Blob1620 Posted November 23, 2015 Share Posted November 23, 2015 (edited) Under load my car gets a miserable vibration that follows engine rpm. Its not a misfire, engine is doing everything its supposed to be doing. under load or not, around 3k rpm there's a vibration through the whole car. I have CXRacing engine mounts too fyi, so they are one step above being a solid engine mount. Question 1: are these engines known for having harmonic damper issues, do they go bad commonly? Question 2: has anyone had engine balance issues after surfacing the flywheel? This one has been surfaced. (seems unlikely just looking for trends) I've tried all the tricks trying to isolate it. When I'm sitting still clutch out in neutral, clutch in in neutral, and clutch in in gear, free revving, the vibration happens at the the exact same rpm. So i feel its somewhere flywheel forward. Let me know if you've had similar experiences. Thanks! Edited November 23, 2015 by Blob1620 Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted November 23, 2015 Share Posted November 23, 2015 Did you have the flywheel balanced with the pressure plate? My L-series became way smoother once I did that. Not saying that is it but if your engine was fine and then you had your flywheel resurfaced and the vibration showed up. That is where I would start looking. 1 Quote Link to comment Share on other sites More sharing options...
Blob1620 Posted November 23, 2015 Author Share Posted November 23, 2015 Did you have the flywheel balanced with the pressure plate? My L-series became way smoother once I did that. Not saying that is it but if your engine was fine and then you had your flywheel resurfaced and the vibration showed up. That is where I would start looking. That's just it, I purchased the engine rebuilt, I never heard it run before first fire up after the rebuild. I've had RB powered cars before though, and this kind of vibration is very new to me. Higher revs and and it comes in like waves of vibration. I'm just trying to pinpoint it without throwing parts at it and was wondering if anyone had seen this before. Removing the trans is a real pain in the balls if its not the clutch or flywheel that's the issue. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 23, 2015 Share Posted November 23, 2015 This guy says RB crank bolts are a problem. http://www.lewisengines.com.au/rb-tech/ Quote Link to comment Share on other sites More sharing options...
Blob1620 Posted November 23, 2015 Author Share Posted November 23, 2015 Oh boy, Thats bad news..... I'll have to take a look when I get home tonight... Thanks NewZed Quote Link to comment Share on other sites More sharing options...
Blob1620 Posted November 24, 2015 Author Share Posted November 24, 2015 This guy says RB crank bolts are a problem. http://www.lewisengines.com.au/rb-tech/ tried a big ol' breaker bar on the crank pulley, seemed pretty tight. To be honest, my biggest torque wrench only goes to 200Nm so I'm not sure just HOW tight it is. Quote Link to comment Share on other sites More sharing options...
900ss Posted November 28, 2015 Share Posted November 28, 2015 You sure the sump isn't touching the crossmember or gearbox rubbing on the ears or the strengthening brace of the tunnel? Or even the exhaust downpipe rubbing for that matter ? Damaged crank pulley maybe ? Quote Link to comment Share on other sites More sharing options...
KAZU Posted November 29, 2015 Share Posted November 29, 2015 Most often RB harmonic balancer bolts are not tightened correctly.We usually see crank snout damage from a loose balancer after a timing belt change where the mechanic ''thinks'' he has the bolt tight. The rb 25/30 bolt must be tightened to 400nm and the larger rb26 GTR bolt to 460 nm. The only way to tighten to this tension is by locking the flywheel in place with a suitable tool. Failure to do this , especially more so on a race RB30, will entail in balancer movement and in shortime balancer and or crank damage. The tightening torque for RB26 is correct but 400 Nm for RB25 stock crank bolt is too much.The pulley bolt of the RB25/30 is smaller in diameter than RB26's. I think the tightening torque of the RB25/30 is around 150 Nm. Quote Link to comment Share on other sites More sharing options...
240zdan Posted November 30, 2015 Share Posted November 30, 2015 (edited) I would also say something is touching, metal to metal. Check to make sure polyurethane or rubber is the only thing supporting your motor and tranny. My tranny was resting on my custom crossmember and vibrated like mad. Exactly as you described. Edited November 30, 2015 by 240zdan 1 Quote Link to comment Share on other sites More sharing options...
Blob1620 Posted April 28, 2016 Author Share Posted April 28, 2016 I've had all I can stand. I'm going to pull the gearbox this weekend and get the flywheel/pressure plate assembly balanced. As far as I can find online the RB's are totally internally balanced and shouldn't require my machinist to account for a counter balance. Is that correct? Going to have a better look at the top side of the gearbox too and see if maybe its been touching anywhere I couldn't see from the bottom. Wish me luck... this has been a problem since I first built the car... Quote Link to comment Share on other sites More sharing options...
grillhands Posted April 28, 2016 Share Posted April 28, 2016 Keep us posted. I hope you figure it out Quote Link to comment Share on other sites More sharing options...
Blob1620 Posted May 8, 2016 Author Share Posted May 8, 2016 Well, after much toil and lost sleep, i found a place at the top of the gearbox that was touching the trans tunnel. Vibration gone... Happy days Quote Link to comment Share on other sites More sharing options...
240zdan Posted May 9, 2016 Share Posted May 9, 2016 Thats what I figured. Engine vibration is 99% of the time engine to body contact. Glad you got it fixed. Quote Link to comment Share on other sites More sharing options...
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