BAG Engine loses timing after doing oil change - why?

[willdudeuk]

I’ve just done a service on my 1.6 FSI BAG engine code and the timing has slipped slightly as it is sounding rough as anything....

Why is this happening?

I never had a problem before.

Any help would be appreciated.

Thanks

[Crasher]

The tensioner is a stupid design, unlike most hydraulic tensioners it has no anti return spring so after an oil change the chain is very slack until oil pressure builds up and if the chain is worn, the cams can easily jump, the 1.2 3 cylinder 12v is notorious for jumping after an oil change. It is such a **** design that I have even known them jump when doing a clutch when the mechanic moves the engine anticlockwise and on one occasion I had a customer with one jump as he left it in gear with the usual failed Golf 5 handbrake and the car crept backwards and jumped the chain. That it is not your fault is no solace knowing you have to rebuild it but when we do oil changes on any chain cam engine we take the plugs out and spin it up on the starter to get oil pressure without any compression pulses. How much would it have cost VW to machine a ratchet and fit a simple leaf spring to the tensioner like the larger EA888 engines have? Mind you, they also jump because the tensioner design was crap even though it has a ratchet!

[willdudeuk]

Thanks @Crasher I’ve got is stripped down ready to be rebuilt.

Looks like the exhaust cam was ever so slightly out....(not sure if advanced or retarded).

It was making quite a racket when I turned it over after doing the oil change (stupidly I didn’t do what you have advised - plugs out until pressure has built up).

Weirdly enough I didn’t get any low oil pressure light on dashboard?

Also noted that when I removed the oil filter housing on top it was bone dry???

I almost suspecting that the oil pump chain may have failed? Or oil pump has gone?

Haven’t got the control housing off yet to see but will update in due course.


FYI the chain was replaced last year. The previous chain was stretched and compared with the new vs old it was quite a few mm longer!



So going forward when doing an oil change always remove plugs to build up pressure.


If you have any further advice please let me know. Appreciate it. Thanks.

[willdudeuk]

Built it back up but the timing isn’t right.....

Sounds horrible so quickly shut it down.

I get checking the timing again and again....

It seems the laser 5742 locking kit I’ve got isn’t doing it’s job....

I must be doing something wrong.

After getting the timing right with the locking tool the chain is nice and tight but when it is removed it goes really slack....valve springs are causing it to rotate out of position and lose the timing....

Not sure what to do so any help would be appreciated.

[Crasher]

In bought that cam to cam lock years ago and it was awful, nearly impossible to use so I bought the genuine VAG version

[willdudeuk]

Any chance I could borrow it? I am seriously struggling......

I managed somehow to do it last time.....


I took the chain off to double check it wasn't stretched....... compared it to the old stretched one and was at least 5mm shorter in length when hung up against each other....


Starting to think I need a new motor.....

I am open to suggestions please (has to be minimum Euro 4 Petrol or Euro 6 Diesel so I can drive my car in city centre....Birmingham has the CAZ clean air zone coming 1st June....)

[Crasher]

Unfortunately we don't lend tools, I was going to suggest that being as they are only £50+VAT that you buy one from a local TPS but there is no UK stock. Also from what you are saying I think the problem is deeper than the valve timing. I want through a living hell at the end of last year/beginning of this year with one of these engines in the 1.5 twin charger format, I had such a nightmare with it in the end I fitted a brand new genuine VAG exchange engine but with your car that is no longer an option as these have been obsolete from VW since 2019.

[willdudeuk]

Yer I’ve looked at it again....

Thought perhaps if I rotated past the sprung point and rotated back it would put more tension on the chain...ie rotate exhaust cam clockwise and intake can anti-clockwise. Then rotate back and engage the T10171A tool....but it was reaching the point where it would spring back to the original position

But that didn’t work.....

I can get the exhaust cam to line up but the intake / VVT cam I cant.

The chain seems too slack when there is no tension from the tensioner....but think that is by design?

When the chain is tensioned it causes the intake cam to rotate anti-clockwise and almost bring it back into correct timing....

Can’t understand why I can’t get it set right.

Could the valve train be damaged?

Chain stretched?

No oil pressure?

Oil pump not working? Pickup pipe blocked?

[Crasher]

Did you replace the VVT hub?

[willdudeuk]

Yep VVT is new.....(well replaced last year - when i did the whole timing chain kit etc....)

Timing Chain.JPG

Timing chain must remain remain tensioned on both sides......

Also from what you are saying I think the problem is deeper than the valve timing.

What else could it be? Thank you

Been following the workshop manual to the letter......

I've only got the BLF version but I understand it to be the same process....