3.0 litre re-build questions

[double-6s 0]

Hi.

The time has come to get my bottom end rebuilt and i'm going to do a 3.0 re-bore. 83mm pistons etc. Will eventually be charged.

Couple of questions please......

 

1. Can i use the standard 2.9 con rods? I'm assuming they're the same? If so, is this something thats likely to be knackered or will my existing be ok? Cromoly ones are available for about 600 quid.

 

2. Is it worth getting the '3.0 engine pack' from EIP in the USA? It's about 1300 quid and has forged 83mm pistons, all bearings, bolts, rings, etc etc. Is that worth doing?

 

3. Is it worth putting an exchange crank in there too?

 

Thanks for any help - obviosuly i'm not doing the rebuild myself as i'm useless, hence the possibly dumb questions ;)

 

Thanks

 

Will

[s.g 0]

would it not be better to go down the 24v route , by the time you have paid for the engine pack and shipping cost's plus custom tax and then paid someone to take out your engine, strip it down then send it off to be rebored and then be put all back together you could have had the 24v bought and fitted for less.

just my 2p worth

[Trig 0]

Or R32.

 

Not a cheap conversion but rebuilding your 2.9 seems like an expensive job when folk like Stan are getting whole 24v conversions done for 3k all in. :)

[double-6s 0]

no i wouldn't mate. not the way i'm going to do it.

there is no tax - will be sent via jersey. alot of the stripping etc will be done by me and a mate (mate has a clue unlike me).

 

anyway, could we stick to the question please - no offence but i'm 34 and know my own mind thanks!

if i want a different engine i'll get one!

 

PS. don't underestimate a bored-out 12v - trust me. especially one with forged pistons etc which will be ready for some serious charging when i can afford it :)

 

edit: i sounded moody and patronising there - didn't mean to! :) :)

[double-6s 0]

trig - the costs involved are horrendous! i'd love an r32 but not cheap.

as for the 24v - not really my thing. i don't crave smoothness etc, i crave rawness etc, and love the 12v vr engine. :)

 

and i already have a rebuilt 12v head!!!!

[Graham_E 0]

I don't crave smoothness etc, i crave rawness etc, and love the 12v vr engine. :)

 

Couldnt have put it better myself, ive come to the point where my bottom end needs a rebuild and im thinking of going down exactly the same route, be interested to see how this works out.

[Rpmayne 0]

Don't think the con rods would need changing as the big end bearings and pins through the pistons (can't remember the name) should take the damage. My original con rods were reused with the bearings and pistons changed. Would get them balanced next time though.

 

When I phoned stealth about getting 83mm pistons they didn't think it was worth it so I went for 82.5mm. Also, 83mm is the biggest the block can reliably go so if anything goes wrong again its new block time. Not alot of price difference between the two sizes of rebore, just went for hopefully the more reliable option.

 

Thought about forged pistons but was put off by stories about the piston slap when cold, and price. Also wasn't planning on forced induction so didn't really need them.

[double-6s 0]

so how much are non-forged pistons mate?

thanks for the info btw :)

[Rpmayne 0]

I can't remember now, but must have been a few hundred more than the Mahle ones (original make of the pistons used by VW). Think the Mahle 82.5mm ones were about £600. May be worth it if you're going forced induction though, but then would you want a billet crank aswell, which I'm guessing would cost a fortune.

[Kevin Bacon 5]

3.0 isn't worth it mate..... think about a 2.8 Highline....makes 190 easily, some make more. Very heatlthy 2.9s make 200-205, so you're only going to get the same increase again with a 3.0.... not very cost effective imo.

 

I know you've got your mind made up and all..... but personally I'd stick to 2897cc (82.5mm overbore mahles) and charge it. You could also take the oppurtunity to lower the compression ratio whilst it's being built by offset bushing the pistons and then you can play about with chargers and turbos all you like without fear of blowing it (or having to use spacer gaskets)....

 

Generally speaking, forged pistons take longer to warm up and are noisier as a result, they don't last as long as cast pistons and cause higher oil consumption......but I think the EIP ones claim to be a lot better than your regular forgeds and don't suffer with noise and wear problems.

[double-6s 0]

i know what you're saying kev, but from what i've seen there's no difference in cost between 2.9 and 3.0?

 

as far as i can tell i will need all the same parts other than slightly larger pistons? and all the pistons i've seen are the same price anyway - 81,82 or 83mm.

 

so if i'm going to charge her in the future (when), is it worth going for forged pistons or not really? i've read quite a bit about the eip ones ad they do seem to be a good cost effective answer. 800 dollar. love you long time :)

[double-6s 0]

i quite fancy this myself.............

[Kevin Bacon 5]

Ate undred dorrar...mmm....sucky sucky.... LOL! Not a bad price indeed.

 

I've never experienced a 3.0, and you're right, it's all in the pistons, so shouldn't be that expensive in theory...but everytime I mention the big three Oh to Vince he says don't bother. I value his opinion since he's built many VRs in all shapes and sizes and has all the dyno plots to go with.....

 

My engine is very rattley and coarse at the moment and is also imminently heading for rebuild land (wouldn't think it with it's output tho, strange)....I'm in two minds.....play with cranks and pistons and exceed 3.0/3.1....or lump it with 2.9 and whack up the boost? :-) I'm favouring the boost personally.

 

Even a regular 2.9 build is going to kick some butt compared to an old, tired engine that's lost most of it's compression. Ze experts just say that 83mm is uncomfortably close to the max bore tolerance and you can't guarantee VW cast every single block the same.......

 

Ah feck it.....ignore me.....go for it mate. Tree Litre sucky sucky that bad boy :-)

 

There is also the R32 option, but can I be fagged? Probably not :-)

[double-6s 0]

no i'm scared now! might just go 82.5mm and be safe.

it's definately going to get charged too - i've stumbled across the path to a free charger!!!

so what does lowering the compression ratio do playsquire?? can you briefly explain, and also why they do it for forced induction motors? :)

[double-6s 0]

mine is going through oil and plugs like a serious mo fo now :(

[Kevin Bacon 5]

Are they fouling up with wet deposits (1 and 6?) in less than 1000 miles? If so, rebuild time!

 

I'd recommend the 2.9 build with cast mahles if you're charging mate.

 

Compression ratio - hard to explain briefly! It's all about cramming bigger things into a tight space :-) The bigger thing in this case being more air/fuel.....if you force loads of air/fuel into a standard sized combustion area, the mixture can explode uncontrollably (pinking) rather than a controlled burn. So lowering the CR creates more space for the extra air/fuel (squish area) for a more controlled burn. You can either drop the piston down or raise the head (with a spacer gasket), your choice. Reducing squish area with pistons is more reliable and can be done cheaply by offset drilling some blank gudgeon pin bushes or by using forged pistons with a dished crown, which is more expensive.

 

VRs can get away with about 8psi without lowering the CR because there is a decent sized combustion area (you need to see a VR block with the head off to see why). 10 psi is pushing your luck and 12 would defo require a CR reduction if you want the head gasket to last more than 3 months.

[double-6s 0]

cheers - i do understand the compression ratio in theory, just in practice, does a lowered CR mean less power? and vice versa?

[A20 LEE 0]

I've discussed this with some of the guys on vortex with VR6 T's. All say keep it simple, stick with 2.9.

[double-6s 0]

cheers mate.

so 82.5 it is then.

 

don't even mention turbos - i really fancy a turbo but everyone has been talking me round to a charger.

 

not many charged C's down here you see.

[Kevin Bacon 5]

Turbos are lush..... quieter, smoother, more torque.....mmm. Have you ever heard a VR turbo up close and personal? Wow.... doesn't even sound like a VR6 anymore....it's a really peculiar sound.....very quiet and creamy...strange, but lovely at the same time.

 

Lowering the CR in theory means less torque low down before the boost builds......N/A engines rely on high CR for torque and power...it's how Audi and BMW get such high specific outputs from their N/A engines...they whack up the CR to like 11 or even as high as 12.5:1! Turbos ideally need 9 or 8.5:1 if you're running 1 bar or more. Chargers are OK as they're linear, but only up to about 8psi where the VR is concerned, so you get the benefits of N/A CR (10:1) off boost and the benefits of boost, on, err, boost!

 

You can however ramp up the ignition advance if you lower the CR to help restore some of the off boost torque...

[double-6s 0]

so basically.....

 

charger - leave the CR as is?

 

turbo - lower the cr?

 

i do fancy a turbo but the quiet and creamy puts me off - i'm rather uncouth me :) loud and hard-edged is more my thing :)

i fekin love the noise a 12v makes tbh - with an induction kit that is

[Kevin Bacon 5]

So basically....

 

Charger - up to 8psi without intercooling - leave CR as is. Up to 10psi with intercooling or water injection - leave as is. 12 psi or more, reduce CR or risk it for a biscuit.

 

Turbo - Ditto, but 1 bar (14psi) or more needs CR reducing and defo intercooling.

 

Turbos spool up a lot quicker and consequently deliver a big gob of torque very quickly, which is harder on engine internals and transmissions....but in each case, if you're sensible with the boost, the standard drivetrain can take it.

[StormchargedVR6 0]

- i'm rather uncouth me :) loud and hard-edged is more my thing :)

say that again :lol:

[double-6s 0]

- i'm rather uncouth me :) loud and hard-edged is more my thing :)

say that again :lol:

 

lol :)

[double-6s 0]

don't think he likes me :(

 

so the CR stays as it is then. certainly not going to go above 10 psi with a charger. i had also read that turbos are more strain on the engine so i guess a charger is the more sensible option.