You most lickly will have to find a German crank that has not been ground on the gournals and is straight and send it to him,. Or you could go DPR in america
Fabo
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
cnfabo wrote:You most lickly will have to find a German crank that has not been ground on the gournals and is straight and send it to him,. Or you could go DPR in america
Fabo
Get a DPR, quality is awesome.
Cheers Col
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
cnfabo wrote:You most lickly will have to find a German crank that has not been ground on the gournals and is straight and send it to him,. Or you could go DPR in america
Fabo
Get a DPR, quality is awesome.
Cheers Col
Colin and Cnfabo are right. DPR produces quality cranks and are a LOT better value.
True. Being the "heart" of any engine but, it's quite important its known weaknesses/ design flaws/inherant shortcomings are addressed to provide the rest of the components a sound basis to work from. Those DPR cranks are good value $$$ start point for addressing the well known issues and risks of spinning a standard crank through 8000rpm
HP figures are not always stated with longevity in mind either.
Always interested to hear of different ways to get the job done tho, what tricks you doing !?!?
I doubt he's building an 8000rpm engine but it's definitely possible on the German Forging even without counter weights.
Biggest trick is to keep the rotating assembly light and balanced, then there is micro-polish, 8 dowel, etc.
I have a Pobjoy crank in the garage 0.10, 8 dowel, non welded.........not sure I want to sell it alone.
It's going in a 1835cc thickwall, Pobjoy Heads, Bugpack Rods, Bugpack Straight cuts, GB 310, Scat Rockers......
bitten by the bug..........several times
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
LOL.......Stan didn't do anything just put his name on it, supposedly came out of a "Pobjoy" 1915cc and I'm not stating that "his" crank will go to 8000rpm, all I'm saying is a German Forging can be made to.
fish26 wrote:I doubt he's building an 8000rpm engine but it's definitely possible on the German Forging even without counter weights
Yeah that's what I thought you were saying
.....and I was just wondering what tricks are used to stop the crank flexing, case getting flogged out, bearings running dry, seizing and the following catastrophic failure of an entire engine's assembly canabilizing itself @ 130 bites a second 😉
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
fish26 wrote:all I'm saying is a German Forging can be made to.
Yep, that's been proven all over the world for decades.
fish26 wrote:you can make 180HP and 8000rpm on a German stock non counterweighted properly built crank, find a good one and call me, I will get it done for you.
So what do you mean by 'properly built crank' if it doesn't have counterweights welded to it ?
Do you get your ones done locally ?
If I gave you a standard "virgin" german crank, what will be done to it (and cost) to make it a 8000rpm crank......without it having counterweights ?
the crank might do 8000 with a std german crank but the shitty mag case will be floged out in a very short time with out counter weights, dpr way to go 360degree counter weightsl drilled lightened blade ground 9000 baja tested rpm in an alloy case all day long, prefer to get my power from e85 boost and freindly to the planet , heard an l big may run at the easter meet at mt panorama next year cheers Rudi ps ive got a pobjoy crank in a complete 1916 minus heads ready to go pm me if u want more details
Never played with full circle counterweights so cannot comment just letting OP know what's possible.
If he definitely wants a Pobjoy crank he should just get one, also lets not forget the amount Stan and others like him have contributed to our hobby and let people decide for themselves which way they want to go, not that Stan's engines are my cup of tea but that's just my opinion.
Heads and cam create power together with induction and exhaust and allow the engine in their combination to breathe more efficiently at higher RPM, they don't just create rpm, they affect rpm which are created by the whole engine combination. No Arguements. It's all about the purpose of engine combination and quality of parts and assembly.
It's misinterpretation of information on these forums that sometimes steers newbies to the hobby in stray directions and impending let down.
Eg.
Hi flow heads, welded, hand ported, large valves
Hot cam FK87
Monza exhaust
Single 34
Stock rotating assembly
Who thinks this "hot" combination will rev past 4000
Craig, I'm happy to give you the details of who I believe is the best crank grinder around, you can let him know what you need but sarcasm won't fly with him and he'll let you know about it.
Don't understand mate you use to be one of Stan's disciples, while I think he is a great machinist, you used to preach that the guy walked on water !!!!