Timing mark

[Uncle Arthur]

Did you connect between the TEN and GND terminals in the diagnosis box?

[fastfreddygassit]

yeap i did

do you have a stable idle?

[john!]

When you say it is bouncing around, how far is it bouncing? I found that it usually goes back and forth round 1 or 2 degrees when you have the timing light on. Any more than that though and I don't know. Is your motor short nose or big nose? Maybe some of the more enlightened forum goers may know more.

john

[fastfreddygassit]

I have aftermarket cams in mine and my timing mark doesn't move around.
are you sure the cams where installed correctly?????

[Russellb]

Sound like the Timing belt tension is set incorretly
this is causing the cam shaft to Accelerate and decelerate as the cam
lobe open and close the valves. causing the timing to advance and retard.
or to bounce around as you see it with the timing light.

Hope this makes sense

[fastfreddygassit]

yeap they are installed correctly...

perhaps not....

[fastfreddygassit]

Take the covers off and check the belt tension - adjust tensioner if needed.
Too tight and it will squeal like a supercharger
If you are confident with your cam install, possibly take it back to the guys
that did it and get them to check it for you.
Did you get a new timing belt fitted when you got the cams installed?
ps. If you're in Melb, I have service manual/mx5 mod books that you are welcome to look at if you want to do this yourself.

[fastfreddygassit]

Take the covers off and check the belt tension - adjust tensioner if needed.
Too tight and it will squeal like a supercharger
If you are confident with your cam install, possibly take it back to the guys
that did it and get them to check it for you.
Did you get a new timing belt fitted when you got the cams installed?
ps. If you're in Melb, I have service manual/mx5 mod books that you are welcome to look at if you want to do this yourself.

I had get them and myself to TRIPLE check the cam timing before i dyno tune it......all good...

Timing belt was replaced at 100,000kms and my car only got 140,000kms and the timing belt is still in good shape.

Fair enough but the question was belt tension NOT the timing. Do you have a stable idle? When you TRIPLE checked the cam timing how was the belt tension?

As an aside, my timing belt was only 36K old but I changed it when I did the cams.
It was only around $100 for the belt and I had to take the old one off to do the
cams anyway. Now I don't have to worry about the belt for another 100K