Vrs engine not the same after a rebuild

[iiPaul]

My vrs was running very well at a strong 235bhp until about a month ago my head gasket went, so I decided to change it myself, whilst the head was off I noticed the valves were pitted so whilst it was off I may aswell get them replaced, I also took the cam out and found a cracked tappet and worn bearings so I replaced everything with new decent parts. But now I have a problem, when I start the car it's rough for about two seconds then it's fine and also a flat spot at 1500rpm.

I have done logs on injectors and timing and they're both good. Also replaced all the injector seals but still have the problem, the car is now where near what it used to be in performance wise either think I'll be lucky if it's 210 :( any help appreciated

Thanks

[theezenutz]

Get in on a dyno you should be able to tell what's happening and where your loosing power if I was running 235 bhp that's what I'd be doing.

Edited 18 November, 2014 by theezenutz

[sepulchrave]

...when I start the car it's rough for about two seconds then it's fine and also a flat spot at 1500rpm.

...the car is now where near what it used to be in performance wise either think I'll be lucky if it's 210

 

Ok, can you do a compression test and also a leakdown test on all four cylinders, it sounds like there may be some variance.

 

Are there any noisy tappets?

Any exhaust smoke off boost?

Any sign of any coolant loss at all?

Do the glowplugs all come on, these are very delicate and removal and replacement can often break the element in old glowplugs, check if any are open circuit.

[SKYHAWK]

My vrs was running very well at a strong 235bhp until about a month ago my head gasket went, so I decided to change it myself, whilst the head was off I noticed the valves were pitted so whilst it was off I may aswell get them replaced, I also took the cam out and found a cracked tappet and worn bearings so I replaced everything with new decent parts. But now I have a problem, when I start the car it's rough for about two seconds then it's fine and also a flat spot at 1500rpm.

I have done logs on injectors and timing and they're both good. Also replaced all the injector seals but still have the problem, the car is now where near what it used to be in performance wise either think I'll be lucky if it's 210 :( any help appreciated

Thanks

mines the same had head ported and polished new headgasket, new waterpump, timing belt, injector seals, oil pump, newmans cams ect and my engine sounds abit tappy bought a asz engine sunday just gone with 45k on it all ready for the gtb2260 really rough and smokey on start up

[joelk2010]

Did you replace the HG or skim it ?

[sepulchrave]

Did you replace the HG or skim it ?

 

I think both, he had the head rebuilt with a new cam and followers and new valves, I may be wrong, if he hasn't had a truth skim then the new HG may not be sealing properly.

[sepulchrave]

mines the same had head ported and polished new headgasket, new waterpump, timing belt, injector seals, oil pump, newmans cams ect and my engine sounds abit tappy bought a asz engine sunday just gone with 45k on it all ready for the gtb2260 really rough and smokey on start up

 

I hope it wasn't polished, polishing ports is very bad for performance.

If you had new tappets were they popped open, pre-charged with oil then compressed before fitting?

Check the glowplugs on that ASZ, chances are one or more are open circuit.

[sepulchrave]

Also, you guys need to check this:

 

http://www.audi-sport.net/xf/threads/how-to-guide-pd-tdi-injector-adjustment-clearance-lash.183040/

 

This must be done after a head strip or the fuelling will be uneven.

[iiPaul]

Ok, can you do a compression test and also a leakdown test on all four cylinders, it sounds like there may be some variance.

Are there any noisy tappets?

Any exhaust smoke off boost?

Any sign of any coolant loss at all?

Do the glowplugs all come on, these are very delicate and removal and replacement can often break the element in old glowplugs, check if any are open circuit.

Done a compression test on all four and they were all the same with a good reading, no noisey tappets, loss off coolant, the glow plugs were replaced, and tried the old ones back in but still the same, no access smoke

[Vinayk]

Have you put the right size gasket after skimming

[iiPaul]

Did you replace the HG or skim it ?

Just replaced the hg and made sure the block and head were spotless

[iiPaul]

I was personally thinking a fault new camshaft or a faulty injector as it was fine before

[sepulchrave]

Just replaced the hg and made sure the block and head were spotless

 

That's no good, how do you know if the head was straight or not?

[iiPaul]

That's no good, how do you know if the head was straight or not?

Checked it for flat using a block of metal and the company that fitted the valves gave it the all clear, it pulled perfectly well before and during the hg was on its way out, so if it wasn't straight surely it wouldn't have drove well?

[iiPaul]

Have you put the right size gasket after skimming

wasnt skimmed, but yes the two hole gasket was replaced by another two hole gasket from tps

[sepulchrave]

Checked it for flat using a block of metal and the company that fitted the valves gave it the all clear, it pulled perfectly well before and during the hg was on its way out, so if it wasn't straight surely it wouldn't have drove well?

 

That's fair enough, just trying to work through all the possibilities, has the injector lash been set up, you didn't say?

[iiPaul]

That's fair enough, just trying to work through all the possibilities, has the injector lash been set up, you didn't say?

I haven't altered it, I just took it out and put it back in, would injector logs show this up?

[theezenutz]

Has the timing been double checked?

[iiPaul]

Has the timing been double checked?

Serveral times now was set up on 0.0 and then adjusted to 1.1 with no difference

[Vinayk]

wasnt skimmed, but yes the two hole gasket was replaced by another two hole gasket from tps

What about the thickness of the gasket same as the one you took out because you didn't skimmed it

[sepulchrave]

I haven't altered it, I just took it out and put it back in, would injector logs show this up?

 

No, definitely not, read the link I posted, with a new cam you should definitely be checking it.

[iiPaul]

No, definitely not, read the link I posted, with a new cam you should definitely be checking it.

I've read through it, I'm quite tempted to put the old cam back in as see what happens

[iiPaul]

What about the thickness of the gasket same as the one you took out because you didn't skimmed it

The gasket was exactly the same thickness as the old one that came out

[sepulchrave]

I've read through it, I'm quite tempted to put the old cam back in as see what happens

 

Everything will have moved, just take it to a diesel specialist to get it set up if you can't borrow a DTI, putting a knackered cam back in is dumb.

[iiPaul]

Everything will have moved, just take it to a diesel specialist to get it set up if you can't borrow a DTI, putting a knackered cam back in is dumb.

Not sure of any local ones around kent, it's not exactly knackered, it has a few signs of wear on the lobes and two bearings are a little worn, if it cured the problem what's there to loose?