Krannick

i've just tested the compression of my engine (vq30)

-1- -2- -3-
-4- -5- -6-

1=162
2=175
3=125
4=124
5=122
6=119

in spark plug holes 1 and 2, there was a LOT of oil....could someone tell me what i can do except replace the engine, and what are the "normal" compression numbers

and, by the way, the engine got 263 000+km on it

mtrai760

iTrader: (19)

Rebuild time, cost depends on where you are losing compression from, but tear down and machine shop cost add up FAST. Would likely be cheaper to just replace the engine, VQ30's are dirt cheap.

200kMax

f that idea. drive it till it dies then vq35 swap..

f550maranello2

iTrader: (2)

werd minimum pressure per cylinder is 145 and 185 is standard... get rid of it..

MaximaSE96

iTrader: (8)

time for a swap 3-6 are on the low side....and there is too much difference between different cylinders and SWAP IT.....if u dont care about speed and love ur max....find a vq30 real cheap

Krannick

something weird about it...starts and runs real good, pulls hard.....but ...yesterday, a sentra se-r passed me in acceleration from 0-80 mph....about 1 car lenght in front of me....it sucks

sky jumper

you say 1 and 2 (going by the way you #'d them) have oil in the plug tubes - those are also the cylinders with highest compression. this tells me oil likely got into those chambers when you pulled the plugs to attach the comp gauge, and that oil helped the rings seal, and hence gave you a higher compression reading on those cylinders. classic test for sticky rings.

what this means is your rings are prolly sticking on all cylinders, giving you the low compression. an engine cleaner called Auto-RX will help solve this problem. go look up auto-rx.com. you will need two treatments. will cost about $40 or so plus 4 oil changes. you should also have the back plug tube seals replaced to stop oil from filling your #1 and #2 tubes. this will cost much more than $40. while your mechanic has the back valve cover off take some pics and post them on bobistheoilguy.com.. those guys love that stuff.

your VQ prolly has a lot of life in it. don't trash it just yet! get on a good engine cleansing regimen and drive it another 100k.

Krannick

a mechanic told me to change my rear valve cover seal, and get an engine flush...gonna try that today, and a contact of mine just got some cars back from the DoJ , and, among them, a 1997 black max se 5spd, with just 20k on it....i'm gonna go give it a test run to see the difference with mine

sky jumper

ok, a few words of caution... be very careful with those 5 minute engine flushes. they are strong, and will quickly dislodge years of sludge and buildup that can break free and block oil passages and starve your engine of oil. and they are hard on your bearings and seals. plus they will probably not fix the compression - to do that you have to clean the rings and their respective grooves, which are baked on harder than sludge, and have relatively light contact with flowing oil, so they will not get clean with one 5 minute flush. the flush is good for other things, but it takes time to clean rings, which means a mild cleanser over many thousands of miles. you can always do one or two quick flushes and then recheck your compression.

also - with the rear valve cover seal - make sure the also replace the plug tube seals, not just the cover gasket. don't assume they know the difference.

Krannick

flush done.....average psi +/- 120 across all 6.....in fact, i lost 5-8 per cylinder...and i was careful to remove any oil in plug hole before removing the 2 "wet" ones.....

sooo.....3.0 or 3.5 swap for later in the summer....

sky jumper

swap if you want, but you are wasting your money. I told you a 5 minute flush would not fix your compression. and you didn't lose 5lbs per cylinder either. gauge innacuracy, temperature, and # of cranks will give you more variance than that. did you have all 6 plugs removed, and the fuel injector and fuel pump fuses pulled? any unburned gas in the chamber will also make a difference.

try this - squirt some oil in a cylinder and then re-check compression on that cylinder, cranking at least 5 times. it will go up by 50lbs or more. sticky rings are not the death of an engine. but its your time and money. good luck.

Krannick

adding oil upped it to 165+

is there an alternative product to your auto-rx???, i'm not the kind of people who buys online, and i'm in canada....products found at wall-mart, carquest, canadian tire, etc....can you suggest something worth buying from that kind of places??

and thz for all the help :P

sky jumper

the only thing I can think of is to just run straight Redline 5W30 synthetic oil. Redline is a Group V synthetic ester, and esters will slowly clean gunk out of your engine. in fact Auto-Rx is a lanolin ester. however -- I have no experience using Redline oil, and cannot vouch for its ability to clean ring packs, which is what you need. this might be a good question to ask over at bobistheoilguy.com. in any case, just don't expect an overnight quick fix. it will take some time.

Krannick

i've put this in this morning....now well have to wait and see....

another question....how much a pain in the a.. is it to replace the check engine light?

mtrai760

iTrader: (19)

Did your light bulb burn out? You just have to remove the gauge cluster and it pops out in the back.

f550maranello2

iTrader: (2)

is it burning oil? if it is its new engine time... period you cant fix busted rings or worn valves....

Motorhead52

Replacing that light isnt a big deal, just undo the screws and pull out that panel where yours kneeds are, then remove all the plastic around the steering column (~6 screws), then remove the black trim around the instrument cluster (2 screws on top plus clips), then 3 more screws to pull the cluster out. Just be careful you dont snap anything trying to wrestle stuff out.

Krannick

it doesnt burn any oil, and the light was changed in under 10 minutes :P

I used the remaining time left in my schedule to re-wire my fog relay to a bumper light +12v

there were 6 cel codes....and 5/6 related to my compression testing...the last one is the infamous knock sensor......since my compression is so low...i will start using 87 octane instead of 91, and leave the knock sensor as it is...i shouldn't change anything, right?