1.8 8v block rebore

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Mk3i
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1.8 8v block rebore

Post by Mk3i »

Howsit Guys,

In need of some advice, would like to find out if an AFV 1.8i 8v block be bored out to a 2lt. if this is possible what pistons would fit the standard 1800 conrod.

would there be any power difference.

Thanks in advance.
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Re: 1.8 8v block rebore

Post by panic-mechanic »

You can't get to 2litre on bore only. You also have to change the crank.
If you go to the bore of a 2l using the 1800 crank you get a 1900.
Piston recommendation will depend on whterh you are using a 1800 or 2l crank. Yes the pistons fit that conrod.
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Re: 1.8 8v block rebore

Post by Mk3i »

Thanks Panic.

If you don't mind me asking how would the 2lt crank aid in increasing the block capacity. I understand the rebore part.
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Re: 1.8 8v block rebore

Post by WeirdSteam »

Its not only the Bore that determine the engine capacity but the stroke as well.

Thats why you need the 2l crank

Here is a nice read en calculator

http://www.had2know.com/automotive/bore ... lator.html

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Re: 1.8 8v block rebore

Post by Mk3i »

if I use the 2lt crank which will create a longer stroke to increase engine capacity would it not push the piston up higher than standard and pull it down lower. if that's the case at tdc would the piston not be higher then the top of the block.

I would like to bring the block up to a 2lt with out replacing it if possible.
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Re: 1.8 8v block rebore

Post by Torker »

Mk3i wrote:if I use the 2lt crank which will create a longer stroke to increase engine capacity would it not push the piston up higher than standard and pull it down lower. if that's the case at tdc would the piston not be higher then the top of the block.

I would like to bring the block up to a 2lt with out replacing it if possible.
2.0 crank and pistons together will work 100%, some minor clearance mods to get the crank to turn and you've got a 2.0 motor.
Current rides:

VW Golf - 83 GT 2.1 16V 2-door with throttles
VW Golf - 78 LS 2.0 8V 4-door (2.1 ABF with throttles in progress)
VW Golf - '08 Citi Storm - 1.4 for now
Hyundai - 1.4 Getz (daily)
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Re: 1.8 8v block rebore

Post by Mk3i »

thanks guys,

would I have to get the 2lt crank, conrods and pistons. what size would I have to bore out the block to.
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Re: 1.8 8v block rebore

Post by Torker »

Mk3i wrote:thanks guys,

would I have to get the 2lt crank, conrods and pistons. what size would I have to bore out the block to.
Your existing conrods will be fine, stock 2.0 bore is 82.5mm, you can take it up to 40thou over (83.5mm) if you want more oomph.
Current rides:

VW Golf - 83 GT 2.1 16V 2-door with throttles
VW Golf - 78 LS 2.0 8V 4-door (2.1 ABF with throttles in progress)
VW Golf - '08 Citi Storm - 1.4 for now
Hyundai - 1.4 Getz (daily)
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Re: 1.8 8v block rebore

Post by panic-mechanic »

2.6 combi piston.
But you have to dummy assemble, check clearances, calculate cr and see that it's all ok.
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'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
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Re: 1.8 8v block rebore

Post by Mk3i »

the current bore size is 81mm and the wall thickness between the pistons is around 6-7mm. if I bore to 82.5 that will leave the wall thickness at 4.5 to 5.5mm. would that be okay.

would I be correct in saying that the needs to be bored out to 82.5mm, get a 2lt crank and pistons. would the 1800 conrod fit the 2lt crank and pistons.
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Re: 1.8 8v block rebore

Post by WeirdSteam »

You need 2,6 combi pistons not 2l pistons, you can safely go to 83,5 you also need the 2l metal head gasket, and the pistons fit your conrods.

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Re: 1.8 8v block rebore

Post by Mk3i »

thanks guys,

I manage to get the 2lt crank and ground of the 2 x points on in the block that prevents the crank from turning. wanted to ask which is the safer route to go, get the intermediate shaft ground down or shave abit of the conrod.

which brand in caravelle pistons and rings should I get, also big ends and mains.
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Re: 1.8 8v block rebore

Post by WeirdSteam »

KS if you can find on the pistons, but there are other brands that are great as well. Alert engine spares sell.

Get the intermediate shaft machined, As for bearings I personally use ACL Bearings.

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Re: 1.8 8v block rebore

Post by Mk3i »

thanks man, I know alert has the AE brand for the pistons, hopefully they also carry KS if that's better. in your honest opinion would there be a slight increase in power with this conversion. im planning to get the short ADY intake if that would make any difference or the original intake is good enough. by any chance do you know the injector cc rating on the 1.8 mp9 and 2.0 mp9 - reason im asking cos the ady intake that I want to get has injectors on it.
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Re: 1.8 8v block rebore

Post by WeirdSteam »

Injectors are the same between the 1,6/1,8 and the 2,0 . I have an ADY and i changed my intake to the Polo intake (long intake) its more torque'y than the short intake, i dont like the short intake at all, going short block 2l has a bit of power increase and its rev happy, but i prefer the 2l longblock torque feel.

As for KS pistons its the best out there but they are getting scarce, remember to get a 2,0 metal head gasket aswell.

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Re: 1.8 8v block rebore

Post by Mk3i »

bru you just saved me a grand cos that's the price on the short intake. the current intake I have is much bigger and has the vw sign on it.

my initial plan was for a long block but the thoughts of getting COR done again and then not knowing the internal condition put me off. its actually more fun going this route.

which brand carry's the metal head gasket, cos goldwagon don't keep. I actually need the full gasket set.
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Re: 1.8 8v block rebore

Post by Torker »

Mk3i wrote:bru you just saved me a grand cos that's the price on the short intake. the current intake I have is much bigger and has the vw sign on it.

my initial plan was for a long block but the thoughts of getting COR done again and then not knowing the internal condition put me off. its actually more fun going this route.

which brand carry's the metal head gasket, cos goldwagon don't keep. I actually need the full gasket set.
Elring metal layer gasket works very well (you can actually re-use it if you want), I use it on all my modified engines and not a single problem.
Current rides:

VW Golf - 83 GT 2.1 16V 2-door with throttles
VW Golf - 78 LS 2.0 8V 4-door (2.1 ABF with throttles in progress)
VW Golf - '08 Citi Storm - 1.4 for now
Hyundai - 1.4 Getz (daily)
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Re: 1.8 8v block rebore

Post by Mk3i »

elring was the brand of gasket goldwagon gave me but it wasn't metal and they said they don't keep the metal ones. if I cant get elring metal gasket which other brand is good.

this might sound stupid but whats gas flow, I know port and polish is were the intake and outlet ports on the head gets bored out abit and polished up for better air flow - do you know any that does this and is it worth it
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Re: 1.8 8v block rebore

Post by panic-mechanic »

It's ok if it's not a steel gasket as long as it is the right bore.
machine the intermediate shaft down.
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Re: 1.8 8v block rebore

Post by Mk3i »

I think I read up on the forum that the part on the intermediate shaft that turns the distributor must be machined down until its 5mm then only the conrod will clear it, would this be correct.

will try to get the head gasket tomorrow. so far so good.
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Re: 1.8 8v block rebore

Post by panic-mechanic »

yes correct.
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Re: 1.8 8v block rebore

Post by Mk3i »

kool, should have the block and shaft back next week. does the crank and shaft need to be balanced.
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Re: 1.8 8v block rebore

Post by panic-mechanic »

nobody will balance an intermediate shaft for you.
Crank - unless you modified on it it should be balanced form the factory.
The rest of the moving assembly is nice to do but to an absolute MUST.
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Re: 1.8 8v block rebore

Post by Mk3i »

howsit guys,

had no luck with the KS pistons only found the nural brand, are they any good or should I keep shopping around.

@panic - the crank was taken of an ady block that was like new, still had the original vw bearings - I haven't modified it in any way, would it be fine to install as is - did you mean its not a must to balance the other parts

I manage to get the oil pump in KS
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Re: 1.8 8v block rebore

Post by WeirdSteam »

I don't know the nural brand so I can't comment there. I always have the rotating assembly balanced. Makes for a better built engine. Allot smoother and safer in the long run.

I know of guys that don't bother with balancing and some motors last some don't but I prefer having mine balanced.

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