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Rb30 Twin Cam Top Dead Center For Crank Shaft

BMYHOE

By BMYHOE,
in Engines & Forced Induction

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BMYHOE Proficient

BMYHOE

Posted
Posted

Hey Guys,

So i just brought a R33 GTST with a RB2530 in it, the wedge holding the harmonic balancer has come loose and stuffed the crank so im in the process of replacing the crank. have the other one getting balanced etc..

so before i started pulling everything down i had the motor at TDC, but after lossing the flywheel bolts i have turned the motor almost half a turn without realising.

THEN i removed the timing belt without marking it on the belt,crank or cam gears.

so now i have the belt off and the tdc markers on the cam gears facing: inlet: 4PM outlet: 8AM

just woundering if i should re install the belt?then turn the motor to TDC?

The Mafia Grand Master

The Mafia

Posted
Posted

No need mate. There are dots you line up on the crank, and cam gears. Just line all the dots up and slip the belt on.

I urge you to check it 10 times and have a smart mate look and see if the dots line up good. I had my iPhone down there taking pics of the crank dot because you can't get your head down there to look at it straight on.

Once all the dots are lined up, slip the belt on and problem solved.

You shouldnt really use marks and hop it goes on in the same place anyway, that's just being hopeful, and not good practice.

BMYHOE Proficient

BMYHOE

Posted
  • Author
Posted

If you are srtipping the motor why are you worried about TDC?

i am just changing the crank so i didnt want to pull the head apart. i guess ill take the rocket covers off and just put the cams at TDC before re instaling the crank.

so is there any marks on the crank for TDC?

do i use the key wedges for the pulleys or is there marks on the pulleys them selfs?

sorry for the noob questions just wanna make sure things are right,

thanks

DAN

r33_racer Grand Master

r33_racer

Posted
Posted

Just use a dial indicator to find exact tdc with number 1 if you have one. Or use the marking on the timing gear to line up with the notch in the oil pump housing. Then use the cam gear dots to line up with the markings on the timing cover backing plate.

Usually tdc is is when the key slot for the woodruff key is facing up.

zebra Grand Master

zebra

Posted
Posted

Or be dodgy like me and use a pen down the #1 plug hole to get it as close as possible and adjust to get everything lined up.

I dont suggest that method though...Dial gauge is much better

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

no need to take the rocker covers off, just leave the cam gears on and line the dots up to the marks on the rear timing cover. if you turn the crank roughly 60 degrees past tdc you can turn the cams without any risk of piston to valve contact

D_Stirls Veteran

D_Stirls

Posted
Posted (edited)

Whip the cams out and then spin the crank to your hearts content, that way while you are putting the engine back together you don't have to worry about any unforeseen piston on valve action.

Edited by D_Stirls
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

did your old rb30 crank have a collar fitted?

if so can you take pics of the snout of the crank of the new crank and the old one.

I might be able to pinpoint WHY this happened and save it from happening to you again a second time. Changing the crank and not investigating WHY it happened is not the right way to go about it if you don't want it to happen again.

let me know if you want my help.

BMYHOE Proficient

BMYHOE

Posted
  • Author
Posted (edited)

thanks guys!

im getting my new crank back on wednesday, then ill get you some pics guilty.

what do you think could of been the cause?

Edited by BMYHOE
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

i have an idea.. and it happened to me before....

crank bolts DONT come lose on their own.

just make sure you send me the pics before you put it back together. pm me if i dont see them straight away.

thanks guys!

im getting my new crank back on wednesday, then ill get you some pics guilty.

what do you think could of been the cause?

BMYHOE Proficient

BMYHOE

Posted
  • Author
Posted (edited)

Sorry mate been busy ...

this is the f'd crank

post-59990-0-37536900-1320148560_thumb.jpg post-59990-0-00373000-1320148636_thumb.jpg post-59990-0-28313800-1320148660_thumb.jpg

this is the new crank

post-59990-0-44339300-1320148739_thumb.jpg post-59990-0-15828100-1320148784_thumb.jpg

i didnt get any more pics of the new crank, hopefully that will help you.

we think that this was all caused by the harmonic balancer bolt coming loose..

Edited by BMYHOE

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