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Discussion Starter · #61 ·
As an old GTV-6 owner this sound like the timing belt has skipped a tooth or two... I remember many years ago helping a friend do the belt on his 12V 164... He didn't remove the cam cover to access the timing marks, he just made some paint marks on the engine because he found an "easier" way to do the belt on-line... Anyway, when he finally listened to me and tried to roll the engine over by hand it wouldn't turn very far before stopping but he could roll it 360 degrees backwards because the way the slack in the belt let the cams/valves and crank mesh. I told him not to make a habit of rolling that engine backwards but it really isn't as bad as everyone thinks if the plugs are out.

DON'T EVER ROLL A BUSSO V-6 BACKWARD WITH THE PLUGS IN, YOU WILL JUMP THE TIMING BELT OUT OF TIME! BAD THINGS WILL THEN HAPPEN IF YOU TRY TO START IT.

Having just done the timing belt and water pump (early April) on my 4C IMO turning the engine backwards with the plugs out isn't going to be an issue, there is plenty of contact around the pulleys and the timing belt tensioner will take care of the slack but I wouldn't make it a habit either.

Still, it is interesting that the engine will not turn the correct way at all. If the clutch were stuck or the engine hydro-locked it wouldn't turn in either direction... What comes to mind is that something broke almost immediately when you tried to start it the first time and now prevents the engine from rotating. But one would think if the engine will rotate backwards it should rotate forwards at least to the point where the damage causes interference.

I went back and re-read this entire post and IMO when you tried to start the car the first time something inside the engine broke. I don't know or why the engine will rotate backwards but not forwards but I'd guess that your manual manipulation of the crankshaft has moved the broken pieces around such that the engine will roll one way but not the other.

Just a guess is that a valve keeper failed and the valve dropped down into the cylinder. It hasn't fallen completely out of the guide but it probably isn't totally straight either. My thought is that when you try to spin the engine with the starter motor the valve locks the engine in place but turning backwards by hand is slow and jerky enough to push the valve back up into the guide. Forward is probably blocked by the damage to the valve and piston causing the broken parts to shift ever so slightly and restricting the engine's rotation.

I'd say go to Harbor Freight and buy one of their $60.00 borescopes and have look down into each of the cylinders. You may not like what you see...
Hi, sounds almost impossible to believe, but of course i can look with a scope surely, have one at work i can borrow..

cover is removed from the belt
A simple test is showing manually cranking the crankshaft, its has at any moment 0mm turning in the normal direction
Nothing is blocking the camshafts

117146
 

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Am thinking the engine might be OK, seems really odd that it cannot be rotated clockwise but spins free back, and appears more than one revolution at this point has been taken. Timing still needs to be checked now before any attempt to start.

I am thinking transmission. There is something jamming.
 

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Hi, sounds almost impossible to believe, but of course i can look with a scope surely, have one at work i can borrow..

cover is removed from the belt
A simple test is showing manually cranking the crankshaft, its has at any moment 0mm turning in the normal direction
Nothing is blocking the camshafts

View attachment 117146
Nothing down at the bottom jamming the crank pulley either?
 

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Discussion Starter · #65 ·
Am thinking the engine might be OK, seems really odd that it cannot be rotated clockwise but spins free back, and appears more than one revolution at this point has been taken. Timing still needs to be checked now before any attempt to start.

I am thinking transmission. There is something jamming.
Thats what my believe is also...
 

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No it runs free (counter clock)
Understood, but for instance something that has fallen at the 3:00 position between the belt and pulley down there (at the crank) would allow counter clockwise rotation, but gets jammed between the belt and pulley when rotated clockwise.
 

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How do I check this, if this is engaged or not?
When I mentioned the E Brake....I didn't mean the hill start brake. I don't think that has anything to do with this issue. I meant the Emergency brake...the pull up brake between the seats.
 

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No it runs free (counter clock)
but have you inspected bottom part? there could be something rolling between sprocket and timing belt. counter clockwise it's just rolling between belt and sprocket, but going clockwise it gets stuck between teeth.
same could be under camshaft cover. camshaft rockers got needle bearings inside and they could be allover the engine. not sure how oil pump is driven.

really weird problem. never heard to happen on 1750 TBi engine. you can try alfaowner or alfabb forums - maybe someone will have more to say as same engine is used on 159/Brera/Giulietta
 

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When I mentioned the E Brake....I didn't mean the hill start brake. I don't think that has anything to do with this issue. I meant the Emergency brake...the pull up brake between the seats.
Well call that the hand-brake down this way.
 

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Well call that the hand-brake down this way.
Still use the emergency brake term since many cars today don't use a hand brake....usually has another foot pedal to push on far left or on my wife's car...a button on the dash that triggers an electric sensor to engage it.
 

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Did you pull the spark plugs out? Do that then crank it.
 

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You know, I just had a crazy thought... I wonder if the impeller(s) vanes on the water pump have somehow come apart? Given the twist so they pump water I would suspect they would slip freely in reverse but would jam if the engine were turning in the correct direction. Have to pull the pump to look>
 

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When I mentioned the E Brake....I didn't mean the hill start brake. I don't think that has anything to do with this issue. I meant the Emergency brake...the pull up brake between the seats.
If you need to stop fast just pull the emergency handbrake on and do a complete 360
 

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Discussion Starter · #75 ·
You know, I just had a crazy thought... I wonder if the impeller(s) vanes on the water pump have somehow come apart? Given the twist so they pump water I would suspect they would slip freely in reverse but would jam if the engine were turning in the correct direction. Have to pull the pump to look>
Thanks, replaced this last year
To me this is highly unlikely as cranking in normal direct has zero movement
 

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Discussion Starter · #76 ·
Will do the camera inspection via spark plugs on Thursday... if this looks ok as i believe it will
Then the only thought i have left is somehow something is blocked in the gearbox
Then i will contact an Alfa garage to discuss this
 

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Hi Henkjan,

I don't know if you can get your 4C up on stands to try starting it.

We had one member on here that had a jammed transmission, and couldn't get the car into neutral to start it. He was able to start the car on stands by applying power to the starter and then swapped through a few gears with the wheels spinning in the air. That released whatever had jammed and it worked fine after that.

I didn't think that was a good idea at the time, but it worked for that forum member and may be worth a try. As long as you support the car properly, there is nothing to lose by trying.

I think the theory at the time pointed to the clutches possibly having stuck in a position where one wasn't releasing properly.

Good luck!

Cheers,

Alf.
 
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