Crankshaft - Buy used or have it reground?

[donpearsall]

At this past BMST event, my turbo motor blew due to a broken rod (Carrillo). After the postmortem it looks like there was a catastrophic loss of oil pressure due to unknown causes (burned crank journals, scuffed pistons, galled cylinders). The existing crank has the rod big ends still attached but the bearings smeared into the journals from lack of oil. One journal is black from heat.

My question is - is it better and cost effective to have the crank reconditioned by a crank shop so as to have a new virgin bearing surface, or buy an eBay $300 used crank. I have never had a crank reconditioned before, even though I have wrecked a few. What is the typical cost?

Thanks
Don

[wildphil69]

get a used one

[Stainless1]

yep, repairs are typically 300 a journal... only repair a special that has 1 bad journal.  Cheapest is find a used... usually one one here

[Rocketgeezer]

At this past BMST event, my turbo motor blew due to a broken rod (Carrillo). After the postmortem it looks like there was a catastrophic loss of oil pressure due to unknown causes (burned crank journals, scuffed pistons, galled cylinders). The existing crank has the rod big ends still attached but the bearings smeared into the journals from lack of oil. One journal is black from heat.

My question is - is it better and cost effective to have the crank reconditioned by a crank shop so as to have a new virgin bearing surface, or buy an eBay $300 used crank. I have never had a crank reconditioned before, even though I have wrecked a few. What is the typical cost?

Thanks
Don

If your talking about running a repaired stock crank vs a used one from ebay, if the used crank looks good and turns easy when installed, there is no difference, also with a repaired part your putting a ton of faith in the machinist, I know most are good but some are not if the repaired crank had a crack in it and it is overlooked you just spent $300-$400 for junk, this can happen if it is not cleaned and examined correctly by magnaflux or X-ray before the welding/grinding, stock cranks can handle big horsepower, as can aftermarket cranks, however if you have oil starvation problem for whatever reason the engine will end up junk

[Nosgsx1300]

about 10,000 miles on a repaired crank.... 1397 with spray and it's current turbo incarnation. 
bike has made 382HP on this crank with the repairs...
still going

for what it is worth

[donpearsall]

Thanks for the reply guys. I will go with a used one. It is a shame that the cranks can't be economically reused. Now I guess I have 30 pounds of iron to put in the recycle bin.

Don

[MJ Williams]

At one time I had a pair of matching lamps made from GS750 cranks.
Just a thought.

[Oz Booster]

Don my logs of oil pressure were scary, better since i added capacity , it used to drop to mid 30 psi during a run and rise again when the rpm dropped below 7500 .
have to check what happened last week at our speedweek , new sensor was not calibrated right so i just need to have a closer look and interpret the figures

but a 3" extension on a 2" pan  with exhaust cutout adds nearly 2 litres to the capacity and makes me feel a lot better 

[donpearsall]

Hey Maj! Missed seeing you at BMST (but they took me away in an ambulance so you could have been there...).

The loss of oil pressure could have been because it just plain ran out of oil due to more oil being pumped than returned. On this engine build I did all the oil mods that Johnny Hotnuts documented. I have a 2" flat pan and started out with oil just above the sight glass which is about 4 quarts. I have not tested the oil pump but it turns OK. The pick up screen is not clogged. The main oil gallery is shattered but I think that is because of the rod breaking. But I am not ruling out that it cracked and leaked during the run. Anybody every heard of that happening? As I said, I don't know why the oil was not being distributed. At 13k rpm and 220 mph it only takes a second to ruin the engine.
Don

[Jay]

Our repaired cranks are fully nitrided and race balanced. Something you don't get from e-bay.

[Rocketgeezer]

Our repaired cranks are fully nitrided and race balanced. Something you don't get from e-bay.

No argument there Jay, my only question is not all crank repair people may be as qualified as you, as proven be reputation, I have seen cranks repaired and chromed and looked like a million bucks make it a run or two and be in pieces,

[fvance]

Simple solution, send it to Jay!!

[Oz Booster]

Hey Maj! Missed seeing you at BMST (but they took me away in an ambulance so you could have been there...).

The loss of oil pressure could have been because it just plain ran out of oil due to more oil being pumped than returned. On this engine build I did all the oil mods that Johnny Hotnuts documented. I have a 2" flat pan and started out with oil just above the sight glass which is about 4 quarts. I have not tested the oil pump but it turns OK. The pick up screen is not clogged. The main oil gallery is shattered but I think that is because of the rod breaking. But I am not ruling out that it cracked and leaked during the run. Anybody every heard of that happening? As I said, I don't know why the oil was not being distributed. At 13k rpm and 220 mph it only takes a second to ruin the engine.
Don

We were way late arriving and with weather conditions and new setup only got 1 run on the busa

I think the oil gallerys will only crack when hit and your problem would be like mine , pumping the pan dry enough to cavitate on long runs
we run much taller gearing , even the 25Xmph runs from 2012 were below 10k rpm including  Neills 224mph naked which was in 5th with same gearing