thats what i had read too but if you have a short throw then you have to have a wide bore in order to get the displacement as the rods have sweet FA to do with displacement.

displacement is quite simply the volume of air displaced in one complete movemnt of the piston so the only two factors to affect it are throw and bore as different length rods only affect CR and move the area that the pistons travels in but not the distance it travels.

thats what i had read too but if you have a short throw then you have to have a wide bore in order to get the displacement as the rods have sweet FA to do with displacement.

displacement is quite simply the volume of air displaced in one complete movemnt of the piston so the only two factors to affect it are throw and bore as different length rods only affect CR and move the area that the pistons travels in but not the distance it travels.

Actually wrong. The sideloading on the crank pins, gudgeon pins, and ultimately bores in an engine of given bore, stroke, and BMEP, running at a given speed, is lower in an engine with long conrods. The proof is too long to post on a website though.

Before taking on a large engine build like this, its best to consider what you want from the engine and then work towards the best to get that. Thier will always be compromises sure, but if you have a target goal then that helps.

If you want low down torque, then you would aim to build an engine with a long stroke and smaller bore (like a classic Austin Heally 3000 for example) and if you want an engine that revs freely and gives good top end power then you aim to build an engine with a large bore and small stroke (like 16v motorbike engines and F1 engines, they have bores like dinner plates but the stoke is tiny).

Hope that helps clear things up

Kind Regards

Garry

Piper Cams Development Mule

Actually wrong. The sideloading on the crank pins, gudgeon pins, and ultimately bores in an engine of given bore, stroke, and BMEP, running at a given speed, is lower in an engine with long conrods. The proof is too long to post on a website though.

and that has what exactly to do with changing the displacement of a 1.8T??

what you posted is all well and good but the rods still don't affect the displacemnt :confused:

and that has what exactly to do with changing the displacement of a 1.8T??

what you posted is all well and good but the rods still don't affect the displacemnt :confused:

Nothing, unless you want to consider possible increases in frictional losses and resultant increases in wear on reciprocating components, rather than just increases in swept volume.

It's not like I'm saying "don't do it" or anything; all I'm saying is that 10/9x displacement may not offer 10/9x power at the flywheel, and may increase engine wear.

thats what i had read too but if you have a short throw then you have to have a wide bore in order to get the displacement as the rods have sweet FA to do with displacement.

displacement is quite simply the volume of air displaced in one complete movemnt of the piston so the only two factors to affect it are throw and bore as different length rods only affect CR and move the area that the pistons travels in but not the distance it travels.

Still got a furby on the drive? Nick the bits and give it a try then call it a storage fee

although not quite accurate thats very similar to how it might go down

and i get what your saying Ken, it just came across differently at first