Engine info please

kasbatts

kasbatts

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Hi all, it would look like I might have a line on an engine and set of Mahle grpA pistons.
It's a 3.3 motor and over size pistons to make 3.5ltr
The guy selling tells me that in Grp A spec the factory ran the longer stroke (86mm) 633 motor and bored the block to get the capacity back up to 3.5 ltr, apparently a better / stronger engine was the result

Does anyone have any info they can share on this?

pros / cons

The one thing I have to check is that the pistons are a "road spec" type with long skirts, if
there a short skirt "race" type piston they wont really be suitable for a road car


Anything you've got appreciated


Steve
 
3.3 with oversized pistons

Steve,

I am running a 3.3 litre block and crank with oversize (91.5 mm diameter) pistons, which yields a capacity of 3.4 litres.

You can calculate the capacity if you know the stroke and diameter in mm:

Capacity = (6 x stroke x pi x (diameter/2)^2)/1000

This will give an answer in litres.

I understand that the 3.3 litre M30 engine can go out 92 mm diameter pistons without a problem, however I only went to 91.5,

Cheers,

Rod
Brisbane, Australia
 
Thanks for that Rod, May I ask why you went this way? does this give a better engine combo than a standard 3.5?
I only ask because it may be money I just don't need to spend if the end result is no better than a standard M30b35


Steve
 
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