Source of Noise Found! And its not good

[Xvetteowner]

Well after many a night looking for the source of the "marbles in a can" sound coming from my 1987 WE4 ( 85K miles) at 1700 rmps. I found it, a rod bearing. The noise goes away when I remove the spark plug wire to a plug. Is the normal couse of action a complete rebuilt or can I just replace the bearing? Engine runs great, 145 psi across the board, steady idle, good vacuum, no blowing of smoke/water.

 

[KevinB]

Probably a rebuild. I tried just the bearing replacement one time. It work for about 15 minutes then it came back.

 

[Xvetteowner]

That's what I was thinking

The purchase price of the car was good, it looks great So why not do it right?

 

[charlief1]

Yes you can just replace the bearing and about 5 minutes after you start the car it will be doing the same thing. You need to at least remove the crank and the offending rod and take them to the machine shop to be checked out.

 

[Xvetteowner]

Why can't things be easy?

Reminds me of a story from 1974, My buddy needed to rebuild his 1966 Corvette, 427 3x2 carb engine. I think he paid $3500 dollars for the car. Anyway it seemed like a good idea at the time to have some guys over to help with the repairs..I can state for a fact four 17 years olds, Led Zeppelin, beer,pot and a toque wrench do not mix. The motor started fine and rev'd one time to about 2000 rmps to break in the cam when all hell broke loose, One of us forgot to toque the rod bolts. It sounded like an M-80 going off in the garage. When his parents came running and asked "What happened?" We told them.... "Nothing" As the smoke filled the garage. He sold the car a week later for 1500 dollars with a broken engine. Watch in 5 to 10 years what these Grand Nationals are worth. $$$

 

[A2000RICH]

Well after many a night looking for the source of the "marbles in a can" sound coming from my 1987 WE4 ( 85K miles) at 1700 rmps. I found it, a rod bearing. The noise goes away when I remove the spark plug wire to a plug. Is the normal couse of action a complete rebuilt or can I just replace the bearing? Engine runs great, 145 psi across the board, steady idle, good vacuum, no blowing of smoke/water.

i have had good luck overall replacing a rod bearing without a teardown-----by that the score is about 7 to 3-------seven that worked and 3 that didn't-------if it can be done it comes down to one thing------was the car run hard or long AFTER it started knocking-------if so it might have caused distortion of the rod cap-----measure it if you have the ability-------if the rod is still round you can lightly polish the crank with a strip of fine grit paper and put in a .001 bearing and odds are very high it will work fine--------not long ago a friend was at the local drag strip-------off the line he detected a rod knock and immediately he got out of the gas-------had his car towed to my shop and within 2 hours his car was running fine and thats been almost two years--------someone else tried it just last week and had no luck-------it can be done and considering the alternative its sure worth a try...............RC

 

[Xvetteowner]

Thanks for the input

I'll find a good shop in Ct Or ever better I look for someone that knows what there doing and ask them to come to the house to fix it. If I can find someone that works on "the side" What is a fair rate? 40 dollars an hour?

 

[GNRick]

$65/hour if it works, $40/hour if it doesn't. Per Richard, we're only talking a 2 hour job.

 

[rtviper]

Wow in 1974 someone had already replaced the motor in their 66 vette? The tri power motor had to be a 67 or newer. Maybe they just put on the tripower?

 

[novaderrik]

Wow in 1974 someone had already replaced the motor in their 66 vette? The tri power motor had to be a 67 or newer. Maybe they just put on the tripower?

i'm sure there were plenty of 66 427's that were replaced before the end of 1966..
my grandpa was telling me about the brand new 69 Z/28 that my dad bought when he got back from his Army tour in Thailand. within 3 months he was on the third warranty engine, and GM bought the car back from him.
apparently, the 302 Chevy didn't hold up to abuse as well as they thought it would..

 

[rtviper]

I bought a new 1968 Nova with the 327/325hp motor after the Service. This was the old 327/350 motor with a quadrajet. I raced that car several times a week for about 6 years without a failure. High 12's in late 60's was a quick street car. Guess I was lucky
Sure miss the good old warantee where they replaced anything no matter how you drove the car

 

[Xvetteowner]

The 1966 Vette had one holley carb

The owner of the Vette sold the car with the 3x2 to my friend. I think it was the addition of that intake that got the four of us thinking that a fresh motor was in order. Leave it to young "kunckle heads' to kill and prefectly running big block in short order. It's funny the cars we drove everday then in the rain and snow, mid year Vetts, my own 1970 Ram Air IV, 1970 W-31 Olds and a real Superbird plus many others were in the parking lot of Commach Hight School on Long Island each day. Now if there still around they are under a cover in the garage used on sunny days only... .I should use the financial show I co-host ( It's pretty big show) to reach out to see if these guys are still around. I got $1650 dollars for my GTO in 1977 on trade in for a new Trans Am....It seemed like a good trade at the time. I got the T/A after passing on a 1965 GTO converted to a L-88 and for sale by Motion Performace in Baldwin N.Y. My father said with 6 mpg its a waste of money, I think it was 5000 dollars. Lord knows what that's worth today

 

[Chuck Leeper]

Yep!!

I bought a new 1968 Nova with the 327/325hp motor after the Service. This was the old 327/350 motor with a quadrajet. I raced that car several times a week for about 6 years without a failure. High 12's in late 60's was a quick street car. Guess I was lucky
Sure miss the good old warantee where they replaced anything no matter how you drove the car

I was a field rep for Chevy back in the late 60's mid 70's..
There were MANY guys that were lucky to have me making the "inspections", and issuing the 740 authorizations for everything from rear ends, to engines!!
Of course, I had first hand experience w/ failures that were always "product related"!!

 

[rtviper]

I remember blowing the rear end out of the Nova in a race. GM replaced my 4.11 rear gears with 4.56 gears.
Friend of mine bought a 63 427 mystery motor Biscayne and was sucking valves about once a month from over revving. The dealer just fixed it no questions asked.
I even took the car in for work with cheater slicks still on the car and headers. The Quadrajet was replaced with Holley but dealer never said a word.
This was in a very small town so maybe that was the difference?

 

[HP Man]

In my days we took an old leather belt and used it as a bearing to quiet down the rod knock so as to sell the car! All fun aside, pull the engine to check it over for the proper repairs. That metal has gone through the engine so more damage is done. Now the radiator engine oil cooler is filled with that bearing material and cannot be flushed out, been there and had a second rebuild after. Tear down the engine and check it over and rebuild it right. MHO. Worth doing it right. Notorious is the 3.8 V6 spinning the #1 or #2 rod bearing. Sorry to say this but many have found out the hard way. Good Luck. Gene

 

[V8killR4U]

Well after many a night looking for the source of the "marbles in a can" sound coming from my 1987 WE4 ( 85K miles) at 1700 rmps. I found it, a rod bearing. The noise goes away when I remove the spark plug wire to a plug. Is the normal couse of action a complete rebuilt or can I just replace the bearing? Engine runs great, 145 psi across the board, steady idle, good vacuum, no blowing of smoke/water.

Im trying to figure out a similar sound...Sounds like rattling/ticking, like something knocking up against the fire wall. How did removing a spark plug wire eliminate your sound?

 

[Just a Six??]

I had the exact same issue at 2200 RPM Same thing exactly & to the eye the bearing looked pretty good until you really looked hard.
The way I did it was unhook injectors until I found it.
For he last poster. The reason you do it is it takes the load off the rod thats got no juice & it will usually shut it up right away. Mine did & seems the thread starter had the same results.

 

[Xvetteowner]

I was lucky,

It was a rocker that caused my problem. I had it fixed before I sold my car.

 

[4-71/Z-28]

Probably a rebuild. I tried just the bearing replacement one time. It work for about 15 minutes then it came back.

+1, besides the crank will need to be cleaned up anyway

 

[Lynn D. Brown]

Rod knocks

Another test that says it's the rods and not the valve train - loose rods usually knock when U "let off" the throttle (~30-40 MPH). It's a medium-to-high pitched rattling, rapping sound. Once U have heard it, U won't forget it

Loose Mains usually do the opposite, they knock when Ur on the throttle, and it a lower pitched, heavier sound. Sometimes they "thump".

Valve train noises are usually high pitched and U will often hear them at idle. But it can vary a bit, since there are so many different pieces that can go wrong.