New engine & cone filter survey

[Christoph 0]

My VR6 went into my local specialist last week to have the excessive oil / fouling spark plugs issues investigated and sorted.

 

The bores were all showing heavy wear, with number 6 being the worst :( .

 

After considering the options, I decided to get a reconditioned engine, from Vege, so I'm running it in at the moment. Already though, it's 100 times better than before.

 

Anyway, the real point of this post is to see if any other people who've had similar problems also have a cone filter?

 

Is there a link between ditching the OEM filter and seeing heavy wear in the bores?

 

Chris

94 VR6

[Kevin Bacon 5]

I think the link is people pressing harder on the gas with cone filters :D

 

Cone filters do no favours to the MAF sensor or the power output but the filtration properties of oiled cotton are good, not quite as good as pleated paper but certainly not bad enough to cause cylinder scratching!

 

Your engine wear is the result of either neglect, abuse, or just old age...or a combination of the three.....and bores 1 and 6 are always the worst....a trait of the engine.

 

A well maintained VR6 engine can last into the 200K region no problem....

[Christoph 0]

If it was neglect, abuse and old age, wouldn't it be more comon in the 2.8's?

 

From what Vince told me, it's something that's peculiar to the 2.9's.

 

Granted that doesn't do my cone filter theory much good :) .

 

Chris

94 VR6

[Kevin Bacon 5]

Nope, the 2.8s seemed tougher for some reason....and Golf VR6 customers were by and large not the same sort of people that bought the Corrado VR6, if you get my meaning.

 

The VR has less room to work in a Corrado than the Golf too, so ran hotter.

 

Agreed, the 1 and 6 bore wear is peculiar but it's not unique to the 2.9, it just seems there more instances of it on the 2.9. Strange....

[Christoph 0]

and Golf VR6 customers were by and large not the same sort of people that bought the Corrado VR6, if you get my meaning.

 

So Corrado owners are more likely to add a cone filter?

 

I'm sure these symptoms occur because of a number of things happening together, but I wonder if the addition of an oil type filter speeds things up?

 

Really I'm wondering if I should ditch the cone filter and go back to an original setup.

 

Chris

94 VR6

[dr_mat 0]

Corrado VR6: sports car (ish)

Golf VR6: grand cruiser (ish (bear with me here) )

 

I can see where the comment is coming from - they're aimed at different markets and driven in different ways ON AVERAGE. (Sweeping generalisations are easier to make when you have scant evidence for it. ;) )

 

It is quite possible that the tiny extra bore-out has exposed weaker metal and that's what makes the 2.9 more prone, but it's also possible that it's caused by the slightly hotter running that the Corrado 2.9 does compared to the Golf 2.8. But who knows? It's something that has happened over the last ten years, it's hard to look back at the history of all those cars now and try to spot patterns.

[Jim 1]

I think Kev means that most people who bought Corrado VR6's bought them to drive them like their pants were on fire! And judging by the state of a lot of them out there now (ie conveniently lost histories, clocking, and thrashed engines) thats exactly what happened.

 

People who bought Golf VR6's just wanted a Golf that had a bit more grunt about it!

[dr_mat 0]

And Jim summarises what I tried to say perfectly.. :)

[Christoph 0]

And Jim summarises what I tried to say perfectly.. :)

 

LOL!

 

On the subject of oil coated filters and the MAF hot wire, I thought the start-up procedure included heating the wire up, to 1000 times the heat of the sun, to burn off stuff like that.

 

Chris

[Scruffythefirst 0]

Dont forget that with a larger diameter piston (2.9) the forces involved with regard to the piston rocking in the bore will be exagerrated a little compared to the 2.8. The fact the the balancing of the engine is critical with the design of the vr if its a little out then the wear will be exagerated due to the narrow angle which will affect the end most. Thats why the wear will be more on the 2,9 than the 2.8.

 

Probably :)

[Henny 0]

Scruffythefirst, I was thinking along those lines too... 8)

[Jim 1]

And Jim summarises what I tried to say perfectly.. :)

 

Hehe.. we posted at the exact same time and.. though you did kinda beat me to making the exact same point, I thought I might as well leave my post :)

[NickVR6 0]

Thats why we got a vento vr for the wife! They have mostly been owned by retired people who just wanted the top of the range! Not allways been mooly codled, but cleaned every sunday, low mileage and never abused.

Plus they are a barg compared to the golf, were half the price a few yrs back but less obv now.......................We got a 97p with 40k 1 owner fully loaded for 3.5k nearly 3 yrs ago, now that was value!

[Kevin Bacon 5]

Yep, that's exactly what I meant Jim :wink:

 

Same with the M3..... a lot of the E36 M3s are beaten up old heaps compared to a 328i for example. Designed and engineered for speed and more speed = more wear.

 

Good theory Scruffy...I buy that. Although the huge flywheel and crank pulleys should absorb any harmonics. Maybe VW didn't review the harmonics on the 2.9 and just stuck the standard 2.8 balancers on?

 

What's also interesting is bores 1 and 6 are the coolest running ones, but wear first! If you look at a 4 cylinder VW lump, bore number 2 usually goes first.

 

Anyway, as Mat says, it's no use speculating and this whole '1 and 6' thing only came about from Vince's observations from rebuilding & working on shed loads of the things over the past 10 years or so.

 

The important bit we need to know is it's gonna cost a fortune to sort, regardless :?

[schrickvr6 0]

AFAIK all OBD1 VR's suffer from the 1 and 6 bores wearing prematurely, i thought the OBD2 had different rings or pistons, or both to stop or at least reduce this?

[Cougar 0]

I've heard of G60s eating cone filter pieces and damaginf the G-Lader.

[Christoph 0]

The important bit we need to know is it's gonna cost a fortune to sort, regardless :?

 

I'm pretty happy with how mine turned out TBH. The reconditioned engine was 1500 notes from Vege (exchange), comes fully timed-up with a 12 month unlimited mileage warranty.

 

I got that fitted, plus a new rad, water pump, rear beam bushes, magnex cat-back, wheel bearings and a load of other stuff that I can't remember for just over 3K.

 

Chris

94 VR6

[Scruffythefirst 0]

What's also interesting is bores 1 and 6 are the coolest running ones

 

Ahh, in that case I would suggest in adition to my previous comments that 1 and 6 run a little rich, which obviously leads to mild borewash which over the course of 100k will cause the rings to eat into the cyl walls as the oil film is diluted.

[Christoph 0]

What's also interesting is bores 1 and 6 are the coolest running ones

 

Really? I thought they ran hotter because they have less cooling, being on the outside ends?

 

Why do they run cooler than the others?

 

Ahh, in that case I would suggest in adition to my previous comments that 1 and 6 run a little rich, which obviously leads to mild borewash which over the course of 100k will cause the rings to eat into the cyl walls as the oil film is diluted.

 

Scruffy, that's exactly what the garage said, but I'm not clever enough to understand why running cooler equates to running rich, and then how running rich leads to borewash.

 

Can you both enlighten me?

 

Chris

[Kevin Bacon 5]

Exhaust

/\/\/\

1 3 5

_2 4 6

_/\/\/\

Induction

 

3 and 4 run the hottest as they are sandwiched between two cylinders. 1 and 6 run coolest as they are furthest away from the mass of cylinders in the middle. Take the head off and look for yourself and you'll see 2,3,4 & 5 are grey and dry, 1 and 6 will most likely be darker in colour and have more carbon deposits from running cooler.

 

1 3 & 5 also suffer heat soak from the exhaust manifold.

 

Cooler running actually leads to leaning off, rather than over fuelling. The hotter and thinner the air, the less fuel is required....hence cold engines needing a big slug of fuel to get them going in the mornings and less as it heats up.....but the ECU doesn't know 1 and 6 are cooler, so doesn't alter the fuelling....but they're not THAT much cooler as to cause significant fuelling problems.

[Christoph 0]

Got it!

 

Nice diagram BTW! :thumbleft:

 

So are there any theories about how this slight leaning off leads to borewash?

 

Chris

[Scruffythefirst 0]

Cooler running actually leads to leaning off, rather than over fuelling. The hotter and thinner the air, the less fuel is required....hence cold engines needing a big slug of fuel to get them going in the mornings and less as it heats up.....but the ECU doesn't know 1 and 6 are cooler, so doesn't alter the fuelling....but they're not THAT much cooler as to cause significant fuelling problems.

 

 

Thats wrong Kev. Sorry. Cooler running doesnt actually lead to a set amount of fuel its the ammount of fuel that affects the running temp. Having the cylinders on the ouside edge won't make much difference to the temperature of the burn which is what causes problems. Extra fuel in the cylinder reduces det / pinking and acts in the same way as water injection. I suspect its mainly to do with the flow charachteristics of the manifold - giving a smidge less air. It may have been equal on a flow bench but the design of the head and the intake is going to lead to variances between cylinders, which may not matter in the short term but over 100k will add up. The cossie has problems on cyl 3 for exactly that reason - the OEM manifold gives it extra air which at high boost can lead to it going lean.

 

The leaner you run the hotter and faster the burn of the charge will be, leading to higher temps and eventually pinking and det followed by a melted engine. Running rich means the extra fuel in the cylinders that left after combustion dilutes the oil (note how garages clean oily parts with petrol) which increases wear on the bores. It won't take much to cause this effect over 100k and you'd be hard pushed to measure it without very special eqpt.

 

So are there any theories about how this slight leaning off leads to borewash?

 

It doesn't. There's nothing you can do about it either, short of spending thousands and thousands.