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Timing chain replacement question

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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.:signLOL:  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  :happy2:

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

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  :stupid:  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.

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