G60 Bore Question

[Ronan 0]

I am looking to buy some forged pistons for my G60, but I am unsure if the ones I have found will weaken the walls of the bores too much. As far as I know the G60 has an 81mm(?) bore, and the JE pistons I have found which will enlarge the engine size to a 1.9, are 82.5mm. What is the general opinion on pistons this size?

 

Thanks....

[TomB 0]

I'm no expert on these matters, but I'm pretty sure that Henny is running a standard block that's somewhere around 1950cc.

[W3RKD 0]

You can go to 83mm without any problems on the pg engine.

[Chris VR6nos 0]

Then you can use my CC-Calc (link in sig) to work out what the CC will become!

I'd do it for you but don't know the stroke

 

 

 

Chris

[Henny 0]

yup, to add what G-man says:

 

83mm is the accepted max overbore of the G60 (either PG or 1H block) by most engine builders - some will go to 83.5mm, but that's seriously taking it to the absolute limit and may limit the longevity of your engine.

 

82.5mm will work nicely... Assuming 81mm is standard bore (which seems to ring a bell) the standard G60 throw works out to be 85.8mm so you'll get a capacity of around 1835cc... 83mm pistons would then give you 1857cc (ish!)

 

Any other resizes need a different crank to achieve... 8)

[Chris VR6nos 0]

So can you reliner these little blocks and make them like a 2.5 or something?

 

 

Chris

[Henny 0]

nope... cast block, crack the bore and you have a nice large door wedge...

 

Think the max you can take this type of block upto is about 2.2, using a different crank and 83mm bore, but then you get problems with not having enough cooling and you have to delete the oil squirters which cool and lubricate the piston crowns and gudgeon pins...

[Crasher 3]

82.5mm will work nicely... Assuming 81mm is standard bore (which seems to ring a bell) the standard G60 throw works out to be 85.8mm so you'll get a capacity of around 1835cc... 83mm pistons would then give you 1857cc (ish!)

 

The stroke of a PG is 86.4-mm so a bore of 82.5-mm would give 1848 cc.

[Supercharged 2]

[stupid question time]

 

So how do people make these 2.0+ G60's - 85+mm pistons or different blocks or am I missing something like the throw is increased or counting extra space in the piston crown / head etc??

[W3RKD 0]

[stupid question time]

 

So how do people make these 2.0+ G60's - 85+mm pistons or different blocks or am I missing something like the throw is increased or counting extra space in the piston crown / head etc??

 

increased throw - Differant crank although i think sams gone even crazier and gone 83.5mm bore too...

[_Monkey 0]

[stupid question time]

 

So how do people make these 2.0+ G60's - 85+mm pistons or different blocks or am I missing something like the throw is increased or counting extra space in the piston crown / head etc??

 

A mate of mine has an Audi bubble block as his bottom end, that get's him a 2ltr.

 

It bloody works too!

[olly elworthy 0]

hey monkey you any idea what pistons he is running?

[Crasher 3]

So how do people make these 2.0+ G60's - 85+mm pistons or different blocks or am I missing something like the throw is increased or counting extra space in the piston crown / head etc??

 

There are at least four ways of building a 2L G60. Use a 2 litre short or tall block or convert the existing block to 82.5 or 83-mm bore with a 2 litre 92.8-mm stroke crank (1984 or 2008 cc). These methods leave you with a small gudgeon pin and a high compression to work around. The T4 van AAC 2L (1968cc) petrol engine with its 81mm bore and 95.5-mm stroke is ideal due to its 8.5:1 compression and 24-mm gudgeon pins but it is a little harsh at revs.

[Henny 0]

G-Man, Yup, Sam's gone for 83.5mm bore AND an increased stroke to get 2032cc IIRC...

 

Crasher, thanks for clearing up the crank throw, I couldn't remember off hand what it was... :oops: :notworthy: Oh, and the T4 route for 2 litre, you've been rather kind to it by saying "a little harsh at revs" there... I seem to remember you described it somewhat less kindly at Inters a couple of years ago when I was talking to you about the conversion I was planning and some of the options! :lol: ;) I've since driven a G60 which used this conversion and it pulled OK at the low end, but was horrible up at the top end of the rev range...

[Crasher 3]

I have learnt to be less OTT in my comments of late, I have been hammered for being to vocal over things I do/don't like and I am trying to take the middle ground these days. Something tells me trying to please all of the people all of the time will probably make me more enemies than being direct but I am giving it a go.

[bennyd 0]

Does anyone know about this kit from EIP

 

http://www.eiptuning.com/eip/enginepackages8V.html

[peteTDI 0]

if

[peteTDI 0]

Does anyone know about this kit from EIP

 

http://www.eiptuning.com/eip/enginepackages8V.html

 

 

the kit maybe good going by the turbo kits on the vr6's (fitting one on a mate at work at the mo) but took 9 months to get here, still cheap on his £2600 with shiping for rods,je's, bb k04 turbo,manafold,ecu, pipes ect ect

 

if my bottom end is that bad i my get one and let you know in around a years time when it gets here

[_Monkey 0]

hey monkey you any idea what pistons he is running?

 

Dunno mate, I'll ask though! :wink: