Weird engine noise...

[Silver_Bullet85]

Been a busy couple days but thanks for the responses! I wasn't able to get much work done but I was able to check the wires and one of them has a cut on the boot thats causing it to arc onto the headers and theres some kinks on the others, I plan on checking them all tomorrow morning and replacing a few.

Rich, I had my brother drive while I sat on the passenger side and the noise was barely noticeable (window up, down, door open, closed). Base timing is at 13 deg. the vacuum advance port was plugged by tristar and its running on 35 deg. total advance.  It runs smooth and has gobs of power but it feels like the power isn't as strong as it should be for 475hp.

I'll check all the plugs and wires I can tomorrow and see what I find, if theres still a problem I guess I should remove the valve covers and look for something odd while its running?

I did remember something significant that happened back when I was installing the engine.  The first time I manually turned the crank in order to line things up I heard a pretty noticeable crunch from the drivers side, there wasn't any resistance at all before or after and I never felt a crunch I just heard it and figured it was just everything settling in.  Never noticed anything odd about how the engine ran at all and it sounds very healthy at idle, just when under load it makes that noise.

Thanks again for the help guys.

[LTZ C20]

That cut and arcing plug wire will really cause a problem.  When it arcs to the header it stops the electricity from going to the plug because the path of least resistance is thru the cut to the header instead of thru the plug to the block as it should be. That short causes a heavy or dead miss fire. Which Rich, Vile and I all suggested. That could be causing the noise. What cylinder was the cut wire on, drivers side cylinder bank, cylinders 1,3,5,7? Would explain why it's louder on drivers side too.

[Silver_Bullet85]

LTZ, it was on the drivers side, #3. I changed all the wires and pulled the valve covers to check while it was running. Noticed there might be a slight knock somewhere but all the rockers seemed to function well, I'll put some vids up at the end.

So after replacing all the plug wires and checking all the plugs and making sure they were gapped correctly (they all were all .040-.045) I took it out for a spin. For about the first 1/4 mile of normal driving around there was no sound at all. I went out in the country and opened it up a little and I could barely notice the sound, sounded more like the exhaust than anything else, but as I drove it I noticed the sound started to come back. This time it was when I passed a concrete barrier on the pass side that I heard it, but it was nowhere near the level it was at. After about 15-20 min of driving it had grown louder still but not loud enough to catch on video.

Some of the plug wires were just barely long enough to reach the dist and I checked them after driving and I guess they had relaxed as they heated up. I might try and get some longer ones to ensure they're not vibrating out of good contact.

New wires with covers off:

https://vimeo.com/115028391

New wires with covers back on:

https://vimeo.com/115028439

Driving with the new wires:

https://vimeo.com/115028533


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[Silver_Bullet85]

One more thing, I think the question was asked earlier but I forgot to answer, I'm running castrol GTX 10w-30 with some zinc added I believe.


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[rich weyand]

What wires are you using?

[Silver_Bullet85]

These guys:




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[rich weyand]

Aftermarket OEM equivalent. 

Get rid of the resistor-core wires.  If you are running resistor plugs, you don't need resistor-core wires as well.  They're just trouble waiting to happen.

When I researched spark plug wires, I found a dozen inquiries on the net that were "If you were going to get new plug wires, and you weren't going to spring for a set of Taylors, what would you get?"  So I got the Taylor helical wound solid core wires.  Next auto club meet, a guy who wrenched a bunch of the dirt trackers around here for years took a look under the hood and said "Oh you put the Taylors on.  That's all we ever used on the race cars."

OK, so they're $55 a set.  Is that real money, given that they work?

http://www.summitracing.com/parts/TAY-74206

[Silver_Bullet85]

Good point Rich, I haven't had time to research some good wires but it was on my list as these feel cheap, thanks for doing the homework for me lol. It probably wouldn't hurt to get better plugs either, I'm a fan of delco but since everything else is a step above stock I'd be cheating myself in not getting the best fire I can. Any advice on good plugs?


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[Silver_Bullet85]

Going to change the oil tonight, engine has probably 100+ miles or so on it and I'm not sure what oil is in there (came full from tristar). Probably doesn't need it but might as well so I can cross it off my list and be certain of what I'm running.



Also noticed the main belt needed a little tightening, maybe that could be contributing to the noise... didn't sound like it but again, process of elimination...

Stay tuned, we'll see what I find in the oil pan next...


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[rich weyand]

Autolite 24.  Same wrencher told me that's all they ran in the race cars.  The Autolites are more immune to fouling than the ACDelco's. 

If you want to stick with ACD, run R45TS.  That's what I'm running, and have had no problems, so didn't switch to the Autolites yet.

Resist the urge to buy hoity-toity expensive plugs.  Waste of money.

(You might want to check the engine recommendations, too.  They should tell you what plugs they recommend.)

[rich weyand]

The FRAM oil filters are supposed to have been improved from dismal reviews a few years back, but that is their bottom-end filter.  The Tough Guard is the better one.  Most people speak highly of the NAPA Gold and the Wix filters.

Probably doesn't make any difference on a new engine, because it's only gonna be on there for 500 miles or so, right?

[Silver_Bullet85]

Good info, thanks a lot. I try to stay away from the waste of money stuff which is a big reason I keep coming back here honestly, but yes, I'll be changing it at least once a year. The weather stays pretty consistent in south Texas so I don't have to worry about that and it's not a daily driver either, heck my daily driver isn't even a daily driver lol. The company truck sees more miles than anything else, almost 30k this year alone...

If I'm still experiencing problems I'll probably upgrade the plugs next, I'll try for the autolites and see how they work.

Well the oil is clean and not burned, ran a magnet through it and got nothing either so that's reassuring. It seemed a little thinner than the 20w-50 but it was a little warm still so hard to tell.


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[Irish_Alley]

just a tip, but if you go napa (which i have been slowly go to since i get a discount with them) ask for the filters in the back. its still the napa gold but without the box, and its srink rapped and is something like 2 dollars cheaper

[LTZ C20]

Sounds alot better. The small noise now sounds like it could be header slap. Sounds alot better tho. I'm using MSD wires, they have been great so far. Also, check your specs sheet for the head to make sure you get the right dimensions for the plugs.

The AC delco oil filter is also good. I'm using a delco filter, and it's also working great, IMO the factory filter does the best job of filtering the smallest pieces.

[Irish_Alley]

i use duralast brand wires on my truck but in my impala i use ac delco cause autozone sells them.