Timing chain replacement question

[skkane]

Hi everyone

My ED30 is making the diesel sound, gets crap fuel economy (13.4 MPG in heavy traffic / 25 mpg in highway stuff driving it gently), spark plugs look petroled as hell and it generally leaves a pretty heavy petrol smell in my garage (no leaks).

Being my first GTI (only TDI's so far from VWs lineup) I've been pulling my hairs out not knowing wtf was wrong as vcds gave no faults.

The car is stage2 with the previous owner saying it has around 310-320bhp. It has an S3 intercooler, 3" de-catted downpipe, evoms intake, pcv delete, r8 coils, bkr7eix spark plugs and a stage2 tune. I took the car to the dyno and to my shock, and everyone elses who was there, the car only managed to eek out 264bhp.  The torque was fine at 422Nm, so it felt like it pulled good to me. Keep in mind I had a remapped 1.9 tdi bkd 105hp previous to this so I couldn't really compare or know how 310bhp on a mk5 is supposed to feel like. I had a 645ci bmw many years ago with the 333hp v8 and this felt about as fast as the bimmer except at over 180kmh speeds (probably due to the golf being ~300kg lighter).

The dyno guy looked in his vcds at group 91 and found out that my timing was 18 degrees off, showing 10 KW instead of the specified 28KW. So the chain is probably one tooth or less out of allignment. I will have it in the garage on friday to have the chain, solenoid, tensioner and those 3 little orings on the cap I believe replaced and the cams realligned properly, I'm pretty sure they will be looking funny when they take the cover off.

Now on to my question, the mechanic says that in order to replace the chain I should also have the timing belt done with the waterpump and rollers, as he will need to remove the belt in order to reallign the cams. On all videos I saw on youtube, I have no mechanical experience, I didn't see anyone take the timing belt off when doing the chain. Was it because the alignment was good to begin with and they did not have to reallign everything correctly?

If it's really needed (pretty short on cash to have the timing kit done also) can I get away with just getting a new belt and leave the waterpump and rollers for a later date? I know it's a big no no to put on the same belt that he will take off and a belt in itself is not as expensive as the whole kit required.

Thanks!

[pudding]

It depends if the timing actually is wrong at the belt end.  As he'll have to remove the engine mount bracket and pull it all apart to retime the belt, it would make sense to swap it all out whilst you're there.

What is more likely is the chain is so slack, the inlet cam timing has drifted wildly. The cam belt is only connected to the exhaust cam, and the chain connects the two cams together via the VVT adjuster sprocket. You can remove the vacuum pump and get a scope on a rope in there to see how extended the chain tensioner piston is, and/or if the plastic pad has fallen to bits and dropped into the sump.

Bad timing certainly won't be helping the power.

[skkane]

Thanks! Hopefully the exhaust cam didn’t drift off and he can leave the belt alone. I’ll report back tommorow with some pics.

[skkane]

The intake cam was off by a slight bit.

Didn't manage to finish the car today. Covers, hoses, battery, hpfp to put back, should be a couple of more hours, on Monday... I just hope group 91/93 test out ok when we put the VCDS on it.

Man, that cam adjuster bolt is a fkn pain in the ass, we wasted almost 3 hours trying to get that sh*t out, using multiple drill bits untill we figured out to use a small thin one to go thru the bolt itself, not the 13 size as recommended by someone. Apparently the tool VW sells to get them off / tighten them back up breaks easily and it's pretty expensive and not in stock anywhere over here. We had one but didn't try to take it out with it in case we broke it... the guy who borrowed it to us would've been a sad panda. So we had to go full ghetto on it.

Hopefully it turns out fine, wish I could just sleep untill monday to make the time pass quicker.

Last pic is how it looked when we opened it.

[pudding]

Good stuff, that will hopefully sort it 

It's the ebay posidrive bit that breaks easily. I've used the VW one 3 times and it stayed in one piece   

The trick to getting that bolt out is to have someone press hard onto the breaker bar whilst you, the second pair of hands, loosens the bolt slowly.  It's only done up to something like 50nm from memory, but it seems to need about 4,000,000nm to undo it    And the bolt head is so frickin shallow, it rounds out like it's made of cheese, hence the second person needed to apply pressure on the tool to prevent it slipping out and butchering the bolt head.

I've heard rattle guns make short work of it, but you run the risk of shattering the posidrive bit as they aren't impact gun rated.

It's looking pretty varnishy under the cam cover......oil servicing left way too long by the looks of it.

[skkane]

I hope so too. My buddy thought the VVT needs changing also as he doesn't trust it and always puts a new one but I have to chance it, that thing is expensive as hell. 548 EUR for OEM and 200 EUR for aftermarket cheapest I could find. I heard its around 300gbp for OEM in the UK. Hopefully it's good, can't afford to have it changed right now.

Yeah, it's looking a bit adams family in there. The previous owner was bragging about how the head has been redone and only has 10k kms on it... cool story bruh. Hopefully it won't crap out on me, I plan on doing it every 8000km's, if it lives that long   

I'll keep the trick in mind for when we redo it, It's only 45nm + half a turn I believe the mechanic said. 4MM nm for undoing sounds about right

[rich83]

Stage 1= 15 ftlbs    Stage 2=  1/8 turn

That’s what I did mine up to…. Maybe it’s loose 

[pudding]

I hope so too. My buddy thought the VVT needs changing also as he doesn't trust it and always puts a new one but I have to chance it, that thing is expensive as hell. 548 EUR for OEM and 200 EUR for aftermarket cheapest I could find. I heard its around 300gbp for OEM in the UK. Hopefully it's good, can't afford to have it changed right now.

Yeah, it's looking a bit adams family in there. The previous owner was bragging about how the head has been redone and only has 10k kms on it... cool story bruh. Hopefully it won't crap out on me, I plan on doing it every 8000km's, if it lives that long   

I'll keep the trick in mind for when we redo it, It's only 45nm + half a turn I believe the mechanic said. 4MM nm for undoing sounds about right

Yeah VW sell a 'repair kit' which consists of the VVT adjuster, chain cover and oil control solenoid. It was about £700 a couple of years ago but I got it from a Skoda dealer for £550    That isn't too bad when you price up the parts individually. The VVT adjuster is £450 on it's own!  None of that has to be replaced though if it all comes off OK and was working fine beforehand.

Hope it all goes well 

[LC5F]

I had to replace my variator, I was fixing timing belt failure & the pin was sheared, the mad price for a genuine one pushed me towards ebay special maxpeedingrods ebay clone - it has been fine for a good few k miles.

[skkane]

Yeah that adjuster thing is really expensive. Hopefully it will work fine with the new solenoid and timing set correctly.

Managed to find some $ to get the belt done also, ordered a new kit with waterpump and rollers, getting that done in the morning.

Anyone knows how much hp you lose per degree of timing wrong? I read it’s like 2-4hp / degree… on a ls1 forum. So I would be off by ~50hp with -18 degrees.

Can’t wait to dyno it again after all is fixed properly 

[breeze]

What is the mileage on your car and could the job have been mis timed before?

Let us know how you get on.

[skkane]

Yes, I think the previous owner mistimed it. Don't think it jumped off on its own. I heard it's easy to mess up if you don't have that alignment tool / bridge thing to check. It should screw in perfectly for a job well done.

I'll report back tonight.

[pudding]

Yeah that adjuster thing is really expensive. Hopefully it will work fine with the new solenoid and timing set correctly.

Managed to find some $ to get the belt done also, ordered a new kit with waterpump and rollers, getting that done in the morning.

Anyone knows how much hp you lose per degree of timing wrong? I read it’s like 2-4hp / degree… on a ls1 forum. So I would be off by ~50hp with -18 degrees.

Can’t wait to dyno it again after all is fixed properly 

Interesting theory, never heard of that before, but it does sound like American forum stuff    So if your intake cam is one tooth off, that's 19 degrees at the cam end, but as the cams run at half crank speed, it's probably ony 9 degrees in reality, in terms of crank - cam correlation.  So the yanks reckon your engine should be down 18hp then, but that still puts it way under where Stage 2 should be, so yeah, they can keep that stupid theory 

[skkane]

Bad news. Car still runs like crap, same 10 degrees. Most likely not set right again, will retry it and 2nd time lucky hopefully. BTW, I have no idea why group 93 shows nothing...

[LC5F]

It's a dark art! - I tied myself in knots getting mine right - at one point I was out at both crank and chain, but in my defence, I had no benchmark of existing timing marks to start

Doesn't help that in a correctly timed state the belt top & bottom marks don't line up 100%

IIRC no value in 93 is too far out