Engine Labouring?

[Mattw_83]

Hi,

1996 R33 GTS25T S2

Car seems to make a pretty heavy 'labouring' sound at around 1700revs. Almost sounds mechanical in noise though coming from gearbox region possibly.

I know this is pretty vague but im curious if this is something common perhaps anyone is aware of.

I also have a feeling synchros are the on the way out. Pretty notchy. Clutch in rolling i can always find a point of crunch if i play around slowly. Gearbox has redline shockproof oil.

Any ideas would be handy before i hand the car over to a mechanic.... or trade it.

MODS

FMIC

NISTUNE R32 ECU

EBC

FULL EXHAUST

RUNS 12psi

200RWKW

125000k

[Birds]

What do you mean by labouring sound? Labouring is a feel, not really a sound?

What clutch are you running?

What gears does it do the noise in? Would be normal to feel it in 5th at that engine speed...pretty borderline for the rest of the gears. 2000rpm is a good engine speed to maintain for flat roads in all gears.

[Mattw_83]

What do you mean by labouring sound? Labouring is a feel, not really a sound?

What clutch are you running?

What gears does it do the noise in? Would be normal to feel it in 5th at that engine speed...pretty borderline for the rest of the gears. 2000rpm is a good engine speed to maintain for flat roads in all gears.

Obviously doesnt get up and go until over 2000rpm with any urgency anyhow. Its kind of a rubbing grinding kind of sound with the usually 'i dont like these low revs labouring feel'. Dont need to have it much throttle at all. noise appears just as it passes those revs. Only time i personally notice it is when i take off from first, or when the missus takes a corner in high gear.... When i drive it never sees those revs unless in first, taking off.

Has an Exedy Heavy Duty

Makes the noise in any gear id say at those revs (although havent actually tested it). Definitely 1st, 2nd and 3rd.

[Birds]

Does it do this in neutral when revving the engine?

In a few minds at the moment...could be a cluster bearing in the gearbox (does it do this in 4th too?), could be an input shaft bearing (does it in all gears including free revving in neutral), could also be a bottom end bearing in the engine. RB25DETs will have a labouring feel when you are below 2000rpm, but it shouldn't be there in 1st gear at all.

[Mattw_83]

Does it do this in neutral when revving the engine?

In a few minds at the moment...could be a cluster bearing in the gearbox (does it do this in 4th too?), could be an input shaft bearing (does it in all gears including free revving in neutral), could also be a bottom end bearing in the engine. RB25DETs will have a labouring feel when you are below 2000rpm, but it shouldn't be there in 1st gear at all.

Ran some tests

Doesnt do it at all in neutral.

Doesnt really do it in 4th. Standard kind of labouring feel.

To be honest second is the worst. Especially with someone in the car.

the more throttle the louder it is too. Tested that theory

Edited March 10, 2011 by Mattw_83

[Birds]

Okay, if it doesn't do it in 4th then it is very likely an issue with the cluster shaft in the gearbox...be it a bearing or the shaft itself. This will require a gearbox recondition, which is going to start at $1200-$1500 depending who and where.

Engine related problems will usually show their face in neutral too, but can't rule out that the problem may only happen under load.

[DVS JEZ]

Check some basics 1st. Look at the exhaust system and nake sure all heat shields are tight and make sure the exhaust doesnt contact the body anywhere.

Otherwise as said the gearbox is noisy

[Mattw_83]

Thanks for the replies.

Ill take a look at the exhaust/ shields etc.

Spewing if its the gearbox. I thought they were tough! Bought it with 55k and it was like brand new. I dont thrash it either. ah well.

Cheers

Matt