Topic: Billet Barrels

[754]

Anyone ever seen one ??

Anyone know the Bore centers for the Suzuki and Kawi big blocks?

I am thinking if  bore centers are close to 754 (sorta doubt it) and you got one cast without the inner cores you could run a huge bore on the street like 1080.. same for a billet barrell.

[Big Jay]

The Kawasaki and Suzuki blocks are all way too big.

Jay

[754]

Thanks, was afraid of that. I had the thought that if you cast the barrel minus the roughed out cylinder holes and maybe the camshaft cavity, that you could then machine it to fit the SOHC. Once the cylinder holes are in you would be hooped.

Sorta thinking about the billet though.. figure a week on a mill would do most of it..

[turboguzzi]

if you know someone who's good with 3D CAD, it shouldnt be difficult to model the block, send it to SLA rapid prototyping and have nice sand casting core in two days. dont forget to ask about the contraction percentage and scale your 3D accordingly.

even with a very good CNC machine and long cutting tools it'll be very difficult making deep fins with taper. just think about how you are going to mill the small corner radiuses deep inside the block between the cylinders and you'll see that a barell is not very easy to do by CNC.

TG

[754]

First off I did not want  it to get out of hand cost wise, labour I can supply. So to CNC is probably out of reach  for a test barrell.

Brief outline of what I thought would work;

Extra finning and  thicker fins

Solid between bores and up to the cylinder studs

Probably holes between inner cyl and Camchain cavity.

Hopefully allow big-bore street use due to less heat and cylinder distortion

To clear up a previous post,
I would not run tapered fins, and leave them thicker or at least full thickness. Easier to cut you can use a horizontal type wheel cutter/ slitting saw about 3.5  or 4.0 dia. Better easier cutting action and you run a toolpath similar to the base gasket outer surface. You could cut a tapered fin with a tapered end mill but now you have to cut from at least 2 sides , if not 4. Just not worth it to me and I like thicker billet fins.

Fins would be  fairly straight across front and rear and ends would be longer like the head (aprox .36 per side) It would be a meaty large cylinder that would not look like stock but is less teltale than a finless block at first glance.

Can be done manually, worst problem I see is making a mistake.. on slip of the handle..#$%$@#$..

[turboguzzi]

slitting saws were indeed used on radial aero engines barrells but those were single barrels per cylinder so easier to do. same story for radial engine cyl heads. Just take into account that hose close fins could work there because they were exposed to the air blast of the propellers, in a bike's case the air is flowing arond the fins much slower and they need to have more space between them to let it cool.


I still think that overall, a sand cast barell made out of a rapid proto mold would be cheaper, also no chance for costly/painfull mistakes :-)

Cheers

TG

[dusterdude]

754,your ideas are the coolest.

[Hondell]

RC engineering used to make LARGE billet blocks for the 750. Try and score one of these.

[crazypj]

You can use closer fins if they are shallower and get the same or greater surface area plus better heat transfer. Huge long thick fins may look cool but don't work so well. Air doesn't move well close to cylinder where temp is highest.
 Take a look at aircooled aircraft engines and the early Suzuki SACS motors
PJ

[754]

I was thinking longer wider fins, not closer together.

The RC block is finless at least the one my buddy has, it has raised ribs sanded off to look like fins..it runs too hot for the street. Also it is cast,not billet.

He also has the original block that was used on his engine, it may have been a sandcast cyl, the lightening/cooling holes between inner bore and camchain hole are parallelogram shaped not 3 cornered (viewed from the bottom) all the holes were stuffed to try to stop oil leaks.

I realize cooling may not be optimum, but some cooling (and a rigid non-leaking cyl) and being able to run on the street, is better than not being able to. I know you have to make sacrifices to get certain gains.. there is no way you can run a 1080 in summerime stop & go traffic with current blocks.

[turboguzzi]

PJ, air/oil cooled GSXR are my second fetish and those motors could get away with shorter finning thanks to tons of oil flowing inside the engine that is cooled by a huge radiator.

looking at the flanks of the barrels of GSXR's, fins might look shallow but I think this was done to keep the width of the motor.  front to rear the fins are quite deep.

can measure them if you want, have a few of them around here in pieces....

TG

[crazypj]

PJ, air/oil cooled GSXR are my second fetish and those motors could get away with shorter finning thanks to tons of oil flowing inside the engine that is cooled by a huge radiator.

looking at the flanks of the barrels of GSXR's, fins might look shallow but I think this was done to keep the width of the motor.  front to rear the fins are quite deep.

can measure them if you want, have a few of them around here in pieces....

TG

yeah, the SACS motor is my favorite as well. (more than the 750 SOHC, preferred 500/550)
 Suzuki couldn't develop it any further though as oil is less efficient at transferring heat. The cylinder is air cooled, the head is oil cooled (although the spray jets under pistons probably remove some heat from cylinder?)
 The assumption is correct though, shorter narrower fins will transfer heat more efficiently as they give greater surface area.
 What motors you got?
I'm looking for a spare 600 cylinder if you have one with no fin damage ( don't care about liners as I'm boring it a 'bit oversize' 
PJ

[turboguzzi]

pj

I'm more into 1100's and am not in the USA anyway...

From what I remember, a 750 top end from a long storke engine with pistons is a straight bolt on. People used to take those 600's even up to 883!

btw, do you know http://oldskoolsuzuki.info/ ?

a great source for gsxr tech articles, I hang out there often

TG