Reading the first issue of VWMA again today and looking at the Targa Bug, it had a 56mm or something crank, how is this possible, and does anybody know where you can get a custom crank made?

reason being is i'd love to make a 60mm crank by 92mm motor to compete in hillclimb up to 1600cc

got one here ready to go!

Sander,

why bother, just go subaru

Cheers

Paul

Do they make Subaru engines smaller than 1600 cc? Maybe out of a Sherpa? or was it a Mighty Boy?

I've never heard of a 56 mm crank, butu you could make one out of, say, a VW 1200 cc 40-hp crank which is 64 mm. You would have to off-set grind the crank journals, bringing the centres 4mm closer to the crank centre. This makes the crank journals 8 mm smaller than stock. Custom rods required. But with 94 mm cylinders, that's 1554 cc.

If you only off-set ground the journals 4mm smaller than stock, bringing the centres in by 2mm, then you have a 60 mm stroke. With 92 mm cylinders that's 1595 cc.

You could also just use the 64 mm crank with 88 mm cylinders bored out to 89 mm, to get 1592 cc.

good one paul, I suppose I deserve that!

Hellbugged? you've got one ready to go? where did you get one, I actually figured I should have 57.5mm with 94 barrels

94 bore x 57.5 stroke = 1596.1 cc.
94 bore x 57.6 stroke = 1598.9 cc.
94 bore x 57.7 stroke = 1601.7 cc.

Probably easier to mess with the bore though, rather than the stroke...

nah, think small cylinders to keep it nice and squishy.......and rev rev rev

the journals would be welded and offset ground, so still same rod journal..........just like welded stroker..........UNLESS you were to get one machined from a forged/counterweighted casting

reeeeeevvvvvsssssssss

62mm X 90.5 =1595cc

or it may be....

64mm X 88mm = 1557cc

i can't remember and will have to look........both size "berg special" P& B on the shelf too

62mm...................69mm.................78mm



62mm de-stroked V's 78mm stroker



damn dude, you only had to ask

I was wanting 92mm or bigger, so I can make the most of a twin igniton, it;s no good really with a bore smaller than 92, BMW did a heap of research apparently with their new bikes and found this out, talking to stan confirmed this

Quote:

Originally posted by hellbugged .......that must be where Dangerous,the two rocket Rods, Ross Freestone, Stoker, Kristen, Volkomen, Pagey...........and all those psycos in the USA are falling short..........only one plug per cylinder!!!, damn didn't think of that did they get Stan to make you one then CYA

Quote:

Originally posted by sander288 good one paul, I suppose I deserve that!

Quote:

Originally posted by matberry Ha ha That crank was custom ground at Crankshaft Engineering in Bris. We used a Toyota rod and 85.5mm bore to get under the 1300cc capacity for the regs. She revved like a banshee to 8500, was a heap of fun to drive, lacked a bit of torque tho

Quote:

Originally posted by hellbugged just need a seven speed close ratio box like those BMW bikes to keep a small stroke big bore in the upper rpm regions

oh dear here we go again............

my point ?

just a question..why did you go to all the trouble to come up with the short stroke 1300 combo ?

Sander, i think you will find a destroked 69mm crank with 94's would be a good combo .......but its over 1600!

So you can fit in big valves

ha ha......geez how big were the valves !

Quote:

Originally posted by 1303 Sander, why bother, just go subaru Cheers Paul

Quote:

Originally posted by Craig Torrens Sander, i think you will find a destroked 69mm crank with 94's would be a good combo .......but its over 1600!

Quote:

Originally posted by hellbugged Quote: Originally posted by Craig Torrens Sander, i think you will find a destroked 69mm crank with 94's would be a good combo .......but its over 1600! but he wants 1600cc! if the magic ratio of hp to CC's comes from a 69 X 94 engine... why wouldn't you want to reduce the cylinders size relative to the de-stroke to keep this magic ratio close

You could press buttons on your calculator endlessly. It's easier to do it in MS Excel.

Put the bore in mm in column A, line 1. Put the stroke in mm in column B, line 1.

To work out the engine size, put the following calculation in Column C, line 1:

=((A1/2)*(A1/2))*12.566*B1/1000

The answer will be in cc. Repeat down the spreadsheet for as much as you like and you can plug different numbers in A and B all day.

Quote:

Originally posted by hellbugged Quote: Originally posted by Craig Torrens Sander, i think you will find a destroked 69mm crank with 94's would be a good combo .......but its over 1600! but he wants 1600cc! if the magic ratio of hp to CC's comes from a 69 X 94 engine... why wouldn't you want to reduce the cylinders size relative to the de-stroke to keep this magic ratio close

I'm guessing Matt that you wanted to be "legal" and not running larger capacity than you are "legally" allowed hence the homework on getting the capacity close to the limit and spending a lot of time on heads etc etc.

It is always nice to win but even nicer to win knowing you are 100% legal to the rules. My uncles rule of thumb when building Formula Vees. Nothing better than beating known cheats with a totally legal engine he reckons.....

Correct that engine had no torque to speak of but I've driven it years ago and boy did that engine rev!An old saying is its not how fast you go its how you go fast.if every body had a 2332 life would be so boring