rayaapp2

Set timing at spec +- what ever it says on the hood... could be 0 with the ZX(some cars have 2-3 degrees of acceptable play). This is a pass/fail requirement for the functional check over. New air filter, plugs(NGK plain copper cores), and oil change are always good before a smog... Usually Id say go for it. An oil change might actually do some good for you here. PCV valve can help, but they only look to see if its on the engine not a functional check(visual). Its a good idea to change it esp if its really old. Personally I stay away from seafoam for that kind of particular application. Im not one for pouring any liquid down the intake of a running vehicle. This is just MY OPINION!, but I feel it does more damage than good! It puts excessive forces on the bottom end bearings, pistons, and rods. I will use Seafoam for some of the other applications listed on the can, but not here. Again my personal opinion, there are people that swear by the stuff. Options for cleaning the engine for me are to run better fuels and maintain a good tune on the car, or tare the engine down and physically clean it. I know those options suck. I have no idea about the effects of seafoam when its read by a smog machine. So if you add it to the tank I would burn through a couple of tank before re-attempting a smog. This was probably already your thought to make sure it did its job, but just thought Id give you a second perspective. Im not sure its worth the effort to dig the vacuum control module out to swap it(I remember those being buried under the AFM area). I would suggest a look through the FSM first(you can download it if you look around). It may be that your other car is missing the restriction in the vacuum line where the stripe is and it opens early, or it could be any number of other things influencing the EGR system... or it could be actually working correctly. The only way your going to be sure is to read up on it in the FSM and determine its operation. Nissan did an excellent job at clearly and concisely spelling out functional operation of each device on there vehicle with specs in the FSM. As for the cat, Id give it a shot. Compare the CO2% between the two cats afterward. BTW, I dont think the cat is really going to look plugged up when you pull it either. The CO2% is still high enough that some of the capillaries will be plugged, but not completely melted down(gone Nuclear). The only way to tell to see whats really going on is to do that test I mentioned above.

I dont have a FSM for that car, but you can bet that it will have very specific readings for EGR specs. Have a look and compare. Personally I would not expect it to work a lot at 15mph and 50% load. Some do though esp older systems. Kinda cool that you have a good comparable vehicle. Verify with the FSM though.

That is what I would expect off the EGR on that car actually. So now you know the EGR system works. Im sure the tech would have done an EGR test on it as part of his funtional check. If it failed it would be on the paperwork. You can double check it with a vacuum pump while the car is running and see if you can stall or almost stall the engine at idle by applying vacuum to the EGR valve. If you get a free retest Id say hell ya use the other cat and compare results. For diagnostic purposes only of course.

Has to be at full operating temp so that is allowed. Some guys cheat and hold the throttle up to heat everything up.

The tech went above and beyond what he was allowed to do for you. He actually cheated and can get in trouble for that. FYI. I stick by what I said above.

Your CO and O2 are close. I wouldnt touch the AFM! Its Most likely in GOOD WORKING ORDER! I would suspect your kitty is is very old and needs to be put down. Hard to tell without putting my hands on it, but I suspect you passed the faster test cause you have a working EGR and the cat was getting nice and hot. I would take the car in and have them do a "cat efficiency test". You CO2 is on the low side during the 15mph run and picks up during the 25mph test. Another thing to think about is carbon buildup in the CC. That will attribute to some of your problem as well. Just my 2 cents. Personally Id take the car to someone to have it really diagnosed. Otherwise its the toss the parts at the problem situation and hope it works. There are consequences in Cali now for replacing a cat and then having it fail again in 2 years so make sure your sure.

Pictures of valve guides that are broken? Before I ask this Id like to make it clear that I dont know anything here about failures like this so this is purely curiosity. Did you happen to notice smoke on decel on the dyno or anything else other than the noise? I ask because Im having oil consumption issues I think are valve stem seals. Im getting ready to pull it apart and see whats up. I have not had any metal noises like that, but that is very interesting that the guides would break. Id expect bent valves first. The weird things that happen when things go wrong Im sure its all in harmonics when it comes to this stuff!

I second that! Its not fair for comparison Nigel!

My Greddy manifold did not have this issue. It was installed before it was boxed. It was all in original packaging still. It appears to be a simple press fit.

Well this project has been put on hold guys. I exercised some stupidity and injured myself very badly. Anyway, in a month or so when they let me loose on society again Ill continue this topic and post some pictures of the timing gear I used with a writeup and my thoughts on this particular gear. Ray

You know what really puts a damper on installing bolt ons... When threads strip out. Pulling the harmonic balancer and stripping out the puller bolt holes provided in the balancer pisses me off Now I have to pull the radiator and driller for a larger bolt and re-tap... Not exciting.

RTV isnt a great idea. Epoxy it in there. traditional JB weld not the instant or fast curing stuff should do the trick. I did one manifold that way. Ideally it would be press fit in and epoxy'd like a freeze plug if that gives you a good idea. I ended up buying a Greddy in the end. Well worth it for the quality.

Speaking of covers, I noticed that seal around them degrades. That is next on my list when I get them powder coated. Replace seal around timing belt cover. Dust seems to get in there no matter what you do, but the seal should help a little. I just removed the coil cover this week to attempt to keep that area from heat soaking more than it needs. It reveals the breather on the back side of the timing cover plate though. I just cant win here I guess. It appears that seal is a special bead of silicone. It doesnt look like a pre formed gasket just a thick bead laid in there and allowed to setup partially before installed to the backing plate. I will have to figure that out soon I guess. Thanks for the link! I did not find that one while digging through SAU. I actually posted over there as well. SAU Thread Here area few of my baseline runs very linear power output. I was not really seeing that flat spot, but I had just installed a brand new Nissan timing belt, tensioner, and idler though. My mileage was about 82K km. Ray

Yeah, Im not doing anything for bling... One look at my car and you can see it looks like a POS, and its purposeful. Ive been debating painting it for several years, but I like the POS look. It really pisses off those with 80K dollar sports cars. All my money is performance items. Some day id like to dial in a set of cams and these cam gears will should allow that. For now id like to squeeze every last torque and pony from the motor by dialing the stock cams. Eventually Im going to powder coat a bunch of the stuff under the hood. Not for bling, but to prevent oxidation of the aluminum. The coast weather is already taking a toll on the radiator, intake, IC, IC piping, and valve covers. Ive only lived here for 6 months and Im seeing oxidation. Ive had the car together for several years now without an issue before these past 6 months. Id like to be able to adjust both intake and exhaust. Im curious what I will actually end up seeing on the dyno though. With the variable cam timing Im not sure how adjustable the intake cam will be before I see a drop in power, but I suspect I can play with a couple of degrees and make a small gain on the intake. I think the biggest gain will be in the exhaust. Its hard to tell with stock cams and the VCT, but Id like to try and see what happens. There isnt much out there on people doing this with real world performance results. I was able to get 33hp and 15torques above my baseline tune(completely stock rb25det and a APEXi SAFC II) from the factory so I suspect I can get a little more out of the cams if the tune from the factory was that far off from performance. Ive installed a lot of performance stuff since the baseline runs. No more SAFC II. APEXi Power FC with FC datalogit, Greddy intake, 3" exhaust, big FMIC, better ign coils, better spark plugs, and a better fuel delivery system.

hmmm Rally cars with cats... I like the windsheild mount better. Just guessing but its probably more likely that they mount it back there for sustainability and its probably a specialized cat.You will not get that cool blue on normal road cars even if you cut the exhaust off right behind a stock cat. You will get the glow. The current cats are good for about 1200*F typically before failure. Rear mounting is not really practical for road cars... yet. The new cold start low temp catalysts that the industry is working on may well work well at the end of the exhaust, when they are available to us. Thats kind of cool though.

So I came across a set(yes both) cam gears for the RB. They are new in the boxes, and less than half the cost of any store out there with them. This particular set is made by Fidanza part # 95048 9. Fidanza lists these gears for RB20, RB25, and RB26. So what Im looking at is an identical set of gears. Ive been poking around on the net searching for how this is done. I have seen references to the stock intake gear being slotted already, but I have never taken it apart to discover this. BTW there was only 1 reference to this and I never found anything else on it. There were a ton of guys just eliminating the variable cam timing components. Thats pretty common. Id like to keep the variable cam timing esp considering I have control over it with the APEXi PFC. I found another reference on skylinesaustralia stating that very few manufactures design these gears to work with the stock varable cam timing components. I believe they were Greddy, Tomei, and a few others, but after searching for pictures of these gear sets I found none that looked much different to mine. I would have a much clearer view of things if I disassembled the timing components, but Im just not there yet. Thanks for any light you guys can shed on the situation.

Well normal speeds up to 70mph read 85-90mph. It didnt before. And the car sees the track so speeds in excess do happen. Ive had the car up to 137.6mph in the straights with the GPS. Speedo is kicked over past the 160mph mark. As for transmission its the stock rb25 trans. The gears and cable are 2 years old and were new. They were lubed up prior to assembly 2 years ago. 2 years old and ~9500 miles on them. Im sure they are still good. Im fairly sure the fault is the speedo and the magnetic coupler. I would also expect wear or a lack of lube to put drag on the components that would slow the whole thing down giving me a lower speedo reading not a faster one. I have other speedos I could install, but at that point I think I would just switch over to the electic speedo and VSS. What strikes me as odd is that it seems to be the act of taking it up to higher speeds that seems to be degrading the coupler. When we initially tested everything the speedo was accurate within 5mph at 90mph on the dyno. I was expecting it to be off at that speed though. These speedos just arent calibrated for those speeds. I didnt think holding it at speeds around that would make the situation worse though. So I was thinking this might be a sign that the speedo is giving up the ghost. It doenst jump around like Ive seen other Z speedos do so I didnt really notice the difference until traffic seemed to be driving 85-90mph in 70mph zones. 80mph is pretty typical fast lane driving around here, but not much above that. To keep the speedo reading accurate I would be limited to 35mph zones or less so that doesnt make much sense.

So I have an RB25det under the hood of my 260Z and its actually capable of going fast. I have a corrected gear drive for my speedo that matches my rear gear set as well. Ive been driving down the freeway and noticing that I was driving rather fast to stay with the flow of traffic. Ive also noticed that the freeway spd sign(the radar based ones) have been saying Im going much slower than my speedo says. So to prevent any tickets I decided to test my setup. Initially the speedo was calibrated on a dyno(as at least verified up to 90mph) and it was good. 2 years later I am noticing changes. So I installed a garmin GPS unit to see how far off my speedo is now. Its off! at 35mp its off by 3-5mph. At 55pmh its off by 8-10mph. At 70mph its off by 15mph. At high speed 134mph it says 160mph. I know these speedos arent really good for high speed already. I believe its going out of calibration simply by taking up to high speed. It seems to be getting worse the faster I take the car. My plan is to eventually go electronic and use the skyline speedo in the 260z speedo housing. Im not really trying to state I have an issue or a correction for that issue here. Im just stating what I have noticed. I think the faster I take the speedo the less calibrated it seems to be. Anyone else have this issue or is my speedo about to die? I would think at normal street driving the speedo should stay close to the actual speed, but it just keep degrading.

Ill ask and see if its possible to put it up on there with the owner. Should be okay. I did it with mine. I just gotta run it in training mode so it doesnt dial out. 77 would be perfect. 76 and newer is in the system with current standards. The older cars are no longer stored in the system as far as standards go. I ran my 240z as a 76 280z standard. gotta put my hands on the 10mm and proto racket. Not sure where they ended up in the move.

Well stated Tony, you left me nothing to fill in. lol You know if you wait until 2012 the state is going to upgrade everyones machines and you will have a good chance of getting one of the old ones on the way to the junk. Most likely they will continue to use the dyno so your on your own there. BTW how you going to get the BAR calibration gas for the 3 day calibration? If I had a test subject to do cat tests on I would. I have the stock exhaust piping and an array of known good cats to test with. Just no car. Im not willing to use my 240z either. The the engine and transmission have to be removed from the car to remove the header and I dont have extra flanges to go from the 2 flange collector setup into one anymore. If I run across any good running donors in the future Ill be sure to tune as close to BAR90 stds as I can and get a baseline then run a cat and see what I can come up with. I have a good idea though of that outcome, but I will do it anyway for the sake of curiousity. Ive done similar tests with other vehicles. Its actually part of std cat testing procedures that MUST be preformed before any cat in Ca can be condemned. Its an intrusive test preformed before and after the cat that BAR requires before any cat can be replaced. OH, and upside down isnt much of an issue(other than the heat shield). Some older cats though have a flow direction. Almost all the new cats are universal installation and flow direction is un-important.

No. This is not the case. If the electronic control system is in good shape you will be fine. Corroded connectors or bad sensors can cause problems, but an overbore is not an issue.

This is normal. That black rubber with the metal wire is a seal on either side. You see the middle with the hole that is threaded? Thread a slide hammer into it and pull it out straight up. Its hard to find a slide hammer with the correct thread pitch so you will have to rig an adapter more than likely, but this is how I do it. It being tight is a good deal and prevents leaks. You will need to buy new seals and replace the old ones including the black rubber with the wire on both sides. Putting it back in straight with the new seals is the PITA! Get it cocked and you risk damaging the surface where it seals.