What can cause rod knock in 5 miles?

[laserspeeddemon]

$15,000 total sunk into this car. $10,000 in parts alone. $2000 in machine work and a few thousand in special tools.

The idea was to do EVERY bit of the build myself. That way I could at least own up to failure. However I have been robbed of that. The first machinist bored my engine way past .40" over. The second machine shop took upon themselves to assemble the rotating assembly. They gave me a spec sheet with all clearances measured and therefore I thought for sure it was done right. At the same time I was a little bit relieved as I questioned my own skill.

But once again the poop has hit the fan. After completing the remainder of the build myself, I started her up and kept the revs above 1500 RPMS. Oil pressure was good. I shut it down and did an oil/oil filter change. Several days later I started it up doubled checked that no oil/coolant/etc was leaking idled until warmed up (idle was about 1400, later discovered the throttle cable was hung up on the main harness) and then took her on first test drive. Revs were kept under 6000 rpms execpt one time and that was only at 50% throttle. I was breaking her in using the motoman method. Oil pressure was fine during the entire run. 20 at idle (high idle) 82 psi MAX confirmed by a video.

5 miles in the car starts knocking heavily. I check things out tonight and confirm something is lose on the bottom end so I'm fairly certain it's rod knock.

What can cause rod knock in 5 miles on a newly rebuilt motor?

 

[Alan11]

im sorry to hear this, i had a 420a that knocked as soon as it started.. it really sucks man.
Any possible reasons i can think of are that.

It was torqued, assembled wrong.
Rod caps are not interchangable. (maybe thats what happened)
Wrong size bearings.

Imo if everything was done right then you can just start the car and go drive it like normal.
The only thing that needs to set (break in) are the piston rings (and that depends on what rings you use). thats just me though.

 

[bryanwheat]

IF it spun a bearing after 5 miles than it was built wrong. Either wrong clearances, crank out of round or rods not machined right. How in the world did you spend 15k on an engine build, let along 2k on machine work? I don't spend that on an entire engine build.

 

[turboglenn]

I'm sorry to hear how things went for ya (read your other thread too) but to be honest i built all my stuff myself (assembled engine in a hurry during x-mas eve and the day before and installed on x-mas night again in a hurry) The only thing i can think of is something was overlooked in the assembly of the engine, or during the fitting of the parts by either you or the machinist. Who's job was it to make sure??- I ask because my macinist will check everything and say "you can just assemble it" with pistons, rods and bearings labeled/numbered - while some machinists just do the minimum and expect you to find any ill-fitting parts like too tight a rod bearing clearance and then bring it all back to have fixed (which in my mind is crappy of a job when you ask for an engine you can assemble yourself with no special machining tools)

 

[crimsondragon]

Lack of oil getting to the rod(s). Improper installation of rod caps, end of rod out of round, improper installation of the bearing, debris. Find out which rod it happened to and work backwards from there.

 

[BogusSVO]

The two main things I can think of, besides loss of oil pressure, is a rod housing bore was out of spec, and trash in the intersectiong oil galley of the crank from the main to the rod.

From the price spent, I would have to think this build had new rods and new pistons.

That leaves the crank.

 

[cbrfrenzie]

Sorry to hear about your misfortunes. Another thing is that the bearings could have been installed improperly. Each crank bearing has two sections, each different. The bottom half with an oil hole, the top half without. If the shop installed the wrong two half's, each WITHOUT an oil hole, then after the assembly lube ran out (~5miles of driving ) the rod that gets it's oil from that main started to get robbed of oil. I've seen this exact thing happen to a buddies car.... quick lesson to learn!

 

[laserspeeddemon]

Here are the two vids that I have of the driving. The two videos amount to less than 3 miles worth of driving. I drove to the gas station and then drove back towards my "break-in" road. The first video is me living the gas station, the second video starts about 3 seconds after the 1st one ends. My camera guy accidentally hit the start/stop button. And started the video again. In the videos you can see that I had good oil pressure.

<iframe width="420" height="315" src="http://www.youtube.com/embed/n_cQZCJjUNU" frameborder="0" allowfullscreen></iframe>
<iframe width="420" height="315" src="http://www.youtube.com/embed/SUiYvD-Jdiw" frameborder="0" allowfullscreen></iframe>

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New development.

Heres video the 2nd start up. The first start up was just warming up the car then an oil/oil filter change. Now that I am listening more closely to the video, I DEFINITELY hear what seems like rod knock. I didn't hear this before because the engine/car was so loud, but my camera phone picked it up pretty clearly.

Anyone else agree?
<iframe width="420" height="315" src="http://www.youtube.com/embed/eVFd8ADbX3U" frameborder="0" allowfullscreen></iframe>

 

[chadillac2820]

What were the stated rod and main bearing clearances on the sheet you received from the machine shop? Does it look as though they actually measured? Or did the cheap out and plasti gauge one of each? Plasti gauge being the crappy way to measure...

 

[laserspeeddemon]

What were the stated rod and main bearing clearances on the sheet you received from the machine shop? Does it look as though they actually measured? Or did the cheap out and plasti gauge one of each? Plasti gauge being the crappy way to measure...

I don't have immedate access to the sheet, but I checked it against the Haynes manual.

And Really? I thought plastigague was the preferred way to measure bearing tolerances?!?

 

[Tyeler18]

Is your balance shaft eliminator installed with both bearings? My front one wasn't and I made it 5 miles. Luckily it didn't do any damaged and a new set of acl trimetals and I've got 500 miles on her now.

I don't have immedate access to the sheet, but I checked it against the Haynes manual.

And Really? I thought plastigague was the preferred way to measure bearing tolerances?!?

Plastigauge Isnt the way to go, an inside and outside Mic are the best.

 

[laserspeeddemon]

Is your balance shaft eliminator installed with both bearings? My front one wasn't and I made it 5 miles. Luckily it didn't do any damaged and a new set of acl trimetals and I've got 500 miles on her now

Yes both are installed and rotated 180 degrees to block the oil port. Plus in the video you can see my electric digital oil pressure gauge oil pressue is good.

Plastigauge Isnt the way to go, an inside and outside Mic are the best.

Yep, I just looked into it. Plastigauge is like a backup to double check your mic numbers. Since the engine was assembled for me. I stopped researching that part of the build. I trusted that a performance shop would know how to build a motor.... that may have been dumb on my part.

 

[GSLENK]

you can start pulling spark... IDK how it works on a COP setup but I would guess you can disconnect the coil (the signal wire to the coil) If the sound goes away... you found the cylinder that is knocking. On an external coil setup you have to pull the boot, connect a spare spark plug and ground the tip (with a alligator wire or something) so you don't fry the coil. Id look into doing something like that before you pull the pan. And if you have caught it soon enough you may only be out a bearing.

 

[delta448]

Sorry to hear this Sean. I would be calling the second machine shop and asking to talk to the person who took it upon themselves to assemble the bottom end without permission. You have proof enough in this thread and your odometer that they should take it upon themselves to make it right.

 

[Tyeler18]

you can start pulling spark... IDK how it works on a COP setup but I would guess you can disconnect the coil (the signal wire to the coil) If the sound goes away... you found the cylinder that is knocking. On an external coil setup you have to pull the boot, connect a spare spark plug and ground the tip (with a alligator wire or something) so you don't fry the coil. Id look into doing something like that before you pull the pan. And if you have caught it soon enough you may only be out a bearing.

Ecmlink allows you to kill injectors individually which will do the same thing just easier.

Sorry I'm on my phone so I cant watch the videos well, I also skimmed the thread quickly so I'm not 100% on all the info given. Do you have a short video of the sound Its making? I'm sure youre trying to avoid starting it, but a 15 second video may help.

 

[crazytsiawd]

In my experience lack of oil causes bearings to fail.

 

[ed1380]

Plastigauge isn't the best but the price/results it has the best ratio. Too bad with a bad bearing its too late for plastigauge.

 

[boost97gst]

Got over $10k in mine. First machinist built it: 300 miles and it started knocking.
He re did it, and im over 400 miles and holding up so far: fingers tightly crossed. I know the feeling bro, it hurts. Makes ya wanna cry

 

[CrashGNX]

Sorry to hear about your misfortunes. Another thing is that the bearings could have been installed improperly. Each crank bearing has two sections, each different. The bottom half with an oil hole, the top half without. If the shop installed the wrong two half's, each WITHOUT an oil hole, then after the assembly lube ran out (~5miles of driving ) the rod that gets it's oil from that main started to get robbed of oil. I've seen this exact thing happen to a buddies car.... quick lesson to learn!

Just for clarification here, The MAIN bearing TOP Halfs have oil holes. The bottoms and the rod bearings do not.

also, just because you have oil pressure doesnt mean its getting to where it needs to be.

 

[Tyeler18]

Just for clarification here, The MAIN bearing TOP Halfs have oil holes. The bottoms and the rod bearings do not.

My acl trimetals have oil holes on both sides, in fact I believe my rods did too.

 

[muddfisher85]

Sounds more like a bad lifter to me. Then rod knock in your second start up video. Mine sounded just like that when I had one bad lifter. It would cause my check engine light to come on for knock but I have it set really low just for that sort of thing. Wow your only like an hour from my house. Maybe me and my buddy could ride up and help you get it done.

 

[laserspeeddemon]

Sounds more like a bad lifter to me. Then rod knock in your second start up video. Mine sounded just like that when I had one bad lifter. It would cause my check engine light to come on for knock but I have it set really low just for that sort of thing. Wow your only like an hour from my house. Maybe me and my buddy could ride up and help you get it done.

I'm going to PM you my number. I'm dropping the oil pan tonight. I took the lifters and rockers out and did a compression test. I could still hear a knocking, so I'm 100% sure it's rod knock.

also, just because you have oil pressure doesnt mean its getting to where it needs to be.

I used a drill on the oil pump socket. I had oil come to the head rather quickly. This is a good sign that there was no open ports. If say the BS shaft bearings were missing, there would need to be more pressure to get oil to come to the top.

 

[muddfisher85]

Ok cool. Hope its not rod knock and its a bad lifter.

 

[crimsondragon]

My acl trimetals have oil holes on both sides, in fact I believe my rods did too.

The top main journals have oil holes. The main caps don't have any oil holes feeding to the bearings. The top bearings are supposed to have the oil groove.

 

[boost97gst]

I'm going to PM you my number. I'm dropping the oil pan tonight. I took the lifters and rockers out and did a compression test. I could still hear a knocking, so I'm 100% sure it's rod knock.



I used a drill on the oil pump socket. I had oil come to the head rather quickly. This is a good sign that there was no open ports. If say the BS shaft bearings were missing, there would need to be more pressure to get oil to come to the top.

Man, my deepest condolances. SMH, i feel terrible for you. If YOU think its rod knock, it probably, unfortunately, IS. You know cars and engines well. The video i heard could def have been rod knock. Even a lifter wont sound like that. Rod knock will trip the knock sensor in my personal experience.