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Discussion Starter · #1 ·
Ok, I'm guna sound like a complete fool here but that's what I am when it comes to engines so I could do with a bit of knowledge :)

I know if you bore out an engine you're making the capacity bigger, but what part of the engine are you increasing? Also, what is stroke and what does it affect?

If you read about engines like 1776cc, 1915cc + are these just original bug engines that have had the bore increased or are they new engines that are based on the original design but made bigger from the start?

If anyone can shed any light it would be much appreciated from this newbie :)
 

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I'm pretty new to engines too but I think bore is the piston/barrel diameter and stroke is how far in and out they move. Both factors effect overall engine capacity.
 

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Ok - expanding from this
what are the stroke and bore of the common sizes
ie
1914
1776
2007
2332
etc etc

I might have the above wrong - but you know what I mean.
 

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metric_thumbs said:
Ok - expanding from this
what are the stroke and bore of the common sizes
ie
1914
1776
2007
2332
etc etc

I might have the above wrong - but you know what I mean.
There are usually more than one way to skin those cats. Look here for specs of the most common performance engine sizes:
http://www.vwspeedshop.co.uk/pg/cataloguepages.htm

:D
 

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beatboxPaul said:
I know if you bore out an engine you're making the capacity bigger, but what part of the engine are you increasing? Also, what is stroke and what does it affect?
a watercooled engine for eg in a golf has a cylinder block with a crankshaft at the bottom, the cylinders are in line above it with the pistons in and a cylinder head on top
the capacity of the engine is the volume that the piston moves in the cylinder
the bore is the diameter of the cylinder
the stroke is how far the piston moves up and down and is determined by the crankshaft ( think of the movement of your knee as you pedal a bike)
with "normal" engines you can have the block "bored out" this means the diameter of the cylinders is machined bigger and then new bigger pistons fitted. ie the bore is increased thus giving more capacity (cc's)
with a vw air cooled motor the crank is contained in the block (crank case) and has the cylinders (barrels) bolted on to the outside of it two either side and the heads (one each side)on top of these. because the pistons are contained in a bolt-on barrel they can be changed for bigger ones to easily increase the bore
if you change the crank for a new longer stroke version to give more movement of the pistons then that will increase the capacity too (longer cranks on your bike mean your knees move higher)
:)
 

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metric_thumbs said:
Ok - expanding from this
what are the stroke and bore of the common sizes
ie
1914
1776
2007
2332
etc etc

I might have the above wrong - but you know what I mean.
1776 = stock stroke (69mm) with 90.5 B&Ps
1914 = stock stroke (69mm) with 94 B&Ps
2007 = 78mm stroke 90.5 B&Ps
2332 = 84mm stroke 94 B&Ps
:)

2110 could be 76x94 or 82x90.5
 

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Discussion Starter · #8 ·
cheers guys, that has helped a lot! that how stuff works page is frickin awesome. i totally get it now :)

so now, my one remaining question! if you get engines that are say, 1914, 1776 or whatever (basically anything larger than stock), are these built from the ground up or are they re-conditioned/bored-out engines from other cars? i presume they just replace pistons and change crank length amongst other things?

actually, i just realised i'd like to know what lightening the flywheel does. can anyone tell me?!
 

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beatboxPaul said:
cheers guys, that has helped a lot! that how stuff works page is frickin awesome. i totally get it now :)

so now, my one remaining question! if you get engines that are say, 1914, 1776 or whatever (basically anything larger than stock), are these built from the ground up or are they re-conditioned/bored-out engines from other cars? i presume they just replace pistons and change crank length amongst other things?

actually, i just realised i'd like to know what lightening the flywheel does. can anyone tell me?!
there's more to it than this but if you take a 1300 beetle engine and swap the barrels and pistons for 90.5mm or 94mm diameter ones then you will have a 1776 or 1914 respectively - the crankcase needs machining to alow them to fit and plenty other stuff needs fettling but thats the basic theory

when you rev an engine it takes time for the flywheel to build up momentum and then when you take your foot off it takes time for the reves to drop cos its the flywheel that keeps it spinning - if you lighten it the takes less time therefore revs up and down quicker
 

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Discussion Starter · #10 ·
ah cool :)

so if i buy a bug with a big engine i should ask who built it and what was replaced i guess! thanks alot dood :hangloose
 

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Get hold of a copy of VW Beetle Performance Handbook an excellent book by Keith Seume ISBN 0760304696. This will tell you all you need to know about upgrading VW engines from mild to wild :D Also covers transmission, suspension and brake upgrades as well ;)
 
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