Dammit Frank, I broke the Crank

[dragonz]

the joys of building high performance engines!

My +4 Stroker crank sheared off on the stator/timing chain side!
Spoke to my supplier today & he said it will be replaced under warranty, but there's still a load of parts to get to rebuild it.
Piston "kissed" the exhaust valves, breaking 1 of the rockers, but the valves appear straight & the head is ok.
Will have to replace all the gearbox & crank bearings (were only done 32 hours ago when this engine was built)

Oh joy..............

[Colorado700R]

Time for a +8

[dragonz]

was thinking more along the lines of either a Falcion Crank, or building a 727.
We have a 750cc upper limit here for racing, so bigger capacities like I would have with the +8 etc are out

[Mad Dog]

Was this an HR +4?

[dragonz]

Was this an HR +4?

MD, yes it was...........
What can you tell me about this?
it broke the stator side, directly against the "throw" of the crank............
Kenz said there had been a manufacturing issue with some cranks?

[Mad Dog]

The consensus had to do with the factory installed bearing having insufficient clearance.  HR initially denied it and then some customer service reps acknowledged it and most of the stories I heard were that HR was replacing the Crank/Rod assembly but nothing else.  The issue appears to have been resolved in subsequent batches (no new stories of these breaking on recently manufactured parts) but was widespread none the less.

Some have re-installed the replacement HR setups without incident while others have sold the part and replaced with Barker/Vitos +4 assembly (which have also had a few failures, albeit fewer than HR and no systematic issues were found).  The crank itself has been the fear with these pre-manufactured / no core required options.  Those who maintain that fear have opted for OEM crankshafts with aftermarket rods from Carillo, Hot Rods or Barker who each make their own quality rods.  If you want to maintain the increased stroke however you will need to find a shop, like falicon, crankworks, or others, who can modify the OEM crankshaft in house and properly balance it.

[dragonz]

Hmmmm,
have shot a line to Falcion, be interesting to see what they have to say.

Whats your take on 719 vs 727 builds?

[Mad Dog]

I really enjoyed my 727.  I never got to do a back to back comparison with the same top end work, but I never felt like I was missing out on any bottom end torque with my Barker HV/Mega x4/105 10:1 Ross setup when compared to ported 10.75:1 and 11:1 719/720 setups.

[dragonz]

I was running 13.5:1 at 719, but I see there is a 14.7:1 piston available for the 727................
Maybe I can break 80Hp with that

[Peelz]

80 hp 660...

shits just gonna go boom-fact of life....

all kidding aside.. DAMN!

[dragonz]

80 hp 660...

shits just gonna go boom-fact of life....

all kidding aside.. DAMN!

Willykiller (on RF) was putting that much or more down with his 3-plug methanol burning speedway quad.................