My second engine failure 2006

[Jason84NA2T]

Re: news:

Dino wrote: Question: Where did this knocking noise come from? We will remount the engine an see if the noise is still there. Our last idee is hydro-lifter (right word for that?). We will know better tomorrow

Well, it could be a lot of things. I had a friend whom had a flywheel bolt back out on his freshly rebuilt motor. It sounded VERY similar to a rod knock and we pulled the engine... funny story really.

Any lifter/valvetrain noise would sound completely different than a knock from the lower end, at least by my ear.

[Dino]

>>Any lifter/valvetrain noise would sound completely different than a knock >>from the lower end, at least by my ear.
also in my ear this sounds completely different and i personally do not give to much to the lifters. I will know more tomorrow and a new clutch will be mouted anyway.

I hope i already got mail from you with your timing map and some other stuff :-)

[craZed]

wrist pin?

[Dino]

>>wrist pin

we checked all the wrist pin for clearance by trying to pull/push and twist the rods. But no clearance.

[Dino]

I am really getting very annoyed of my problem. We remounted the engine with new bearing (although the old ones were like new) and when we restarted it, the noise is still there like before. Nobody knows what to do now. I drove around then for 100 km and found out, that the ticking noise gets louder under accelerating (even if i accelerate very very smooth) and gets calmer (sometimes almost dissapears) when i hold the speed.

My friend said it could be a lifter, but the lifter should not care if i accelerate or not, so for me it still sounds like a bearing thing.

I do not know what to do any more, the bearing change costed me another $700 with zero result. FUCK

Has anybode of you ever had a defect wrist pin? Any Experience?

[Dino]

.. further examinations of my ticking noise: I seems to appear with half the frequence of the crankshaft. I sticked kind of a small white sticker on the crankshaft pulley so i can have a look to the frequency of the cranksahft @ idle. It appears that the noise has half the frequency of the crankshaft. So i think my noise is located in the heads and not a bottom end problem. Am i right?

[Jason84NA2T]

Dino wrote: .. further examinations of my ticking noise: I seems to appear with half the frequence of the crankshaft. I sticked kind of a small white sticker on the crankshaft pulley so i can have a look to the frequency of the cranksahft @ idle. It appears that the noise has half the frequency of the crankshaft. So i think my noise is located in the heads and not a bottom end problem. Am i right?

That seems perfectly logical to me. Did you try using a stethoscope or anything similar to detect where the noise is coming from? You can use a piece of pipe with a hose on it, stick the hose in your ear and the pipe on various places on the engine to listen for the sound.

[Dino]

Yes, we used a stetoscope, and it seems to come from the head area of cylinder 6. I think i will change the hydro lifter of that side.

[j30_vg33et]

Is the compression still good? Could it be a bent / stuck / loose / burned valve? How about a broken valve spring? If you're going in the head I'd spend some time looking at that stuff.

Also, about the AF, down there (9-10:1) you're deep in the afterburner and will see super high EGT's. You can also go into a rich missfire or knock condition that get's ugly as well. Try re-tuning in the low 11's with like 10 deg less timing, then go from there.

[Jason84NA2T]

I'm now thinking you're hearing a lifter or rocker. Actually, I can see how that would sound like a little like a rod knock as I had one doing that a little while back.

rich misfire... tell me about it. My enigne won't run under boost any richer than 10.5:1, it breaks up badly.

[j30_vg33et]

Jason84NA2T wrote: rich misfire... tell me about it. My enigne won't run under boost any richer than 10.5:1, it breaks up badly.

One explanation is that there comes a point that the "fine mist" from the injector turns into rain. This liquid fuel either wet's out in the chamber or turns into big drops, which in either case eliminates the surface area, and simply doesn't want to burn. As we know, it's the fuel vapor rather than the liquid that is combustible. So you get a missfire.

Later in the cycle, way past the point the plug fired, some of the liquid may return to a vapor state and ignite = bad. Raw fuel passes into the exhaust manifold = bad. Excess fuel isn't cleared from the chamber on overlap, fattening up the next cycle = bad.

At what point this happens is engine dependent. Combustion chamber turbulence has a huge impact. A flame-thrower of an ignition can help too. Regradless, you're way past the point of making power anyway.

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[G-E]

One explanation is that there comes a point that the "fine mist" from the injector turns into rain. This liquid fuel either wet's out in the chamber or turns into big drops, which in either case eliminates the surface area, and simply doesn't want to burn. As we know, it's the fuel vapor rather than the liquid that is combustible. So you get a missfire.

not in our engines, it's more like you take a watering can and water your pistons, or maybe pouring a can of gravy on a turkey... ok I'll stop now

the only vaporization comes AFTER the fuel enters the cylinder and boils off the piston

no I think the answer is simpler, you're splashing too much fuel on the plug

[Dino]

Ok guys, i understand what you mean, i should try to go leaner, maybe around 11,0. Ok, i will check that tomorrow, thank you for your detailed posts, what a nice forum. I made some test runs on the autobahn and the car was running quite strong but my AF was around 9,3!! I hope to gain some extra power when leaning out to 11,0

Speedo 110 to 250 km/h in 19,5 seconds @ 16 psi






Bad news from the "ticking noise": We changed the hydro lifters today and.....no change. I Assume one again:
- Compression is perfect
- Bearings are brand new
- wrist pins seem to have have no clearance
- Hydros have benn changes
- all he mechanical parts we had to take off to change the lifters also seem to be ok
- the head lokked very clean, well maintained engine
- noise is permanently present after cold start and during warming up
by warming up i sometimes dissappears but returens after some seconds or minutes
- The frequency is half the crankshaft-frequency
- My latest guess: the oil feed bore to one lifter is blockated
- The niose suddenly appeared while test driving at high speeds, so it did not come step by step but suddenly. I drove hundreds of miles before without a noise
-----
Maybe I will pull the engine again because i want to get rid of that problem

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[Jason84NA2T]

I guess you need to pull the lifter guides again and clean them out? Check the bores on the lifter holes too. If the clearance is too large maybe it can't build pressure???

It could also be a valve issue, but with the engine seeming to be having plenty of power I'm not sure how that could be.

[G-E]

I would suspect the rocker arms, if you don't carefully tighten down the rocker shaft some rockers might deform, as strange as it sounds, sometimes even just turning them on the shaft will deform them a touch...

the shafts have these star shaped grooves underneath that will eventually eat into the rocker and create a star shaped hump on the bottom inner surface of the rocker

you should remove the rocker/lifter assembly and try wiggling the rockers side to side, and I don't mean sliding them on the shaft, try to wiggle them in a bunch of directions, if they are good they will be tight, if they are bad and wobble then they will make noise similar to lifter tick but harsh