1.8 8v block rebore

[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.

[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.

[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.

[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.

[Torker]

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.

[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.

[Torker]

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.

[panic-mechanic]

2.6 combi piston.
But you have to dummy assemble, check clearances, calculate cr and see that it's all ok.

[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.

[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.

[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.

[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.

[Torker]

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.

[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

[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.

[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.

[panic-mechanic]

yes correct.

[Mk3i]

kool, should have the block and shaft back next week. does the crank and shaft need to be balanced.

[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.

[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

[Mk3i]

the only reason I asked about balancing the shaft is because I read it up on this forum. besides the crank and intermediate shaft what's else is to be balanced. hope there's some reasonable guys in durbs that does this.

these pistons seem to be made by federal mogul, on the box their name is there with "ae/glyco/goetze/nural/payen"

these pistons come 6 in a box - hope they the right ones

will try and post some pics

[panic-mechanic]

Nural is just fine.

[Donavan]

You can buy 2.6 combi pistons from Goldwagen aswell and you don't have to buy a full set of 6

GW sells them separately.

[Jakez 994]

Hi all. Im new to the forum. Regarding the rebore of the 1800cc block. I have an 1800std block. I want to build a reliable strong 8v carburetor engine. I want to bore it to 1900cc reuse the conrods and crank. Is the kombi 2.3, 2.5 or 2.6 pistons the best to go?

[missioner]

Hi all. Im new to the forum. Regarding the rebore of the 1800cc block. I have an 1800std block. I want to build a reliable strong 8v carburetor engine. I want to bore it to 1900cc reuse the conrods and crank. Is the kombi 2.3, 2.5 or 2.6 pistons the best to go?

2.3 microbus. Also fitted to the Audi 500 from '88 to '94.

The rest wont work in your application.

Wrist pin height is your enemy wrt to the other pistons. 2.5 and 2.6 are the exact same thing and would need a 2l crank to work in a short block. The 2.3 motor has the same stroke as a 1.8 and is why they are good for the conversion. Ie: the 2.3 is a 5 cyl 1.8 with a slightly bigger bore.

For a little safety get the pistons either std 82.5 or 83mm. That way you still have some meat for another rebore if you break the engine.