Engine Timing Confusion

bl@ckst@llion00 · May 2, 2016

I have a 2000 mustang gt. It had blown head gasket when I got it but I done gasket jobs before no problem.
I've time everything up and rotate it for clearance..cranks but won't start.
So I go back to timing instructions, I've seen like a thousand ways...

Last attempt..cranks timing mark at 6o'clock..rotated clockwise until mark is at 12(visible) line up LH cam marks..rotated back counterclockwise so crank Mark is at 6.
Repeated for step RH chain. But rotated it counter clockwise and line up RH chain. So I place crank back at "10:30" Marks are all lined up. RH cam@11...LH cam@1

Can someone help me!

wmburns · May 3, 2016

Pictures would help a TON.....often people will mistake the left hand cam bump for the timing mark.

Did you rotate the crank with only one chain installed?

Did you mark the mid points of both chains?

Not a good idea to ever rotate a modular motor backwards.

Do you have an ODB2 scanner?

bl@ckst@llion00 · May 3, 2016

wmburns said:
Pictures would help a TON.....often people will mistake the left hand cam bump for the timing mark.

Did you rotate the crank with only one chain installed?

Did you mark the mid points of both chains?

Not a good idea to ever rotate a modular motor backwards.

Do you have an ODB2 scanner?

No I don't have pictures. I'm taking it apart as we speak. But I have a new ? also. Do I set the crank pulley notch at TDC or 10BTDC on front cover before removing everything?

I'm tackling this again bc I'm getting backfire through intake...no good

bl@ckst@llion00 · May 3, 2016

Initially I did rotate with only lh chain installed. However laid chain out links side by side and marked the two end links. But have a scanner though.

I have the timing marks on chain and sprockets(crank&cam) all lined up. Crank tdc..timing@6o'clock...LH cam is about12-1oclock and RH is at about 11o'clock.

wmburns · May 4, 2016

IF you rotated the crank with only one chain installed, the likely result is now the left and right cam banks are 180 degrees out of phase to each other. This means that the individual banks are IN TIME so there's not PTV contact. But because the banks are out of phase to each other, the fuel injector is firing when the intake valve is closed.

Sometimes the motor will start but the exhaust on one bank will be MUCH cooler than the other. Backfire is another likely symptom.

Also confirm that the PCM is seeing the CKP signal. Using the ODB2 scanner monitor RPM's while cranking. IF the RPM's change, this means the PCM is seeing the CKP sensor. If the RPM's stay at zero, STOP and find out why as it will never start.

bl@ckst@llion00 · May 4, 2016

wmburns said:
IF you rotated the crank with only one chain installed, the likely result is now the left and right cam banks are 180 degrees out of phase to each other. This means that the individual banks are IN TIME so there's not PTV contact. But because the banks are out of phase to each other, the fuel injector is firing when the intake valve is closed.

Sometimes the motor will start but the exhaust on one bank will be MUCH cooler than the other. Backfire is another likely symptom.

Also confirm that the PCM is seeing the CKP signal. Using the ODB2 scanner monitor RPM's while cranking. IF the RPM's change, this means the PCM is seeing the CKP sensor. If the RPM's stay at zero, STOP and find out why as it will never start.

Ok so I'm just now getting back to it. I have covers off but still have the chain and tensioner installed. I haven't taken it off from yesterday's startup attempt. From what I can see...crank is in right position tdc. If I'm lining up the cams with timing marks.. how am I 180 out? Valves over #1 cylinder are closed on compression stroke. What am I missing?

wmburns · May 5, 2016

Pictures of the timing set up would help a ton.

Note, you say that you have researched this and know HOW to do it. Well............ Either you are making a mistake or there's something else wrong. For example the reason for the crank with no start is NOT timing related.

All I know is the 4.6 modular motors are not easy to time. I personally have helped SEVERAL people that swore they knew how to do it (they didn't). If you really want someone in Internet land to help you, then post pictures of the timing set up so that we can see what you think you are seeing.

Engine Timing Confusion

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