9 replies to this topic

[mjpuds]

ok my problem started with a quick replacement duplex chain easy...sadly to find i had a odd chain and cam wheel setup fitted..so my spare duplex chain was no good..so out came my spare cam belt kit and off came this rare but odd 11 link duplex chain monsters of a chain (look back over old posts to see photos)all was going well then we went on holiday mid set up...im pretty sure nothing moved..cam wheel and crank took off lined up replaced lined up ....but when o got back from hols..refitted belt ..set up it ran nasty number 1 chamber missing the beat not firing odd spark (yes)ok rechecked every thing to find tdc was not tdc .when the dot line up chamber 4 is at closed valves stage and rotor arm is firing on four not one..and when rotor arm is firing on one (at two oclock ish)valves are both not closed...ok .. is there any way i can do this with keeping engine in car ...i can remember (weeks ago now)matching up dots carefuly removing old drive setup..refitting tipex to mark wheels....all i can think i must of done was to remove old cam drive setup when not using chamber 1 as tdc but may be using chamber 4....ahhhhh..

any one know anyone in the winchester area..that could help out ...just i dont want to move it ..either for money or parts.....

[lrostoke]

I'm just trying think if just swapping the plug leads round would work...I can't actually think why it wouldn't

just move all the leads round 2 places.

Although I don't think you can actually put the cam in wrong if you just do it by lining up the dots on the cam gear and crank gear ??

Was the dizzy drive shaft removed, maybe thats in 180 wrong

Edited by lrostoke, 02 July 2010 - 09:10 AM.

[Guess-Works.com]

Just looked for the photo, when you said 11 link chain.... GrahamC gave you the answer, it's a KENT HVC, and to be honest.... knocks spots off a belt drive you should have kept it on there... they are bullet proof...

I've had one for years and I suspect when I next strip the engine, it'll find it's way back on without me even looking at it..

[Ethel]

Am I right in thinking No4 should be firing when the dots are lined up?

[GraemeC]

Swapping leads around won't work, you need to alter the cam timing if it is incorrect, not the ignition timing.
Can be done in car, take rad out and off you go.

[lrostoke]

Am I right in thinking No4 should be firing when the dots are lined up?

Think your right there, that confused the hell out of me when I last fitted a chain and sprocket set
You'd expect everything to work of TDC No1, but its actually No 4 @ TDC (compression) when the dots on the gears line up.

Edited by lrostoke, 02 July 2010 - 10:37 AM.

[Ethel]

Swapping the leads round would work - if it was wasted spark, like the MPI 1 & 4 would both fire together and you'd never notice. The odd pluglead might be too short though, and to avoid further confusion, it might be easier just to set it a tdc with the valves rocking on 4 then refit the dizzy and its drive gear.

[mjpuds]

Just looked for the photo, when you said 11 link chain.... GrahamC gave you the answer, it's a KENT HVC, and to be honest.... knocks spots off a belt drive you should have kept it on there... they are bullet proof...

I've had one for years and I suspect when I next strip the engine, it'll find it's way back on without me even looking at it..

Sadly it was very slack 40mm movement... I was looking at putting a tensioner on but it looked like a lot of slack to make up..

[Guess-Works.com]

Am I right in thinking No4 should be firing when the dots are lined up?

Think your right there, that confused the hell out of me when I last fitted a chain and sprocket set
You'd expect everything to work of TDC No1, but its actually No 4 @ TDC (compression) when the dots on the gears line up.

This is correct, to time a cam properly you need no1 to be at tdc but on the exhaust stroke otherwise you would not be able to measure the LCA of the inlet cam lobe, which will be opening... The LCA ( Lobe Centre Angle ) is the number of degrees after TDC that the inlet on No1 is open at it's maximum, obviously on the compression stroke and after the inlet is closed... This is where the quoted figures like 106 degrees (normal LCA for Kent cams) comes in. So for example, if you are checking a 'dot to dot' set up, using a DTI and a timing disk you can actually see how accurately the timing gears and cam are machined, and can adjust ( if not a vernier setup ) with offset woodruff keys... I've known 'dot to dots' to be over a tooth out in timing...

However, when you think about it, it's not the position of the crank which determines the 'stroke' it's on, it's the cam, so with pistons 1 and 4 @ tdc, you then turn the cam so that no1's inlet and exhaust are "on the rock", and then fit the timing gear.

Edited by Guess-Works.com, 02 July 2010 - 11:34 AM.

[mjpuds]

any idea of any good mobile people to do this work .in the hampshire area.. i had loads of longterm prostate problems and i get so little moments of pain free i just dont have the time to one work this out and also just do it..

engine was kicking out over 105 bhp before
so i dont just trust any old harry on it..

michael