How many things "Sound" like a rod knock, but arn't!

Had a crazy experiance this weekend at the Showdown.

After about 7 laps of cramming mud in every inch of my car, I got back in line for one more turn. I was standing behind the car and Denise was moving it as the line went and I heard it....The most perfect sounding rod knock noise coming from the pan.

My heart sunk, I pulled the car out of line and had a few people listen to it and everyone though the same thing. It had that unmistakable echo sound that comes from the pan when a rod is knocking real good. Even had a pro engine builder take a listen and he thought it had the familar sound of a rod knock. Bummer now what.

Well I'm almost 600 miles from home and this is not even gonna make it back to the hotel by the way it sounded. So I go get a U-haul truck and Trailer and figure I'll tow it home. So I go get an over priced tow rig to haul the roadster home. I get back to the show and figure I'm all set.

Well I fire it up to move it over to where I had the truck and My new best friend Mike with a very cool hemi powered 32 sedan hears it and gets under says it "Feels" like it's coming from the inspection cover for the flexplate and converter. So I get under and put my hand on the cover and sure enough it seems like the noise is actually coming from there.

Now Mind you it still sounds EXACTLY like a rod hammering away. So I figure I have nothing to lose by dropping the cover and seeing what happens. So we take the car over to the camping area and Tony from the PackRats(Thanks again man) helps me get the car up on some blocks so we can get under it easier and get the pan off. We get the pan off and guess what, about a pound of mud and rocks !!!

So I start it up and nothing, no noise My luck day!!!!!!!!!

The after market chromed inspection cove has small louvers in the bottom to scoop air for alittle extra cooling for the converter I guess, OR to scoop mud to ruin my day at the showdown hahaha!

Seems a stone must have been hitting the converter or a converter bolt and making a sound indentical to a rod nocking.....unbeliveable

Well needless to say The over priced tow rig goes back to Screw-Haul,,,,Oh I mean U-Haul .

And now it's atoo late to make anymore hot laps hahah like I needed to get any more mud on the car .

So the moral of the story here is how many other noises have you ever hear that sounded like a rod knock or someting you thought was something for sure and turned out to be something else?

Photos available of the muddy roadster avaliable elsewhere on the HAMB

 

A cracked torque converter can make a knocking noise... more of a "popping" knck though...

Sam.

 

New crank hitting oil pan. That took awhile to find!

 

Wife in the trunk...

 

rockers bumping against valve covers. sounds like a knock but is usually consistant even at idle... knocking... not tapping.

 

Cracked flexplate.....

 

A cracked flexplate will make a rod sound.

 

Long ago ... when I was a teenager ...
I was having the same sounds ... and I was pretty brutal on the little 327/4speed 55 Chevy ... so I figured that was a rod knocking.

I was taking the fuel pump off ... to get ready to remove the engine ( already had the headers, starter and radiator off ) ... and the fuel pump fell into pieces in my hand ... Knock-knock-knock The lever was broken ...

Never have I seen that before or since ...
Got a new fuel pump ... put everything back together and went back to abusing the 327 ...

Glad you got it figured out ...
I lost a engine on the way to the NATIONALS in Kentucky one year. Over 600 dollars to roll back it home ...

 

Torque converter bolt backed out just far enought to catch the webbing on the back of the block. And if you ever thought you had a rod knock this IS it. Tighten bolt, rod knock goes away.

Frank

 

what makes the sound of a rod but isnt.......The palm of your hand hitting your forhead over and over because you went and paid money for a Uhaul you did not use....

 

Just glad to hear it had a happy ending. Next year, leave "Big Olds" home and bring Denise. You would never hear it if it WAS knocking over the screams and laughter!!! You Michigan guys are a trip!!

 

I had heard that you may have been having some troubles.Im glad that it was only MUD .You were hub deep a couple of times in turn 3 and On the gas!!!

 

We have already discussed that. Bringing two cars is CRAZY! CRAZY expensive. The Showdown is for cars exactly like Rudys roadster. Big Olds will not be attending a Jalopy Showdown in the future as long as I have a boyfriend with a cool *** roadster that loves to laugh and get muddy as much as I do.

and honey, you forgot to mention that not once did I call you a dumb*** or get pissed because I only got to do 7 mudd laps all day. Don't I get some sort of perfect girlfriend award for the weekend.

 

Mechanical fuel pump, loose Harmonic balancer, loose torque converter and the aforementioned cracked flex plate have been some that I have experienced. Pull one plug wire at a time while its running, and if one cylinder has a knock, it will stop or change tone when you pull the plug on the effected cylinder. Good luck! - Mike

 

You two are the perfect couple .Glad to hear it was something minor.A piece of carbon on top of a piston will make a hell of a noise. I also had when plowing snow the dizzy hit the firewall and ****ed it it. made a noise . I always look before I jump now.Cookie were good.

 

The wife in trunk version cracked me up...

But seriously... loose bolts from the torque convertor to the flyweel. Doesn't even have to be cracked...

Happened in my 348 3x2 hooked up to an aluminum PG. It's bad enough that I am deaf, but a deaf guy trying to find an obvious knock is like a blind guy trying to find the same chick in a crowded *****house on payday. So finally one guy says check the flexplate and sure enough, 1 bolt was gone and 2 were loose. Fixed it (after checking for elongated holes) and the knock was gone and I found my chick in the *****house

Travis

 

the way i determine where something is coming from is use a stethscope, broom handle, stick, or piece of water hose to determine where, then find out why. had it happen several times.

 

The lady at the toll booth asking what the hell happend to you to get to muddy and then saw my car

That was priceless

 

Loose lead in the combustion chamber from the old gas.

 

Thats good you found what it was! any now you know there is a price to pay for having all that fun in the mud!!

my buddie had a similar experiance, one day he started his car and heard what sounded like some kind of clicking from near the valve covers, now he figures it's some thing in the valve train and calls me up and as he is about to go through the valves i come over listen to it, laugh for about five minutes before i explain that its a terrable exaust leak in his header that was drilled and tapped for some sensor, keep in mind though he is much of a mechanic!

 

Loose timing chain slapping the cover...

Glad you found it...





JOE

 

I had a cracked oil pump shaft that knocked like a rod. Didn't find it till I towed it home (I also had no oil preasure ) to tear it down, Got lucky nothing but the oil pump. Thanks to AAA, didn't have to pay U haul.

 

I had a 283 one time, and sometimes it would develop a God awfull knock. It would scare me just about to death, then it would go away for a few weeks, then when you least expected it, it would come back. I was offered various opinions---sticking hydraulic lifter, piston slap----Never did find out what it was. The engine was still running and still holding good oil pressure when I wrecked the car on a snowy road one morning going to work.

 

Strongly suggest you pull plug wire before starting engine -- according to my son trying to do it while engine is running is a rather shocking experience

 

1970 Chevelle SS396, 4spd...loose flywheel bolts can definately sound like a rod knockin...

a 250 inline 6 that someone shoves in a 59 biscayne can develop sounds much akin to a rod knocking. Especially unnerving at 2:00 AM on an old dirt road along the Mulberry River, with a girlfriend who just got "spooked" by "something" that she swore was watching the two of you (edited), drove the car home, parked it for two weeks, started it up, it never knocked again..wierd.

 

I know it is another worst case senerio but a wrist pin also sounds like a rod knock except it can be a lot worse if not caught it time. I had to dump the scored block and start over again. Gumpa

 

You should of known better, that things been running great. Even Race couldn't blow it up. Glad it was just mud.

 

Good point Gus, and we all how hard he tried

 

I've seen it a bunch of times. All on SBC it seems too. I got a buddy a nice score on a 305 that was supposed to have a rod out. When we were loading it I see this badly cracked flexplate. Ended up being a nice runner for the price of a core.
Loose flywheel bolts will do the same thing.

 

Hey Rudy, my pleasure..happy to help out anyway i can.
i'm just REALLY glad it was nothing serious....and that you got that truck back to "screw haul" before they closed..
When you started it and there was no noise, it just made my weekend.

Great to see you guy's again.

had to add this.. one of my 283's had a very distinct knocking noise develope, sounded very much like a rod knock and was coming from the front of the pan area. I thought it was a rod, especially hearing the noise toward the front lower part of the mill knowing that the front of the crank is the last of the journals to get oil..just about all the rods i've seen develop a knock are in the front of the motor on sbc's.
After spending some time going over everything, i had found the balancer had become loose and was actually knocking around on the crank snout..
These don't have crank bolts, so there was nothing to ensure it stayed put..
I drilled the crank, used a nice new crank bolt and installed a new balancer...
Sure made me happy

Tony