355 Cam phase sensor malfunction

I do not know. Things moving at speed move more than things moved at hand crank speed. A few things you can do are: If you have a borescope look the plug holes. I like cleaning my intake valves when I do majors. That means plenum off so you can get an easy look at the condition of the intake valves. You can put the belts on the assembly marks then on a good bank side move 2 teeth in the errant direction and lock that down. Now gently hand turn the motor in driven direction and see if you feel any resistance. You have to be careful and stop if you feel any. If not you have a better chance of having not hit anything. You can also leak down the motor. That should be real fast since it is out of the car. Good numbers imply everything can seal. If you really thought about it, you could probably do the math and see if you have mathematical interference.

 

No, I don't really think a back fire was the cause. A backfire might be the result. It's strange because I believe you said the car was running right. Sometimes a engine will move backwards a little on shut down if one cylinder stops on compression just before TDC. I can imagine the engine rotating correctly with the belt tight in the tension side and floppy on the bearing side and then jump a little backwards and the drive pulley doesn't engage the loose belt to pull the cams with it. But that's just a guess.

You will only know by checking timing.

No. If the cams are retarded the exhaust will close late witch could lead to the exhaust being bent. But your original diagnostic codes seem to point to bank 1 as the cam sensor is on bank 1. So the codes are saying the cam and crank sensor are out of sync.

You a compression test will tell you if there is damage. A borescope through the plug holes will tell you the extent of the damage.

 

From my personal experience 10 years ago, those Hill Engineering tensioner bearings need to have a certain clearance to the tensioner arms they mount to. There is no published spec but I always check with a feeler gauge AFTER installation to make sure I get at least 0.50 mm or more. The first time I used the Hill Engineering bearings on a OBD 2 car my timing skipped one tooth, and if I drove it more, it would have skipped another tooth.

Secondly, the pivot arms need to have free movement with the bushing not binding. You want to check and replace as needed.

Third, the mounting bolts for the bearings need to be torqued correctly, to spec, and with the correct technique.

Grant, you coughed up to a couple of these errors (brave man) so I would venture these to be the causes. As to what to do now....

1. Find TDC on Cyl 1 with a degree wheel or a piston stop (I prefer degree wheel).
2. Inspect the assembly marks on the four cams. Out by 2 teeth will be very obvious. The bank giving you trouble will identify itself.
3. Stick an inspection camera down the four spark plug holes of that bank and see what damages if any on the pistons
4. Replace the belts, retime the cams again with a degree wheel to specs, torqued properly
5. Perform a compression test and a leak down test with the engine out of the car. That will give you even more information.

If no issues are found with compression and leakdown, put the engine back. I think you are getting to the real cause of this issue and no longer chasing your tails. Good man.

 

I'd perform the borescope inspection first. I can not imagine there would not be some marks on the pistons if the valves are bent. If there is damage, doing the test won't result in more. Check 1-4, then 5-8. You don't even have to rotate the engine. Either al cylinders on one back have bent intakes or exhausts or none do. No sense in going to all that trouble of timing and new belts if it has to come apart.

 

Use the factory assembly marks. Using paint marks increases error. Placing a belt where it was last time increases error. Assembly marks are the key reference point Ferrari intended along with TDC found with dial gauge. Doing this job without knowing TDC is just guessing and hoping.

"Tighter" is not the answer and can lead to failure in a different way. Proper torque per the factory spec is what you want. Lacking a torque spec we use experience and approximate torques given fastener size and material. You can just google those. This is a no force job. An arthritic 60 y/o is all the strength you need. a new belt is stiff. Doing things like removing cam cogs to install cam time etc make for zero effort belt install. the new stiff belt is no different in size than the one that cam off but it feels like it is too small especially with lock and swap methods. Often the belts are placed and the tensioner placed last and forced into position and that can lead to an installation error.

I don't think you need a lot of fancy. The motor turns by hand now without interference I assume. With cam covers off you hand crank the motor a couple of revolutions and the 4 cam marks don't ever line up (pretty close) your timing is off. My method I posted before I'm a cam shaft remover. That closes all the valves and you can spin the crank at will. That allows you to very very quickly leak down every cylinder and see where you might be as far as damage. Big leak head is coming off.

 

Wow that is bad news Grant. Do a leak down test to see if they leak or not before you take the head off.

You want to take the head off and send it to a machine shop and have them determine whether the valves are bent and no longer usable. I would not automatically throw out the pistons and rings until you get to see what the damage is with the head off the engine. You do want to check the condition of the liners since they will be visible.

Will you be doing the disassembly yourself?

 

Not good. Sorry to hear that. If they hit the pistons they are bent. They won't seal. Pistons and rings are likely fine. That you can't see 3 marks on all 4 cyls indicates they didn't hit hard. Pull the head. Do a leak down on the block. You can check the valves individually with the head off, at least the side two. Turn the head upside down and pour a little gas around the valves. The rest is obvious.

 

True but it also opens at a different angle and sit deeper in the head. But maybe just enough carbon build up in that cylinder for the center valve to touch. What is surprising to me is that if 3 touched in #1, I would have expected all 3 to touch in the rest as well.

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Hope this works out for you. Making me nervous about doing my own major next year!

 

long 15mm wrench, box end, ground edge thin to fit, cut the open end off to fit a short cheater pipe.

 

Grant,

What kind of damage was noted on the cam?

Barry