VR bottom ends are NOT strong

[NormanCoal 0]

had to share what I have seen with two seperate VR bottom ends I have worked on this week

 

never seen either in this sort of state before

 

 

 

The knackered piston pictures came out of my rado yesterday. Dont quite know what caused it, but I thought it was the head gasket till he head came off

 

Big up to Matt and Nick and Designadubs for sorting me out a new bottom end for it. One rebuild later (and 15 hours of work) and I drove it home. In at 10 am monday morning, running again at 01.30 early hours of tuesday

 

The corrado now goes like a train :D choo choo :twisted:

 

The last pics shows the block that has donated its Schrick BVH for my other project. The head is fine, which is more than can be said for the block

[beavis 0]

Looks like you had a weak/failing injector. We have seen 5-6 G40 engines and a couple of G60 lumps with the same type of failure. Look at the colour of the piston crowns. All have uniform carbon deposits on them barring the failed one that looks like it has had some serious detination going on. A good injector will atmoise the fuel leaving a layer of unburnt fuel on the piston crown which effectivly cools the crown. With a paritally blocked injector it will cause the one cylinder to run lean and effectivly superheat the piston hence the damage. A injector may be supplying the correct amount of fuel, but if the spray pattern is poor and not atomising the fuel you will get the same damage as the fuel will not burn efficently.

If you have not already, replace that paticular injector and consider having all the injectors flow tested. Replace them if at all in doubt.

I've know of a couple of people melt a piston, rebuild the engine without getting to the route of the problem and then two later having a identical failure.

[stevemac 0]

I've seen a couple of Merc's with exactly the same problem. One of them had actually melted the whole piston - it looked like a large glob of alloy stuck to the con-rod. :shock:

[Roger Blassberg 0]

I'm thinking that there may be a similar or related problem with my coilpack VR. It pinks under acceleration despite using 97/98 RON petrol, new plugs, knock sensors cheked on 1551 and VAGCOM, new cylinder head including injector seals, standard ECU.

 

How much are injectors? Can they be serviced? Are they easily removed?

 

Thanks in anticipation of anyone's advice.

 

Best wishes

 

RB

[beavis 0]

Yep, injectors are a very hard worked but dismissed component forn servicing. Many large Bosch dealers have the facility to clean and check the spray pattern onn injectors. This addresses problems with physical blockages in the units but does not address the problems of the small electromagnetic coil failing in the unit.

 

Injectors are obsene money from VAG, about £87 + vat per unit!!!

 

It is possible tom souce them from abroad for cheaper, proberbly looing in the region of £190 per six.

[dr_mat 0]

I think someone said you can buy them direct from Bosch for about £50 each? Still looking at £300 notes tho..

[Kevin Bacon 5]

I'd be interested in 6 injectors for £190!

 

I agree totally with Beavis. Injectors are always overlooked or last in the process of elimination chain. Probably because of their cost, but having said that, a coilpack and MAF from the dealer will eat £580 of your hard earned straight away.

 

I have 6 injectors sitting at home and I think I'll get them checked/cleaned etc and stick them in.

 

Can't really accuse the VR engine of being weak based on those two neglected engines. All the failed units I've seen have been down to neglect and it's the same with all marques.

[Storm 0]

All the failed units I've seen have been down to neglect and it's the same with all marques.

Agreed. Although I'm pissed with VW for selling something that cant be rebored and have just bigger rings put in.

[STORM 2 0]

All the failed units I've seen have been down to neglect and it's the same with all marques.

Agreed. Although I'm pissed with VW for selling something that cant be rebored and have just bigger rings put in.

 

wasn'r the VR6 bored out to 2.9 from 2.8 by VW?

[Storm 0]

Yep it was, but what I dont understand is that when it wears out for some reason you are not recommended to have a rebore and larger rings. You have to have a rebore and new pistons?

[Kevin Bacon 5]

Yeah the VR reboring is all a bit strange. This is why I personally feel a 24V upgrade is better but it depends if you can find one at a good price and can cope with the wiring. Either that or take the 2.9 out to 3.0 with JE pistons and rings.

[NormanCoal 0]

Can't really accuse the VR engine of being weak based on those two neglected engines. All the failed units I've seen have been down to neglect and it's the same with all marques.

 

I think its harsh to say that my engine was neglected Kev. Its very hard to know when an injector isn’t doing its job properly, and as you can see from above, when it doesn’t the results are catastrophic. The injector on that cylinder has been changed.

 

I wouldn’t profess to be a VR expert, but an engine that doesn’t blow any kind of smoke under any situation would be thought to be a good unit. This is what mine was like Having now replaced the bottom end, I know that the chains and guides are all good as they have been replaced. I was fortunate enough to be in the position of having everything at hand as I am building a VR for my project car which was going to require these bits. It just means that I now have to replace them. I also took the opportunity to change to the solid plastic MK4 12v upper guide as well. Did you know that 96 on Sharan’s use these bits along with the MK4 12v metal head gasket? (engine code AMY from memory)

 

I don’t know what happened to the other block, the one with cracks in. I suspect that its got very hot, either with the oil or water, and that happening is through neglect or whatever else you would like to call it

[Kevin Bacon 5]

Sorry, wasn't meant to be a harsh remark. I wasn't trying to say the neglect was intentional, it's just that it's easy to overlook a rough idle or flat spot, hesitancy etc as a 'VR6 trait' when it could have been number 6 injector playing up. Either way, that is really sh1tty luck and that's the first holed piston I've seen in a VR :?

 

Good move using the solid tensioner. Mine's beein in for 10,000 miles now and apart from a slight groove worn into the middle of the pad (where the centre links roll over on the sprocket) there is no wear on it, so it's looking good for future longevity. The pad has just 'shaped' itself to the duplex chain and will now just wear normally as it would on a MK4.

 

No one has done any high mileage tests on a duplex chain with the solid tensioners, so it's a bit hit and miss. The only thing that concerns me is the centre lubrication hole in the original pad is not present on the solid pad...... but it shouldn't matter too much.

 

Did you rebore a 2.8 out to 2.9 then?

[NormanCoal 0]

In 15hrs? I cant work that quickly unfortunately. :|

 

In that time I took the spare block that I had set aside for my project, added all the ancillaries to it, cleaned it up, changed the sump over, and rebuilt the head – well changed a valve which has piston stuck to it, and lapped them all in. Changed all the chains etc. Assembled it all back together, fitted it back in, changed the injector and fired it up.

I also changed the plugs whilst I was at it. The BERU ones I got from C&R recently and were in the engine didn’t look very good, so Bosch platinums went in. So far so good, I must have done the best part of 200 miles since it went in, no problems as yet – I hope that it stays that way

[Rpmayne 0]

Stealth sell both 82.485 and 82.985 mm mahle pistons and rings for reboring a VR6. When I took it into a garage for a check they phoned around and you can apparently rebore a 2.9VR6 twice, the maximum being 83.0mm. Re-reading your message storm, VW do sell oversized piston rings for a 2.9VR6. Just didn't think it was generally advised to just them with a rebore, plus when my pistons came out they had been slapping about abit so they probably needed doing anyway.

[MoonlightVR 0]

I also changed the plugs whilst I was at it. The BERU ones I got from C&R recently and were in the engine didn’t look very good, so Bosch platinums went in.

 

If you're after spark plugs for the VR but don't want to shell out on (40k life) platinum go to VW and buy the shorter life versions (good for 20k) which are made by NGK. They are far superior than the Beru versions.