Technical Engine Timing setup 1.4 8v VVT

[QuboPete]

Hi GrandePunto PL

OK here goes:-

Take 1
I am confident that I made the first incorrect set up by failing to realise that the VVT pulley wheel outer had shifted its position (possibly back to its default locked position) whilst the cam was out for the head gasket job. During this attempt, I had locked the flywheel ring gear (and thus hopefully the crankshaft) and the cam end slot with my home made tools before removing the belt and the head. I had also left the VVT pulley wheel secured to the cam. I left the ring gear (crankshaft) lock in place whilst I reassembled, and the belt went back on with the front run taut and with my cam end slot lock in place. I was thus convinced everything had gone back as it had come apart. I guess any shift in the VVT pulley must have been exactly a full tooth (or exactly several full teeth) for this sense of false security to have arisen. A slack belt front run would have set the alarm bells ringing.

Take 2
I achieved the second incorrect set up using the correct locking tools and following guidance from various locking tool manufacturer's instructions, including the instruction to slacken the VVT pulley bolt. A double check after tigtening the pulley bolt and turning the engine 2 complete revolutions by hand saw the locking tools go back in OK. This attempt failed possibly because the VVT pulley hadn't returned to its default position. It maybe that the ECU had tried to sort out the incorrect cam position from 'Take 1' and this had left the (still oil filled) pulley in a different position. The recheck with the tools after running the engine saw the cam retarded. The other possible explanation is slippage of the VVT pulley on the cam during running due to incorrect assembly techniques - see my post of 4/1/25.

Following the excellent guidance from you on cleaning and testing the VVT pulley default lock with compressed air, and observing your graph traces of its movement during a test run have been instrumental in the apparent success of 'Take 3'. I think it remains a possibility that the VVT solenoid valve may have developed a fault that may have contributed to the pulley settling in a random position with the engine stopped, and thus to an incorrect timing set up.

I cannot thank you enough for sharing your obviously hard won professional experience. I am just an amateur whose enthusiasm often exceeds my abilities!

Kind regards

QuboPete

 

[GrandePunto PL]

OK. That is interesting case study and lesson for everyone: pay attention to details like that (is your VVT at "home" position etc.), watch out for traps.
Those VVT actuator wheels act like an oil centrifuge. There is a dirt accumulating inside. Hard to wash out.
Full cleaning is possible only if you disassemble whole thing. There are videos on YouTube (go figure).

Kerosene (lamp oil) soup.

Collect the debris and test with magnet... A lot of magnetic stuff.

Next, pop the rotor. The o-ring size is 100 to 105 mm range diameter (both will fit), thickness 2,5 mm.

Wings/flaps/arms (whatever) can be worn and rattle around. This is the internal leak source (and VVT noise, rumble during startup).

Wear pattern, "witness marks". Technically possible, but not economically viable to repair. Buy new VVT wheel.

By the way. The camshaft seal can cut the groove in the VVT wheel. This could be restored (but also not a cheap option for an average Joe).

Micro-TIG welding, my test piece (junk VVT wheel). Not pretty (there are some defects, like "undercuts"), but acceptable.

Test cut (lathe) and quick polishing. Good for a very first attempt. There is a room for improvement.

Nominal size is 40,00 mm. There is an (0,01 mm) excess "meat" to grind/polish.

Check also latest Guide Discussion posts: https://www.fiatforum.com/threads/1-2-8v-evo-2-engine-cam-belt-replacement.237966/post-4763155 !

And if your engine looks like this, don't be "surprised" when (multiple) problems occur. People neglect their cars and then play dumb. Get a grip, mate.

More entertainment like that can be found on YT, "Just rolled in" channel: https://www.youtube.com/@JustRolledIn/videos!

 

[QuboPete]

Hi GrandePunto PL

Many thanks for your interesting post of the dismantled VVC pulley and your repairs. That's a fantastic welding / remachining job. There will come a time in the not too distant future when new VVC pulleys are no longer available, and commercial remanufacture becomes uneconomic. Such repairs will then be the only way of saving a whole car.

The dirt centifuge effect in the VVC pulley is an interesting point. Most early Honda motorcycles used crankshaft mounted or crankshaft driven centifugal filters to good effect. Without them, the centrifugal big end oil feed galleries in the inner crank webs would have become blocked in no time.

I'm glad I have never bought into this long recommended service intervals nonsense - its a marketing ploy by marketing men who don't care how long an engine lasts beyond the warranty period. I have logged 12 oil changes in the 40,000 miles or so I've had the car. I think I am reaping the rewards as my engine looked pretty clean judging by some of the examples you have posted.

Thanks again for all your help and to other contributors for their valuable advice. I'll be making a contribution to the Forum kitty.

Kind regards

QuboPete

 

[tarquini]

Hi GrandePunto PL

Many thanks for your interesting post of the dismantled VVC pulley and your repairs. That's a fantastic welding / remachining job. There will come a time in the not too distant future when new VVC pulleys are no longer available, and commercial remanufacture becomes uneconomic. Such repairs will then be the only way of saving a whole car.

The dirt centifuge effect in the VVC pulley is an interesting point. Most early Honda motorcycles used crankshaft mounted or crankshaft driven centifugal filters to good effect. Without them, the centrifugal big end oil feed galleries in the inner crank webs would have become blocked in no time.

I'm glad I have never bought into this long recommended service intervals nonsense - its a marketing ploy by marketing men who don't care how long an engine lasts beyond the warranty period. I have logged 12 oil changes in the 40,000 miles or so I've had the car. I think I am reaping the rewards as my engine looked pretty clean judging by some of the examples you have posted.

Thanks again for all your help and to other contributors for their valuable advice. I'll be making a contribution to the Forum kitty.

Kind regards

QuboPete

I'd like it thank GrandePunto PL and Qubopete for all the info in this thread.

After replacing the head gasket in my wife's 1.4 Mito, similar engine, same VVT pulley and solenoid, I ended up in the exact same situation as QuboPete as shown in this picture.

I have done the timing belt before on this car with no issues so I didn't think I'd have any issues this time.
I used the locking kit to hold cam and crank in place, loosened the cam pulley, set tension, locked pulley. I checked everything was ok by turning engine over by hand and refitting the timing locks. everything lined up perfectly.
I refitted the intake manifold and sparks and coils but when I started it ran very poorly, in fact I could only get it to stay running by pluggin out the map sensor.
It sounded like a car with the timing out so I refitted the locking kit and crank was about 4 teeth advanced to the cam just like in QuboPete's picture.

Thinking I made a mistake I went though the whole procedure again, reset the timing with locks, rotated by hand, rechecked with locks on and everything lined up perfectly once again..
But yet again when I started the car it ran poorly and when I refitted the tools the timing was out by the exact same amount again.

lot's of head scratching and reading began, and I found this thread.
After reading through it I realised that this change in timing is caused by the cam pulley being phase advanced by the ecu when engine starts, but not being able to return to its rest position.
The relationship between the crank and cam pulleys remains timed perfectly of course, but the camshaft itself is in the retarded position still.
Rotating the engine by hand causes/allows the pulley to return to its rest position which adds to the confusion because it appears nothing is wrong and it times up perfectly again, until the engine is started.

Hopefully I'm explaining that well, very long winded I know.
I did the compressed air test of the vvt unit and was able to advance it and get it back to it's rest position.
I then dismantled and cleaned the solenoid unit which was indeed fairly grubby inside and probably the cause of the problem.
Once reassembled everything is back to normal and car running great.

Thanks again for all the comments above!

 

[GrandePunto PL]

Cold start procedure is to be investigated. You can expect negative spark advance first minute or so.
But the VVT operation right away, not so sure...

 

[tarquini]

hi, my solenoid unit didn't look as bad as that but it did have some build up in the casing itself which I think was preventing full movement.

WRT VVT operation, on the Mito it definitely advances the pulley (retards the camshaft) immediately on startup. Whether this is correct operation or was part of the problem caused by the pulley not being in it's full rest position I'm not 100% sure.

My knowledge is based purely on my experience over the past few days and reading this and a few other threads, I'm a diy mechanic and not an expert!
I did read that this exhaust cam retardation is done for emmissions purposes to heat up the cats faster, which could suggest it might happen straight away by design?

 

[GrandePunto PL]

Looks like it is activated at cold start (but this is data from engine with timing a bit off, VVT1 ~110 deg., but no fault codes).

 

[QuboPete]

Hi Tarquini

Sounds like a re-run of my experience. Glad you found my experience and the information (particularly the extensive information and help from GrandePunto) useful, and well done for sorting it all out.

That's an interesting graph trace from GrandePunto showing the significant adjustments to valve and ignition timing when cold just after start up. Amazing what the design engineers have had to do to meet emission targets for less than 2 minutes cold running. I hope the ECU defaults these parameters to normal running if a temperature sensor should fail!

Qubo is still running fine (touching a large plank of 6x2 a I write this)

Kind regards

QuboPete

 

[tarquini]

Yes QuboPete, pretty much a repeat of your situation, as soon as I saw your picture of the crank locking tool in that position I couldn't believe it! It was identical to me, out by the exact same amount so I knew it wasn't a coincidence. Looks like it is caused by the variator being advanced but not able to move back to its normal position due to the solenoid not releasing the oil pressure.

Glad to hear the Qubo is still running well; did you replace or just clean the solenoid?

For Grande Punto I'll grab a graph from the Mito tomorrow to see how similar or not it is with the 16v engine...... and also to share how many degrees out my timing is lol

 

[QuboPete]

Hi Tarquini

I wasn't intending to replace the solenoid; but, when the special little circlip took flight across the garage probably landing in a pile of swarf on my lathe, I went straight down to the spares place to order a new one. Didn't expect it to be £130 though - possibly the most expensive circlip ever.

Amateur night (again)!

Look forward to your timing post.

Regards
QuboPete

 

[tarquini]

My graph looks very different, I can't figure out how to make text and graph lines bigger, but 2 things I notice straight away compared to other pictures in this thread

1. the Bosch Me 7.9.10 in the Mito doesn't show any info about learned tooth position, nor does it have the function to phonic relearn in the Adjustments section

2. There is maybe sill something not right with my vvt because it is not able to achieve the desired cam position

car is running ok, so just posting for info/comparison. This graph is from cold start

 

[GrandePunto PL]

Poll, query (8V units): how many of you get "closed loop" status ("Phase variator control" parameter)?
And if so, what's the VVT1 value (and others)?
Mine ECU (and FES, not MES) reports "excessive advance" no matter what the timing is (VVT1 from 97, 105, 106, 108 to 113 degrees).
Based on the internet, most common value should be 106 (100-106 deg. range). Maybe it's not enough (there are other conditions).

 

[AuctionGrande]

Poll, query (8V units): how many of you get "closed loop" status ("Phase variator control" parameter)?
And if so, what's the VVT1 value (and others)?
Mine ECU (and FES, not MES) reports "excessive advance" no matter what the timing is (VVT1 from 97, 105, 106, 108 to 113 degrees).
Based on the internet, most common value should be 106 (100-106 deg. range). Maybe it's not enough (there are other conditions).

These are from my two grandes. I was just wondering that closed loop thing when i saw this thread because mine shows excessive advance and i'm using multiecuscan version 5.1