Jump to content
SAU Community

Rb30 Severe Crank Damage (pics)

ST240

By ST240,
in Engines & Forced Induction

 Share

Recommended Posts

ST240 Enthusiast

ST240

Posted
Posted (edited)

EDIT: I must be clear; this is a shortblock that i purchased here in canada. I have no ideas about it previous running condition or lack thereof. The guy who i bought it from said it had excellent compression, thats all.

So i pull the harmonic balancer and goto pull the timing pulley and i notice its kind of loose.

I finally jiggle it off and i see this:

SDC10761.JPG

Any idea what the hell happened? Looks quite severe. You dont just mash through a keyway like that easily... There obviously had to be a difference in torque on the crank between the rotating assembly and the timing belt for something like that to happen.

SDC10762.JPG

I dont think id trust the timing gear again...

SDC10764.JPG

Whats left of the pillaged key.

I think i can save the crank by milling the keyway straight through and making custom keys. There was no evidence of this at all when the harmonic balancer was on. Everything seemed tight and the bottom end spun nicely by hand. Any ideas anyone? Is the crank salvageable?

Edited by ST240
Link to comment
https://www.sau.com.au/forums/topic/307684-rb30-severe-crank-damage-pics/
Share on other sites
Neil Grand Master

Neil

Posted
Posted

Personally I'll bet the balancer bolt was left loose at some stage,,,the gear has moved in and out of the crank,,,killed a belt and the previous owned slapped it back together and sold it to you. That crank is in a bad way,,,normally I would be happy to fix it but thats very bad.

Neil.

ST240 Enthusiast

ST240

Posted
  • Author
Posted (edited)
:P . anyone have a crank?

I'm going to see if the crank is damaged otherwise. If not I am going to attempt to mill a keyway 180 degress from that set and i should be away.

PS: DiRTgarage can you please email me at andrem85 @ telus dot net and we can discuss futher. I can pm until i have a post count of 10 and i dont feel like spamming this great board up you folks have just so i can pm you back :D .

Edited by ST240
GTRsean Grand Master

GTRsean

Posted
Posted

Mine did that from a bolt not being tight enough. Had a new crank keyway milled into the opposite side (180deg) when I was rebuilding my eng.

No probs, just be aware that the timing mark on the crank gear will be 180deg out.

ST240 Enthusiast

ST240

Posted
  • Author
Posted

Good to hear guys. Thanks so much for the replies! Glad im not the only one; and that the damage isnt the end of the world :) . I have the pistons out, working on the girdle right now. The rod bearings look slightly worn, but maybe its normal. I borrowed some telescopic gauges, a micrometer and a dial gauge from my machinist to measure it all up.

I'll post some pics up and see what you guys think.

ST240 Enthusiast

ST240

Posted
  • Author
Posted (edited)

Ok so with everything apart, here are some pics. These pics were the worst i saw. Some were worn like this, some weren't:

SDC10767.JPG

Rod

SDC10771.JPG

Another rod.

SDC10774.JPG

Center bearing. Seems like its getting some thrust wear. In any of the above pics, you can't actually feel the "wear" with your finger nail, you can just see it.

SDC10785.JPG

Last but not least, i measured runout. I removed all the bearings except the outter two which made sense to me, otherwise the other bearings might interfere, effectively lifting the crank up when it is rotated, showing less runout than there actually is. It was only out about 1.5 thou, which is 3.8 mm. Happy days!

So my big question to you experts is: replace the bearings, or not? I'm no expert so I'm not sure to what degree the bearings are worn. All I know is they don't look super prestine haha. I guess I might as well while she's apart. Futhermore, it looks like quite the rigamarole to mic out all the bearings so i might as well do that with new ones.

Edited by ST240
T04GTR Grand Master

T04GTR

Posted
Posted

no. its 0.6mm

looks like its not had the oil changed for ages. or has had a lrg gas conversion and the oil has been nitrated. (acidified from the lpg and not using a lpg oil)

and yeah, loose crank pully. although ive not seen it happen on the timing gear, but rather the crank pulley key way.

it can be fixed pretty easily, you need to get a good quality ceramic tile. shape it with a angle grinder to make a dummy key. get a good mig welder and fill the dammaged part of the crank with weld, then linish it back to round and remove the tile, you will have a good strong keyway slot.

not ideal but provided the crank pully does not come loose again, will last forever.

ST240 Enthusiast

ST240

Posted
  • Author
Posted
no. its 0.6mm

looks like its not had the oil changed for ages. or has had a lrg gas conversion and the oil has been nitrated. (acidified from the lpg and not using a lpg oil)

and yeah, loose crank pully. although ive not seen it happen on the timing gear, but rather the crank pulley key way.

it can be fixed pretty easily, you need to get a good quality ceramic tile. shape it with a angle grinder to make a dummy key. get a good mig welder and fill the dammaged part of the crank with weld, then linish it back to round and remove the tile, you will have a good strong keyway slot.

not ideal but provided the crank pully does not come loose again, will last forever.

I'd rather not weld anything at this point; Id rather machine a keyway on the other side. I think welding is last resort.

I made a typo. Its 0.038 mm no? Lol anyone else got an estimate? And to think we're trying to build engines here :) .

Futher to this damage, It looks like something got in one of the cylinders at one point:

SDC10791.JPG

But i think i can reuse that piston. What do you guys think? There was some slight scoring (you can just barely feel it with your nail) in the bore too upon closer inspection which I'm hoping can improved by honing. I don't know what amount of scoring is acceptable before you need a rebore. Can anyone comment?

ST240 Enthusiast

ST240

Posted
  • Author
Posted
reuse it?

at a minimum i would be binning the rod,s crank and pistons and starting with fresh items (good cond 2nd hand crank) with new rings and bearings, then you'll have a half decent engine...

Lol :) . I was just going to do a build on stock RB30E internals for a "low" ( :) ) power application for this summer then go forged/full build next summer. You don't think I should reuse anything?! That's a bit extreme no?

our12 Enthusiast

our12

Posted
Posted

Hi.

What you need to do is take crank rods pistons to a machine shop who know what they are doing. Explain your situation to them re rebuilding in the short term and have them measure everything up and be guided by them- ask questions re honing and bore wear. Ive seen much worse pistons used succesfully in the past.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      sold listed as a Tomei LSD 1.5 Way For 1998+ Nissan Skyline ER34 25GT RB25DE w/Open R200 https://www.ebay.com/itm/174006114594?campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=&mkrid=711-53200-19255-0&loc_physical_ms=108689&loc_interest_ms=&campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=71883f2ccc571356e0a757bc7adfdde2&mkrid=710-53481-19255-0&loc_physical_ms=108689&loc_interest_ms= it went in like butter all gears, alignment, back lash etc, rotation and clearances correct, and if rolling all rotates smooth and free when coasting down road , clutch in or out over 10 mph smooth... its the binding, clunking and jerking from a stop that is most concerning, also seems like its going to tear the tires off in 10 miles of normal road driving. 
    • Kinkstaah
      new 1.5 LSD issues/concerns

      By Kinkstaah · Posted

      What 1.5 way? There's no such thing really as a 1.5 way, just different ways of explaining 2 ways with different ramp rates. HOWEVER. In any driving in a straight line your 1.5 or 2 or 1.7 way should have no clunking at all. With the clutch fully depressed the diff should be silent (unless it's welded but I'm assuming it's not). Something aint right here.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      Clutch is a spec brand, new clutch system,( PP, flywheel, friction disc, etc. pull type) installed 100 miles ago, with no problems.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      looking for some help and maybe some insight on others experience with a new LSD. R34 GT ran and drove beautifully, but always alot of grip loss due to the open R200 rear end, so I just installed a new 1.5 LSD way into the stock open R200 for a ER34. Simple. Everything seemed right. I test drove for the first time this weekend. as I started to back out the garage the first time slowly with tires straight it sounded and felt like I had a loose or half disconnected drive shaft...that was clucking around loose and shaking entire vehicle, and making it feel like the trans clutch was spontaneously slipping then grabbing very roughly while just letting out pedal slowly. I backed it out went to pull forward with the same noise, shake and slip grab feeling with hesitation, I turned the tires to back out more and then pulled ahead some same thing but worst because of added wheel resistance (which that I expected) puzzled … pulling it back in checking everything over and finding nothing wrong, I tried it the next day. same thing, couldn’t believe how it shook everything again making a terrible noise and making it feel like the trans clutch was slipping and grabbing, but I got it out of garage into the driveway, got it straight, drove forward and then reveres a few times in a straight line everything shaking , causing what felt like clutch slip and grab every time, sounded like right behind front driver tire and I could feel it in the floor board with my feet,... worst right when beginning to let clutch pedal out to engage slightly, shuttering and sounding terrible along the way…I managed to slowly get down the road, babying it the whole way, once I was rolling (out of 1st) seemed to be better and between shifts, then clutch felt closer to normal…not slip/ grab etc., but back down to any stop, straight road or turning, same thing. Made no difference if all tires were straight or if I was turning. All other gauge read out correct. with in 2 miles as planned I reached the empty parking lot and performed the break in procedure that came with lsd, essentially to drive in a figure 8 a bunch.  Did this, binding chattering, and shaking the car the whole way. I drove it back home seemed somewhat normal once I was in straight line and past 10 mph or so, and I know it will “bind” on corners and cause some tires squeal when turning especially from a stop, but when I begin to move it still causes what feels like the trans clutch to slip and jerk badly as well as shaking the entire car, and sounds terrible, that I didn’t expect. I used the fluid they supplied with LSD kit and did the breaking, planning to change fluid as they suggest after breaking, but wondering will it get smoother or less aggressive with use? maybe a 1.5 is just too aggressive for normal road driving?   I have a LSD that I put in my 71 cuda when I restored it, with amazing smooth , quite yet effective results. Different style LSD but that ones a joy to drive. maybe expecting too much from this R200?
    • Matt Z
      SAU NSW - Archies Flame Grille Meet & Cruise to Kurnell

      By Matt Z · Posted

      Join SAU NSW for a flame-grilled feed & flame-spitting cruise! Sunday 17th August 2025 3:30PM Meeting Archies Flame Grille Sylvania Waters 4:45PM Cruise Departure 5:15PM Arrival at Cape Solander Kurnell Meet Location: Archies Flame Grille Final Destination: Cape Solander Kurnell *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
×
×
  • Create New...