While driving home from a Japanese car meeting, my engine started ticking.
It happened while I was pushing it hard in 4th, at around 7k rpm (might have been up to 7600, as my limiter is set to 7650rpm).
No weird noices right then and there, but when slowing down I heard the engine ticking.

I have a D16Z6, with P29 pistons, Crower stage 2 cam, and crower valve springs and retainers as far as relevant parts go.
Engine was overhauled about 2000 km ago, by myself.

Could it be the valve lash suddently being wrong? I checked the nuts a few minutes ago, and they seemed tight.
All valve springs look allright, and as far as I could see the cam is fine (hard to see though).

I recorded a small video, from different angles, so you can hear for yourself.
Tried to see if it got louder when close to the head, but really hard to tell.

http://s16.photobucket.com/alb...8.flv

We have checked both the rod and main bearings, and they seem fine.
Next thing is to reset valve lash, and see if that helps. If it doesn't I suspect a bad valve.
But first, the lash I guess.
Funny thing is, when opening the oil filler cap, the noice level stays the same.
I would assume it got louder if it was infact the valve lash...

Any comments or help, as to what it might be, and things to check?


Modified by s_18 at 2:55 PM 6/13/2006

 

sound like ****.
how did you check your rod and mains?
i bet thats from the bottom end not the top

 

you redlined it in fourth? damn, that is going pretty fast.

 

Worst case scenario...maybe a bent rod??

 

That sounds like complete **** maybe a valve floated and kissed a piston.

 

Today we have carried out some tasks...

First we measured the rod bearing clearances:

Cylinder 1
Lower: ,038mm
Upper: ,030-,035mm

Cylinder 2
Lower: ,038mm
Upper: ,030-,035mm

Cylinder 3
Lower: ,038mm
Upper: ,030mm

Cylinder 4
Lower: ,038mm
Upper: ,038mm

I'm quite satisfied with the readings.

After mounting it back together, we took a compression test (on cold engine)... It showed 230, 195, 220, 160
So it turns out that the compression in cylinder 4 is low. We suspect something wrong with the valves.

Even after adjustment of the lash, it ticks just as bad.

So I will probably get a new set of valves (Omni or something), valve guides and a 3 angle job.

Of course the tuning session will be pushed back a bit, that's just how it is...
Here's a few pictures of the prosess.

 

Problem probably is that the valves have 160 000 km on them...
My rev limit is moved from 7400 to 7700, so I don't think this is enough to break them alone.
But when the valves are old, it could happen I would think.

First step is to take the head off, and inspect it for damage.
I'm guessing I need to renew a few things up there.

 

i was gunna say rod bearing. bearings look ok though?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by strictly.business &raquo;</TD></TR><TR><TD CLASS="quote">i was gunna say rod bearing. bearings look ok though?</TD></TR></TABLE>

Yes from the looks of his pictures, bearings are not spun. I also think its the valve so good luck with the inspection. But if its not the valve, theres something up with cylinder number 4 anyhow.

BTW:

my Y8 with p29 pistons read over 300PSI on the compression gauge. The gauge was not broken, it read 170ish on a Low compression GSR. Your numbers look a little akward to me, but it may just be different numbers from different gauges.

 

If you have a adjustable cam gear check it. Goodluck on troubleshooting, Soon I will start my P29'd z6

 

Have now taken the head off, and what we have seen is scratches on the camshaft...
I haven't seen it myself yet, but time for that today or tomorrow.

I don't know how bad it is, nor what caused it.
Too early to say anything.

 

I was gonna say it seems like one valve is bent, but that's realy weird...double check the timing b4 u pull the head off, might have jumped a tooth and pulled one valve

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by s_18 &raquo;</TD></TR><TR><TD CLASS="quote">Have now taken the head off, and what we have seen is scratches on the camshaft...
I haven't seen it myself yet, but time for that today or tomorrow.

I don't know how bad it is, nor what caused it.
Too early to say anything.</TD></TR></TABLE>

scratches on the cam? wtf?

 

valve timing?

 

Well, took a look at the head today, and it didn't look all too well...
The cam itself has quite a few scratches, and the bearing surfaces on the head has the same thing...
The funny thing is on one of the exhaust lobes on cylinder 3... Seems a piece has chipped off.
Not sure how come this is... But the scratches might be due to bad lubrication?
Kind of worried my oil pump is bad. I will replace it now I think, just to be certain.

Bearing surface - cam.


Bearing surfaces - head.


Rocker arm assembly - couldn't see anything wrong here, but I'm no expert.


Chip on ex.lobe. This isn't normal, for sure.

 

I have heard of problems with other crower cams, I just don't know what to trust in my car anymore.

 

Could it be that your camshaft is seizing? Does your timing belt make a whirring noise?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpkelly &raquo;</TD></TR><TR><TD CLASS="quote">Could it be that your camshaft is seizing? Does your timing belt make a whirring noise? </TD></TR></TABLE>
No, I haven't heard any noices except for the ticking noice... Engine has run great the whole time.
I don't know weather or not it runs great now, because I have been as careful as possible since it came.

I will get myself a new head (stage 2 porting by Endyn and new vavles), a Crower stage 3 cam (either by warranty or just a new purchase),
and a new oil pump I think, just to be sure everything is all right.

 

Do your pistions move with easy? My car made the same noise before it blew I had a nice hole in my block with a rod on the rad support

 

Whats the piston to wall clearance?

 

One of the pistons seem a little on the slow side...
Should I get new oem rings, just to be absolutely certain they're ok?
I have Hastings rings on there now...

 

low? what do you mean by that? Because if it sits low in the cylinder that could mean bent rod... did you check the rods?

 

what kind of head studs are you using... could be head lifting?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Otherguy &raquo;</TD></TR><TR><TD CLASS="quote">low? what do you mean by that? Because if it sits low in the cylinder that could mean bent rod... did you check the rods?</TD></TR></TABLE>
I said Slow, didn't I? If you move it from underneat (while the rod cap is off the crank) it sits a little snug in there.
Might be a broken ring or something.

Thinking about buying a new set of pistons and oem rings just to be certain.
Have learned alot about how to do things after I did this, which was my first rebuild,
mostly thanks to Omniman han his great video

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ekcivic9 &raquo;</TD></TR><TR><TD CLASS="quote">what kind of head studs are you using... could be head lifting?</TD></TR></TABLE>
I have ARP studs, so I'm pretty certain it's not them, atleast.