scutter
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| posted on 5/5/09 at 04:48 PM |
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Cam timing Vs Map
Just want to run a few things past you lot before I strip my head down again.
I've just ported the 1800 cylinder head on my 2L blacktop zetec( the swap was done to raise the compression ratio), after a while messing about
with the shims all the valve clearances are at the upper limit ready for them to bed/close in.
Now the problem, I've a high idle, around the 1400rpm mark and the map value has risen from 42/44 from before to 49/52 now.
Could this have been caused by the inlet being one tooth out?
I used the 5mm bar to lock both cams in position and had a dowel in No1 spark plug hole to find TDC.
Getting bored with the problem and sorely tempted to leave it in the garage this summer.
Dan.
The less I worked, the more i liked it.
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Danozeman
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| posted on 5/5/09 at 04:55 PM |
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Is it actually a tooth out?? It would give you problems. Have you checked the timing since you did it?
Are you injection?? A change in compression ratio can alter the fueling required,.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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scutter
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| posted on 5/5/09 at 05:21 PM |
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The only problem i can see with the timing belt is I wound it the wrong way(did without the manual) I went crank pully- 2 pulleys-exhaust cam-inlet
cam-tensioner.
In theory, the compression raised from 10 to 10.7, not sure how much affect this will have. I've ust been out and sprayed around the inlet
with the engine running with easy start, no rise in RPM so i'm assuming no air leaks.
ATB Dan.
The less I worked, the more i liked it.
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diyer
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| posted on 5/5/09 at 05:49 PM |
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It is normal to use a crank locking pin in the side of the block to gaurantee bottom end timing.
Hug a Hoodie!
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scutter
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| posted on 5/5/09 at 05:56 PM |
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Those are great when you have them
Dan.
The less I worked, the more i liked it.
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Rob Lane
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| posted on 5/5/09 at 06:00 PM |
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If it's steady state 1400rpm, with no fluctuation. Can't you adjust idle screw.
Is there no idle screw in throttle quadrant?
[Edited on 5/5/09 by Rob Lane]
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GeoffT
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| posted on 5/5/09 at 06:16 PM |
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Dan, it can't run at 1400rpm without a supply of air. IF your throttle quadrants are fully shut, then you've got an air leak, and the
higher kpa figure seems to support this.
I know you've already thought down these lines, but worth a further check around the t/b's and inlet area I reckon. I suppose the
t/b's haven't got horribly out of balance by any chance?
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MikeRJ
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| posted on 5/5/09 at 09:11 PM |
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quote:
Originally posted by scutter
and had a dowel in No1 spark plug hole to find TDC.
Did you just turn the crank until the dowel appeared to be at it's highest position? If so it's probably miles out.
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ned
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| posted on 5/5/09 at 09:18 PM |
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Agree with Mike, you need a dial gauge to get it accurate.
beware, I've got yellow skin
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scutter
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| posted on 6/5/09 at 08:41 AM |
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ok I kinda worked out TDC, the amount of dead travel at the top of the rotation is quite large, so I measured the amount of rotation between the end
of it rising and starting to fall again then halfed it. That should be it shouldn't it?
Off the the shops now to get a dail gauge, infact I'll go and nick one of Cheffy. ;-)
ATB Dan.
[Edited on 6/5/09 by scutter]
The less I worked, the more i liked it.
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scutter
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| posted on 6/5/09 at 11:55 AM |
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Ok update time, I've checked the cam timing. I'm within <1 deg of TDC with the 2 cams slots aligned, so I was worring over nothing
(not bad for the MK1 eyeball)
I've pulled all the plugs to make it easier to turn and 3 are good with one fouled, I suspected the coilpack so a new one is on it's way(
i've already replaced the plugs and leads).
I tried to balance the bodies, 1-3 all come within each other and No4 cylinder sits low, the idle adjusting screw is not in contact with the arm so
should i try to bend the tab between 3&4 cylinders to allow more range of adjustment?(everythings screwed down tight at the mo).
Need to grab some more petrol and wait for the coil before i can play anymore.
ATB Dan.
The less I worked, the more i liked it.
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GeoffT
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| posted on 6/5/09 at 12:52 PM |
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Bending the tabs between the itb's to get adjustment within range should be ok, just be careful how you do it, you don't want to twist or
bend the spindles.
Whilst you're doing this it's probably worth checking that you've got no spring or slack from end to end (i.e. 1 to 4) on your
throttle linkage between individual bodies, and into the tps - I know from experience that this messes up your off idle fuelling, especially if
you're running alpha-n which relies heavily on the input from the tp sensor.
I've found the easiest way to set up the balance is to remove each injector plug in turn whilst it's ticking over and check that the
change in engine note (i.e. the drop in rpm) is the same for each cylinder. This ensures that it's ticking over evenly on all 4 cylinders, which
is the object of the exercise really.....
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scutter
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| posted on 6/5/09 at 01:34 PM |
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Geoff, I use a 4 gauge balancer, plumbs into the spare ports on the throttle bodies and the fuel pressure reg take off.
I'll give it a go tomorrow, looks like the coil pack had failed or I might have fitted the U/S one that was on my shelf by mistake . The other
I had had a problem with another cylinder, so swapping them over has moved the fowled plug.
ATB Dan.
The less I worked, the more i liked it.
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GeoffT
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| posted on 6/5/09 at 02:16 PM |
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Ok mate, sounds like you're making proress, hopefully it now won't be sulking in the garage all summer
You shouldn't have mentioned your bells and whistles balancer, there'll be a waiting list to borrow that now..........
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scutter
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| posted on 6/5/09 at 06:37 PM |
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Bugger, didn't think of that
Dan.
The less I worked, the more i liked it.
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scutter
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| posted on 8/5/09 at 02:40 PM |
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I think I found the problem
Dan.
The less I worked, the more i liked it.
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GeoffT
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| posted on 8/5/09 at 04:18 PM |
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.....wanna share it with us Dan?..........
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scutter
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| posted on 8/5/09 at 08:45 PM |
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Sorry for giant image, my inlet port egde sits at the bottom of the inlet rubber seal in the photo, with new seals which haven't been flattened
(roughly half the width) the seal was not in contact with the cylinder head, hence a lot of sucked in air I borrowed an inlet of cheffy and it now
idles nicely.
See add in wanted section for some old seals, yes i threw them away!!!
ATB Dan.
The less I worked, the more i liked it.
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