the-31

Anyone have any other info on this?

After Cams were installed. No nothing majorly wrong at all just running abit rougher than usual, short window for testing as I had clutch issues so just parked it up. Going to start pulling the box to replace clutch but thinking I should pull engine and install rear head oil drain as I still have issues even with oil restrictor installed in gallery. I dont think I have enough room behind the head for the drain, 20mm between firewall and head.

Hello, I looking at cylinder compression on my RB30/25DET, Its an older build in a R31. The block was built around 2008 with 40thou over size forged pistons (can't remember brand, maybe acl) they were only 8.5compression ratio (can't remember why) Ran it as SOHC with around 200rwkw for a few years. Had Boost works in Adelaide complete the 25det head conversion and it was putting out 297rwkw for a year or so and then I had Jaustech give it another tune after I installed cams and they had it running just over 335rwkw which is has stayed around that since. That was late 2013 they did a compression test and it recorded: 1 - 125PSI 2 - 125PSI 3 - 120PSI 4- 125PSI 5- 130PSI 6 - 130PSI the car has only been drivin 3 times in the past 3 years, only to the local drag strip. Shes due for a new clutch.(looking for recommendations on this also, looking at NPC 10" single plate?) Last Easter at the drags it had clutch issues and over rev'd a few times, ive only just done a compression test (12 months later) and the results are: 1 - 100PSI 2 - 100PSI 3 - 96PSI 4 - 100PSI 5 - 105PSI 6 - 110PSI as you can see its nearly exactly 20PSI drop over all 6 cylinders, there is also 7 years between these figures. I tested with all plugs out and throttle open, tested each cylinder twice with a brand new TOLEDO compression tester. I did a search for info but maybe searched the wrong area. Is it too low? What other tests should I do?

Thank you Djr81 for a Much more informative response than the previous. There doesn't seem to be as many setups and issues exactly the same as the ones I have, so trying to find specific answers in the threads hasn't been very successful.

So after 3 years of this topic being dead im bring it back with the hopes of some further information. I have a RB30DET with around 350rwkw, have a N1 oil pump and restrictors in the block (no rear head drain and no larger oil gallery drains) I don't intend of pulling the head off any time soon to do modifications. I have had my PCV blocked off for many years and have both rocket cover breathers Tee'd together and running to a catch can (not baffled, no access for baffling) then to atmosphere. When ever I do one or two decent drag runs I need to empty my catch can which is a pain and generally embarrassing. After having this setup for about 6 years I've just Decided to tee into my turbo drain pipe which is fine at the moment apart form smoke coming out of my breather. Now it sounds very similar to what quimby asked and what KiwiRS4t responded. Now what is the best way for my to get rid of all this oil? Am I'm plumbed completely wrong? There is too much oil to plumb to intake. Would a non return valve work on the can drain or would the oils weight not open an inline non return? I'm after some help. Thanks Adrian

Well it seems to be stuffed. Pressure plate fingers look to be good, still meat on the clutch but it seems to have worn the pressure plate and the flywheel. Any recommendations for a new clutch? Something cheap, drivable and capable of 350rwkw. IM not looking to push more out of the engine. Thanks

I under stand the slipping. Just don't understand how it's such a fine line between crunching gears and having traction or shifting smoothing but slipping clutch, with the length of the push rod. It could be something in the clutch itself but I hope not. By the sounds of what information you have given the pushrod shouldn't affect it and should never have been changed?

Once the hydrulics are at full stroke the fork doesn't move back in on it own as if there is fluid bypassing?

Is there any difference between 25 and 30 slave cylinders? When i first did the conversion the orgnial/factory pushrod didn't suit so I made another one and that has worked for around 7 years. Untill my current issue. I have no fluid leaking from slave or master. As mentioned it still engages the clutch soild without slipping but not great when changing in any gears.

Hello All, I'm trying to narrow down what my clutch issue may be, so here's some information about the car and setup. I have an Aus delivered R31 Ti, its converted to RB25det box and Has either a clutch to suit the rb30 box/fly or rb25det box/fly, I can't recall as it's been in the while but it Is an Exedy 5 puck clutch. R31 NSK-6797HDB Heavy Duty Button Clutch Kit Or R33 NSK-7056HDB Heavy Duty Button Clutch Kit It has had a lot of abuse which is what the car was built for. I had the car at a drag meet and all of a sudden it ended up becoming hard to select gears, now I'm trying to find the issue. The master cydiner and slave are both rb30. Box is 25det as mentioned. Fluid was abit mucky so I replaced and bled it. The pedal was abit sloppy, a small plastic bush/shim that conect the pedel to the adjustable master cydlinder rod was shot and gave the pedal abit of play as the small pin (6-8mm) that's connects the two goes though a 10mm hole with a shot bush to pick up the slack. I made a new bush and also adjusted the pedal so it had more throw on the master cylinder. When I release the clutch pedal I am moving the pedal abit before the clutch engages which tells me I'm getting enough travel out of the pedal? Next was the push rod between the slave and the fork, with some help i had the clutch pedal pushed in I manually moved the fork to see how much more travel it had after the slave was fully engaged and it could move around another 10mm so i made a new push rod about 7mm longer which made the car shift into gear easily but under boost the clutch slipped. Any other suggestions? Obviously I don't want to pull the box, do I just need a push rod 3.5mm longer than standard? Is it the diaphragm/fingers on the pressure plate? Probably not important but the car is running a RB30DET with 350rwkw. Thanks Adrian

http://www.skylinesaustralia.com/forums/topic/436842-new-harmonic-balancer-info/

So my aftermarket harmonic balancer has fallen in two, im In the market for a new one, it was balanced with the rest of the motor (balancer too pressure plate) The balancer weighs 4kgs and is under driven, it's been on the motor (25/30) for the past 5-6years. Im After Info - where to buy? - What brand? - Stick with under driven? - Does it have to still be 4kg? Cheers for info and any links.

Got some good news and some bad, Good news is I got it off,key way looks good, key looks good, harmonic balancer no good. Standard balancer alright to use?

Need some help with Harmonic balancer removal. After a race yesterday I realised the main bolt for the harmonic balancer was loose and the back of the balancer (plate with timing marks) had come away from the rest of the harmonic balancer (I assume the rubber has let go and I need a new balancer, this balancer is after market, can't remember the brand) Normally is takes me 15mine to remove all belts and the harmonic balancer I've done it a few times in the past and it's 99.9% my fault the bolt was loose. But I've now spent over an hour and the balancer just won't pull off with the pulley puller, I thought maybe it was crooked so I tightened the main bolt back up and hoped to pull the pulley straight and tried to pull it off again but it's taking way too much pressure from the puller and something's going to break and it's not going to be the harmonic balancer. So does any KNOW why it won't come off? Cheers. Gotta get it sorted ASAP, it's a 30 bottom end