I would check your cam timing which can be hit and miss with the stock pulleys. It should be around 35 thou lift at TDC on the inlet and 30 thou lift at TDC on the exhaust.
There is an article on my website on how to check this.
www.dvpower.com
Dave
VVC Exhaust cams in a 1.6K, poor running.
Morning guys and girls,
I fitted a pair of VVC exhaust cams to my 1.6 16v the other week and it idles very lumpy first thing (and if you leave it for a few hours) as if i had more aggressive cams in it.
It does smooth out after about 15 minutes or so of driving and it is fine throughout the rev range, its just the idle.
I know a few people that have fitted VVC exh cams to 1.4's and 1.6's and havnt had this problem so im abit baffled.
Ive also got a misfire, which is starting to get worse but ill be checking the ignition system this weekend to try and solve that.
I did have to space out the distributer as i found the spigot drive must not be far enough in as the rotor arm was wearing the inside of the distributor cap away (have both been subsequently changed)
If you take a look at the video i have attached, if i compress the breather pipe from the inlet to the throttle body, the engine calms down but driving with this compressed (as i experimented) makes the engine bog down big time and usually stalls under load.
http://www.flickr.com/photos/[email protected]/4981959369/
As you can see its got a VVC inlet, 52mm throttle body, ZR 160 ITG panel filter, and the exhaust system is now a decated Metro GTi system (video shows it as a Scorpian exhaust but have changed that since).
Im not sure if its because the ECU cant cope with the new cam specs, might it be worth trying a 135 ecu set?
Hope someone can help as its doing my head in now.
Thanks
Andy
I fitted a pair of VVC exhaust cams to my 1.6 16v the other week and it idles very lumpy first thing (and if you leave it for a few hours) as if i had more aggressive cams in it.
It does smooth out after about 15 minutes or so of driving and it is fine throughout the rev range, its just the idle.
I know a few people that have fitted VVC exh cams to 1.4's and 1.6's and havnt had this problem so im abit baffled.
Ive also got a misfire, which is starting to get worse but ill be checking the ignition system this weekend to try and solve that.
I did have to space out the distributer as i found the spigot drive must not be far enough in as the rotor arm was wearing the inside of the distributor cap away (have both been subsequently changed)
If you take a look at the video i have attached, if i compress the breather pipe from the inlet to the throttle body, the engine calms down but driving with this compressed (as i experimented) makes the engine bog down big time and usually stalls under load.
http://www.flickr.com/photos/[email protected]/4981959369/
As you can see its got a VVC inlet, 52mm throttle body, ZR 160 ITG panel filter, and the exhaust system is now a decated Metro GTi system (video shows it as a Scorpian exhaust but have changed that since).
Im not sure if its because the ECU cant cope with the new cam specs, might it be worth trying a 135 ecu set?
Hope someone can help as its doing my head in now.
Thanks
Andy
1 - 12 of 12 Posts
There is an article on my website on how to check this.
www.dvpower.com
Dave
Thanks Dave.
Timing isnt my strong point, someone else fitted them and timed it with the engine in the safe position making sure the pulleys lined up, turned it over by hand and made sure they lined up again and that was it.
Does it sound like a timing issue? Would this not affect the engine through the rev range?
Thanks
Andy
Timing isnt my strong point, someone else fitted them and timed it with the engine in the safe position making sure the pulleys lined up, turned it over by hand and made sure they lined up again and that was it.
Does it sound like a timing issue? Would this not affect the engine through the rev range?
Thanks
Andy
Depending on which cam is out, how much it is out and in which direction the results of incorrect cam timing can even mean an improvement in performance in some parts of the range. Just checking that the three timing marks are lined up is very simple and a good starting point.
If you have too much overlap this will mess up the MAP signal that the ECU relies on to run the engine, at idle this is critical. Once above 2000 RPM, this has a much smaller affect and you are much more likely to notice the change in the torque curve.
It's worth investing the time to check it before you go of on a wild goose chase.
Dave
It's worth investing the time to check it before you go of on a wild goose chase.
Dave
Thanks both.
Just to make sure im checking the right thing, do i need to turn the engine over so that the bottom pulley is marked at TDC then check that the lettering on the cam pulleys line up?
As i say timing isnt my strong point, but i appreciate the help
Thanks
And
Just to make sure im checking the right thing, do i need to turn the engine over so that the bottom pulley is marked at TDC then check that the lettering on the cam pulleys line up?
As i say timing isnt my strong point, but i appreciate the help
Thanks
And
Brilliant thanks fella
also buy a cheap engine vacume gauge as poor idle vacume will confirm cam timing and ignition timing issues, and as the ignition timing cant be tinkered with unless you have flywheel or crank sensor issues that leaves the cam timing.
for a 16 valve engine i would expect 12 inches of mecury min, dave andrews should be able to give you a most precise normal figure
for a 16 valve engine i would expect 12 inches of mecury min, dave andrews should be able to give you a most precise normal figure
Sorry but that only checks that the pulleys are in the right position and it needs to be done at 90BTDC. There is so much latency in the belt drive train that the cams can be a long way out even when the markings line up, in some caes up to 12 degrees.Thanks both.
Just to make sure im checking the right thing, do i need to turn the engine over so that the bottom pulley is marked at TDC then check that the lettering on the cam pulleys line up?
As i say timing isnt my strong point, but i appreciate the help
Thanks
And
with stock cams this is realtively unimportant as they are short duration, the more duration /valve acceleration you have the more significant this becomes.
The way to check your cam timing is right is to measure the lift at TDC and there is a method for doing this on my website at www.dvapower.com.
Lift at TDC for those cams should be 35-40 thou (.875 -> 1.0mm) on the inlet and 25-30 thou(0.625-0.75mm) on the exhaust.
If there are significantly different to this then that could be your problem.
Dave
I have had a look at it today and think i have solved the problem.
I checked the ignition side first as i had to fit a new distributor drive peg a few weeks back (the position of the previous one meant i had to spin the distributor drive round about 30degrees so that it would run) so on the offchange that i had fitted this one in the wrong place i twisted the distributor round anti clockwise about 5 degrees and it seems to have solved the running problem, rev fine through the range and idle well.
Im not sure if its still worth checking the timing, will see how it runs.
Need to design a permanent way of fitting the distributor in this position or get another drive peg.
I checked the ignition side first as i had to fit a new distributor drive peg a few weeks back (the position of the previous one meant i had to spin the distributor drive round about 30degrees so that it would run) so on the offchange that i had fitted this one in the wrong place i twisted the distributor round anti clockwise about 5 degrees and it seems to have solved the running problem, rev fine through the range and idle well.
Im not sure if its still worth checking the timing, will see how it runs.
Need to design a permanent way of fitting the distributor in this position or get another drive peg.
I also noticed a white very very fine powder on the distributor and on the rotor arm, is this caused by the misfiring?
1 - 12 of 12 Posts
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