1800 Bore

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ssshannah
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1800 Bore

Post by ssshannah » Sun Jul 14, 2019 4:58 am

Hi guys. Id would like some clarity regarding the 1800 - 1900 conversion. I know the pistons I need to get is the Kombi 2.3 pistons (83.5mm) and need to skim the pistons 1.5mm because they are taller. I would like to find out how much bore should I have for 83.5mm pistons to fit?
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Saiendra
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Re: 1800 Bore

Post by Saiendra » Mon Jul 15, 2019 7:49 am

What block are you using to start the conversion?
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panic-mechanic
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Re: 1800 Bore

Post by panic-mechanic » Mon Jul 15, 2019 7:48 pm

not entirely sure what the question is. You need 83.5 mm bore to fit a 83.495 mm piston...
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Re: 1800 Bore

Post by PapaJo » Mon Jul 15, 2019 8:33 pm

Panic answered your question.

Why don't you get 2.6 combi pistons as they will sit flush in the block, with only the squish pad sticking out. You are planning to do this to a 1800 8V block with 1800 crank and std 1800 rods.
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Re: 1800 Bore

Post by ssshannah » Wed Jul 17, 2019 4:18 pm

Saiendra wrote:
Mon Jul 15, 2019 7:49 am
What block are you using to start the conversion?
1800 Engine
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Re: 1800 Bore

Post by ssshannah » Wed Jul 17, 2019 4:22 pm

panic-mechanic wrote:
Mon Jul 15, 2019 7:48 pm
not entirely sure what the question is. You need 83.5 mm bore to fit a 83.495 mm piston...
I've read that in order to have a true 1900 motor you need to use 83.5 mm pistons kombi pistons. so my question is what Bore should the block be machined to fit 83.5mm pistons?
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Re: 1800 Bore

Post by ssshannah » Wed Jul 17, 2019 4:26 pm

Also is it worth going 1900 while still running Carburator? and how much power will i get from going FI?
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Re: 1800 Bore

Post by PapaJo » Wed Jul 17, 2019 5:53 pm

ssshannah wrote:
Wed Jul 17, 2019 4:22 pm
panic-mechanic wrote:
Mon Jul 15, 2019 7:48 pm
not entirely sure what the question is. You need 83.5 mm bore to fit a 83.495 mm piston...
I've read that in order to have a true 1900 motor you need to use 83.5 mm pistons kombi pistons. so my question is what Bore should the block be machined to fit 83.5mm pistons?
Please, Read panic’s statement again.

Block gets bored to 83,5mm to fit the 83,495mm pistons. That leaves you with piston to block clearance of 0,005mm.

You cannot bore piston and block to the exact same size. The thermal expansion properties of the piston and block can be different and that is why clearance is required.

Buy the (83,5mm referring to bore size in block) pistons and on the box it comes in, it will give the piston size, clearance value en then the engineering shop will know exactly what size to bore the block to. No rocket science required
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