VQ35DE in S13 in progress.....

[myS13wantsaVQ35]

As of right now most of my gauges are not working, the ones that I really need to work are the speedometer and oil pressure. My temp gauge and tach are working.

[s13andrew]

ok im sold vq it isdamn fine work sirmy s13 coupe will be getting z power

[SpecDRacing]

So more on the piston to head issue.

The only noise coming from my engine comes durring cold idle, and only from #3 cylander. I do think this is piston tap, that is a very real possibility. Im anxious to put the bore scope in and see what I can. Untill then though, I am really not that worried about it. Anyone who is building this though should clearance the pistons.

I may have gotten lucky here, but if I did, here's the reasons for it.

My reasons:

One, clearancing the pistons will give you the gap you need without sacrificing any of the compression gains for using these pistons. Installing a thicker headgasket, even 0.015 thicker will drop compression a tiny bit.

Two, Dont follow the "loose engine" theory of building performance engines if your cylander pressures aren't requiring it. This engine will not produce those pressures. This is only neccesary if you plan to boost/nitrous the engine and are using forged pistons that are specific for high output. Most manufacturer pistons that are forged are not as prone to expansion and contraction as race pistons. Todays engines (especially imports) have very tight tolerances compared to older engines and domestics. There is a reason for this, efficiency. When I built my engine, I made sure that if I was using a #2 piston, that my bore had the correct clearance for that piston. When building any engine with extremely high cylander pressures (not this one) you do need to account for heat expansion. One thing to remember though, when building an engine that is open deck is that the sleeve will eventually increase in diameter as well as the piston. Not as much, but it will, so using the "loose" ideals are a bit extreme....and again, I'm speaking of a street engine, not a 600HP+ monster.

Three, Piston selection is crucial. I have gotten emails from many people who have ordered pistons from Nissan without having taken the engine apart. This is wrong and will result in damage. There are 5 sizes available 0,1,2,3 and 4. If your engine has a 2 in Cyl #1, a 3 in Cyl #2 and a 1 in Cyl#3, you need to use that size again, unless you have it honed to the extent that enough metal was removed to do up a size (which is alot). Normaly with VQ's, just a good round with the dingleberries will take the glaze off and be ready to roll again. I have not had to have a sleeve bored over yet for any reason. Bearing selection is also cruicial. While the bottom of #1 may take a brown for the cap and a green for the rod. Dont forget that.

What Trav4011 found out is great! The area where its clean on the piston does look as if it has made contact, but not enough to damage the casting. I'd be interested to see what the head looks like. The HR pistons have a shorter skirt since they were designed for an engine with a longer bore (120mm). This reduces the pin ratio therefore reducing the rotating force that rocks the piston in the bore. Down side is, these pistons are being used in a block that is only 100mm, adding several degrees to the wrist pin movement. Add that to the small amount of piston that exits the block and into the head gasket area and you get the ability of the piston to rock. Every piston arrives at TDC slightly angled, no matter what engine. That was what I was worried about when I first started this engine. I was sure it would pop since I had so little clearance. I built my engine as close to minum clearance as I could to reduce the chance of this.....apparently its only a short time thing. But then again, High comrpession engines aren't meant to last long.

When the Sentra is finished and I can finaly pull this engine apart, I will post pics for everyone, including the final pics of the pistons being milled.

Everyone, this is really good input, what Trav4011 took the time to do is more than most people and he has potentially saved you all a bunch of money! Thumbs up man! Keep us posted with any progress you have on your builds.

[s13_350sx]

hey i was thinking, instead of rigging up the potentiometer sensors to keep this thing out of fail safe, why cant you just hook the etc motor relay to ignition power instead of the ecm controlled power wire? this would basically bypass fail safe mode since the ecm would no longer control the throttle power. the reason i am asking is cause i have not hooked up my potentiometers yet but i wanted to rev it up so i jumped the etc relay to power. it ran fine.

[SpecDRacing]

The potentiometers have nothing to do with the ETC relay. They are for SENSOR POWER SUPPLY. The ECM has a built in voltage limiter for these sensors. It takes the source voltage (battery or alternator) and controls it to a constant 5 volt signal. This is sent to each sensor and monitored via a voltage drop test inside the ECM. It's looking to see these sensors are operational. Trust me, the way I have this wired is a safe way to get things working. It has worked on every car I have wired, and will not fail unless something is broken or hooked up wrong. I hope we can find some new tricks to this ECM, but this is the best way I know to keep that particular code from popping up.

On the relay, you are saying you bypassed the coil and hooked ignition straight to the thottle. If so, there will be a code stored for ETC Relay in the ECM. This can cause fail safe. If you can start your car twice, and it rev above 2500 rpm both times (consecutively), then you are ok. This one is weird, on some cars, it will cause fail safe every time, while others it only happens one out of 10 times. Remember what I said about the Sensor Power Supply code and how the ECM is watching the voltage drop on those circuits at all times.....well, the same goes for the throttle motor....except there are about 5 different codes for it, not just one. Any of which will lead to fail safe. Again, if you can start this car over and over and it not go into fail safe, then you should be ok, but if it goes into fail safe, think about where you could have been when it happened (long road trip, late night at the club, etc.).

I'd still hook up the relay. Not to mention, if something gets fried, the ECM will shut it off and keep all the juice from burning up the throttle motor too.

Good research! Keep finding new ways, maybe one day this will be less of a wiring project!

[s13_350sx]

yep. i looked in asist and your right. also i found that it only started 2 times normally like that then 3rd trip it went into fail safe mode. i test drove it and it was a blast!!! now i jut have to hook up the potentiometer for evap . my potentiometer for the refrigerent ps is working ok but the psp one is not for some reason it has power source and ground and no matter what voltage i set it at it will not get rid of the p0550 code. any ideas? yes it has continuity from sensor to ecm with no shorts to power and ground and the potentiometer is operating correctly but cant get rid of p0550.

[SpecDRacing]

Ah, you have found P0550.....but it causes fail safe....yet the car will still run. Another little secret of mine I forgot to tell everyone. You will have that because the ECM is looking for variations in the signal. The Refrigerant sensor can stay at one voltage due to inactivity of the A/C system (just not turned on) and the Evap sensor can stay at one voltage because of a P045*, because any number of problems could exist with the evap system, but the P/S sensor should have a voltage change on start up. From no pressure (key on engine off) to pressure (idle), and that is what the ECM is looking for. The up side is that this is a P/S sensor operation code for rationality, not normality. The sensor power supply code is a normality code only, meaning as long as the sensors are plugged in, that code will not arise, therefore keeping you out of fail safe. Like I said, we use codes to interupt the ECM logic, in order to effectively stall it's processes, to keep the "bad" codes from popping up.

You'll never get rid of it, and that's exactly what you want! Good going!!!!! Post up a video, lets see it! Glad to see another one running!

[s13_350sx]

ok so i got all that potentiometer stuff taken care of. i used a g35 sedan drive shaft and a shop made me a new one for about 100 dollars, not bad. all i have to do is hide the ecm, bcm, and finish the hood scoop. i will post a video soon. ive been driving it all day and at first it was overheating badly and overflowing coolant but i put a new radiator cap on it and its perfect now! 195-203*f. it runs smooth and has a lot of power. so far i have an aftermarket gauge cluster with temp, volts, and oil psi and i have the stock fuel gauge. soon to have stock tach and speedo via dakota digital convertors. got a couple exhaust rattles to fix and a bad exhaust leak from my custom driver side manifold. the only issue i have now is that my ecm is sending the proper ground signal to the etc relay but its not a strong enough ground to switch the relay on, i had to wire a toggle switch to ground in conjunction the the ecm wire to the relay and when i start the car i have to key on, flip the switch, then start the engine. this seems to be the only way i can trick the ecm into thinking that its controling the relay with out going into fail safe from p2100 low voltage detected, or p2103 relay stuck on. when the ecm see's ign on signal it turns on the throttle relay, this is what im immitating with the switch to groung since the ecm cant do it on its own. i thought this failure was just poor ecm grounds but i re-routed all the ecm grounds to about 6 different locations. not sure what the issue is, if you guys got any ideas let me know but for now i just assume that that circuit in the ecm is just bad. ill post a vid soon!

[SpecDRacing]

It does sound like a bad ground circuit in the ECM. I'm sure you already know this, but I have to say it, scrape the paint off of the metal to get a good ground contact. Also, poor grounding could be caused by a poor source voltage to the relay. Make sure the power to the relay is strong as well.

One more thing, if your battery is weak, you will get that code. If the voltage is only 10 volts or less with everything off, the battery itself will cause alot of codes.

Sounds more like you have voltage signal wire. Did you do a voltage drop test on it? Try measuing the voltage from the signal wire (at the relay) to ground with the KOEO, and again at the ECM. You should see 0v everywhere on that wire. If you see any more that 0.5V, you need to clean your connections and if its up to 0.8v or more, you have feed back on that wire. Could be from the ECM or something else...but I think you said earlier that you had already checked all that.

Let me know what you find.

[myS13wantsaVQ35]

speedometer? that is what I really would like to work

[decherdtech]

I'm in the progress of rebuilding my vq35de and you are the only person so far that I've been able to find that has done this before. I'm hoping you can help me. I'm having trouble ordering my main bearings. The dealership says that they don't have a chart to tell them which bearings I need and are wanting to give me a "standard" bearing that they don't even know the thickness of. My block grade is LPNL and the crank grade is TJLN but they say the grades should be #s. I know this is'nt true because I work for NIssan manufacturing in the crank machining department. At work when assembling the engine you input the crank grade and the block grade and it gives you a color because all the bearings are color coded. The dealership laughed at me about the color coding and said they had never heard of any such thing. Do you know of the chart I need? Any help would be appreciatsd. Thanks.

[SpecDRacing]

DECHERDTECH - - -

YES, they are color coded, and any parts man that does not know that is an idiot (you can tell him I said that). You need to look at a service manual. Make sure its for the car the engine came from. I don't think there was any manufacturing differences between the bearings for the VQ's, but colors may have changed over the years (doubtful). More than likely, you'll have different colors for the block and caps. You have the correct information from your block. Next you will need to find the service manual and look up under engine overhaul for the bearing selection chart. It will tell you to cross the letters on the block with the letters on the crank with a chart. That chart will give you your colors.

Hope this helps!

[SpecDRacing]

A new developement on the PISTON SITUATION. I took a plug out and used a boroscope the other day....guess what.....NO PISTON DAMAGE. I did this after rebuilding an MR20DE engine (thats a new sentra engine) at work, that had heavy ring blow by. What did I find inside the 2.0L that made me want to look further......well, I found that the pistons in the MR20DE looked EXACTLY like TRAV4011's pics of his pistons. So does that mean that all factory built MR20DE's are hitting the head? No, what it means is that the quench area is so small on the sides, that the carbon does not stick due to higher pressures and heat. I dont know what cuased his engine to cease, and I will not make any attempts to guess at what happened. For safety sake though, I do still agree with his shaving the pistons .010" even though it might not be necessary (I havent yet). There may be a combination that will cause damage so make sure of this:

WITH ANY HIGH COMPRESSION ENGINE, make sure to use puddy to check clearance to the head. If its too small, it may hit under high rpms or excessive cylander temperature situations.

Again, I still agree with TRAV4011 about clearancing the pistons...I just haven't had to yet.

[myS13wantsaVQ35]

so any help with my gauges?

[SullivanRacing06]

lol yea never take a car to a shop in tampa! yo wtf was it really worth all the tim en hastle swappin in that v6 when you coulda had a rb20 or 25 in in under a couple of hours?





and the wiring rubbign on your wheel, thats your fault man, u should double check everythign the "shop" dose, ive never taken any of my cars to a "shop" to have any work done, all of my work is done is house

[keith0486]

wow some 1's cocky.

[myS13wantsaVQ35]

dude the rubbing happened while they had the car at the shop, how is that my fault?

[SullivanRacing06]

oh sporry didnt knwo the shop did that, damm man, they gonna fix it? thats really shady of them! sorry yall im currently gettin screwed on a rbnew rb25 transmission and im a lil pissed, sorry if i sound pissed or act like a as$ but im really stressed, hope they fix it!

[myS13wantsaVQ35]

no love lost! they patched it so I could make it home. I already fixed it myself.

[SullivanRacing06]

so what shop gave u ur car back with that bare wiring? did they notice it or did you? dam man, that really would suck to get your baby back from the shop and it be messed up

[SpecDRacing]

You pick on someone who had no control of a situation. You mock him for being different and trying something new (rather than follow the herd). The RB series engine is strong, and can be very powerful, but was also out of production prior to the VQ35 start up. This means all the parts for it are no longer in production, that NISSAN themselves found it inferior to use in modern day cars. It's very heavy (200 lbs heavier) and has a bad tendency to blow head gaskets. To make 300 HP, that engine required a turbo, the VQ does not.

Shall I go on. Well, as the creator of this forum, I am here to help those who are willing to help themselves do something they love to do. Build cars. If you need help with your RB, I would be happy to offer my services (of which are probably more expansive than yours). I only mock you for comming onto a thread that, so far, has been nothing but positive conversation for a bunch of people who have a CAN DO attitude and wont let the easy road look so appealing.

So, unless you plan to be of assistance, in either technical or moral support, stay on your easy road as long and leave the harder path for us to pave (so that one day it may be easy enough for you to conqour).

To everyone else on this thread. I'm still here. I appologize that I can't be on here enough and I hate to see that someone would deliberately sink so low as to mock another person. I assume this is only because he has not gained enough recognition for his own vehicle. I think RB's are cool, but I also think the MR20DE is cool. So lets get back to the real issue here and lets all help each other build something different.

Later all.
Modified by SpecDRacing at 9:32 AM 12/24/2008

[SullivanRacing06]

true, sorry man, didnt mean to piss ya off, just thought you drove your car away from the shop w the wiring like that, thats why i said it was your fault, sorry didnt read enough, nice swap. ive got a 3 layer metal h/g on my rb, so thank god no h/g popping for me!

[myS13wantsaVQ35]

I noticed it when I drove 14 hours to pick up my car and it would not make it across the street to put some gas in my car. I had to stay an extra night in tampa so they could finish my car, which by the way was over 3 weeks late getting done.

[fireslave]

this swap is awesome. I think im going to try it myself soon. The wiring still scares the crap outta me, but atleast I know it's doable.

sweet 240.

[SpecDRacing]

That's cool. I really do like the RB engine. The ability to swap so many components from so many cars makes it more verastile than a honda. Good move on the head gasket too. You should be good to the 800HP range with that, as long as the internals are up to it. We assembled a few that peaked over 1000hp (not for long, but hey, they did! LOL) Post up a link to a few pics. I might bite back hard sometimes, but its all water under the bridge, and we really do want to see pics! Thanks for seeing my point and I'm glad we smoothed it over.

[s13_350sx]

Hey guys its been a while but im back. Wow it looks like the flaming has started! hopefully this thread wont go to hell like the others. anyway, ive been driving mine for a couple weeks now with no problems and man is it a blast! still no tach or speedo yet but when i do that stuff i will share my experiences with you all. my throttle control relay ground problem did turn out to be the ecm so for now i have a toggle switch so i can ground the relay manually after key on since the ecm cant do it. i seem to remember accidently crossing a couple wires while hooking up that relay. i think thats what took out that circuit in the ecm. i still have not had access to a video camera so you guys can see it but im working on that and hopefully i can have it up on here soon. i ended up going with a racers edge 255lph fuel pump with an ebay regualtor. i have high air flow alpha readings when its at 51psi but i dont have any vacuum leaks so i have it turned up to about 61psi and it seems to run great! i also made a cowl hood using my stock hood and a center cut of an 07 altima hood for the cowl which i am currently molding in with fiberglass. there are some nice projects on this thread! keep them coming! later people.

[irax]

thought about hooking up a Dakota Digital to an abs sensor for speedo and modifying your tach for 6cyl? or you can get a Dakota Digital converter for that too.

[RideNslidE]

hey spec d ive read this whole thread about 3 times and there a few things left to mystery like the wiring from the ecm to bcm ( it looks like the dash harness) and integration of some of the existing systems on the 240. believe me im not putting you down or anything i love the work you've done and its a true inspiration. my real question is are you ever going to do a "write up" or could you please clear up some confusion for the wiring connections needed to integrate the electrical systems in the 240 to the engine and dash harness from the 350. i have a service manual for both cars but its on my computer and kind of hard to decipher .... also did you utilize the ipdm if not how did you bypass the starter / ignition / throttle control motor relays.

sorry for this being so jumbled i just bought a 05 350z eng, trans, ecm, bcm, eng harness. so i need the dash harness, petal assembly,maf sensor, nats equipment (key, amp) and obviously mounts / drive shaft. please inform me of anything else that im missing besides all of the know how.

im just a working guy and don't have enough know how to do it on my own and don't have the money for someone else to do it for me

[sbird1]

Hey Mark, I'm mad at myself. I was in the Charlotte area a few days ago visiting my girlfriends parents. I wish I would have thought to drop you a line. It's ok. next time! I got tired of reading, but I hope your piston slap issue got resolved.

[g35paul]

i recently just blew my motor in my s/c g35 and its now getting a fresh motor,so im going to have a spare vq and im going to be throwing it in my s13.... i was wondering why u guys go with a fwd vq motor, they r not the same as what ive been told by sharif at forged.... just wondering