Low compression...thoughts?

[nissanman04]

So I tried to start my S14 the other day. It cranked, but it wouldn't fire. I thought this was weird, since I experienced no problems the last time I drove it. It had only been sitting for two days, maybe not even. I pulled the spark plugs today, they all smelled like fuel. I cranked it over and saw that I had spark, too. So now that I know I have fuel and spark, the only thing that could be causing the issue would be low compression/timing issue. I did a cold compression test (yeah, not the most accurate, but if I could do a warm compressions test, I wouldn't be making this post) and I got 70, 60, 80 and 140 psi from cylinders 1-4 respectively. I thought maybe the gauge wasn't sealing right, but I tested two cylinders on my S13 and got about 185 psi for both. Could I possibly have jumped a tooth on the timing chain? I have no signs of head gasket leakage, and it seems weird for the rings to be fine one day and be that bad the next day. Any thoughts?

[airman86]

pour a little bit of oil into each cylinder and run the compression test again. if the compression doesn't change, then you either have a borked head gasket or bent valves. if the compression ratio gets a lot better (probably 120 or 130+) you're probably looking at rebuilding it because that shows your rings are bad.
Modified by airman86 at 8:23 PM 4/2/2009

[nissanman04]

pour a little bit of oil into each cylinder and run the compression test again. if the compression doesn't change, then you either have a borked head gasket or bent valves. if the compression ratio gets a lot better (probably 120 or 130+) you're probably looking at rebuilding it because that shows your rings are bad.

Thanks...that was my plan for the weekend

[ZOMG.SR20]

try a leakdown test it saved me alot of headache

[carkook]

Thanks...that was my plan for the weekend

Yeah sounds like your educated enough to figure out what went wrong, anything im going to tell im sure you have already thought about and planned to do. But anyway, heres my thoughts, since cylinder #4 did get such a higher compression, I doubt the cam timing was off. My guess is that it got hot with out you knowing and blew the headgasket/warped the head.

[sebazztard]

i blew a fuel pump relay and had no idea till i tried to start my car the next day and all it did was turn over. check your fuses and relays under the hood, use a test lamp. hope its something simple.

[pearl1996zenki]

CHECK FUSES, BATTERY, DISTRIBUTOR TIMEING. JUST TRYING TO HELP

[asoomal]

CHECK FUSES, BATTERY, DISTRIBUTOR TIMEING. JUST TRYING TO HELP

No you're not, you're just trying to get your 10 posts.

[nissanman04]

So I finally got around to investigating the cause of the problem. I did a leakdown test and the air was obviously escaping through the valves. OK, so something had to go wrong with the timing somehow. I pull the valve cover and at TDC, the cams looked a bit more advanced than they should, but there was nothing out of the ordinary with the upper chain assembly. I took off the upper timing cover, and I believe I have found the problem:



It seems that the lower chain jumped a tooth or two. I plan on pulling the engine (easier access, and this car is not my DD anymore) to see how much damage there was. Hopefully I can just replace the timing chain components and be all set. If I bent valves, I'll be looking for another engine.

[carkook]

Its a constant game of pistons chasing valves, hopefully none were bent. Keep updating interested in seeing. At least theres hard evedince on your car like that timing issue. A collapsed lifter ended up causing one of the exhuast valve seats to be damagaed, took forever to figure that one out.

[S13xCrazy]

If I bent valves, I'll be looking for another engine.

Don't be a pansy a**.I just got done rebuilding my head literally 5 minutes ago.It's easy as hell, and if you really want I can do a writeup on it.

[carkook]

Just fine another head and slap that baby on there!

[dreek96max]

whatsup s13crazy do you mind doin a write up on the head rebuild...I tried to add you as a friend but dont see how

[PyR0NiAk]

whatsup s13crazy do you mind doin a write up on the head rebuild...I tried to add you as a friend but dont see how

This thread is from 2 years ago... I doubt he'll even look at this thread

Try this, though: http://www.nicoclub.com/FSM/240sx

[OutToWinPAHC]

pic not working, but my guess is tension stopped working correctly and you made spaghetti

[dreek96max]

Thanks....can anyone tell me how to add friends and send pm's on here?