matt1900 0 Posted July 2, 2007 put a 2 litre head on my 1.9, had it properly skimmed and mount corrected. although it now flys above 3k, it runs with a very lumpy idle. i re-checked the emissions and the co is still at 2.5 to 3, but the hydrocarbons are sky high now at about 1300. im sure they were no higher than 400 before. does anyone have any ideas what might cause a slight misfire at idle with this conversion? also anyone know if i'd fail an mot with my hc this high? nice one Matt Share this post Link to post Share on other sites
Dom9 2 Posted July 3, 2007 What cam are you using and is it all timed up ok? The amount of skimming on the XU10J2 head usually means you need to adjust the timing, hence most (if not all) of us who did the conversion used a vernier pulley! Share this post Link to post Share on other sites
matt1900 0 Posted July 4, 2007 What cam are you using and is it all timed up ok? The amount of skimming on the XU10J2 head usually means you need to adjust the timing, hence most (if not all) of us who did the conversion used a vernier pulley! i just used the standard 1.9 cam, is deffo timed correctly. hard to go wrong with pins and marks on belt and pulleys. have to say it didn't occur to me the timing would be affected, i'm a bit of a novice when it comes to mods. vernier pulley it is then- nice one Dom Share this post Link to post Share on other sites
Dom9 2 Posted July 4, 2007 Yeah, the problem is that when you skim 1mm - 2mm off the head to get the compression up, the timing marks are no longer in the correct place! You might be lucky and be a whole tooth out, so you may want to try moving the cam a tooth? The other thing is, do you know how much you did have skimmed off? Does it pink at all? Your compression could be higher or lower than the original 1.9, which may affect things... Or your dizzy could need swinging? A bit of trial and error would probably get it sorted! Share this post Link to post Share on other sites
Anthony 1,002 Posted July 4, 2007 Something's definately amiss with the HC that high as that's alot of unburnt fuel (and high enough that it will fail an MOT). The CO is high but not excessively so (should be 1-2%) so I wouldn't say that it's running mega-rich and hence something else is causing the high HC's. It's certainly not something that's a problem with all XU10 head swaps - my own 1.9 8v with XU10 head has emissions low enough that it will nearly pass a CAT test. Share this post Link to post Share on other sites
matt1900 0 Posted July 5, 2007 Yeah, the problem is that when you skim 1mm - 2mm off the head to get the compression up, the timing marks are no longer in the correct place! You might be lucky and be a whole tooth out, so you may want to try moving the cam a tooth? The other thing is, do you know how much you did have skimmed off? Does it pink at all? Your compression could be higher or lower than the original 1.9, which may affect things... Or your dizzy could need swinging? A bit of trial and error would probably get it sorted! thing is it flies top end, astoundingly so in comparison to my experience with 1.9s', so could it really be a whole tooth out? i had 1.65mm skimmed off after searching for the info on here, which hopefully would have raised the compression a tad. yeah it does pink, worse when hot. i'm still undergoing the trial n error. doesn't seem to accelerate quite as hard when i retard it to reduce the pinking though. is it really possible to stop these cars pinking entirely though? cos there always seems to be an initial pink under sudden accelleration no matter where u got the dizzy. or am i wrong? Share this post Link to post Share on other sites
matt1900 0 Posted July 5, 2007 Something's definately amiss with the HC that high as that's alot of unburnt fuel (and high enough that it will fail an MOT). The CO is high but not excessively so (should be 1-2%) so I wouldn't say that it's running mega-rich and hence something else is causing the high HC's. It's certainly not something that's a problem with all XU10 head swaps - my own 1.9 8v with XU10 head has emissions low enough that it will nearly pass a CAT test. i was kind of linking the high HC with the lumpy idle, thought if it's missing slightly down low when the emisions are being read then lots of unburnt fuel will be getting chucked out. so hopefully solving one prob will cure the other? thats the plan anyway lol Share this post Link to post Share on other sites
j_turnell 136 3 Cars Posted July 5, 2007 Sounds like the advance curve is wrong possibly, have you checked your ignition timing? Share this post Link to post Share on other sites
Mattsav 1 Posted July 5, 2007 Either the cam timing is off or a valve is bent/seating badly Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted July 5, 2007 With the head skimmed you really ought to use a vernier pulley to get the cam timing correct again. I am currently looking into this for a friends car that has a skimmed 1900 head & cam fitted on a 1.6 bottom end & I've run out of adjustment on the dizzy slot trying to get it to run perfectly. The previous owner of the engine in that car said with the timing pins fitted the cambelt was approximately half a tooth out so there is definately some room for adjustment. I'm hoping to do this the easy way rather than have to get a DTI etc set up to check the cam is timed correctly by fitting the timing pins & marking the cam so I can check it hasn't moved & then fitting the vernier I have from a 106 TUD engine & then loosening the vernier bolts so when I tension the belt it moves the gear teeth rather than the whole cam thus keeping the cam timed to the crank as intended. Graham. Share this post Link to post Share on other sites
matt1900 0 Posted July 6, 2007 nice one lads. think i'll get myself a vernier and have a play, hopefully this can improove things. really hope there aint a dodgy valve - they all looked ok. so it's possible to run out of adjustment on the dizzy? great that should complicate things no end! thanks again. matt Share this post Link to post Share on other sites
welshpug 1,656 Posted July 6, 2007 Whenever the cam timing is altered the Ignition timing needs checking and re-setting as the dizzy runs off the cam on an XU. Share this post Link to post Share on other sites
matt1900 0 Posted July 23, 2007 been pretty busy and only just got some time to look at this problem again. haven't managed to get a vernier pulley either, which i'm probably gonna have to do, but i'm tempted to slip the cam pulley a tooth to see if there's any improvement, so i've got 2 quick questions to ask. someone told me that skimming would have retarded my cam timing so i need to advance to correct it, can anyone confirm this?? also, is there any risk of me causing damage by shifting 1 tooth? just wanna be sure. ta matt Share this post Link to post Share on other sites
puginfo 0 Posted July 25, 2007 so it's possible to run out of adjustment on the dizzy? great that should complicate things no end! >>> how did you get the XU9 dizzy onto the XU10 head? was it going direct into the place where the original coil pack was or using the XU9 water sensor housing? Share this post Link to post Share on other sites
Anthony 1,002 Posted July 25, 2007 Just use an XU9 thermostat housing rather than the XU10 one. Dizzy then goes straight on with no hassle. You shouldn't run out of adjustment unless either the cam timing is way out or there's a problem with the dizzy itself Share this post Link to post Share on other sites
matt1900 0 Posted July 25, 2007 (edited) advanced the cam by 1 tooth, started pinking very badly so had to retard the dizzy loads to stop this. seems to be more power below 3k now but maybe not quite as much as before ubove 3k. suspect the cam wasn't a full tooth out so gonna have to get a vernier pulley. of course i haven't really got a clue what i'm doing, so it's trail and error all the way. matt oh yeah, and the dizzy has a lot more range on the adjustment now. Edited July 25, 2007 by matt1900 Share this post Link to post Share on other sites
matt1900 0 Posted August 2, 2007 found the reason for my misfire at idle, i was losing compression through spark plug no3. so i was arsing around with the timing for nothing, what a bell end i am. ive put it all back the way it was before. defo gonna wait till i get a vernier and the help of someone who knows what they're doing with a dti gauge before i try messing with the cam timing again. till the next pointless thread, i bid u farewell. matt Share this post Link to post Share on other sites
