Banger rod knock

R

Rokkern

Junior Member
First drive with new clutch innstalled, ran great ! So great it threw a rod bearing. I was doing about 50mph which should'nt be a problem right?
Wondering about either
1. Opening the oil pan, remove some shims and doing an easy fix
2. Pulling the engine and rebuild, while innstalling an unknown condition banger to get me thru the summer.

An "easyfix" sounds pretty old school and cool to me.
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If it's Babbitt I don't think removing a shim is going to help, others may correct me.
Pull the pan and rod cap, then decide what to do. FWIW
Paul in CT
 
If you threw a rod bearing, you better just remove the engine and start working on getting it rebuilt. Any babbitt bearing that breaks or is damaged is not usable without replacement. Remember, something had to cause it. No quick fixes for this.
 
I usually find that a "quick fix" turns into a major repair of rebuild later, usually at the most inopertune time.
 
What do you mean "threw" a bearing? Out the side of the block, or you had a knocking start, and how bad? A simple knock may well be fixable by removing shims. Look at it first.
 
Good point by James. A center main is fairly easy to do an old school adjustment. Providing there is no babbitt damage. Of course you cant tell from the bottom if the block side of a center main is damaged. Have you isolated the problem to a rod?
 
I will be following this one.. My engine knock is getting worse day by day. That's Okay if it's toast but engine is coming out to go through it as little as I can get away with.

I am mostly concerned with accessibility and easy of replacing the pan and rear main seal without pulling the motor.
 
PC/SR said:
What do you mean "threw" a bearing? Out the side of the block, or you had a knocking start, and how bad? A simple knock may well be fixable by removing shims. Look at it first.
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It ran just fine, a few misfires and I adjusted the air mixture to try and correct it, and then it changed motor sound. Took it down rpm´s immidiately and inspected clutch, all looked fine.
Had to drive a few miles on the highway to a gas station and then two three hours to get home. FIgured I was in for a rebuild anyway so as long as it ran..
Knocking was consistent and audible, could feel the knock at the pedals but not in the seat or steering. Knocking was consistent the whole time. Not getting worse.

Deacceleration - not audible
Acceleration - not audible
Cruising - knocks pretty bad.

I guess you could say it´s not the worst kind of rod knock.
 
PC/SR said:
Good point by James. A center main is fairly easy to do an old school adjustment. Providing there is no babbitt damage. Of course you cant tell from the bottom if the block side of a center main is damaged. Have you isolated the problem to a rod?
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Not at all, had some experts listening to it to get second opinions. We all think it sound like a rod. Have not inspected it yet.
 
If it ran for 2,3 hours to get you back home, I too doubt its a rod bearing. I'd be more apt to think its a main bearing or even something inside the bellhousing.
 
Like James, my first thought is also the center main. When I first bought my 29 Tudor, it sounded great at idle and very low speed, but anything over 15 MPH and the engine sounded really bad and had a bad vibration. There was no babbit left on the center main.
 
The sound is there at idle too, I can make it worse or better as I drive by adjusting the timing too.
I pulled the inspection cover for the clutch, everything looked ok, all bolts and nuts where there.
I did also have a pretty big oil leak between engine and bellhousing. A few drops each stop, but did also leak about a feet big pool two different places at one time during a gas stop. Two hours after the knock appeared. Didn't happen before or after ??? The sound is comming from the rear of the engine, thinking maybe the rear main bearing is shot too.

I do have about 1/4-1/2" endplay at the crank.

What's involved with replacing the main bearing?. I know they are babbitt, but not much more about the type of bearings. Is it even possible to replace them ?

On vacation now so won't be able to do any work on it next 8 days..
 
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Rokkern said:
The sound is there at idle too, I can make it worse or better as I drive by adjusting the timing too.
I pulled the inspection cover for the clutch, everything looked ok, all bolts and nuts where there.
I did also have a pretty big oil leak between engine and bellhousing. A few drops each stop, but did also leak about a feet big pool two different places at one time during a gas stop. Two hours after the knock appeared. Didn't happen before or after ??? The sound is comming from the rear of the engine, thinking maybe the rear main bearing is shot too.

I do have about 1/4-1/2" endplay at the crank.

What's involved with replacing the main bearing?. I know they are babbitt, but not much more about the type of bearings. Is it even possible to replace them ?

On vacation now so won't be able to do any work on it next 8 days..
Click to expand...

That is way to much end play. It must leak a lot of oil. Sounds like it is time for a rebuild.
 
The engine can be rebuilt but, where you are it is going to be tough. I would say babbitt men are few and far between in Oslo, Norway. I will say there are several people in Norway that post here that might help.

End play should be .003 on a new engine and no more that .014 on an old one. More than this and it will leak. The leak will be as bad as the end play with the leak being more as end play increases.
 
Luckily my engine builder and friend here in Norway has done flathead bangers before. He has three in his shop as we speak! I had no idea because he's a mopar guy and I've only taken chevy stuff to him before, never talked bangers with him.
He's doing a normal bearing conversion, f head conversion, pressurized oiling and has bored these blocks before many times. I just bought the car three weeks ago so we never got to talk bangers.
This is just great. I'm sure he can build me a mean banger. Now I just need a stock engine to get me thru the summer.
 
Opened her up today.
Rod number 4 had approx 2mm/0.0787" play in it. Measured by eye.
No play could be felt at 1,2,3 or any of the main bearings.
Also measured by eye (where workin in my fathers shop without my tools, the crank had somewhere between 2-3mm/0.0787-0.11812 of endplay, too much I know but hoping it will take me thru the summer while doing a rebuild in the winter.

So how do I fix this the easiest way ?
1. Have someone poor new babbitt on that particular rod
2. Have my engine builder convert to insert bearing on that rod (is this poosible without other modifications to oil system ?)
3. Get another used rod with good specs on the babbitt´s ?

Seems to me it is possible to remove the rod from the engine from the underside, slide the pin out and let the piston stay. Anyone done this ?
 
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