MarcL

Took the car to the track for the first time since installing the SC, and by the time I got to the end of the track it was blowing oil.

This is VQ35 from a 2002 Maxima, running with the 1995 JWT ECU (555 injectors, with Z32 MAF). I was only getting about 6 lbs of boost, so this mishap has me puzzled.

It is what it is, now I have to decide what to do.

Get another junkyard VQ35 and swap it?
Rebuild this one with some better parts?

I am looking for advice/suggestions/cost estimates from others who have been down this road.

Thanks

Specd_out

What do you mean by blowing oil?

perkman87

iTrader: (6)

prob blue smoke.

K-Ryder

iTrader: (1)

You sure it isnt burning oil...Didnt that year engine have oil burning issues. Why not get an 04 engine.

MarcL

Smoke pouring out of the crank case... I have a breather filter on the PCV ports, that is where the smoke is coming from.

Specd_out

Hmm cant say I have ever heard of smoke coming out of there. I have my pcv system drilled out on my sentra, and it smells, and on cold days you can kinda see a vapor. but thats it.

K-Ryder

iTrader: (1)

It could be that you need a new valve cover or it could be a bad piston ring

MarcL

Considering it happened going down the track, I am thinking a cracked ring too... But, I thought this setup would be "safe"? I read about others running 10+ LBS of boost on otherwise "stock" engines.

Sure, I can open the thing up and replace the ring.. But, I don't want to have this issue again!

maxgtr2000

iTrader: (29)

Fixed. If you open it up replace the rods too but you may see some other damage due to the stroke of the vq35. I'm doing some research to find out if the "violent piston stroke" theory is true because some people have never had problems with the 3.5 but I'm always reading about the ones that do when they go F.I. N/A not as many problems. I'm just theorizing.

MarcL

Any specific suggestions for rebuilding this engine to avoid this problem in the future?

Nealoc187

iTrader: (23)

6psi SC on a VQ35 is perfectly safe assuming you don't have some radically incompetent tune in there. symptoms (though fairly poorly described) sound like cracked ring land to me possible, but you surely didn't do it from power. either some problem with a supremely poor tune or some other issue (if cracked ring land is indeed your problem). VQ35s are completely safe in my book up to about 450whp with a good tune. you're not making anywhere close to that kind of power with a 6psi SC setup, so that's not the problem.

MarcL

Maybe this was just the straw that broke the camel's back? The initial tune from JWT was lean, they re-did the map for me and the AFR usually shows rich when I am under boost. Possible I damaged something before, and this beating on the track sent it over the edge?

I have almost 2K miles on the car since installing the SC, most of that was with the "rich" map.


So, what I am getting from this is (your opinion) my easiest/cost effective fix would be to get a new junkyard block and start over? Is it worth while to replace the bad ring(s)? Or is it likely I have damaged the sleeve too?

Looks like junkyard VQ35 engines are in the $1000 price range. Significantly more than I paid for this block back in 2005, but it is what it is...

Is it worth while to go with a VQ37 block instead?? I'd have to drill the cams again (I am assuming VQ37 cams are not the same), but other than that I am hoping it would be the same "conversion" to move the VQ30 timing stuff, and lower engine housing to a VQ37 as it would be a VQ35?

Thanks.

TurboA32

iTrader: (36)

yea you probably fried one of the rings so jus put a solid proven vq30de in and you would be safe with extra money in your pocket

Deckdout2

iTrader: (151)

Here you go. I have one for you for a good price!

http://forums.maxima.org/5th-generat...ood-price.html

MarcL

Saw that.. NC is a little far for me to go for a high-mileage engine.

I am looking to save money, but after all that I have in to this already I would not feel comfortable bolting all of this up to such a tired engine. It is a good price for someone looking to get an old car running though!

streetzlegend

iTrader: (8)

1k for a 3.5, no day dude. I bought my original 3.5 for 500 bones in hialeah. Anyway, your symptom sounds like rings, my VQ30 would smoke ALOT. I would come to a stop sign and cover the entire front of the car with smoke. However when I got on the gas the thing would still hawl ***. Mine was probably due to bad tunning, when I was spraying.

The JWT ecu you have is for boosted application or NA? Might have had too much timing and was knocking this whole time without you knowing or hearing it.

MarcL

I have yet to see any complete running VQ35 for sale anywhere for $500 that has under 100K on it. If you know where to find one, let me know!

The JWT ECU I have was set up specifically for my configuration. I ran it with the laptop hooked up, and had them fine-tune it further (it was running lean initially).

New bit of information; I started the car up to move it tonight and the smoke did not start coming out for about 30-45 seconds. I got excited that maybe I misread the symptoms, but the smoke started to come out.. I also noticed that it now seems to be leaking antifreeze. Got me to thinking, maybe the water pump sprung a leak and what I am seeing is steam and not smoke?? I did check the oil, and saw no water droplets in it... So maybe this is not as likely as I would hope.

Maybe this weekend I will have time to open the thing up and see what is going on.

streetzlegend

iTrader: (8)

How are your coolant temperatures when car is warmed up? What does the smoke smell like? You will definitly tell if its coolant, if its major blowby because of broken ring/lands you will notice a different weird smell not exactly like burning oil but different.

Flava_24/7

iTrader: (46)

You took to the car to JWT and they tuned the ECU with your laptop? Did the laptop have an OBD adapter or something?
Just curious on how it was done.

MarcL

No, I never been to their shop. They sent me a map, and I ran the car and collected data on the laptop. After they analyzed the data, they sent me a new map.

streetzlegend

iTrader: (8)

How is it than JWT can flash or change the roms on our ECU but no one else has done that? Do they have special privileges with nissan or some crap?

MarcL

They add a daughter board to the ECU that has a ROM on it with the maps. I assume they modify the ECU somehow to use their ROM instead of the one the stock Nissan ROM. So, they are no flashing the Nissan part.

Flava_24/7

iTrader: (46)

Im well aware of the small daughter board soldered onto the main board, but how are you uploading the new maps and what application did you use to log the data to be sent to them?
This is the first Ive heard about this capability and Im curious on how its being done.

MarcL

I used Blazt to log the data, and they sent me a new chip that I had to physically install.

Flava_24/7

iTrader: (46)

Aaahh....
Interesting, first Ive ever heard of them doing this. How much did they charge you to change the mapping?
Also, does the Blazt monitor and log the AFRs?

streetzlegend

iTrader: (8)

Its logs if its lean or rich per bank but does not give you exact AFR.

Kevlo911

iTrader: (36)

yea since we don't have widebands stock like newer cars, you would have to send them your afr log as well.

MarcL

Blazt lets you log the ECU and WBO2 at the same time. They used that data to reset the maps.

I think they charge $100 to do a new map, but they did not charge me because the initial map did not work properly to begin with.

MarcL

Got to work on the engine today.. Not sure of the cylinder numbers, so this is my reference;

<Back of engine> <Front of engine>

Compression test was;
1- 190
2- 190
3- 190
4- 170
5- 70 (Yes, this is the bad cylinder!)
6- 170

I am wondering why the 4 and 6 are so much lower than 1, 2, and 3. Is it possible the cam on that bank is drilled wrong reducing the compression?

Clearly seeing a problem on #5, I pulled the head off. I found the intake valves to be burnt looking, as well as the top of the piston (on the side near the intake).



Sorry for the crappy cell phone picture, but I thought it would be better than nothing.

I think my next step is to get another VQ35 donor.. I am seeing that the 2007/2008 Maxima is NOT the same as the Altima? So, I want to confirm what engines I can use for the "swap" (using the VQ30 timing/ECU). I can get another 02/03, but they all seem to have higher mileage on them for about the same cost, so why not get something newer (if it will work...).

Next question is, why did this one blow up? Will I just do the same to the next one?

Again, looking for any advice and suggestions.

Thanks.

t6378tp

iTrader: (69)

injector maybe

MarcL

Had the same thought.. I am running brand new 555 injectors from JWT. I think they a NISMO? I guess it is possible I got a bad one, but how likely is that?

maxgtr2000

iTrader: (29)

I heard as long as you are within 15% of the readings you should be fine so the 2 cylinders reading lower may be normal because not all may read exactly the same.

t6378tp

iTrader: (69)

it's not likely but is are my guess

1# you were low on gas hit full boost for a extended but short amount of time the the walbro pump sucked the tank dry, injector #5 flows alittle less than the others leaned out cylinder and burnt everything up

2# got some bad/watered/lower octane gas hit full boost the engine pinged and knocked like crazy burnt everything up

3# high egt's from either a crushed or small exhaust + too much or too little timing and burnt everything up

4# a combo of 1, 2 or 3

TurboA32

iTrader: (36)

facing the engine from left to right cylinders 1,3,5 are in the back and 2,4,6 are in the front so cylinder 4 is bad for you

TurboA32

iTrader: (36)

just do your self a favor..........................VQ30DE

MarcL

OK, convince me...

maxgtr2000

iTrader: (29)

That is almost like going from turbo to na. You get used to the power of the 3.5, but in a sense there is more reliability with the 3.0 imo. I would just rebuild it or get another if possible, because accidents happen.

MarcL

Great, now I just need someone to confirm which engine I should be buying!

I keep reading that the 2008 engine is OK for the swap, but then I read the Altima and Maxima had different versions in 2008. So, which one do I need?

Kevlo911

iTrader: (36)

If you can get a newer engine, why not?

As for the Maxima/Altima 08. When I wanted to do the swap, I wanted the Altima engine since it had updated heads. I figure some things will be different from a regular vq35 swap but since it has the plastic manifold, I think it is worth it. You might have to use the oil pan you have now, I think the newer vq's have different placement for the crank sensor.

MarcL

I am using a Kenetix 350Z intake with the SC setup, so I dont think the plastic intake will do me any good.

To run the VQ30 ECU, I need to change the timing chain/gears/and related components too.. NO? Will they fit on the Altima heads if it is taller (as I have read here)?