11 replies to this topic

[bluemini1979]

What would be happening if a camshaft was timed in wrong? Trying to start project for first time but just getting back fires in the exhaust. Ignition timing is definitely set correctly and set up firing no1 on compression stroke. I've not had the engine running at all and now starting to question whether the cam is timed in correctly.

Thanks

[nicklouse]

for it to be a cam timing issue it would have to be quite far out. if the dots are aligned it should start.

 

double check you do actually have the ignition timing right.

[bluemini1979]

It has fitted a swiftune belt kit which doesn't have any marks on it. Ignition timing is specialist components efi kit which is all set up to their instructions. Doesn't sound like it's trying to fire only in exhaust.

[DeadSquare]

What would be happening if a camshaft was timed in wrong? Trying to start project for first time but just getting back fires in the exhaust. Ignition timing is definitely set correctly and set up firing no1 on compression stroke. I've not had the engine running at all and now starting to question whether the cam is timed in correctly.

Thanks

 

In my experience, the A series can just about be made to run with the chain one tooth out on the cam sprocket by twiddling the dizzy, but it is very obvious that something is wrong.

 

It is not too long a job to take out the rad and remove the the timing chain cover to check the timing.

 

Towing a car with a recalcitrant engine, can often coax it into life.

[Spider]

The Cam timing needs to be a long way our before the engine won't run.

 

Note that you feel sure of yourself that the Ignition timing is right, but I'd suggest it's 180⁰ out.

[bluemini1979]

Ignition timing is on trigger wheel not distributor

[Rorf]

Firing into exhaust - timing way out. Sounds like 180 degree out.

[MiniMadRacer]

I have had this issue on an engine when I mistakengly put the Dist Drive in 180deg out. May not be relevant on this though if its a trigger whell

[mini13]

What cam is it? Put it at Tdc no 1 and check the valves on no 4 are both open ( I think it's no 4)

[sonscar]

Strobe the spark timing and remove any guesswork,sorry if you have already done this but it is vital to do this with trigger wheels.Steve

[InnoCooperExport]

If like you say that because of the way the ignition is set up it can´t be wrong, have you considered the plug leads might be out of order? If that order is reversed it could give the same symptoms as timing being 180 degrees out

[mini13]

checking your other posts is running megajolt? If so have you checked that the triger wheel is positioned to the sensor sees the missing toothe 90 deg BTDC? this catches a lot of people out. if your running edis, you can check the timing  witth a dial back meter witht he ecu unlugged fromt he edis, and you should get 10 deg advance ( failsafe advance) , also beware that most timing lights will read double due to the wasted spark setup, so you'll likly see 20 degrees advance instead of 10.

lean mix can also caus poping out the exhaust ( or even inlet) as the lean mix takes longer to burn etc,

how was the cam timed? dot to dot? or did you measure it, if measured its easy to get BTDC and ATDC mixed up, also if its timed in BTDC i think you get cam lobe contact, below is a handy protractor a freind knocked up, its got Inlet / exhaust BTDC ATDC on it to avoild this issue.

http://www.turbomini...ts/268751-1.pdf

Edited by mini13, 15 November 2019 - 08:29 AM.