I'm looking to have my Mk2 8v head gas flowed and bigger exhaust valves put in but was wondering, where do you get the new valves from? Are they taken from another car? Im looking for 40mm intake and 35mm exhaust. I believe the intakes are that as standard so it'd just be a case of finding the 35mm exhaust ones? Also, on the head I'v got, what is the standard exhaust valve size? Edited by: JamesB
Your head has got 40mm inlets & 33mm exhausts... You want to leave the inlets alone & go 35mm exhaust! 35mm exhaust Valves are available from Autotechnik in Southampton, TSR, C&R etc etc..
The 8v engine is restricted on the inlet. You can net big gains from the inlet ports, manifold and by fitting bigger valves. It is not so essential on the 16v lump, but definitely more so on the 8 You can buy the valves from TSR for 140 plus Vat inlet and exhaust. THese are their Pack C Sizes. 40mm and 35mm respectively. All you need to do then is find a good head builder to assemble to a flowed head. Where in the UK are you?
if that is true why do the likes of TSR or Stealth when they build a BVH change the exhaust valves from 33mm to 35mm and leave the inlet at 40mm? im not saying you wont see an increase from bigger inlet valves, as i have 40.5mm inlet opposed to 40mm, but you would see a better gain from having bigger exhaust valves.
Yeah I'm going to just change the exhaust from 33mm standard to 35mm. Cant see the point in changing the inlet valves. Im based in Norfolk. I have someone in mind who said he can flow the head and fit the bigger valves but if anyone can recommend anyone to me, it'd be appreciated.
So the TSR pack C head has the same inlet size as standard. Doesnt sound to me like the inlet side is where the massive restriction is at... On my own 8v I gained 21BHP@ flywheel (before/after @ Stealth Racing) by using a 40/35 Pack C head instead of a 40/33 Pack A.. I think you are a bit confused perhaps? The Exhaust side is where the most gains are on an 8v head!
i have a complete spare rebuilt 8v stage 2 head with 35/40 valves and a split profile eurorace cam if anyones interested.
There is indeed a head in the classifieds. A good one too. This has 40mm/35mm valves and a Newman 272 deg cam too.
TSR's Pack C and D heads BOTH use bigger inlet valves. I also said that porting of inlet tracts and the manifold nets big gains on the 8v. Been there myself................
It depends what head you had to start with, PB heads already have the 40mm inlet valves whereas on earlier 8v golf gti heads they dont have such large inlet valves in the first place, However in both cases they do replace both the valves with new stainless steel valves.. In either case The statement stands though that the pack D head utilises both larger inlet and exhaust valves..
