What is the formula or is there a table to help me determine engine size. The diameter of the piston, the stroke of crank & length of the rod are the variables but I dont know where to go from there.

I have a 1.8 that needs some help and I see all of these pistons for sale.

I would like to write an excell file that will give me cubic inches based on the piston dia.

Thanks

David

Radius of the bore squared x Pi x stroke x# of cylinders.
The rod length has nothing to do with the displacement.

I don't have a calculation for you
but changing 1 thing necessitates changes of other things also....

ie: if you go to a big displacement then you have to rework your heads to increase valve sizes and flow at the cost of a couple of thousand...

so if you use your stock crank and rods, the 94mm pistons are stock and a 1.8

if you put 96 pistons in (with stock crank and rods) you will have a 1911

it may be physically possible to go larger, but the normal technique above 1911 would be to change your crank and rods to those from the 2.0 motor. This is a factory "stroker" crank and will give you 2.0 with the correct 94's, and give you 2056 with the correct 96's

I say correct because the wrist pin height in the piston changes when you change to the 2.0 crank and rods. Thus the 96's from a 1.8 will not fit into a 2.0 crank and rod combo... you have to buy a different 96 with the correct wrist pin for it.

of course there are combo's out there much larger... but your also going to need to spend well over 5grand in heads, exhaust, intake, etc.. to support those larger motors.

the durable large motors are approximately 10 grand motors depending upon options. (it can be done cheaper... but it can also cost more in the long run)

Thanks

What is the stroke on a 1.8L?

Not really the answer to your question but ....

stock 1.8 is 66mm stroke and 93mm bore.
1.8 with 96mm pistons is about 1911cc <<-- corrected my error here.

There are engine cal programs out on the web.

Area of a circle (your bore) pi times radius squared
Volume of a cylinder is area of the circle time the length of the stroke.
Volume of an engine is the volume of a cylinder time the number of cylinders.

Jim

At his stage of my research I believe that I want a 2.2L. I understand that some good porting & polishing will be in order as well as a set of tangerine headers are in order.


Thanks for the input

David

9.6cm x .5= 4.8
4.8x 4.8=23.04
23.04 x 3.142=7.24
7.24 x 66mm=477.8cc's
477.8cc's x 4=1911.4cc's

I am no expert on this but suggest the teener going out to 2200cc by increasing the bore look at the other issues..
I have just found my "new" 2.0 had 103mm bores and still 71mm stroke. It had heaps of torque and not a lot of top end power.
So now I am asking lots of questions.
I am told the Type IV head is the weak point so if you go machining the heads to accept 102mm bore you weaken it further.
At the risk of stating the obvious, if you start changing one part you need to change other parts like Carbs instead of D-Jet to get enough fuel in, then camshaft and so on.
Apparently the smart money is on keeping the bore size at around 96mm and going for longer stroke but the answer is not just as simple as, bigger bore-more power no problems, because doing that creates other issues which will need sorting if you want a balanced and strong Type IV.

Paul, just by way of explanation, the reason I stumbled across my 103mm bore size was when I blew a hole through the side of the head on #1 cylinder. Every bit of research I have done in the last few weeks to work out where I go from here, points to going back to 96mm x 71mm which in my situation means a new case.
So make sure you have thought the whole package through.
Good Luck.,I will be interested to see how you get on as I am still trying to sort out which piston/cylinders and heads I am going to use.

bore xborexstrokex3.142=cc's of engine

Here is an online calculator-
Displacement Calculator

What bore and stroke have you picked to get 2.2?

2.2 can be made with 96mm bore and 76 mm stroke. 78mm stroke will bump you to 2258.

So if you use a 76mm stroke, you're going to have to adjust all the parts to accomodate a longer stroke (piston will be "higher" in cylinder/farther from the crankshaft centerline, pushrods will have to be custom made longer, longer cylinder head studs, clearance the case for the new rod movement). Have you thought out all the extras required for a "stroker"?

(Do you use shorter rods for a stroker engine to avoid these complications?)

This should help with an understanding of the possible combinations.

Click to view attachment

Thanks Jake,

That is exactly what I was looking for.

Dave