3.0 Help Please

[Mick A]

I'm surprised at the 90Nm torque.  Would have thought it were angular.

Only with one-time-use head bolts, not with head studs which is what his engine has.

Cheers.

[V AR 164]

Yes I will tighten them up after the first few drives.

Glad to say that the car did start and does indeed run, however, I noticed that the timing belt was not running 'smoothly' and was vibrating up the top in-between the cam gears.

I turned it off and had a look and found that the belt was not sitting right in the gear:



Definitely not right and was wondering what I should do to fix it?

Cheers, Andrew.

[Citroënbender]

Not ideal! This is a SOHC or DOHC motor?

[V AR 164]

It's a single cam motor.

Pretty sure there is too much slack between the cam gears. I am going to slacken off the tensioner tomorrow and try to move the belt over one tooth on the left cam so there is more tension between the gears. Then the tensioner can take up the additional slack on the one tooth. The picture is of the right cam gear.

I think this is the right thing to do as if I pull the belt to the right on the picture, I can make the teeth slot in correctly, meaning there is not enough tension.

I believe it's the right thing to do? Hopefully that makes sense.

Cheers, Andrew.

[bonno]

Hi Andrew
Yes it sounds and looks like the tensioner has not been adjusted correctly. I would go thru the process of resetting the timing marks and attach belt per the manual, paying particular attention to the tensioner is functioning correctly by turning the engine by hand several revolutions to see timing marks line up and no slackness in the belt. Once this is done you should be ready to fire it back up.

[Citroënbender]

I don't think it's a tooth out, if one or both sprockets are bolted to a hub boss, you just need to make sure the cams are locked in place, then loosen the sprocket fixing bolts. Counterhold the sprocket while re-tightening.

[V AR 164]

Thanks guys for the input!

Yes I have come to the conclusion to take off the valve covers and check timing marks, then re align everything and install the timing belt again. Just a pain as the plenum has to come off as well as all the timing covers which are a pain to access.

I will definitely be coming to Spettacolo with the 164, even if it involves staying up all night the day before! Come and say hi, always down for a chat 

Going to upload a video of the first start and run, was scary at first because I had a couple ignition leads switched around.

Cheers, Andrew.

[LukeC]

There is a special tool that you need to do the job correctly (that is if the engine has the original type detensioner). It is a simple stepped pin. You install it into the unit to set the tension. I will make one and tomorrow and overnight it to you with instructions.

[V AR 164]

SOLVED!!

Probably one of the stupidest mistakes I have ever made. Indeed it was the tensioner, but it was my fault.

Initially when I took the belt off, I loosened the two 13mm bolts that adjust the tensioner, moved it out of the way then tighten both bolts down.

Fast forward 3 weeks, I completely forgot these bolts existed and just adjusted the oil mechanical part of the tensioner.

After reading through the workshop manual, it said to 'tighten the two bolts'. Ahhhhh, it clicked. I forgot these existed, when I loosened them it immediately placed more tension on the belt. Set the oil tensioner settings, cranked the motor and it was solved!

A small mistake on my part which luckily didn't cause any damage to the motor.

Nevertheless, I will never forget these bolts again!

Thanks, Andrew.

[Citroënbender]

Good catch. Glad it was a quick and easy solution.

[LukeC]

Nevertheless, I will explain how this thing works and the correct procedure in setting it up for anyone interested (and why the procedure is critical).

I whipped up a tool this morning (through the fog of jetlag from flying back from France) to send to Andrew, but he seemed confident to solve the issue.

You first have to understand the device: It is actually a tensioner/detensioner! There is a hydraulic piston operated by engine oil pressure and three springs. Number 1 spring is a compression spring and sits behind the cast piece and is there only for the initial setting up. Number 2 spring is a compression spring internal in above the hydraulic piston (below the aluminium cap). Number 3 is a relatively weak tension spring acting on the steel lever (and is covered by a black plastic sleeve).

The set-up pin (pictured with a workshop sketch) is shown below. It is inserted into the unit as shown to compress spring 2 to a pre-set amount (normally before the unit is fitted back to the engine as it should be re-kitted when belt changes are performed. The unit is mounted on the engine and rotated so spring 1 is compressed and unit withdrawn with nuts nipped up (and belt can be fitted). The belt is fitted with all the timing marks in the right places. The nuts are then loosened so that spring 1 can act on the unit and place some tension on the belt.

This part is critical: The engine must be turned at least two full cycles (4 rotations) slowly and ensuring that the engine does not turn backwards at all. When the engine is back at TDC (this position we know the cams will maintain a static position), and the timing marks all lined up, the two nuts are now tightened. Spring 1's job is over! Now the pin is withdrawn and spring 2 can act through the piston and add more tension to the belt. At this time, the engine can be safely be turned anticlockwise safely (if you wanted to).

When the engine starts, idles and stops: i.e. oil pressure is low, the pressure from spring 2 maintains high belt tension. This is because of the cams tend to flip/flop over their lobes and without this tension the belt may jump a tooth (remember, this was early cambelt design and the teeth were not as aggressive as later engines). As the engine revs climb, so does oil pressure and the piston withdraws and reduces the tension on the belt. Now, only spring 3 is applying tension to the belt. High tension is not required as cam inertia will overcome the tendency to flip/flop as with low engine speeds.

The other thing to remember, is the engines do not stop dead when turned off. They will often do a revolution or two, come up against a compression stroke and rotate backwards a bit. This extra tension added at low oil pressure times guards against this.

The stepped pin set-up is necessary to ensure the relationship between the hydraulic piston high tension at low engine speeds transition to low tension is correct. One may get is right without, but there is only on way to make sure it is perfect as Mr Alfa wanted.

Complex: yes. Old fashioned: yes. Better ways now: yes (like the mechanical tensioner available)... But so Italian!

[LukeC]

The tool (under 10 minutes on a lathe starting with a 10 mm bolt - LOBO of course!):

[V AR 164]

Thank you for the detailed description of how the tensioner works, definitely learnt something!

Again thanks for going through the trouble to even make a tool! However I am confident I have everything under control. Took the car out for a drive tonight, being careful to watch temps and not to rev the motor unnecessarily. Happy to report that everything is running fine with no issues at all.

There are no oil or coolant leaks and no cross contamination in the oil or coolant, which means the head gasket is installed correctly.

I have to say, the car is completely different to drive. I have found it to be much smoother and actually sound different as well. It has got a lower note to the exhaust and seems to idle more calmly than before. Overall I'm very happy with the end result.

Thank you everyone for contributing to the thread and helping me along the process, time to go out and enjoy the car.

See you all at Spettacolo!

Cheers, Andrew.

[V AR 164]

Quick pic of the finished engine bay. Took alot of time cleaning everything and painting things to make it look presentable.

Andrew.

[ACE]

Excellent work Andrew.
Well done.
And it looks very nice too!