Rik 0 Posted January 7, 2006 Are the 1.6 gti and 1.9 gti valves interchangeable? i.e. are they both the same? Rik Share this post Link to post Share on other sites
pacey205 2 Posted January 7, 2006 The very early 1.6 heads (the 105bhp ones) are different to the 1.9 heads but the late 1.6 heads (115bhp ones) are basically identicle. Only the cam is different. So the valves between a late 1.6 head and a 1.9 head should be interchangeable yes. Michael Share this post Link to post Share on other sites
Anthony 1,003 Posted January 9, 2006 Valves are identical between later (1987-on) 1.6's and 1.9's (XU5JA and XU9JA/XU9JAZ) engines and have exactly the same part number. As said, the valves on the early 105hp 1.6 heads (XU5J) are different as they're smaller than the later valves. There's very few of these heads around now though, and with the later big valve heads being so cheap to buy you'd be better off upgrading at the same time. Share this post Link to post Share on other sites
MartinR 0 Posted January 9, 2006 in the later heads, the cam profiles are pretty much the same, but the way they are machined is different... So the cams are interchangeable. Share this post Link to post Share on other sites
GLPoomobile 958 Posted January 9, 2006 So presumably there is absolutely no gain to be had by putting a 1.9 head and cam on a late 1.6 block then? I've heard some people mention it as an upgarde but thought it was s*ite as they are the same. Do the 1.6 and 1.9 engines run the same compression? Share this post Link to post Share on other sites
boombang 2 Posted January 9, 2006 1.6 is higher compression but its nowt to do with the head. Share this post Link to post Share on other sites
Anthony 1,003 Posted January 9, 2006 9.8:1 for a 1.6 GTi, 9.6:1 for a 1.9 GTi, and 9.2:1 for a 1.9 GTi CAT Apparently speaking to someone who's done it (having not done so myself), using a 1.9 cam on a 1.6 makes it loose some of it's camminess and revviness and feel more 1.9 like. No idea what happens the other way around though... Share this post Link to post Share on other sites
GLPoomobile 958 Posted January 10, 2006 using a 1.9 cam on a 1.6 makes it loose some of it's camminess and revviness and feel more 1.9 like. Would that be a bad thing then? With the 1.6's power deficit, surely it's the revviness that is the only plus point over the 1.9. Share this post Link to post Share on other sites
Anthony 1,003 Posted January 10, 2006 Well from he described, it basically loses you all that's fun about a 1.6 lump but doesn't give you the torque of a 1.9 lump (as there's no way a slightly different grind of cam is going to make up a 325cc deficit in capacity, and torque is within reason a function of engine capacity). Thus I'd say it's a lose-lose situation. Certainly the guy that tried it went straight back to the 1.6 cam from memory - can't remember who it was that I was speaking to about it now though... Share this post Link to post Share on other sites
Dom9 2 Posted January 10, 2006 Doesn't the 1.6 cam have more lift but the 1.9 cam have more duration... Since these XU 8v's seem to like duration, I thought the 1.9 cam was considered an upgrade to the 1.6 head, albeit a mild one? I would have thought it would make it 'more revvy' if anything? Has anyone ever actually stuck a 1.6 on the rollers, then dropped a 1.9 cam in and seen what it does? It would be interesting to have a definitive answer! Considering you can get a 1.9 cam for free or £5 worst case scenario, if you had to rebuild the head and you got a couple of brake more, it might be worth it... And the actual cam wears better than the 1.6, right? Just food for thought! Share this post Link to post Share on other sites
Anthony 1,003 Posted January 10, 2006 According to the main site, the 1.6 cam has 1.8mm more lift and 4.5 degree (inlet) and 5 degrees (exhaust) less duration. Share this post Link to post Share on other sites
