Oil in cylinder 5 (Page 1/7)
1985 Fiero GT JUN 27, 03:17 PM
I recently (250kms ago) finished a top end rebuild because I had coolant in my oil (pretty sure it was the lower intake gasket) which consisted of: remaned cyl heads from 82 T/A with new valves/seals, etc, all new gaskets for heads, all intake gaskets, valve cover gaskets, exhaust manifolds, etc, 1.6 roller tipped rockers, and port matching/porting the 3 intakes, as 82 T/A outlines on his site, valve lash set according to Patrick's method.

Immediately upon restart, and over the last 250kms, it has been consistently slower than it was before the "rebuild". Before I was getting 7-7.5 seconds 0-60, now I'm getting between 9-11 seconds, same road, same conditions. Engine sounds aesthetically good, much more thunderous/rumbly than before (has a smooth idle, had massive exhaust leaks before, so hard to compare), power is severely lacking under 2000rpm, and it really chugs/lugs under 1750 with much load. Power continues to be lacking across all rpms, but doesn't chugg/lug noticeably above 2500. The only thing I have to work with, is oil on cyl #5s spark plug, all other plugs are perfect grey/brown, white insulator, cyl 5 was almost wet, and completely black, insulator, electrodes, everything, and smelled like oil. The oil I put in this time is semi synthetic 5w30, which remained perfectly clear until recently, but is currently a little dirty looking, and appears to have dropped a little bit.

I have literally no blow-by, removing the PCV valve from the valve cover with the engine running results in NO airflow in or out, no smoke out the exhaust at any time, startup, engine braking followed immediately by hard acceleration, nothing. No vacuum leaks at all, idles perfectly. Timing is set correctly, finding TDC cyl 1, and confirming the balancer is solid and not misaligned, have tried 8*, 10*, and 13*, basically no difference between them on the "butt-dyno".

I do have a little bit more valve train noise, quiet enough that unless I told someone what to listen for, they wouldn't notice it, and even when told might not, noise seems to increase as the engine warns up, but I attribute the noise to the roller tipped rockers (many people seem to complain about a noise increase with them)

Any ideas, troubleshooting steps, etc. I can get any additional info/pictures as needed. I do not have a cyl compression tester, or the money to get one.

[This message has been edited by 1985 Fiero GT (edited 06-27-2024).]

Patrick JUN 27, 03:52 PM

quote
Originally posted by 1985 Fiero GT:

I do not have a cyl compression tester, or the money to get one.



Doing a compression test on all cylinders will tell you a lot. Beg, borrow or steal a compression tester. (Auto parts places often have one they'll lend out for free.)
1985 Fiero GT JUN 27, 04:06 PM

quote
Originally posted by Patrick:

Doing a compression test on all cylinders will tell you a lot. Beg, borrow or steal a compression tester. (Auto parts places often have one they'll lend out for free.)



Yeah I know, I've wanted to buy one for a while, all the auto parts stores here require a deposit of the full purchase price (refundable when returned) to borrow a tool, at the moment I can't afford that haha.
Vintage-Nut JUN 27, 04:22 PM
Well, not really "free" as many auto parts {like AutoZone} require a deposit, which you get your deposit back after returning it.....

AUTOZONE ENGINE COMPRESSION TEST
https://www.autozone.com/di...ine-compression-test

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

Patrick JUN 27, 04:35 PM
Well yeah, unless you're a total doofus and lose the tool, you get your money back.

I've had good luck buying used automotive tools (as well as electronics etc) for a fraction of their original price through Craigslist, eBay... or even FB Marketplace. (I've never used Kijiji as it's never really caught on in this area.)

[This message has been edited by Patrick (edited 06-27-2024).]

CSM842M4 JUN 27, 08:24 PM
Patrick and Vintage-Nut are correct, the compression tester is a nice tool to have. Yes, a good one can represent a bit of a financial commitment. I've collected also a leak down tester, which helps figure out where your compression is going after you find which cylinder/s aren't holding it. Also not exactly cheap, but it's kinda neat to be able to tell (and show) your friends that they have some leaking exhaust valves AND a likely bad head gasket on one side of the LS they were just moments ago so proud of having put in their S10...
82-T/A [At Work] JUN 28, 08:08 AM

quote
Originally posted by 1985 Fiero GT:

I recently (250kms ago) finished a top end rebuild because I had coolant in my oil (pretty sure it was the lower intake gasket) which consisted of: remaned cyl heads from 82 T/A with new valves/seals, etc, all new gaskets for heads, all intake gaskets, valve cover gaskets, exhaust manifolds, etc, 1.6 roller tipped rockers, and port matching/porting the 3 intakes, as 82 T/A outlines on his site, valve lash set according to Patrick's method.

Immediately upon restart, and over the last 250kms, it has been consistently slower than it was before the "rebuild". Before I was getting 7-7.5 seconds 0-60, now I'm getting between 9-11 seconds, same road, same conditions. Engine sounds aesthetically good, much more thunderous/rumbly than before (has a smooth idle, had massive exhaust leaks before, so hard to compare), power is severely lacking under 2000rpm, and it really chugs/lugs under 1750 with much load. Power continues to be lacking across all rpms, but doesn't chugg/lug noticeably above 2500. The only thing I have to work with, is oil on cyl #5s spark plug, all other plugs are perfect grey/brown, white insulator, cyl 5 was almost wet, and completely black, insulator, electrodes, everything, and smelled like oil. The oil I put in this time is semi synthetic 5w30, which remained perfectly clear until recently, but is currently a little dirty looking, and appears to have dropped a little bit.

I have literally no blow-by, removing the PCV valve from the valve cover with the engine running results in NO airflow in or out, no smoke out the exhaust at any time, startup, engine braking followed immediately by hard acceleration, nothing. No vacuum leaks at all, idles perfectly. Timing is set correctly, finding TDC cyl 1, and confirming the balancer is solid and not misaligned, have tried 8*, 10*, and 13*, basically no difference between them on the "butt-dyno".

I do have a little bit more valve train noise, quiet enough that unless I told someone what to listen for, they wouldn't notice it, and even when told might not, noise seems to increase as the engine warns up, but I attribute the noise to the roller tipped rockers (many people seem to complain about a noise increase with them)

Any ideas, troubleshooting steps, etc. I can get any additional info/pictures as needed. I do not have a cyl compression tester, or the money to get one.




I would be interested to see what compression you get on all of those cyls as well. Remember, when you test compression, you need to do so with the throttle body at WOT (with fuel and timing disconnected of course). Cyl 5 does seem like oil is getting past the rings.

Still, I don't think this really would be causing a 2 second drop in performance.


I'm more interested in this: "I do have a little bit more valve train noise"

You went with the 1.6:1 roller rockers, right?


I'm wondering if maybe you don't have the valve lash set properly. Remember that the valves will only open to their fullest extent (or duration) when valve lash is set properly. If the valve lash is set too tight, then you're not getting full compression (different problem than leaking valves) because the valve likely never fully closes. If the valve lash is set too loose, the valve will open later and never "fully" open. You'll also get a little bit of lifter and rocker arm clatter.

It's actually pretty common to have to re-adjust valve lash after putting a motor back together, because everything kind of settles... in so far as your pushrods, rocker arms, etc., all tend to break in a little bit. Especially if you went with the 1.6:1... there would be some break-in. You'd also have some additional wear on the cam as a result of the coolant leak into the oil, though I'd definitely say that is so minimal that you'd not even notice it, and certainly wouldn't affect your performance. The V6/60 is not a zero-lash motor... so any wear that may occur in the valve train components (rocker arms, pushrods, lifters, etc.) won't really result in a loss of horsepower. It's different from a zero-lash motor like the Iron Duke where all the wear on components literally results in less valve-action if you will... haha.

Can you do a video / audio recording of the engine... since you say you have a bit more valve train noise? I'm interested to see if we can hear that.
1985 Fiero GT JUN 28, 09:23 AM

quote
Originally posted by 82-T/A [At Work]:
I would be interested to see what compression you get on all of those cyls as well. Remember, when you test compression, you need to do so with the throttle body at WOT (with fuel and timing disconnected of course). Cyl 5 does seem like oil is getting past the rings.

Can you do a video / audio recording of the engine... since you say you have a bit more valve train noise? I'm interested to see if we can hear that.



I just don't understand how oil could be getting in with no vacuum leaks, and no blow-by whatsoever?

I will do that this morning, but I doubt it will be audible, as I said it is very quiet, my ears are quite sensitive haha, similar volume to the fuel injectors.
82-T/A [At Work] JUN 28, 09:38 AM

quote
Originally posted by 1985 Fiero GT:

I just don't understand how oil could be getting in with no vacuum leaks, and no blow-by whatsoever?

I will do that this morning, but I doubt it will be audible, as I said it is very quiet, my ears are quite sensitive haha, similar volume to the fuel injectors.




I mean, some oil does get in regardless... but I also wonder if it's leaking from somewhere else too and getting into the intake... though I'm not sure from where that's possible.

First, the valve clatter concerns me (not in a bad way, but I'm suspect of it)... this can absolutely lead to reduced performance because it directly correlates with the cam's ability to open and close the valves.

But I would also be interested in knowing if perhaps any of this could be as a result of fuel issues (clogged injectors from sitting, etc.), or timing issues.


The oil thing is definitely a concern. I mean, it sucks... but this is part of the evaluation process. Like the others have said, definitely check compression, and if it's all good... then that's a sigh of relief. Don't let the valve clatter go on for too long though, as it'll cause damage to the rocker arms and the tips of the valves, like this...



or this...
1985 Fiero GT JUN 28, 09:48 AM

quote
Originally posted by 82-T/A [At Work]:


I mean, some oil does get in regardless... but I also wonder if it's leaking from somewhere else too and getting into the intake... though I'm not sure from where that's possible.


But I would also be interested in knowing if perhaps any of this could be as a result of fuel issues (clogged injectors from sitting, etc.), or timing issues.




The only place it could get into the intake would be where the lower intake meats the head, the intake ports are right beside the pushrod cutouts that oil returns down.

When I removed the fuel rail, it went straight inside, and I taped over the injectors, and all fuel ports (I was painting the rail), and just yesterday I rechecked the timing, stuck something down cyl#1 to find TDC, confirmed balance was at 0*, wiggled, pulled, shoved, twisted the balancer ring to ensure it was tight, it was, timed to 10* before TDC, with aldl jumpered