Alright here is the situation ... The valve in my 1800 kombi broke and shattered the piston and head ... I was told that it would be just as cheap, if not cheaper to bore the old girl out to a 2lt. As the pistons are more freely available ... I did this - got the new 94.5mm pistons, bored the barrels and got new heads ...

Problem is ... as prob you all know - is that the newbies don't go onto the existing 1800 conrods - they are physically completley different, which leaves me in a bit of a tight position ... what do I do ... can you get 94.5mm pistons that fit onto the 1800 conrods ...

Thanks for your help

- Isaak

:bounce:bounce GO THE DOCKERS :bounce:bounce

1800 pistons are 93mm and two litre pistons are 94 mm. The Bentley manual lists two oversizes, each 0.5 mm larger, which means that you possibly could have got some 1800 pistons in 94mm anyway. Beyond 94 mm, you're supposed to replace the cylinder.

Nevertheless, I didn't know there was a difference in the setup. The Bently manual lists the gudgeon pin diameter as 23.996-24.00 for all dual-carb or efi models, so I would have assumed that 1800 and 2-litre pistons shared the same gudgeon pin setup, making them interchangable.

The 1800 had a 66mm stroke, and the 2000 was 71mm. I've always just assumed that the conrods were the same, and the cylinder height was taller on the 2L to bring the compression back down, using the same conrods. Does anybody know if 1800 and 2L conrods are different, especially at the little end?

Isaak, are you absolutely sure you've got the right pistons?

Sad to relate, from the Haynes manual:
"the [2.0 litre] engine is very similar to the previous 1.8 litre version except that it has a larger bore and stroke with the obvious differences in piston and conecting rod dimensions..."

2.0 Journal diameter is given as 49.98 to 50.00 mm.

Looks like you need a matched set of Pistons, Cylinders and Rods.

hth

[Edited on 5-9-2003 by modulus]

Peter, thats the dimension for the big-end, which won't effect the fitment of the piston. Any idea if the little ends are different for 1800/2L?

a 2 ltr crank is basically on offset ground 1800 crank I think the small end is 5 mm smaller on the 2 ltr pistons
so you'll either have to get new pistons and barrels $600 ish
or a 2 ltr crank and rods
who did the boring for you? shouldnt they have known the pistons were different?
marcel

You're right Kol,
the Haynes manual doesn't give the little-end dimensions for the 2.0 update, nor does it have gudgeon pin info. for the pistons (for the 2.0 update section).
But, as Isaak says they don't fit, I guess there must be a difference.

As the original approach would not have resulted in any appreciable capacity increase (I guess 93 - 94.5 might give about 1850 cc) and the pistons are bought and the bores bored, it might be best to continue towards a 2.0 by sourcing a 2.0 crank and rods as a sort of path of least regret.

I've also just noted a vague annotation in the Haynes manual "Essential differences between 1700, 1800 and 2000 engines ... Piston pins - thicher wall section". This is not very helpful as it doesn't get more specific.

hth