14 replies to this topic

[Mctb]

Currently have a mini which my son is using in his first year of autograss, last time out we had a problem with the car not running right.
Have today tried to set the engine to tdc but when no 1 piston is at tdc the the timing mark is a quarter of a turn away also the rotor arm is not at the 1 o'clock position I have tried rotating the engine 4 times plus same result each time. Any ideas

[nicklouse]

rotor arm position has little to do with anything as long as it is pointing to the correct terminal on the cap.

 

damper may have failed. causing the mark on it to move rather than the mark on the pulley.  or they are incompatible cover and pulley, or you may have a failed drive key which has allowed the pulley to rotate.

 

check check and double check.

[weef]

The timing does not slip by the amount you mention and even if the crankshaft pulley was u/s the engine should still run.

You will have to remove the rocker cover and observe the valve position for No1 cylinder . At TDC with No1 on the firing stroke both valves should be fully closed..

If you are unsure of the engine position you can remove the inspection cover on the clutch cover and check the timing marks.

This will have to be your starting point, No1 TDC both valves shut ie clearance on both tappets.

If this is the case you then set the advance required and time the engine. If the timing is well out as you say suspect some mechanical failure.

[Wim Fournier]

With the rocker cover off, you watch the nr 4 cyl rockers: the exhaust is closing whilst the inlet is opening. When the both rockers stand eqaul bended down;, this is the very point the piston in 1 and 4 cyl is at TDC.

[Mctb]

Have checked with the rocker cover off, the timing is 90 degree out, the engine was fully running and used for the last 12 races now the rotor is not match the leads / cylinder

[weef]

Do you mean the valve timing or the ignition timing is out? 

[nicklouse]

Have checked with the rocker cover off, the timing is 90 degree out, the engine was fully running and used for the last 12 races now the rotor is not match the leads / cylinder

so who took the dizzy drive out and changed it?

 

or are you thinking it is out as you have the wrong cylinder on the compression stroke.

[minimans]

It's all a bit confusing to me? If you have the valves rocking on Number 1 then the piston/crank should be at TDC on number 1. Are they? Use the timing mark on the flywheel (if you have any) Lightened flywheels don't always retain the marks.

If all this lines up then check distributor position and change if ness. by removing and refitting the drive shaft. Then see if it will start, I have no idea how it could have moved since it last started but it's a case of going back to the basics at this point and making sure everything is where it's supposed to be.

 

If the valves are rocking on Number 1 and the piston is not at or near TDC I would say check the timing gears and chain as something has slipped or broken.

[weef]

Maybe some of your autograss opposition have just swapped the leads on your distributer cap when you weren,t looking.

[Ethel]

All the above is good.

Be methodical...

Engine is at tdc with the piston at the top of its stroke - pull the spark plug out of no1 (nearest radiator) so you can stick a screwdriver through the hole to check. The timing marks should also line up, if they don't the marks have moved relative to the crank so investigate the pulley.

Next is to confirm the cam and valve timing by seeing if 1 & 4 cylinder valves are as described above - if they're not something is amiss with the cam drive, you'll need to remove the timing chain cover to investigate.

The rotor arm should still point at the dizzy cap plug terminal you've determined is firing from the valve position. If it isn't, either the dizzy drive has failed or, more likely, the dizzy casing has turned in the block.

[nicklouse]

It's all a bit confusing to me? If you have the valves rocking on Number 1 then the piston/crank should be at TDC on number 1. Are they? Use the timing mark on the flywheel (if you have any) Lightened flywheels don't always retain the marks.

If all this lines up then check distributor position and change if ness. by removing and refitting the drive shaft. Then see if it will start, I have no idea how it could have moved since it last started but it's a case of going back to the basics at this point and making sure everything is where it's supposed to be.

 

If the valves are rocking on Number 1 and the piston is not at or near TDC I would say check the timing gears and chain as something has slipped or broken.

Ok this term rocking can cause confusion i have found this before. 

 

if the the rockers are rocking on Number one then piston four is at TDC firing. if the rockers can be rocked by hand on number one then number one is firing.

[Spider]

If you are working from the timing marks on the Harmonic Damper, then your Harmonic Damper is karput and I would strongly suggest not running the engine until it's been replaced, or a bsted crankshaft may result.

[minimans]

 

It's all a bit confusing to me? If you have the valves rocking on Number 1 then the piston/crank should be at TDC on number 1. Are they? Use the timing mark on the flywheel (if you have any) Lightened flywheels don't always retain the marks.

If all this lines up then check distributor position and change if ness. by removing and refitting the drive shaft. Then see if it will start, I have no idea how it could have moved since it last started but it's a case of going back to the basics at this point and making sure everything is where it's supposed to be.

 

If the valves are rocking on Number 1 and the piston is not at or near TDC I would say check the timing gears and chain as something has slipped or broken.

Ok this term rocking can cause confusion i have found this before. 

 

if the the rockers are rocking on Number one then piston four is at TDC firing. if the rockers can be rocked by hand on number one then number one is firing.

 

I've always thought this term to be a bit misleading myself but seems to be the industry term for what we are talking about since I was an apprentice Many many years ago!

[nicklouse]

 

 

It's all a bit confusing to me? If you have the valves rocking on Number 1 then the piston/crank should be at TDC on number 1. Are they? Use the timing mark on the flywheel (if you have any) Lightened flywheels don't always retain the marks.

If all this lines up then check distributor position and change if ness. by removing and refitting the drive shaft. Then see if it will start, I have no idea how it could have moved since it last started but it's a case of going back to the basics at this point and making sure everything is where it's supposed to be.

 

If the valves are rocking on Number 1 and the piston is not at or near TDC I would say check the timing gears and chain as something has slipped or broken.

Ok this term rocking can cause confusion i have found this before. 

 

if the the rockers are rocking on Number one then piston four is at TDC firing. if the rockers can be rocked by hand on number one then number one is firing.

 

I've always thought this term to be a bit misleading myself but seems to be the industry term for what we are talking about since I was an apprentice Many many years ago!

 

i  agree and i think it is something that should be stated clearly when discussing TDC as to what we mean, also being clear which is number 1 cylinder as people get that wrong as well.

[weef]

Well Mctb have you found your trouble yet?. The good advice posted should have pointed you in the right direction in finding why the timing is out.

If not just get back and tell us what you have found .