metalmonkey47 Posted February 11, 2014 Report Share Posted February 11, 2014 Hoping someone might have some kind of idea as to what I might want to dig into. I've been digging into this for a week when this showed up. It's a pretty steady knock that's shown up on my freshly built long-rod LZ. Very consistent in frequency and pattern. I ONLY hear this at idle, when the motor rocks about a bit from the big 'ol cam. At first thought it was a rod knock... so far I have: -Changed the oil/filter. Running fresh 15w50 with K&N HP-3001 filter. Oil was dirty and probably well worn, but no chunks, shiny bits, flakes, etc. Came out perfect. -Unplugged wires from dizzy one at a piece, no change in frequency of the knock on any cylinder. -Oil pressure is 50PSI at idle on a warm motor. Up to 80PSI cold. Doesn't seem like it could possibly be bearings. -Timing chain is tight, guides, tensioner, etc all new and looked great when I did the head gasket a few weeks back. I triple checked everything when it was re-assembled. Sounds like it could be coming from the bottom end, but honestly it was built so well, and everything is literally pointing towards everything being fine in the bottom end. I haven't cracked the pan yet, but I will if I can't find it. I just don't see a reason why I need to check there yet. Been throughout the motor with a stethoscope and can't find a source, the knock sounds like it's coming from everywhere. Pan, waterpump, block, etc. Anywhere I go I can trace the sound. I also have a slight vibration when accelerating. The motor mount looks like it's collapsing over to one side, and the 'L' shaped plates that are on the top and bottom pieces of the mount might be tapping, but pulling the motor over to one side doesn't seem to affect the noise. Although it would explain the tapping only when the motor rocks, and the vibrations when I accelerate (motor twisting on the mounts.) Both mounts are less then 1.5 years old. Although this thing could be tearing them up. It was suggested that it might be a loose flywheel, but it seems if that would be the case then the knock/rattle would disappear or change it's frequency/consistency when the clutch is pushed in. I have yet to pull the starter to feel the flywheel. It was balanced and turned before the motor was assembled and the bolts were torqued and loctited to spec when assembled, with a good clutch. No reason why I see this thing backing out. (Ignore the mess on the block. It's been cold outside and I need to clean the leaks off the motor that i just fixed. oh and I know my header leaks. It's annoying. ) http://youtu.be/XSGR5ULKzrg Just hoping maybe someone can think of something I might be overlooking. It's pretty damn frustrating hearing this thing. I'm pretty close to buying the black top SR from my boss and selling this LZ. Quote Link to comment
ggzilla Posted February 11, 2014 Report Share Posted February 11, 2014 Two common causes: * exhaust touching body, frame or transmission * motor parts hitting something maybe pan hitting crossmember 1 Quote Link to comment
bananahamuck Posted February 11, 2014 Report Share Posted February 11, 2014 Is the gap between trans plate and engine a optical illusion or is there a good size separation there? .20 seconds in 1 Quote Link to comment
metalmonkey47 Posted February 11, 2014 Author Report Share Posted February 11, 2014 Checked both of those, the exhaust tap is more of a ping, I sat under with it on ramps and saw nothing contacting. Quote Link to comment
metalmonkey47 Posted February 11, 2014 Author Report Share Posted February 11, 2014 Is the gap between trans plate and engine a optical illusion or is there a good size separation there? .20 seconds in holy wtf brb I'm gonna check that in the morning. I didn't see that from below Quote Link to comment
flatcat19 Posted February 11, 2014 Report Share Posted February 11, 2014 Completely unrelated. I just had a rig in my shop come in. Complaint is loss of oil pressure/no start. Engine seized. K&N oil filter collapsed in. Suffocated oil pump. K&N is the new Fram. Quote Link to comment
Ranman72 Posted February 11, 2014 Report Share Posted February 11, 2014 holy wtf brb I'm gonna check that in the morning. I didn't see that from below I noticed the gap also check the bottom 2 bolts for tight also sounds like K7N might also be crap filters check the waterpump and pully also some strange noises come from those sometimes make sure bolt on front main pulley is tight the washer can make an odd sound if loose for more suggestions post in biebers gift basket :fu: :fu: :fu: :fu: :fu: :fu: :fu: :fu: 1 Quote Link to comment
Driftease Posted February 11, 2014 Report Share Posted February 11, 2014 I had a similar problem on my stroker it turned out to be the keyway in the damper had worn. It sounded like a rod bearing too. There is a lot of energy there for it to absorb especially with an aggressive cam and a little play on the key will be quite loud. Quote Link to comment
banzai510(hainz) Posted February 11, 2014 Report Share Posted February 11, 2014 loose alternator????? mount/alt? crank hitting oil pan? all trans and engine bolts tight? Quote Link to comment
smoke Posted February 11, 2014 Report Share Posted February 11, 2014 If that gap is just an illusion, it sounds a bit like end-play knock. With it running, put it in gear, put on the brake, with no throttle, let out the clutch just enough to drag the engine down a bit. Does it get worse or stay the same? Quote Link to comment
jrock4224 Posted February 11, 2014 Report Share Posted February 11, 2014 touch the front upper section of your oilpan where its flatest..... while its running..... my connecting rod bolt was tapping on it in my l20b...i can barely hear anything in the video ...except a lumpy ass cam also with a warn alt belt my saturn alt can touch the idler arm on a very lumpy idle from motor shake........ new belt fixes it but it only does it when its idling like yours ..... at its shakeiest lol... Quote Link to comment
jrock4224 Posted February 11, 2014 Report Share Posted February 11, 2014 oh shit i suggested before asking for a donation to the bieber gift basket too ... damn it 1 Quote Link to comment
datzenmike Posted February 11, 2014 Report Share Posted February 11, 2014 Engine off, grab the valve cover and try rocking the motor from each side to simulate a rough idle. If you hear something it's likely outside of it like a MM or lose alt/starter, pan to cross member??? Quote Link to comment
jrock4224 Posted February 11, 2014 Report Share Posted February 11, 2014 Video this ......^^^^^^^ do wanna see Quote Link to comment
metalmonkey47 Posted February 11, 2014 Author Report Share Posted February 11, 2014 Just read your suggestions guys, I'm at work right now... be back after work!! And about the donations...lol check the thread later. I'll explain everything. Quote Link to comment
jrock4224 Posted February 11, 2014 Report Share Posted February 11, 2014 TRUCK THREAD OR BEWBS THREAD? Quote Link to comment
flatcat19 Posted February 11, 2014 Report Share Posted February 11, 2014 Bumpity the bumps. Quote Link to comment
datzenmike Posted February 11, 2014 Report Share Posted February 11, 2014 Poor MG..... :crying: :bye: :lol: :lol: :lol: Quote Link to comment
metalmonkey47 Posted February 11, 2014 Author Report Share Posted February 11, 2014 TRUCK THREAD OR BEWBS THREAD? Both! Well maybe not the truck thread... Poor MG..... :crying: :bye: :lol: :lol: :lol: Damn mike, we aren't sympathizing with a floozy girl are we? Screw her 7 times over :ninja: So the truck went up in the air today at a buddies shop. They took a few minutes from playing with the customers Mach 1, and the other dudes Trans Am to load my truck in a bay and get underneath. After about 1.5 minutes we found the noise right below cylinder one. You can feel the tapping on the pan. Not sure if one of those BBC rod bolts are tapping the pan for some reason, or if the bearings gave way. I'm gonna go ahead and order bearings and hope that's all that it is. In the meantime it will be parked. Anyone got suggestions for good quality oversize bearings? .010''/.25mm oversize. I was told this motor got ACL race bearings, but I don't even see them on their catalog. Quote Link to comment
ggzilla Posted February 11, 2014 Report Share Posted February 11, 2014 That's bolt touching pan. Quote Link to comment
ggzilla Posted February 11, 2014 Report Share Posted February 11, 2014 That's bolt touching pan. For great bearings, buy Nissan which are multi layer type. Quote Link to comment
datzenmike Posted February 11, 2014 Report Share Posted February 11, 2014 Damn mike, we aren't sympathizing with a floozy girl are we? Screw her 7 times over :ninja: no MM, I'd never do that. :no: Quote Link to comment
smoke Posted February 12, 2014 Report Share Posted February 12, 2014 Agree with the guys about maybe the rod bolt hitting the pan. Easy enough to check out. Quote Link to comment
jrock4224 Posted February 12, 2014 Report Share Posted February 12, 2014 pulled my pan and bfh'ed it back to shape...i was running no pan gasket too though Quote Link to comment
flatcat19 Posted February 12, 2014 Report Share Posted February 12, 2014 Problem solved. Post tits. 6 Quote Link to comment
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