jtek 0 Posted October 26, 2007 about 6 weeks ago i rebuilt a spare a cylinder head i had for my 1.6 with new seals, reground valves etc. it was also skimmed quite heavily as it was fairly warped (by 8 thou?) the engine now runs really well with this new head on, pulling hard through the mid rev range. however, i expect probably due to the skim i can't run much ingition advance or the car pinks under heavy load lower down the rev range. as i can't really run the advance i seem to have sacrificed a few hundred rpm at the top with the revs running out at 6250. i also know that skimming down a head can retard the cam timing, is this likely to have a large effect? dizzy vacuum advance is working, and i am going to try some 99 octane on the next tank and advance it slightly but does anybody have any other suggestions? thanks Share this post Link to post Share on other sites
Stu 18 Posted October 26, 2007 an 8thou skim is nothing mate, thats around 0.2mm (10thou is approx 0.25). I would expect the difference in C/R to be next to nothing. Has anything else changed since putting the head on? is the cam timed up correctly? did you keep the same cam/pulley? Share this post Link to post Share on other sites
Bally 4 Posted October 26, 2007 To me 8 thou isnt a whole lot unless the head has been skimmed before, did you use a std gasket or a repair gasket(it is thicker) Share this post Link to post Share on other sites
jtek 0 Posted October 26, 2007 no i used a standard gasket, and the head had not been skimmed previously to my knowledge. the cam is a standard 1600 as is the pulley and its all timed as it should be. Share this post Link to post Share on other sites
DaveK 0 Posted October 26, 2007 yeah i second/third the 8 thou, its bugger all, i frequently need to remove over 15 thou on some badly warped heads Share this post Link to post Share on other sites
Anthony 1,003 Posted October 26, 2007 Are you using the same cam and everything as your old engine? Most 1.6 engines that I've driven have been rubbish and not revved like they should (feel more like gutless 1.9's), and I know that alot of people say about the 1.6 cams suffering wear - could be that the head you've rebuilt has a worn cam and that's why it feels a bit lazy, as like the others have said, 8 thou is nothing really to be concerned about. Try playing around with the ignition timing and see if that improves matters - I usually set them up so that they're just starting to pink at WOT in 5th at 30mph odd (2000-3000rpm) and then knock it back a touch, and that generally seems to work well. Again, if you're using another dizzy, try the original one. Share this post Link to post Share on other sites
jtek 0 Posted October 26, 2007 the cam could well have been worn, the engine still pulls very aggressively up to just past 6000 where it tails off sharply. in that aspect the problem isn't very serious, and maybe just reflection of the effects of 130,000 hard lived miles haha. i will look into getting hold of a younger cam at some point probably Share this post Link to post Share on other sites
welshpug 1,678 Posted October 26, 2007 the cam could well have been worn, the engine still pulls very aggressively up to just past 6000 where it tails off sharply. in that aspect the problem isn't very serious, and maybe just reflection of the effects of 130,000 hard lived miles haha. i will look into getting hold of a younger cam at some point probably that's perfectly normal, peak power is around 600RPM so it would tail off quickly! Share this post Link to post Share on other sites
jtek 0 Posted October 26, 2007 yeah i wouldn't really expect an older 8v engine to go to really high rpm, i had just heard limiter figures of around 6600-6800, and to be fair i haven't been in a 1.6 that runs as well as mine so maybe its not an issue really? i need a ride in a really healthy 1.6 to compare, or maybe just a ride in a gti-6 to confirm thats a step for the future Share this post Link to post Share on other sites
