Megabusa catastrophic engine failurere

[dinanminicooper]

Blew up the motor today at the track. Redline 6th gear on main straight, downshifting 5th, then 4th, then boom! Sayonara bye bye!

 

Elwood: Oh no! Jake: What the f@&$ was that? Elwood: We threw a rod! Jake: Is that serious? Elwood: Yup.

 

Rod bolt failure on one cylinder, threw rod out side of crankcase. New engine needed, hope valves not damaged.

 

Ideas on rebuild please? Get used crankcase, or complete used engine and rebuild? Considering Carrillo rods, CP pistons, head work. Also looking at 1397 kit. Want to stay away from turbo but want nice strong motor.

 

Better to make me upgrade and enjoy sooner than later than wait and say I will do it next year.

 

And at least my oil trail spun out a Shelby Mustang....

Edited September 23, 2012 by dinanminicooper

[Mondo]

Sorry to hear it... well sounds like a good excuse to make something faster. Good luck.

[Croc]

Ow - blowing up motors always is expensive. And BEC's seem to do this with frustrating regularity. I did like your Blues Brothers reference though!

 

From your description it sounded like you used the downshift as engine braking (with regular wheel brakes) to slow down? I always thought engine braking was a bad thing on a BEC?

 

My question is how much extra reliability/durability/extra mileage do you get from upgrading the spec you are considering (or drooling?) over? If there is not a meaningful difference then stick a complete engine and transmission in it and go fang it and wait for it to go boom again. I am not familiar with the 1397 kit and suspect most people here have no clue given the number of car engines?

 

If you want to talk Hayabusa drop a PM to Ottocycle on here as he knows his ways around them very well. If he does not answer quickly - let me know and I can ping him by phone/email.

[Fimi 7]

I learnt this lesson several years ago in a GT3 race toyota, gear down when ready to accelerate out of the corner, not when going into, it looks and sounds pretty on a race car, but the timing of gearing down is tricky.

 

With that said, my suggestion would be to just buy a complete fresh motor. Strip off the good stuff from the blown motor and go again. Dump things like the oil cooler and lines, you will never get the metal parts out of it.

 

I am running the hayabusa and based on what I have read, going with Carillos is not a bad thing, but the gain in reliability is marginal. What most have found is the supercharger/turbo kits are the best bang for the buck with as minimal changes as possible to the engine.

 

If you are going to build a big power motor, give up on reliability. If you want reliability, either keep it stock and drive restrained, beef up the motor for reliability and not performance or move to a car motor.

[BusaNostra]

I blew my busa @22 psi of boost --- Rod went south - oil all over the track -- limerock was mad!!!!

[Kitcat]

I thot abt buying that car-so I must have cursed it w/my magical ability to make se7ens fall apart:).

 

Seriously tho, as one who has recently blown up an engine on a new se7en purchase, I feel your pain. Take it a step at a time, build per your budget, dont be in a hurry and, as noted, what better excuse to upgrade???

[Mondo]

Maybe you should get one of these... automatic rev to match downshift

 

http://www.flatshifter.com/

[dinanminicooper]

I don't think the flatshifter is the solution. My right foot works fine on braking and blipping for downshifting along with the left clutch and right hand. In addition, the previous owner had that "paddle shifted bitches" kit on and couldn't get it to work properly. I am guessing because too much friction in shift mechanism with the actual manual shift kit remaining.

 

In any case, my downshift technique is by no means the reason why 12,000 mile OE conrod bolts to crank failed. I learned my very expensive lesson. Used bike engines WILL blow up in BECs.

 

Also, how can you be fast out of a corner when you need to downshift as you are coming out of it? Are you kidding me? Lastly, how do I convert my Megabusa kit to a car motored one? It doesn't work that way folks.

 

So I think I go balls out and 1441 with CP pistons, head work, 08+ crank, Carrillo rods, and lower compression for torques, and tune for lower max revs. Also need taller tires for gear. If it blows up again, then I give up and sell to some other maniac with a $1.5k Ebay motor.

[fastg]

What sort of oiling/sump setup are you using? Get someone with experience to check the engine out and look for a reason, maybe you have an oiling problem. A slipper clutch would take the strain off the downshifts.

 

Find someone that has built a LOT of high power 'busa motors and talk to them. I can put you in touch with a motorcycle shop that has built 100's, and a lot of high power turbo bikes.

 

Graham

[dinanminicooper]

Graham - thanks for the advice and offer. I have started to contact a number of engine builders but I'm not feeling the love with all of them. The oiling system is a SBD Motorsports dry sump system, UK based. Would an oiling issue cause conrod bolts to fail? Unlikely I think.

 

Yes, I would appreciate talking with that shop. I am also talking to other BEC car owners (CSR/DSR/F1000) and learning from them. I have time, not planning on doing anything soon, will wait until winter and do my research and then build a really good, strong motor.

 

Thanks again.

DMC

[fastg]

DMC, as for your comment about oiling causing a bolt to fail, not directly, but did the bearing spin, is the crank flexing, are any of the other bearing showing stress. How do the other rod bolts look. Do you datalog the car? if so does that show anything? It sounds like you have a good oiling setup, and that is a must for a BEC.

 

get in touch when your doing your research and I will put you in tough with Brian.

 

Graham

[BusaNostra]

dinan I have a very good bec machine shop that deals with competition, if you need info pm me.

would you mind to tell where you from?

[MichaelD]

FYI a blown engine is a Catestrophic Loss. At least it was considered one and approved by my accountant for deduction as a Tax Loss. It was also approved by the IRS several years ago. Check with your accountant for present day IRS rules for Catectrophic Losses.

[dinanminicooper]

I think fastg has it. SBC dry sump from what I am learning is somewhat sensitive to pump install. Although motor not out, failure likely due to crank bearing oiling issue.

 

My thought after chats with BEC racers (CSR/DSR/F1000). Custom wet sump pan that works. Simple. Lighter. Baffled (not me) to 2g++.

 

Sealed Low Miles motor. Rice dust intact.

 

Any way, this gonna costa. Anyone want to buy it and have some fun after I do it up right? Flat shifter going back in too.

[MeteorMotorsport]

Running a full closed loop paddle shift system is the way to go on protecting both the gearbox and engine.

 

It will block downshift (It simply won't do them) if the revs are to high for the corresponding gear below.

 

They always perform a perfect gear change and so gear wear is significantly reduced and that engine remains unexploded.

 

Hope you get it sorted. I snapped a cam chain on my 1396 last year at 10500 revs. Lucky it was just a few valves and tapets/followers.

 

I now have a top spec 1396 Mistral with 205 at the rear wheels. Its about as much as a 1396 can do with longevity built in.

 

Hoope you get yours sorted soon.