banging noise part 2

[BMFB]

I just got done rebuilding the motor, and have about 300 miles on it, and a banging noise started happening. Its strange, it doesn't sound like rod or main knock, as its much less noisy. it happens basically anytime the motor is revving past 1500 rpm, power or decel, higher the rpm, the louder it revves higher (still no where near as loud as my main know I had)

I checked my dp, and my flex plate and such and it seemed to be tight.

It also seems to be coming from the back of my motor, but It doesn't seem any louder from under the truck. ( say this from word of mouth of my friends who climbed under it)

I hear it best standing just where the front fenders meet the door, on the driver side.

its metallic, and pretty sharp.

I can feel it in the floorboards when I'm driving, faintly.

Its in time with engine rpm, and doesnt go away with the removal of the belt.

there is metal coming out of my motor, but there was when I first started it due to used cam on new bearings and was deamed normal. Its much less than the first oil change, and its not anything close to the usual bad bearing grey gravy. it looked a bit like glitter, and a few people I showed couldnt even see it.

any ideas?

 

[ty166]

Re: banging noise part 2

i would look closer at the flex plate , might not be loose but might be starting to crack around the bolt holes.

 

[Don W.]

Re: banging noise part 2

You did the assembly? Do you specifically remember torquing the flex plate? Have you checked the TC bolts? Remove the bell housing bottom cover and listen again. And, duh, the starter is tight correct?

I always like the term: "seemed to be tight." I've used it myself. Have you actually checked? Examples: Stock DP has a bell housing support. 3" DPs are a tight fit.

And the usual, cut the oil filter. And I mean cut it open and lay out the element so you can look inside the pleats.

After it has sat over night my motor makes a horrible racket when I start it. "Collapsed" lifters. One in particular. Even takes a moment for that last one to quiet down. So the question is was the rocker pre-load set correctly?

Random thoughts...

 

[SY-1193]

Re: banging noise part 2

Don't know much about your truck. Something comes to my mind when I saw this post:

My first question to you is was your rebuild with Eagle rods?
If so did you clearance the oil pan?
If not that could be your noise. Read this post: http://www.syty.net/forums/showthread.php?t=63494&highlight=eagle
Not every one has this problem...can be related to the thickness of the oil pan gasket, how tightly you make the oil pan bolts, twist in the block, many other factors.
HTH

 

[Don W.]

Re: banging noise part 2

Good call. Pan clearance is very tight even with stock rods. Should be able to hear that from below. Wouldn't the noise be there all the time though? If block is not clearanced I would think the motor wouldn't even turn over.

 

[SY-1193]

Re: banging noise part 2

Good call. Pan clearance is very tight even with stock rods. Should be able to hear that from below. Wouldn't the noise be there all the time though? If block is not clearanced I would think the motor wouldn't even turn over.

I was thinking more of the oil pan clearancing...

As rpm increases I would venture to say there is less oil in the pan and more in the top end so it can make noises at different rpms and temperature conditions I would guess.

Another thing to think about:
Whenever you rebuild an engine I recommend a new radiator and oil lines. Why you ask? When your engine blows up the fine metal particles (and those that are not so fine) go into the oil, lines and oil cooler portion of the radiator. They get stuck there. When you rebuild your engine put in in all fresh and new and hook up the old oil cooler lines/ remote oil filter lines and it all heats up they dislodge and go thru your bearings tearing them up. Even pressure cleaning of the lines doesn't get everything out especially the radiator cooler for the oil. My friend learned that lesson the hard way. A new radiator is $145. and oil cooler lines cost about $85. to replace alot cheaper and easier than pulling a motor and having the bearings redone. And for those that think the filter catches everything you have to consider there are bypasses in most filters that open up when a filter is full. There is a bypass in the adapter for the remote oil lines on the block (small pinhole) bypass on the engine block and at the remote oil cooler and in most oil filters.

BMFB's noise could be any of many things going on. Not saying the above is the problem but it should be considered as a possible problem for a new rebuild.

Another common problem is with hydraulic lifters. People install them dry or just rub some lube on the pushrod ends and the bore surfaces and stick them in. They should be submersed in oil and then put in to help with a dry start and help to pump them up when they are installed. People adjust their rockers with them when they are not at temperature also. Overtightening / Undertightening is also a source of these noises.

I would get a mechanics stethoscope to try to isolate where the noise is coming from.

 

[BMFB]

Re: banging noise part 2

well, Ill take a closer look at the flex plate, and the TQ C. the down pipe is stock, and bolted in, tightly.

I did all of the assembly with the exception of the short block. I know that I torqued the flex plate.

I havnt cut the oil filter yet. when I redid the motor I simply got rid of the oil cooler, cleaned the lines to the filter and turbo, and primed the oiling system thoroughly. Its not even close to as loud as a bearing. I don't know how long it takes for a bearing to go from ok to ruined. I'll climb under it and listen to see about the oil pan clearancing, but it didn't make the noise when I first started it, or the first 200 miles, but that doesn't mean that it didn't get hit. But, with that being said, it should be super loud next to the pan. I need to climb under it myself.

rocker preload is a good question, I did what I was told to by my builder, and from what was recommended on this site, but i;ve never done it before, and could have made a mistake. Is there and easy way to check for something like that, because this sounds close to my problem than anything else.

 

[SY-1193]

Re: banging noise part 2

What lifters are you using, what rockers...details needed.

 

[Don W.]

Re: banging noise part 2

Yup, details are needed on the rockers but the only way I know of is to redo them. Little bit of time required to gain access and get the rocker covers off then fairly simple procedure. But you MUST follow it.

If you did it wrong I think the symptoms would be a noisy rocker and/or a weak cyl. All the time, not at some arbitrary RPM. When you crank it does it seem to crank evenly through all cyls? Or is there one (or more) cyls that don't have the same "resistance?" A compression check might be easier before you redo the rockers.

 

[Big Mike]

Re: banging noise part 2

Any way you could video your running condition?

 

[jpalmer]

Re: banging noise part 2

my guess is flex plate. i would look in detail to it.

 

[Ty#365]

Re: banging noise part 2

My guess is flex plate too.That is the sound my s10 makes about once a year until I replace it. Always cracked around the bolt holes.

 

[jpalmer]

Re: banging noise part 2

When the flex plate cracks, the separated pieces click or knock together. it can be kinda quiet, to very loud. mine was cracked and i bought a sfi approved piece so it would never happen again.

 

[BMFB]

Re: banging noise part 2

the lifters are just a standard lifter, not crane or comp, but some brand my builder uses and says he's never had an issue with. I can't recall now, but I have the box out still at home. I followed the tightening (lashing) instructions to the T, although like I said, Ive never done it before and would not be surprised if I messed something up. it...seems to run evenly, its always kinda had a girgle thats hard to describe, but I think its normal. when it cranks it seems even, but I havn't tried to hand crank it or do a compression check yet. The only way I can think of to check the flex plate is to loosin the converter from it, push it farther into the trans and then try and wiggle the flexplate for and aft. Rockers are stockers, reused from the original engine, along with the cam. I'll see what I can do for a video today that has good sound.

 

[Hongkongtyphooey]

Re: banging noise part 2

For what it's worth, when I stripped my engine down I found that there had been major scratching and wear to all crank journals and bearings and that one or more of the cam timing gear bolts that screw into the camshaft front end had been heavily scoring the stock sheetmetal timing cover which left a nasty 'crop circle' pattern on it. Must have been bent inwards slightly but sure caused a lot of bearing damage.

Glitter like particles will be from a cut surface where one hardened component is milling another softer one, as in my case; a hardened bolt head grinding on a mild steel plate.

I was going to flush the oil cooling/filtering system but after reading Keith's post, I think I'll buy new parts and hoses!

Another possible source of vibration when driving might be an out of balance front propshaft. I would think that the flexplate must be way out of true with the TC for there to be a problem with cracking around the bolt holes? I can't see how that's possible though unless it's down to sheer power, in which case a stiffer flexplate is the only answer.

Maybe the starter gear isn't retracting properly from a dodgy solenoid and as rev's increase, the flexplate contacts the gear? Mine has a rounded edge to the teeth on the plate where the pinion has worn on it but that might be from normal retraction and false starts where the starter is engaged whilst the engine is rotating.

Let's hope it's just an external issue like that and not rod clearances. :tup:

 

[BMFB]

Re: banging noise part 2

Took the truck to a trusted friend who owns a shop. Says the oil pressure drops for a split second whenever you give it throttle before rising. Noise seems to be coming from deep within the motor. Talked to my engine builder, said he's look at it as soon as I could get it to him, and hopefully have it turned around within a month. I hate having another person touch my truck, but with work full time and school full time, I don't have much of a choice. I'm sad

 

[Hongkongtyphooey]

Re: banging noise part 2

Sounds like it's either the oil pump or bearing damage from the crap that's going through them. Might have a partially blocked oil passage into the pump?

If the crank/rod journals/bearings were badly worn you'd get a drop in pressure, for sure and if metal particles are coming out in the oil, it's a probability, to say the least. Check the timing cover for clearance of the cam bolts.

Can't see how an oil pump could be the problem in itself unless it's starved and running dry momentarily. Check for oil pump strainer clearance with the pan as well 'cos it could block it if too low in the sump apparently.

 

[BMFB]

Re: banging noise part 2

I was actually worried about a blocked passage, it seems as though this happened really early in the motors life. I know the block was cleaned, but I don't know if they look specifically for something like that. I know my builder and he's a good guy, as well as my *sigh* mechanic. I sign because I've never had one before, which really bothers me. First time my anything (engine machining aside) has been in the hands of another person...and actually the first time my engine machining has been done by another person, I've done it on my other motors.

 

[Hongkongtyphooey]

Re: banging noise part 2

Who installed the bearings? There's also an oilway softplug near the pump that needs removing for cleaning aswell as cam bearings needing removal and proper brushing out of oil ways. I was tempted to leave mine in but the gunk that collects in the cam oil ring grooves is a great place for particulates to collect and needs a rotary wire brush on a flexible shaft to get into the corners.

Basically, the whole block needs a really good scrubbing internally and anyone charging an hourly rate to do it will never have time to do it thoroughly unless they're seriously fussy and hardworking but the job will usually be given to the youngest, cheapest employee with the least skill, or they'd be assembling or machining.

You might be ok just changing the oil again as normal wear-in produces a lot of gunk but as a previous poster said, cut the filter open and examine it. The noise could even be the distributor pinion mashing on the cam gear and bedding in, grinding off metal. Obviously the dizzy drives the oil pump so it could be related.

Insufficient rod clearances would be immediately obvious and continuous and would never stop until you had a hole in the pan. Any tighter (against the block for example) and it probably wouldn't turn over. Besides, you'd have to be very lazy not to check for this during assembly, as it's standard procedure. You wouldn't be able to rotate the crank to install the pistons and surely you'd turn the crank a few times once the pan is torqued down.

 

[BMFB]

Re: banging noise part 2

Well, my engine builder got the motor today and tore it apart. He says that my thrust bearing is worn right out of it. He also mentioned that the rest of the motor looked good, with the exception of some slight scarring on the mains from the bearing material working its way through the motor. He recommended that I have the crank turned, and rebuild it.

He believes that the problem is from a balooned torque converter. I called a local trans shop with the best rep for racing trans in the area, and talked to him about. he said that with a v6 there wasn't anyway that i could have harmed the TC, and I told him what else was being pushed into the v6 and he got kinda quite. I explained how I had installed the motor and bolted the trans up and torque converter, and he said that is wasn't likely due to the way I installed it, and he said he knew my builder, and he had never heard of any bad things coming from his shop, so he offered to inspect my tc for free this monday and get an idea of what could have happened.

as of right now, my builder knowing that it wasn't his fault for what happened is still offering me free labor for the rebuild, and all I need is new bearing with the recommendation of turning the crank. which I think is pretty good.

gonna have to go head hunting tomorrow...

anyway, has anyone here ever heard of such a thing? I looked, and the only person I could find who has commented on this was ken once, saying that it happened more often then you heard about. but it still seems rare, and Id be surprised if i made enough power to do this where others have not.