they have been specifically ordered by Jabba yes. I'm not saying its a good or bad price for them, but they aint just OEM valves from another VAG car.
Title: Re: Big exhaust valves.
Post by: hayesey on December 12, 2009, 01:09:50 PM
yeah they are made to suit. hence the price.  Pitstop once played with using mk2 golf gti valves which are 4mm bigger than the polo ones but it left too small an amount of material between the valves and the exhaust valve and the spark plug hole which would be prone to cracking.
Title: Re: Big exhaust valves.
Post by: breadman on December 12, 2009, 06:38:42 PM
Thanks for clearing this up for me guys.