Tuning tips: Reboring an engine

obi_waynne

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To increase the power of an engine you can increase the cylinder capacity.#! The best way to increase the cylinder capacity of an engine is by physically making each cylinder a larger diameter.#! Firstly sit down and do your research.#! You need to check that you can get a gasket, piston with rings and other [...]
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What do you think of this tip then, read the article and post your comments in here.
 
One of the important factors here is a well tooled and knowledgable machine shop. In order to rebore an engine they must either supply the parts in order to 'blueprint' the build or we supply the parts for them to machine to. They will also inspect the block prior to any machining commencing. The well known engine builders know every trick and combination to gain those extra cc's, like you said from stroker kits to offset bores. One guy I used to race against, who has his own business, built an 'A' series engine that was 1600cc IIRC, that was a long time ago and he did rallycross, back in the days of Porsche engined Beetles.

Back in the early 90s I built an Audi 5 pot that ended up as a 2.4.
 
A lot of modern engines (but not all of them) are aluminium with liners and these AFAIK are not easily reborable. If you have a cast iron block then you are in luck.
 
It also depends on how think the liners are. Some owners of Z22SE vauxhall engines go for a slight over bore in the standard liners as they are quite thick.

Also to note, if you are planning to turbocharge or supercharge your engine then bigger isn't always better with bore size, because you will have problems with blowing headgaskets and even cracking the block in extreme cases. Essentially you are weakening the block by taking material out of it, and care should also be taking when going bigger not to intrude into any oil galleries, there might be plenty of space between each cylinder but you have to make sure all the pathways aren't going to get disturbed in the process else you'll end up with a very big and expensive mess...

Reboring and overboring is usually a practice used on NA engines to gain extra power/torque as they say, theres no replacement for cubic displacement and to be fair, I totally agree....
 
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