Club G40 Forum
Technical => Engine and Transmission => Topic started by: dani1326 on February 14, 2011, 12:03:12 pm
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Right iv found out my engine has been bodged, the cam nuts have been over tightened and striped the threds so the cam could of bounced out but hoping a heli-coil kit will sort that as ther only need to be 6nm and 90*
but also found out the pistons could be almost dead
What do I need for a larger bottom end and to forge it?? I really need your help with this people, specs, what the parts come out of well everything
Thanks for your help
( I have had a search and seen I need a W1 crank and 77mm forged pistons but what do they come out of??? And do I use the G40 bottom end or another one?? )
or is there an easier one where I wont need to find a crank??
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Crank's from 1.3/1.4 diesel engines from VW, Seat etc. Accralite forged pistons readily available on E-bay. Your PY block can be bored to suit. As usual in life you just missed the sale of the century. A 1.4 block,crank and pistons sold for £800 ? See parts for sale. The advantage of the 1W block is it's fitted with additional oil supply to the cylinders. Sure there's a lot more on this in FAQ's either here or on CP.
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Crank's from 1.3/1.4 diesel engines from VW, Seat etc. Accralite forged pistons readily available on E-bay. Your PY block can be bored to suit. As usual in life you just missed the sale of the century. A 1.4 block,crank and pistons sold for £800 ? See parts for sale. The advantage of the 1W block is it's fitted with additional oil supply to the cylinders. Sure there's a lot more on this in FAQ's either here or on CP.
Iv had a good look round but can only find dribz and drabs
So i will need mine boring out to the spec of my pistons... Was hoping I could of used another polo bottom end but hay never mind lol
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what is wrong with your current bottom end?
you only need a 1W crank etc.. if you are wanting to increase the stroke. If you just want to increase the bore then use either Wossner or Accralite 77mm forged pistons (something like £500-£600 for a set with rings). Then you need to get the block bored, just buy the pistons first and take them and the block to whatever machine shop you are going to use.
That's all you really need but you will probably also want to replace all the bearings and the oil pump at the same time and all the bottom end seals & gaskets.
You need to factor in about £1000 for this assuming you are going to do most of the work yourself. I'd probably double or more that if you are also wanting to use a 1W crank to increase stroke.
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Long story but I don't mind about increasing the stroke just won't to make the bores new,
I'll be doing all the work except the boring out....
So forge pistons, and bore out my block any other parts I should replace??
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well, oil pump, bearings, seals and gaskets as I've mentioned already. There's £200-£250 worth of stuff there.
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well, oil pump, bearings, seals and gaskets as I've mentioned already. There's £200-£250 worth of stuff there.
i dont mind the price i just wont it to be done how it should be.... thanks for all you help and advice
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i have a bottom end with 20k on since new rings/bearings/oil pump. Just had bores rehoned, new gaskets.
Pete
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i have a bottom end with 20k on since new rings/bearings/oil pump. Just had bores rehoned, new gaskets.
Pete
what bore is it as im going for more capasity??
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just a stock bottom end. 1272cc don't want much for it - max you can go is 1341cc with an over bore and new pistons and 1473cc with a diesel 1w crank and new pistons.
depends how expensive you want to go.
for a 1341 expect to pay the following
£550 pistons
£100 boring
£100 oil pump
£250 bearings and gaskets bolts etc
so £1000 +labour for the bottom end
head refurb £150 on a stock head
headgasket adn bolts, coolant oil etc £70 ish
So all in a refurbed engine with increased bottom end capacity to 1341cc would be about £1250 i'd say if you were doing it yourself. add about £400 on top again to go 1473 as you need a crank/block (200-300?, head bolt holes boring out, crank balancing £100 - pistons can be dearer too)
Expect about 3 full days labour I'd imagine for that.
Also a stock head won't net the benefits of increased capacity - your probably better off adding another £150 for porting.
so £1800+labour ish. At £40+vat an hour=£1k labour.
So 1w walk in/out prince with a flowed head £2.8k i'd guess. (though new clutch for bottom end, lightened flywheel etc would increase cost)
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i have for sale a 1W bottom end and crank. i want £180 for the it and it comes with some G40 rods- just add pistons and bore for a 1473 setup. the block can also be used on its own (i want £100 for block)with a standard G40 crank and pistons to add oil squirters to your setup or if bored out a 1341 with oil squirters.
or if you just want the 1W 1.4 crank thats also £100 only for sale after i sell the block.
im having a lambda bose welded to the block soon so it will be G40 ready.
perfect if you are wanting a block to bore out or if you need a new bottom end.
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i have for sale a 1W bottom end and crank. i want £180 for the it and it comes with some G40 rods- just add pistons and bore for a 1473 setup. the block can also be used on its own (i want £100 for block)with a standard G40 crank and pistons to add oil squirters to your setup or if bored out a 1341 with oil squirters.
or if you just want the 1W 1.4 crank thats also £100 only for sale after i sell the block.
im having a lambda bose welded to the block soon so it will be G40 ready.
perfect if you are wanting a block to bore out or if you need a new bottom end.
I'll have it pal pm me your number please
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What will i need to create a 1W 1473 g40 and where will I find them??
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accralite pistons from accralite for the stroked g40 conversion
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accralite pistons from accralite for the stroked g40 conversion
http://www.accralite.com/accralite/index1.htm
Is it the bottom one??
Also do I use the 1.4 bottom end or the g40??
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type "g40 stroked" into the search box. comes up with bore 77, comp height 34.45 (i think) pin 20.
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The pistons are special order only, iv got to order 12 pistons to even get a price, what are my other options??
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Either find some peeps who are willing to go in on a deal and buy a set or find one of the few sets that's out there and hand over some big bucks. There's gotta be 4 or 5 sets out there, with at least 1 or 2 sets that are sitting in someone's shed doin' sweet FA.
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Dig deep in your pockets and get some quotes from other manufacturers like je for some one off pistons but as I highly doubt you know the exact spec unless somone who has a new set (young prodigys!) would like to let you measure them up and get a custom one of set made
Either way it's going to be big bucks but if your building a new 1.5 g40 motor you better get used to big bucks my 1341 cost plenty and this will cost a bit more
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The pistons are special order only, iv got to order 12 pistons to even get a price, what are my other options?
I'm seeing 77mm Wossner pistons for £550 on ebay
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you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc
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you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc
Yer that's why there special order or is it possible to skim a standard set??
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thats what my plan was with my other engine! skim a standard set to the 34.45mm deck height.
i really need to work it out. if i dont flog my bottom end- i will CAD it up and work out what i need to do to the pistons in order to attain 8.0:1 comp ratio.
when i fo it will be a super cheap way of having a 1398 bottom end. i will measure up the 1W pistons aswell so i can see whats needed for a 77mm set
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I'll be ordering some custom JE 8,5.1 for my 1W soon
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you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc
I haven't got the maths for it but could you downstroke the crank? There must be plenty of meat on the 1W compared to the standard G.
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You what?
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You can alter the stroke of a crank by re-sizing the journals.
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Don't make me quote myself.
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You can alter the stroke of a crank by re-sizing the journals.
You really can't...
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the difference in the pistons is in the height. they are like normal 77mm pistons yet are not as tall and have a wider bowl on them to deal with a higher compression ratio then on a stock G
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You can alter the stroke of a crank by re-sizing the journals.
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You really can't...
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Regrind the journal giving it a smaller diameter with a centreline further from the centreline of the crank. Conrod is sleeved and smaller bearing shells fitted..Conrod now has increased travel up and down cylinder. Or reverse.
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I understand completely what you're talking about- but the stroke is still the same, no matter what journal diameter you have.
The only way what you're talking about will work is to offset the journal, but it's pointless and a highly expensive task for any machine shop, and you've built a compromised crank as it willbe far weaker.
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Just out of intrest are 1w cranked 77mm bore engines less "rev happy" because of the increased stroke ? Or is it not increased by enough to make a difference?
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I understand completely what you're talking about- but the stroke is still the same, no matter what journal diameter you have.
The only way what you're talking about will work is to offset the journal, but it's pointless and a highly expensive task for any machine shop, and you've built a compromised crank as it willbe far weaker.
Offset grind has been fairly usual in drag racing circles, but normally they have found standard size rods with smaller journal that can be used, eg using Chevy BB rods in stroked Ford BB's
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Thats what I was talking about Pete, I said a reground journal with a centreline further from the centreline of the crank. I assumed you knew what I was talking about, the description was aimed at Rich who seemed oblivious to the idea. As stated, I didn't have the dimensions to see if it was possible.
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I'd be surprised if there was enough meat in the crank to make it viable on a Polo- main thing is cost, machine shop time is by no means cheap, especially for custom tooling and one off jobs.
I'm only aware of this being done to get within capacity regs for specific motorsport applications, I'm still unsure why you'd bother with it cost wise, when a custom set of pistons is circa £600/set.
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I will be selling a complete 1473cc engine very soon.
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Isn't it already sold?
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It's not the modification of the crank that increases the stroke, it's offset of the sleeved conrod that would alter the swept distance. Totally fucking pointless in the grand scheme of things. Lets get some perspective here, this is a polo engine (!) not a 10000 horse drag machine burning an oil drum of alchohol every 50 yards. Fucks sake.
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Isn't it already sold?
No, I have two, one in bits that is sold, and one built that I haven't listed yet.
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would it be easyer to bore mine out to 77mm (1341.11cc) then slap in some Wössner 77mm pistons??