**RB2530**

Just run a plumb back BOV to keep it quiet...No performance loss...Less defect potential...

Maybe someone should start a 'RICE MODIFICATIONS' thread!!!

Mate I also used my common sense to determine that the BOV leaked. I am a mechanical engineer and know a fair bit about material science, use of alloys and methods of production, manufacturing tolerancesetc etc etc and know that the Mitsubishi manufactured BOV wont seal 100%. Two mating surfaces of equal hardness that are not lapped with relatively buggerall force pushing them together them will not seal all that well. There is not even a tapered seat (such as valves in cyl head) to help out. In fact the degree of seal will be quite variable within any given batch. Some ok, some bad. And of course the mechanic didn't have any part in the creation of the Mitsu BOV NOR did he have any part in the creation of the RB25DET or any other engine for that matter...but he still knows a bit about them.... As far as DIY my stock induction pipework is long gone (all custom fab) but I will post some pics of how I am using the Bosch BOV currently. I will also get the Bosch part number for everyone although I am sure I am not the only member using one...

I was told by a very experienced Nissan mechanic that they do leak. And of course, there is the bleed hole. The bleed hole is there as you say to make the BOV smoother in operation and the difference I noticed was probably due to effectively removing this leak. Nonetheless it is still a leak. The actuation diaphragm that connects to the plenum is sealed and doesnt seal up the BOV. And when I say leak, I dont mean massively, but enough to make a difference because: When the BOV leaks it passes air back into the compressor via plumback line. This is a waste of energy as you are effectively bleeding air you have already compressed / cooled, away from the engine. If you are running the stock GTSt turbo that is undersized anyway the last thing you want to do is make its job even harder.. Once again its only a small loss but when you add up all of the minor losses in any motor car they become substantial. Some you can reduce, some you can't. A leaking BOV is easily fixed. Thats why I did it... To me a BOV is just a device to make life for your compressor easier..As long as it can hold boost pressure, can react fast enough and vent the pressure, its a winner...Doesn't matter what brand or what it costs as long as it does its job properly...If I can do it successfully with a cheap Bosch OEM part...good luck my team...

Yes the Bosch one is plastic body, with a rubber diaphragm mounted on a brass disc. The seal is plastic seat on rubber diaphragm. This creates a better seat than alloy on alloy for air at ambient temperature..Happy to get into a debate about material science and whether or not this is good engineering practice if you like...Plastic has its merits... The version I use is a Porsche spare part but also used on some SAABs. There is a low and a high pressure version out there..About $10-15 bucks difference. As far as proof that the stock BOV do work..of course they do!! I believe you. What I also believe is that with the example you give (314rwkW with stock BOV) a BOV that doesn't leak may indeed turn this into 320rwkW... What I can firmly attest to is that when I first got my Skyline, I gutted the stock BOV, used the body as an adapter and put a Bosch BOV on.The car was completely stock and there WAS an improvement...The stock BOV was perfect apart from the leakage... So in my mind, based on my experience Bosch BOVs DO work on skylines...If they work on a Porsche, SAAB, VW, AUDI etc they will work on a Skyline... At the moment I am trying to find the money to buy a twin or triple plate clutch to hold the power I am making (with my Bosch BOV)..The 5 puck single plater cerametallic is not up to the task...Now if I had spent $600 -700 on a shiny BOV that can make 5 different pphhttt oooosh noises my clutch would be little bit further from reach than what it currently is....

1. I never said that the bosch BOV is a direct fit...there is a hose tail on both ends and you need to run some tubing to it...If you've got money to burn and dont like tools buy a direct fit... 2. There is a version of the Bosch BOV that is good for about 20 PSI. Just like factory it has an actuator on the low pressure side fed by manifold pressure. ie the higher the boost, the greater the force on the diaphragm and therefore tighter seating inside the valve. Higher pressure version has brass button reinforcing diaphragm to cope with larger forces. 3. Stock BOV leaks in two ways. The way you have mentioned (BTW if you block of the small breather hole you better make sure the screw is in tight as the only place it will end up is in engine) AND it also leaks because the valve actually consists of an alloy disc seating on an alloy body. Not the best seal... 4. I have been using Bosch BOVs on my Skyline for 4 years without a drama!! I have been running around 260rwkW (1.1 bar) for the last 12 months and the BOSCH BOV is fine. Sorry mate we dont agree....

Yep no probs, tear away

I dont own a 180. never have and never will....I hate stickers you see, and dont the 180s come with heaps of stickers as stock?... On a serious note if you want some good advice on BOVs read my previous post...Running an expensive BOV is like running billet tyre valve caps...Just trying to give some good advice and stop some of the RICE modifications occurring to skylines...Anything to get the cops of our backs...

The factory BOVs always leak...They are designed to leak. Pull one apart and you will see what i mean.. I use a Bosch OEM BOV...You buy it as a SAAB or Porsche spare part for about $60-70 dollars. If you are keen I cab get the part No..They are plastic but will hold up to about 1.5 bar reliably...They are also a plumb back...Leave you factory one installed and just fit the Bosch one into the hose coming from the factory one.. No cost, no fuss, no vent to atmosphere, no fu(ked up air flow calculation at idle with stock ECU, no defects and NO NEGATIVE publicity to other skyliners for RICE SOUNDING BOV sounds...

I will be needing a Twin Plate clutch some time in the next 6 months..Will consider 2nd hand if it is in good brand (OS Giken etc) and in good condition or is suitable for rebuild... Will be pulling out an Excedy cerametallic that is holding 220rwkW (for 30,000km) but slips when I run slightly more than this and will offer this as exchange + plus cash... Also have a stock GTSt clutch in fair condition of you want it....

The stock gauges are not very good. They are much slower to react and are not very accurate. I recently did the reverse. My stock sensor was hardly reading at all at idle and often would drop to zero. Oil light would come on as well. I checked and there was plenty of oil and it was still getting to the head even though gauge was showing zero pressure. Then it would jump straight up to 2kg/cm. Would often fluctuate between 0 and 2. It only happened when engine was hot. It was reading normally at all other rpm ranges and temperatures so I wasn't too concerned. I put an HKS mech gauge on and it was much faster to react and never dropped to zero..Concluded that the stock sensor was buggered. Hope this helps

Good thing about exhaust manifolds they generally fail just by developing slow cracks that are easy to see and detect so if you do have one fail it doesn't end up being damaging anything else...apart from your wallet for the cost of the manifold and a new Nissan gasket... As far as pulling the manifold off and putting it back on I can now do it in my sleep I have done it so many times... Its a low mount though and every time I do it I swear next car I do will be a high mount!!!

No probs.. I suppose the point I was just pointing out what can happen if you are a newbie... The HPI ones might be great and only time will tell. And your right ssome has to try them...Also Just Jap is a good reputable supplier and I am sure if you have any problems they will help you out..

The manifold in the photo looks good...I wish you the best of luck with it... I have had some very bad experiences with low mount tube manifolds in the past and got to the point where I gave up... My first experience was with a cheap chinese shit manifold...I should have known better but I was a newbie...I am sure many guys have gone down this path. Anyway after about 2 months it cracked. I took it back to the guy who sold it (and fitted it). He able to TIG weld the crack with it on the car. It then cracked again underneath and it had to come off...I pulled it off again and it cracked again...meanwhile a couple of stripped studs new manifold gasket.. I was then given the details (though a major parts supplier) of an alleged brilliant fabricator (also a tech teacher) based in Rutherford (not Lilford exhaust) who could make one for $1200 (due to forum rules I wont name him but if you live in Newcastle or Maitland PM me BEFORE you talk to any guys about making one for you - he is a f**king shonk). He did a good job (thick flange etc) but told me it would be steam pipe and therefore (telling is not a guarantee apparently) that it would not crack...Well it cracked and warped...Once again off the car to be weled and straightened it. When he straightened it he bent one of the runners a very small amount but still noticeable. Anyway it didn't recrack where he repaired it and I thought all is good BUT it later cracked where the runner was bent...I went back to see him and he told me it was now 6 months old and the only thing he would do make another one at cost. He told me I probably didn't tension the nuts properly or put a hose on it WTF??..No way!! By this stage I had gone through 2-3 manifold gaskets and done countless thread repairs...Unfortunately it was a cash job so i didn't have much recourse - But once again PM me before you get anyone in Rutherford or East Maitland to make you one. I now run an HKS cast iron manifold with seperate runners that for some reason HKS dont make any more. I bought this manifold second hand from wreckers in Japan and it is awesome...It came with 60mm HKS wasegate that fits to the top of the manifold via a flange that is made for that WG...Fitting it was easy even to the RB30DET...Just had to grind small amount off the base of the flange so it didn't hit the RB30 block. Hopefully the HPI one is better...Part of the problem is that an RB25 low mount manifold is long and thin and the runners run longways. The main flange runs a lot cooler and the long runners esp at the front expand a lot more then the flange and they have no where to expand...High mount manifold dont have this problem.. My advice is go for a Cast Iron manifold for street or everyday use until the HPI manifolds are proven...

Well its done!! All is good and so far no damaged bearings from shavings...Not expecting any either.... I put compressed air onto the port that the VVT solenoid valve screws into. Once I had drill the 1st small a spurt of oil shot out....Bingo...at least I knew I had hit the gallery. The oil that came out was very dark probably from being stagnent. ie when you plug the gallery it becomes a dead spot..Air then came out of the small hole but by the sounds of most of the air was exiting somewhere else in the head. Anyway I had 15cfm air flow and at least some was coming out the hole drilled in the gallery...Enough to blow grease off the drill bit and tap. The vacuum cleaner idea worked very very well. After drilling and tapping the hole I then filled the gallery with WD40 using the fine tube that comes with the can...I then used some of the very fine plastic tubing that they use on small MIG welders for shielding gas on a decent vacuum cleaner (you use a short length of bicycle inner tube and some cable ties to connect the thin tube to the vacuum cleaner. Use some 3mm vacuum hose as an intermediate connection.) After filling the gallery with WD40 I was able to get the MIG gas tubing into the drilled hole and slide it down to the bottom of the gallery. When the VC is on you can see the WD40 and shavings travel up through the small tube...I did this about 5-6 times. A couple of times 1 or 2 shavings blocked the small tube...Anyway after doing this I was 99.999% confident there were no shavings left in gallery... Tapping the thread is not for beginners....very easy to stuff up....It would be very easy to bottom out the tap and tear the thread out...Then it would be head off engine and off to the cyl head repair gurus...I used 1/8th" bsp nipple with heaps of loctite 567...I then put a 90 screw on elbow. I had to modify so the thread sockets were shorter because it was fouling on the cam pulley backing plate...Now it just fits..If anything the cam pulley backing plate keeps the elbow fitting captive into the head drilled/tapped hole...So if it fails it will leak slowly as opposed to pissing oil everywhere draining the sump in a 30seonds or so... The roads were wet all weekend so I couldn't do much road testing...The first thing I noticed though is that the idle is much smoother and stable..Before idle rpm would fluctuate and now it is very stable...I had check and cleaned the idle control valve without much luck...I know think that this idle behaviour may have been due to the fact the VVT mechanism was not getting any oil and maybe jamming or moving around...Over time I wouild say that the stagnent oil would gum up and the cam advance may jump around??? Not sure on this but based on my experience I would strongly recommend removing the VVT pulley and running a standard pulley (if you can find one that fits the VVT inlet cam) if the oil gallery is not connected to the oil supply. When driving the car even lightly it seems a lot smoother...Will do some G-tech runs when it stops raining....

Spoke to Anthony about it..he has not done one with the head on before...I told him what the plan was and he said he couldn't see a problem with the process...Am gonna give it a go on the weekend..Oil gallery in question appears to be about 5mm in diameter so some 3mm pvc hose connected to vacuum cleaner should get all shavings out. Shavings will fall to bottom of gallery because it is vertical. Very very unlikely they will end anywhere else...Sydneykid also reckons they do heaps of that sort of stuff as well...Can be done successfully as long as you are careful... I will take heaps of pics and post it when it is done...Just chasing around at the moment for fittings and a hose...Will use 1/8th bsp (same as thread in oil pressure sensor) in the head and use JIC fittings on hose...1/8th to JIC fittings are common...can get elbows as well...

Yeah i have decided to go in from the front of the engine...Now to do this I need to remove the backing plate behind the cam pulleys... By the look of it I just need to 1. Remove CAS and the front pulley cover upper, 2. slacken timing belt, 3. remove the cam pulleys and then the backing plate...4. Also remove the cooling fan to give a bit more access...Timing belt can be held out of the way but does not need to come off?? The Harmonic balancer doens't need to be taken off to do this??? Can anybody confirm??? I have access to a 90deg power drill designed for tight access and am hoping to drill the hole without removing the radiator... any help appreciated....

Guilt-toy Are you positive the entire front of the engine needs to come apart. I was thinking that maybe just cam gears then the backing plate need to come off. Obviously you need to slacken the timing belt to renmove the cam gears but I can remove the bottom half of the timing belt cover without removing harmonic balancer. From memory there are two bolts that are a bitch to reach but i think i made some special spanners to get at them...I have had it off onec before without taking H balancer off... cheers... btw tried Anthony but he was out...will try again this afternoon...

Guilt-toy, Thanks for that. Do you know if he has done them with the head on before??...I appreciate its not the best thing to do but I dont really want to take the head off unless I have to...It will cost me atleast $1000...and time I dont have.... cheers

Shane, Yep i can see where you are coming from...I am not sure how much risk you expose the bottom end to though when you consider that if any shrapnel does get into the oil gallery undetected, it first goes through the inlet cam gear and bearing, through the exhaust cam bearing and then into the head. The into the head oil drain then into the sump...if it makes it to the sump there is a very good chance it will end up in the oil filter...It doesn't get a chance to find the big end oil circuits...worst case is a damaged cam bearing or two...still not desirable but I am planning on cam upgrade anyway... Don't get me wrong at the moment I am in two minds as to whether or not to try it...I just always try and do a realistics risk analysis before I do anything like this rather than just relying on whims... cheers

Yep motor has forged internals...I assume thats what you mean?? I assume the silly comment refers to doing it with the head on due to risk of getting swarf in gallery...or is there another reason other than this that I haven't considered?

Yep found the pics...heaps of em very helpful...looks like the neatest way is to go in from towards the front...have to remove the cam gear backing plate to get in there though by the looks of it...

Chris, Thankx...I will check out the attachments....yeah I take your point about drilling and tapping when the head is off the motor...ideally this would have been done but the guy who built the motor for me 'assured me' that it did not need to be done to get the VCT to work...I now know otherwise...As far as shavings are concerned a couple of tricks that I know are as follows: 1. Clean out the gallery with a good degreaser and dry it out so that there is no oil in the gallery.... 2.Drill a very small pilot hole first. I mean small such as 1mm dia. Cover the drill bit in heavy grease so that any shavings are caught in the grease...then place compressed air on the gallery and give it a positive pressure...not much...you dont want to blow out any seals....just enough to produce decent airflow out of the hole....Then when you drill main hole use a very sharp drill bit on slow speed so the shavings are large. Any shavings get blown outwards by the compressed air through the flute of the drill bit....same goes for when you tap the thread....keep the air pressure up so the air flow blows swarf outwards... 3 Once the drilling tapping has been done connect some small diameter hose (PVC tubing) to a vacuum cleaner and stick it in the hole and suck out any small shavings that may have gotten past the air rushing out of the hole when drilling....This oil gallery must be vertical as it picks up from the block below so any shavings would just fall down and just sit on top of the welded or plugged section at the bottom of the gallery anyway... In my mind the if the above process is used, the overall risk of damaging the head is lower when compared to risk of damage (and cost) of removing replacing cyl head. Anyone else reading this post please feel free to add comments or shoot me down in flames...Am always open to criticism...There also may be a good reason not do it based on something I have missed... cheers Paul

Dan, I have never ran two WGs but I would say definitely block the internal one if you can. If you run both WGs I think they may cause unstable boost control as they would open/close at different times. They may end up oscillating and causing unstable boost. An EBC wouldn't even be able to control them... If they were indetical WGs it may be a different story but external and internal gates have different fluid flow characteristics. You also want to try and block off the internal one because in theory you would introduce lag by allowing the exhaust to leak or bypass the turbine all the time. One advantage of ext gates is that they dont leak when they are closed and by having a leaky internal gate (even if it is not activating) you would loose the advantage of the external gate. ie No leakage when closed... I dont have any suggestions on how to block the internal gate though??? Can you get an ungated exhaust housing for that turbo??

Hey Guys, I have read nearly all of this thread looking some detail on how to do the oil feed under the VCT solenoid and can only find out that you need to tap into the oil gallery. Does anyone have any photos? I have been running an RB30DET for nearly 2 years now and want to get the VCT running...Note that the oil gallery in bottom of head has been plugged... Things I need to confirm are : 1. Where do you put the hole. ie vertical distance from solenoid + in from side or front of head... 2. What type / size of thread (1/8" BSP etc ) can you get in there? 3. Is it possible to do while the engine is in the car?? I suspect that you will need to remove the inlet manifold to get a drill in there..... Once again I realise that there is heaps of info out there but i cant find any photos cheers