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R50 Engine repair or replace


max
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A few days ago VQ35DE was pulled out from my pathfinder and opened to see the reason - why it is eating oil. And it looks like this engine is not in good condition at all.

 

Mechanic says that there is a significant wear of some parts. (sorry for my English, hope you'll understand it) And we are figuring out what can be done with all of that. It looks like cylinder liners need to be replaced and also cylinders itself (with other related stuff) should be replaced too, crankshaft should be grinded (is it good idea to do this on this engine?) and probably some minor parts should be replaced.

 

So, the question is - is it really possible to find parts for this repair (eg: are repair cylinder liners exists for this engine)? Or will it be easier to purchase whole cylinder block (it is expensive like a hell here)? Or is it better to find used Engine (if yes - where to buy it, how to know if used is in better condition then mine, and eg: can I buy VQ35DE from NISSAN MURANO Z50)?

 

Would be very very appreciated for any info and help or experience from you guys! Thanks in advance.

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http://www.cleggengine.com/nissan-3-5l-vq35de-pathfinder-dohc-24v-01-04-engine-rebuild-kits.html for rebuild kit... There is others i'm sure... If your engine suffered the dreaded valve screws falling in the intake, you cylinder walls might scored and scratch therefore letting the oil pass the rings.

 

I doubt this engine is using cylinder sleeves.. others can chime in to confirm this.. If I were you I would start listing any junkyard for a used engine... I will search a bit for you to see if I can find any web sites listing those...

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fleurys: thank you for all infos. it looks like this engine has iron cylinder sleeves.

 

latest update: measured cylinders and it looks like it is possible to get repair cylinder sleeves, now next question comes up = what pistons are available for that size, needed something to fit near 95.58mm ?

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for the sleeves, I just learned something !

 

Go here : http://www.briancrower.com/makes/nissan/vq35de.shtml and navigate by clicking on the camshaft or pistons, misc, etc... this is all that is available for the vq35de and you will see in the misc section, the darton sleeves are available there...

 

 

hope this helps..

 

S.

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fleurys: there is info about bode size, but part number is related JF or CP.

 

Would be nice to figure out what original Nissan piston grade (1,2,3 or OS=20) are most close to 95.58 bore.

So I know Nissan part numbers:

A2010-4W100 = A2010-4W110, A2010-4W160 - STD GRADE 1

A2010-4W111, A2010-4W161- STD GRADE 2

A2010-4W112, A2010-4W162- STD GRADE 3

A2010-4W170 = A2010-4W171 - OS=0.20

A2010-4W176 - OS=0.20

 

It seems like STD GRADE 1 should be a standard bore 95.5 mm. And OS=0.20 probably is over-sized by 0.20 mm, so probably it is 95.7mm. But what bore is STD Grade 2 and 3? ...

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  • 1 month later...

Just for info. It looks like story almost finished. It took more that 2 month to rebuild engine block: crank shaft and cylinders was grinded, pistons rings and other minor things was replaced. To be completely sure that my engine is 100% ok - need to drive 2k miles in safe mode.

 

Here few pictures:

 

in progress

IMG_0711.JPG

 

assembling

IMG_0733.JPG

 

Now it looks like any r50 under hood, but probably need to be cleaned (will do that after installing snorkel :)).

Edited by max
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Nice. Glad ti worked out good for you.

Have any more pics of the rebuild process? Any learned lessons along the way to pass on?

 

Thanks. No, unfortunately don't have pictures as was very busy during that time. Only stupid lessons was learned like: - don't believe in internet theories and myths, - never postpone repairing.

 

So, still don't have an answer for one question ... How to know engine condition of used car (like when you want to buy it)? Mine was eating oil from the very begining I bought it but it was runing fine all that time (probably except of some power lost), no noticeable smoke, nothing ...

 

Well. Next thing I want to fix is exhaust. Again - no parts available. So, probably will build new one from similar parts, probably will do bigger diameter, but would like make it sound good. Does anyone here know what is the best configuration for r50 exhaust or how to calculate it in right way?

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Id run the exhaust the route the factory runs it, dual to muffler, then single or dual out. Personal preference, I have always liked Magnaflow Mufflers. But not sure what is available to you.

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What a mess! Sorry to hear about you going through that.

 

And as far as exhaust- I have the factory route but with a magnaflow 18" dual in/single out muffler, and resonator delete with stainless tip- love the sound!

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Found local manufacturer of exhaust parts from stainless steel. Looks like it has next configs of muffler: 2 in/1 out, 2 in/2 out, one camera (direct), 3 camera. Probably will chose 2 in/1 out, 3 camera.

 

Other question (how do you guys think): I removed catalytic converters (stuff inside, only box is left), added mechanic lambda separators (only one way to turn off Check Engine light). So, how do you think - will it be OK for engine and lambdas to replace catalytic converters to solid pipes (will drill holes for O2 sensors)?

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  • 1 month later...

After 2k km of driving was found oil leaks under rocker covers. Replaced gaskets and its gone. Then found coolant leak from aluminium pipe that connects two cylinder heads (just fixed that). Cleaned injector. After those fixes some MIL light flashes a few times with random misfire error and swirl valve solenoid. Replaced knock sensor (error was shown). Reassembled intake as those error might be related to air leaks. Now everything is fine (want to believe) but Idle speed is always around 900 rpm, but should be 750 (and it was before repairs). So ... what I found in manual, that Idle Learning procedure exists and I would like to try it, but unable to do that. In manual is described how to do it with CONSULT-II and how do Idle Learning without CONSULT-II. I've tried second method but it looks like it does not react on my action at all.

 

Untitled.png
Does that mean that my accelerator position sensor is not working or I'm doing something wrong? Does somebody did this procedure successfully (or probably tried to enter diagnostic mode playing with accelerator)? (on 2001 SE with VQ35DE, MT)
Or should I check something different to fix Idle problem?
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  • 5 weeks later...

on my 96, i had to adjust the idle air control valve near the rear of the intake, then do an idle relearn. worked fine after that. im not sure about the VQ's because mine is a VG. guess i was no help, sorry =(

Edited by fixinto
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  • 4 months later...
WIN_20140513_135733.JPG

 

Found this guy broken. It sits on steering pump and takes air right after MAF and supplies it directly to intake manifold. It's number is 49762-AA000 (VALVE ASMY AIR).

Our guess is - that this valve used to add RPMs when steering pressure grows (probably important when turning on idle). Can anybody confirm our assumption?

It was sucking air into intake from broken hose connector all the time, so we just closed it, till new part will be delivered.

 

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After 2k km of driving was found oil leaks under rocker covers. Replaced gaskets and its gone. Then found coolant leak from aluminium pipe that connects two cylinder heads (just fixed that).

 

Im curious, were new valve cover gaskets not installed during the rebuild?

 

And for the crossover tube, were new gaskets used aswell? Im curious how it would leak so soon, I heard you cant replace those gaskets without removing the transmission to gain access to the bolts, how did you manage?

 

 

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Yes, all gaskets was replaced to new and for rocker covers I had extra new gaskets that was used last time for fix oil leak problem. Probably it leaks as first time gaskets was not aligned or tightened correctly.

Not sure about crossover tube, as mechanic did that job without me, but believe that is does not require to remove transmission to access it - as job was done in one day. Only I know for sure that coolant leak happen because it is a aluminium tube that is rigid and does not allow to compensate (by metal flexibility) some small offset between heads that comes after rebuild.

 

 

Now I had problems with Idle and error P1130 (SWIRL CONTROL VALVE CONTROL SOLENOID VALVE). Manual says that one of the possible cause might be Intake system (Intake air leaks). And today we found that broken valve on steering pump that was causing air leaks in intake. So will see if this error will comes again, but Idle is still not stable (sometimes 750, sometime between 800 and 1000). That makes me think that there are another problem, probably with air leaks in intake manifold. So, I;m waiting for ordered gaskets for intake to open it and see what is there.

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I'm not familiar with the VQ motor, so I can't answer your question, but you might be able to look it up in the Factory Service Manual. Go here to download your own copy. ;)

http://www.nicoclub.com/FSM/Pathfinder/

 

B

 

Seems you already have a copy. That is what I get for walking away mid-post... :doh:

Edited by Precise1
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The rear crossover tube can be removed if you drop the engine about three inches and tilt it back. the factory studs make the clearance a bear. That's how I did it under warranty. The problem that the factory had when they leaked was they would torque the crossover tube first and then the heads. Ultimately causing a twisting effect on the tube causing it not to seat properly. Eventually the gaskets leak. On the swirl valve code-make sure the lines are not plugged or crossed from the solenoid to the sensor and vent. The problem the factory had with that code is when they assembled the hoses with lube it would dry up and clogged the vent side of the solenoid. The ecm does not know that. All it knows is the system is not working properly. On the VQ35 engine as a whole is a great motor as long as the oil is changed. Once the rings collapse due to lack of lubrication it's done. I put three engines in a clients 350Z before the factory said no mas. The Murano's use the same engine and get the same results.

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  • 3 months later...

Replaced solenoid to new one. Still having P1130. Checked +12V - OK. Could not check ECU signal line as manual says that it is grey wire 29-pin on ECU plug, but in my case 29-pin is empty ... magic, so I assume that signal line is OK. Tubes are not clogged (at least those are connected directly to solenoid). So, will continue to check other places where vacuum leak might be.

 

Also it is weird thing happening with RPM when there is no load on engine and I'm pressing accel pedal ... I thought that RPM must grow smoothly as I press accel pedal, but in fact after 1500 RPM it begins to jump to ~1750 and returns back to 1500. After I continue to press pedal it continues to jump but from higher RPM to ~1750 (line from 1600 to ~1750, from 1700 to ~1750), but period of jump increases. After pressing accel pedal more - RPM normalizes but it is happening only like after ~2500 (hard to say exactly). This happening only on hot engine (cold does not have this effect). Also, Idle is almost OK (sometimes little higher that should be, but always constant). Also, it is not very comfortable to drive on low RPM on first gear :)

Probably someone knows - where to look to fix this?

I think it might be connected with P1130 as ECU takes signals from throttle pos sensor, engine speed sensors, coolant temp sensor, MAF sensor. Probably one of those sensors telling wrong voltage to ECU and it has influence on P1130 detection and RPM jumps. Or accel pedal should be calibrated (but it is mechanical ...).

Would be great to read you ideas - what it might be.

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  • 2 weeks later...

No, didn't check TPS. Read in manual about idle learn, but did not have chance to do this procedure as I could not enter idle learning mode by pressing acceleration pedal, probably because it is not electronic.

 

But today I found something. It is vacuum hose squeezed, broken and disconnected. It goes from swirl control valve solenoid or vacuum tank to somewhere under intake or near it. So, it is not accessible without dissembling intake. Fortunately I have all gaskets for intake and will do this job on the weekend or next week. Will see - if it fix P1130 (should do) and RPM problems.

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UPD: I closed that disconnected hose (that is temporary, we will connect it on a weekend). And after I closed it - P1130 went away. Probably I'm not right, but I think - when this hose was open swirl valves was always closed, and now when I closed hose - swirl valves are always open. It also feels like engine have more power now. Actually I'm curious what do you guys think - can driving with swirl valves always closed be a reason of engine eating oil? Like on higher RPM it is not enough air going to cylinders and pressure in cylinders grows too much and it sucks oil in to cylinders ... Asking, because it is eating line 0.5l per 2k km. Will see results later after fixing swirl valves problem, but it is interesting side effect if it is true.

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Eating oil? hmm no oil in coolant? No obvious oil leaks? If not to those. Pull your plugs, if your bleeding oil past the rings, then they will be black and oily. Exhaust will also have a blue tint smoke to it. After that, check your PCV valve. Rest of it, not familiar with the 3.5. But wish I was, sorry.

 

BTW, Be safe over there. From what we get on the news here on the Ukraine. Its not so good over there.

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