1776 or 1915cc ? thats the ?.

[sweat69]

Right I'm taking the engine out of my bay it has a oil leak I think it's coming from the oil
Cooler seal.
The case was new around 3000 miles ago so was all of the other parts it's running 1641 p&b
And a 110 Engle cam. Which needs reving to get any getting any power out of.
Which pistons would be best 1776 or 1915cc p&b. I will be keeping the original gearbox as the
Bus is used for camping and I have a small trailer.
What are your views is any one running 1915p&b with stranded stroke crank?

 

[Trikky2]

1776 is stonger because the barrels are the same thickness as stock.

To get a larger displacement its better to go with 1776 (90.5 pistons) and fit a stroker crank on a bus since it will give better torque than just increasing the bore and retaining the original stroke. Over square engines perform better at high rpm with lower torque available - fine a a bug but not ideal in a bus IMO.

 

[sweat69]

1776 is stonger because the barrels are the same thickness as stock.

To get a larger displacement its better to go with 1776 (90.5 pistons) and fit a stroker crank on a bus since it will give better torque than just increasing the bore and retaining the original stroke. Over square engines perform better at high rpm with lower torque available - fine a a bug but not ideal in a bus IMO.

Yeah longer stroke engines have better torque what's the best stroke to go for.
If I do stroke it will I have to modify the tin wear and longer push rods. :?

 

[sparkywig]

No, and yes.

 

[sweat69]

1776 is stonger because the barrels are the same thickness as stock.

To get a larger displacement its better to go with 1776 (90.5 pistons) and fit a stroker crank on a bus since it will give better torque than just increasing the bore and retaining the original stroke. Over square engines perform better at high rpm with lower torque available - fine a a bug but not ideal in a bus IMO.

Yeah longer stroke engines have better torque what's the best stroke to go for.
If I do stroke it will I have to modify the tin wear and longer push rods. :?

 

[sparkywig]

No, and yes.

 

[sweat69]

I seem to have posted 2 quotes the same.
Are you saying no and yes. :lol:

 

[sparkywig]

No, you don't have to modify the tinware unless you go for a really long throw crank.
Yes, you'll need to change the pushrod length depending upon your crank throw, rocker set up, spacer thicknesses, etc

 

[the_troupster]

92mm thick walls are an option...

You know you'll need to get your heads n case machined right?

What carbs n exhaust have you currently got?

Engine width can be tweaked to a certain extent by the combination of stroke, b pistons and rod length. Pushrod length should be measured for every non stock build...

Jim

 

[sweat69]

92mm thick walls are an option...

You know you'll need to get your heads n case machined right?

What carbs n exhaust have you currently got?

Engine width can be tweaked to a certain extent by the combination of stroke, b pistons and rod length. Pushrod length should be measured for every non stock build...

Jim

Hi
I'm running 34ict's phat boy stainless steel exhaust. Yeah I know I need machining done.
Are the walls of the 1915 p&b thin?

 

[the_troupster]

If you don't want to change your carbs then I'd stick with a stock crank. Possibly 74mm if you want to go counter weighted.

Cylinder wall thicknesses:

The new 92 mm from AA (4.55 mm)

Modern machine-in 88 mm (4.5 mm)

Stock 85.5 mm (4.15 mm)

Modern 90.5 mm (3.75 mm)

94s mm (3.55 mm)

87 mm slip-ins (3.4 mm)

Old 90.5 mm (3.25)

Old 92 mm (3.0 mm)

88 mm slip-ins (2.9 mm)

Hope this helps...
Jim

 

[the_troupster]

PS a 92x74 is 1968cc

http://www.cbperformance.com/v/enginecalc.html

 

[Trikky2]

If you don't want to change your carbs then I'd stick with a stock crank. Possibly 74mm if you want to go counter weighted.

Cylinder wall thicknesses:

The new 92 mm from AA (4.55 mm)

Modern machine-in 88 mm (4.5 mm)

Stock 85.5 mm (4.15 mm)

Modern 90.5 mm (3.75 mm)

94s mm (3.55 mm)

87 mm slip-ins (3.4 mm)

Old 90.5 mm (3.25)

Old 92 mm (3.0 mm)

88 mm slip-ins (2.9 mm)

Hope this helps...
Jim

Interesting - where did that info come from BTW?

 

[the_troupster]

Lifted from ShopTalk forum...

 

[sweat69]

If you don't want to change your carbs then I'd stick with a stock crank. Possibly 74mm if you want to go counter weighted.

Cylinder wall thicknesses:

The new 92 mm from AA (4.55 mm)

Modern machine-in 88 mm (4.5 mm)

Stock 85.5 mm (4.15 mm)

Modern 90.5 mm (3.75 mm)

94s mm (3.55 mm)

87 mm slip-ins (3.4 mm)

Old 90.5 mm (3.25)

Old 92 mm (3.0 mm)

88 mm slip-ins (2.9 mm)

Hope this helps...
Jim

So it looks like the best ones to use are the AA 92mm.

What are the AA pistons like.any good?

 

[sweat69]

The 92mm AA p&b are only £112.
I never take my bus past 3400rpm
So should not be to stressed.
My crank was brand new 3000 miles
It's only the 4 dowel one would thet be ok?
If not could I get it drill for the extra dowels.
:roll:

 

[Trikky2]

The extra dowels are to cope with the extra torque (twisting forces) rather than rpm.

 

[MisterListerSir]

mines a 1776 and love it, plenty quick enough