TheSamba.com :: View topic

Tue Nov 10, 2009 8:22 am

After waiting several months for SCAT to have their forged chromoly "Superlite" crankshafts made-up,
I finally have the bottom end and ready to start assembling my Denzel bottom end..... Cheers!

Tue Nov 10, 2009 8:53 am

wow..high end in material and also in money :(
whats the plan for the engine in cc and all the stuff?
that will become exciting
beautiful

Tue Nov 10, 2009 9:01 am

grueni wrote: wow..high end in material and also in money :(
whats the plan for the engine in cc and all the stuff?
that will become exciting
beautiful
Dont want to divulge too much information at the moment. Im building two of these at the same time
and the owner of one does NOT want any info. given out on his Denzel engine build. Cheers!

Tue Nov 10, 2009 9:30 am

but if one is yours ;) nene kist kidding. it's more than enough to see that rarity build up
have fun with it!

Tue Nov 10, 2009 12:22 pm

oh man, one of my favorite engines. Are those DCM-2's?

looking forward to updates.

Tue Nov 10, 2009 1:26 pm

This will be a fun build to watch... there's not many Denzel heads around to be had, that pair looks real clean

Tue Nov 10, 2009 2:00 pm

What strokes is Scat offering? Are they 36hp VW mains or 356 Porsche?

Tue Nov 10, 2009 5:38 pm

Hello-

They offer a 74mm stroke with 55mm mains (356 SC/912). You can, however, have a crank custom ground. :wink:

Paul

Tue Nov 10, 2009 5:46 pm

gimmesomeshelter wrote: Hello-

They offer a 74mm stroke with 55mm mains (356 SC/912). You can, however, have a crank custom ground. :wink:

Paul
Paul is right! I have (3) that SCAT "made" with 50mm mains and (2) that have 55mm mains.
I got a small discount for buying (5) SCAT "Superlite" crankshafts at once...... Cheers! 8)

Tue Nov 10, 2009 6:28 pm

Hello-

While I understand that installing a 55mm crank into a 36HP case has its challenges, it also has its rewards. Stiffness (torsional rigidity) is proportional to the 4th power of the diameter. All other things being equal, a 55mm crank is 46% stiffer than a 50mm crank. Not bad for a 10% increase in diameter.

Paul

Wed Nov 11, 2009 3:22 pm

gimmesomeshelter wrote: Hello-
a 55mm crank is 46% stiffer than a 50mm crank. Not bad for a 10% increase in diameter...

unfortunately that's not the entire story... torsional rigitity is one part of the equation. There is also bending where the cheeks meet the main journal, and cheek meets the rod journal. The larger the rod journals and main journals and less the stroke, the stronger the crank. This overlap, often refered to as 'lap' in crank grinders parlance, is a big deal in 3-main bearing cranks like a VW. Who's to say which one matters most, or if we should care at relatively low power levels :|

IMO if a guy has a choice, the bigger the diameter the better, to the point in which you now weaken the case but alignboring it to accomodate those larger main bearings :wink: then there is the problem of paying $400 for a set of Porsche main bearings :roll:

Wed Nov 11, 2009 4:42 pm

Tom Simon wrote: gimmesomeshelter wrote: Hello-
a 55mm crank is 46% stiffer than a 50mm crank. Not bad for a 10% increase in diameter...

unfortunately that's not the entire story... torsional rigitity is one part of the equation. There is also bending where the cheeks meet the main journal, and cheek meets the rod journal. The larger the rod journals and main journals and less the stroke, the stronger the crank. This overlap, often refered to as 'lap' in crank grinders parlance, is a big deal in 3-main bearing cranks like a VW. Who's to say which one matters most, or if we should care at relatively low power levels :|

IMO if a guy has a choice, the bigger the diameter the better, to the point in which you now weaken the case but alignboring it to accomodate those larger main bearings :wink: then there is the problem of paying $400 for a set of Porsche main bearings :roll:
Granted! I agree with Tom. These "little" engines that are being built for the street will never or hardly ever see RPM blasts of over 5500 rpms. The lifter/cam/valve spring design in the 25hp/36hp engine was never intended to go beyond 5500 rpm's safely so unless you do something with those "weak links" first, then I would worry about what size the crank journals are.....In my 35+ years of building these early engines, I have never had a crankshaft break either stock, stroked or billet. If you are experiencing broken crankshafts then something else is wrong?!?! These engines are NOT producing the HP that the drag racers are laying down at the strip.

Another note: When you machine the magnesium case for the larger 55mm main bearings, you are weakening the block. Remember, the S-90/SC
and 912 Porsche engines all use ALUMINUM blocks which were designed to use the larger 55mm main bearings. Cheers! Mr. Okrasa 8)

Wed Nov 11, 2009 10:11 pm

Mr. O'

Quote: In my 35+ years of building these early engines, I have never had a crankshaft break

Is there a common point(s) of failure for these engines?

Paul

Wed Nov 11, 2009 10:51 pm

If you aren't breaking parts you aren't making enough power.

I have a 3 piece 36HP crankshaft on my trophy shelf.

Wed Nov 11, 2009 11:57 pm

Jake Raby wrote: If you aren't breaking parts you aren't making enough power.

I have a 3 piece 36HP crankshaft on my trophy shelf.
Yeah!........I know. :-({|=

Wed Nov 25, 2009 11:18 am

Any updates? :D

Wed Nov 25, 2009 11:45 am

sled wrote: Any updates? :D
nope..... :sleeping: