Timing Issues With Btdc Marks

[Leeroy94]

I reset my timing today on my rb20det. But in order to get 15 degrees BTDC on idle, the CAS had to be turned almost fully clockwise.

Once fully clockwise the idle would drop until stalling and it was also hunting. I have played around with the AAC valve, turning the idle adjustment screw both clockwise (decrease idle) and anti-clockwise (increase idle) and nothing happens.

I'm thinking that the BTDC mark isnt the true mark. Maybe the key slipped out of the crankshaft when the timing belt was changed (previous owner).

Would that explain why the idle adjustment screw on the AAC valve isnt working?

Im really lost and dont really want to remove everything to check if they key is there.

[jiffo]

Only a 5 minute job to pull the top cover and check cam timing against TDC on the balancer.

Cam wheels each have a dot referenced against their respective timing marks on the back cover.

[blind_elk]

If you used the loop on the ignitor, some timing guns double the timing, so you end up setting idle timing @30 BTDC.

[Leeroy94]

Only a 5 minute job to pull the top cover and check cam timing against TDC on the balancer.

Cam wheels each have a dot referenced against their respective timing marks on the back cover.

I did all that. Lined it all up. As far as I know the base timing is good.

[Leeroy94]

If you used the loop on the ignitor, some timing guns double the timing, so you end up setting idle timing @30 BTDC.

Hmm.. Ill look into it cheers

[jiffo]

I did all that. Lined it all up. As far as I know the base timing is good.

Then why suggest the key had slipped on the crank?????

Trouble shooting must be done in logical steps.

Ensuring cam timing is spot on must be one of the first checks.

[Leeroy94]

Then why suggest the key had slipped on the crank?????

Trouble shooting must be done in logical steps.

Ensuring cam timing is spot on must be one of the first checks.

I put a timing light on my car, which showed that my timing was out. Then i took my cas off, followed by my cam cover. Then with a breaker bar and a socket i rotated the camshaft until number 1 cylinder was TDC, and matching the cam wheels.

If the key had slipped on the crank, would it not make the actual TDC mark not accurate? because is has actually slipped out of place? Which would make the engine seem like the timing is out even though the timing light says 15 degrees BTDC?

[Missileman]

when you lined up the marks on the cam gears to the back plate, where did the marks line up on the harmonic balance? Also when you adjusted the screw on the AAC valve did you unplug the electrical connection?

[Leeroy94]

when you lined up the marks on the cam gears to the back plate, where did the marks line up on the harmonic balance? Also when you adjusted the screw on the AAC valve did you unplug the electrical connection?

Yes it all lined up. I just took the harmonic balancer off to check if the keyway was still there and its all right, I double checked.

I disconnected the brown plug connected to the AAC valve, it dropped to 600rpm and then lasted about 5 seconds before stalling. I also tried multiple adjustments on the screw and no difference.

[Missileman]

Quite possibly an air leak if it wont idle when the AAC is disconnected.

[Leeroy94]

What are the methods for detecting air leaks? And where should I start etc?

[Missileman]

An automotive engineer will offer you a smoke test, but some of the backyard boys might suggest you listen very carefully to every rubber pipe, then spray spay start -u - bastard on them to seen the RPM increase...

[Ben C34]

Pressure test to find leaks. search how to pressure test.