Jump to content
HybridZ

It just got even WORSE... AGAIN (compression test done)


Guest bastaad525

Recommended Posts

Guest bastaad525

I'm going crazy here

 

For anyone who missed it, I was going for a drive around the block today when my water pump sprung a really bad leak... temp got REAL hot before I got it home (was only a block away...). Didn't think it was that big a deal after some words of reasoning from these boards calmed me down... bought a new pump from auto zone and had it on in an hour. Went for another ride around the block... car seems okay... get on it a little... and I think I hear a little ping... so I reconnect the TPS (which I had disconnected because the car seems to run better w/o it, but last time I tried this test I thought I heard some ping too... I'm an idiot). Go around the block again, everything seems fine. Go around again, come to a light and suddenly the idle is real lumpy, like a cylinder isnt firing. And there is smoke coming from the exhaust again. It's dark so I can't tell exactly what kind of smoke it is... it's definately not black smoke... looks like the same smoke I had before rebuilding the block, oil smoke, but I"m not sure. Turn the car off... recheck everything I can see... go to start the car, and a very familiar sound comes... that sound, when you're cranking the car over, and one of the cylinders has no compression. I've heard that sound before from when I had a bent valve. I checked the oil but I dont see any signs of water... thought maybe I blew the head gasket from when it overheated. Or from the ping, IF that even was ping. It's a new felpro metal gasket... and I trust the guy who did the rebuild, as far as... did he torque the head down enough and did a good job putting the motor together. So now... I'm really thinking... I just f**ked up those brand new rings. I can't really dig into any more tonite to try to find out what happened... I gotta get ready for work... but I feel it in my gut...

 

please give me some oppinions here guys... ideas? Are new rings more or less likely to be damaged from a split second of detonation? Is a newly installed head gasket more or less likely to blow from overheating? I wasn't exactly gentle on the old rings... this is after it started smoking, after we put the rebuilt head on, and I got on it with the TPS disconnected, and I thought I heard that ping... I got on it quite a few times to confirm what I was hearing or not (I'm still not sure). The smoke didn't get any worse from that or anything, nor did the idle get lumpy, but now just getting on it once with the TPS disconnected and hearing some possible ping coulda screwed them enough to completely lose compression in one or more cylinders?

 

what is the more likely possiblity?

 

why do things keep getting worse? I know that this time it may very well be my fault... but damn...

Link to comment
Share on other sites

Guest bastaad525

guess I'm on my own on this one... I want to clarify that since putting the new rings and bearings in I have been taking it REALLY easy on this engine, rarely letting it get over 3k rpm, never letting it get above 4k. I've been light on the throttle too accept for a few times I have given it maybe 3/4 and a couple times flooring it but for only like a second. I read on a post someone made in my ring break in thread, that short bursts of hard acceleration are actually helpfull in properly breaking the rings, or I'd never have even gone that far. Other than that I've been following the recommended break in procedures pretty well (but I guess that would depend on whos recommendations you subscribe to). Anyways... I can't help that the water pump decided to start leaking and leaking bad at the moment it did.. if that is indeed the cause, which I have little reason to doubt. If it did ping, and that damaged rings, then that is my own fault, for trying a solution to another problem, that maybe I should not have tried... but I only persisted because bridging the TPS connector like that really made a huge difference in how the car would run... sooooo much better...

 

someone please answer me this, if it pinged very briefly, but somehow that was enough to damage one of the new rings, what type of damage and how severe could it be? I'm going to check the spark plugs and do a compression test today, but I can kinda tell from the sound it makes when I crank it over... I fully expect at least one cylinder to have little to no compression... to me, if that is the case, it would make more sense to be the head gasket... and that's because, even though the old rings were definately bad, to be smoking as bad as they were, the cylinders still had decent compression and the engine didn't idle like it was running on five cylinders, the way it did when the valve got bent, and the way it is now. What kind of damage could brief detonation do that would screw up the compression that badly?

Link to comment
Share on other sites

Guest bastaad525

cool... very cool... that eases my mind a little bit, thanks sleeper :)

 

I know nothings definate until I get the head back off and see..... but it still makes me feel better to know that I'm not the only one who thinks that it's unlikely that the block got damaged so easily. I'll definately take the head back to the machine shop... I have little doubt it got warped... damn thing was so hot, when I splashed some water on it when filling up the radiator, the water instantly started to BOIL!!! Just like when you put a pan you've been cooking with in the sink..... siizzzzzzlllleeeeee

 

The odd thing is... I had reconnected the TPS (hence eliminating any possible ping) and had driven the car for some 10-15 minutes more, before the idle got lumpy. I would think if ping had damaged something it would have been more or less instant wouldn't it? But then I guess I could say the same for the head gasket...

 

one more question, if I find that it's definately burning oil again, and not burning coolant... does that mean it's definately rings again or can the head gasket have blown in a way as to leak oil into the cylinders instead of water? I know there's only like two oil passages from block to head right?

Link to comment
Share on other sites

You need to be careful adding water to a radiator like that. Pouring water into something that is that hot can have very bad results (cracked block, cracked head, etc.) :( . Just playing devils advocate here I personally think you blew a head gasket :roll: . Just pull the head and check everything out really good.

Link to comment
Share on other sites

Guest bastaad525

yeah that thought occured to me when I saw the water boiling when it splashed onto the head... I froze for a second and was just waiting to hear a loud POP sound of something cracking... I made quite a few stupid mistakes today :( but at least that one has had no effect (that I've seen as of yet anyways).

 

well that's two guys leaning towards the gasket... So even if it was pinging a bit you guys still think it more likely to be the gasket eh? Heh maybe the overheating just weakened it and then the ping pushed it over the edge... heck I haven't even retorqued the head yet... I wonder if it worked loose?

Link to comment
Share on other sites

Make sure that you check the head surface for trueness when you pull it!

 

My 2c worth....whenever rebuilding a motor, replace the water pump, oil pump, freeze plugs (esp the ones in the front of the engine in a L6), and the timing chain and tentioners. Don't forget to prime the new oil pump.

 

Good luck....you certainly need some at this point.

Tim

Link to comment
Share on other sites

Guest Want aZ

Bastaad,

 

I had the same thing happen once on a straight 6, got hot, blew the head gasket. Was a recently rebuilt engine, I pulled the head and had it machined just to be on the same side. Had it back together that afternoon, along with a new water pump. Everything worked out fine and it only cost me like 4 hours work and a few (relative) bucks.

 

You must think positive though, you are working through your other problem as well. And have it just about solved from the sounds of it.

 

Good Luck,

 

Damon

Link to comment
Share on other sites

Let me add one more thing. You seem extremely concerned about the pinging. The L28ET is a very strong motor; if it was pinging and you weren't running high power, I highly doubt you hurt the motor. I posted a thread this summer about a "close call" I had running at the strip. I forgot to turn on my electric fan before staging, and my temperature rose to about 200. I was getting detonation at the top of third, and midway through fourth gear. Checked compression later and it was fine. My point is it's easy to get minor detonation if the cylinder head gets hot, and I got no (apparent) damage even running wide open.

Link to comment
Share on other sites

I know this is going to be unpopular, but might I suggest something other than a Fel-Pro gasket? These have a nickname in my cirle of Datsun friends - Failure Prone. Everyone I know personally that knows Datsuns runs a factory or Stone gasket. This includes a Nissan master tech and quite a few weekend warriors. Seems like on all the internet lists I've been to everyone is concerned with head gasket issues, and everyone talks about using Fel-Pro exclusively. Maybe there is a connection???

 

I changed the cam in one of my L engines without pulling the head, and was told that I was going to have gasket problems by people on the internet who use Fel-Pro. Never happened. That motor ran for another 40K before the front crank pulley came loose and damaged the snout of the crank, and I autoxed every month and ran as many days at the track as I could, probably 8 on that head gasket.

 

I'm not blaming the gasket for your current failure. Obviously driving around with no coolant caused your problem. I'm just trying to help you out for the future.

 

That's my experience, take it for what it is worth,

 

Jon

Link to comment
Share on other sites

Here's another example about how tough the L6 is from my experience - Last time i went to the track, i couldn't get down to the 12's i ran before mostly due to track conditions soooo...i cranked the boost up a little more, then a little more and, right at about 15-16psi, nearing the end of the track she was pinging lightly. I made three consecutive runs like this with it lightly pinging through the trap with no problems afterword. Yes, i know i shouldn't have, especially with the stock head gasket, but i was sort of pissed that i wasn't back in the 12's and figured if she blew, i'd be forced to rebuild it, but i'd get to build it stronger :) Anyway, i wouldn't worry if she pinged lightly on you that once and you got right back out of it. I'm leaning toward head gasket as well. It could have definitely been from pouring cold water into the radiator when she was running hot. I did the same thing on my first Z back in 1987 - 19 yrs old - warped the head a little then blew the gasket. Those aluminum heads don't react nicely to quick temp changes like that. I hope you get it all figured out soon.

Link to comment
Share on other sites

I know this is going to be unpopular' date=' but might I suggest something other than a Fel-Pro gasket? These have a nickname in my cirle of Datsun friends - Failure Prone. Everyone I know personally that knows Datsuns runs a factory or Stone gasket. This includes a Nissan master tech and quite a few weekend warriors. Seems like on all the internet lists I've been to everyone is concerned with head gasket issues, and everyone talks about using Fel-Pro exclusively. Maybe there is a connection???

 

I changed the cam in one of my L engines without pulling the head, and was told that I was going to have gasket problems by people on the internet who use Fel-Pro. Never happened. That motor ran for another 40K before the front crank pulley came loose and damaged the snout of the crank, and I autoxed every month and ran as many days at the track as I could, probably 8 on that head gasket.

 

I'm not blaming the gasket for your current failure. Obviously driving around with no coolant caused your problem. I'm just trying to help you out for the future.

 

That's my experience, take it for what it is worth,

 

Jon[/quote']

 

Yeah, I hear not so good things about FelPro, but I've used them on 3 L28ET head installs including my current one - never had any problems. None, period. That includes one overheating episode, the pinging episode I wrote about above, and numerous overboostings from a bad MBC.

Link to comment
Share on other sites

Guest bastaad525

Afshin said the same thing, regarding the felpro... I was going to use a stock Nissan gasket but none of the dealers in my area had any, the closest one that had it was in sacramento, would have taken about a week to get sent down, and my friend didn't want my car in his driveway that long :( I've never had problems with felpro's before but then again I've never had a turbo motor before.... I'll do some more digging this time see if I can't find a better gasket.

 

I will definately take the head to a machine shop to have it checked before putting it back on.

 

normally I wouldn't have even considered the possibility of some brief detonation damaging rings, but I've heard so much about how much worse ping is in a turbo engine... even then I wasn't worried that much when I (thought I) heard it... I know the L6's are pretty strong. I only got worried when i thought about the fact that the rings are new and not even fully broken in yet, and maybe detonation COULD do some serious damage under that condition. I dunno... gonna go do the compression test right now, I'll post results as soon as I'm done.

Link to comment
Share on other sites

Guest bastaad525

bad news...

 

pulled the plugs... all looked good except #5 (damn #5 AGAIN!!!) which was drenched in oil. Did the compression test, all cylinders show 118-120 (funny how the numbers are LOWER than when I had the old, bad rings in there!!!) except #5, which would only get up to 15-20psi or so. Just for the hell of it I checked the valve adjustment on the #5, exhaust was a little tight... fixed that but no luck.

 

Now, if I'm not mistaken, there are only two oil passages from the block to the head right? One up by the timing chain, and one in between the #3 and #4 pistons right? So wouldn't oil and low compression on #5 almost certainly suggest damaged or broken rings? Or is there some other way oil could make it's way over to the #5 via a bad gasket? My friend says it's gotta be rings... please tell me that it could still be the head gasket.....

 

Well if it IS the rings I am now faced with three options.

#1 keep trying to fix it.... this would entail taking the head off and having it checked/resurfaced, and at the least, replacing the rings on the #5 piston, OR, trying to find another block to put in... either just used, or getting one and getting it rebuilt, or taking mine out and having a full rebuild done. None of which will be cheap or easy

 

#2 I talked to the guy I sold my 2.9L N/A motor too, and he is considering a straight trade, the turbo motor for the N/A. The N/A was in good shape, only had about 30k miles on the block, and about 10k miles on the head. It's overbored .060, flat top pistons, N42 head stock except for polished valves, no other head work though (power to be had there) 470/280 cam, rebuilt Ztherapy SU's. Put down 170hp at the wheels. I gotta admit... I'm very tempted...

 

#3 a friend of my friend has a '95 Ford Contour which he says is in really good shape, that he'd straight trade for my Z the way it is now. This is the least appealing offer to me, but at the same time... I really really need some transportation. The offer is even less apealing because the Contour has some 190k miles on it. The head has been rebuilt recently, along with a lot of other important parts replaced... but something in my gut says not to trust a Ford bottom end with that many miles on it.

 

What do you guys think.....

Link to comment
Share on other sites

Guest bastaad525

Also, anyone know what I should expect to be a reasonable price to fully rebuild a block? Are there any places around that sell rebuilt blocks for these cars? Would that be cheaper?

Link to comment
Share on other sites

Man, that sucks. I can't believe it. I'd of course do your first option. 170hp to the wheels may sound nice, but it's not a turbo. And to trade a Z for a Contour :oops: . Just MHO, and you can find good turbo engines if you look. Pick-n-pulls, and of course you have the option of putting in an n/a bottom end until you are able to find a F54 (or rebuild yours leisurely).

Link to comment
Share on other sites

Guest bastaad525

Sleeper - I'm guessing by your reply that my friend is most likely right? :( Oil and no compression in #5 HAS to be rings? Shiiiiiiiii.... well... *sigh* damn. Yeah the Contour is 100% OUT... no way... getting my N/A motor back is tempting, but only because I need a running car... and it was a good motor. Anyways, I've already got another turbo block lined up, and it will be free. My friend is basically going to trade his block for my block... an even trade, as they both need to be rebuilt, and he wont be using his any time soon :) So I can pick up his tommorow, and drop it off at a machine shop as soon as I find out how much $$$ it's gonna cost and how long it will take me to save that. I'm thinking it will be about a month or so. And he'll help me out with the swap, also pretty much for free. So I guess that's what I'm gonna do... just sux... another MONTH w/o a damn car... gonna be killer.

Link to comment
Share on other sites

Guest bastaad525

The more I read the harder I find it to believe that a possible, brief moment of detonation induced by the overheating would destroy new rings so fast... everything points to head gasket. I did the compression test again on #5, and this time after the initial test I squirted oil into the cylinder... forgot to do that yesterday... anyways, the pressure did not rise at all after putting the oil in there.

 

Can anyone see any way that the gasket could be blown that would allow oil to get into cylinder #5??

 

I know I really need to take the head off myself to be certain... problem is, as I keep mentioning, I can't do it here... I could take it to my friends house and do it, BUT, if we pull the head and the gasket is fine, and it ends up being the rings, there's no way I could leave my car at his house for the next month while I save up and get the block rebuilt, and I dont want to put a possibly warped head back on and buy ANOTHER new head gasket just to drive the car home... a lot of extra work for nothing. I'm gonna bring the car to his house to do the block swap, but by that time I'll have already spent the money on rebuilding the block... if we take the head off at that point and find it was just the gasket... it will be a bit too late :(

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...