Tom Wesenberg
Well-known member
Be sure to also measure the side clearance on the rings. It looks a bit loose in the one picture, and it might be time for a new set of 4 pistons, rings, and rods.
Banger rod knock
- Thread starter Rokkern
- Start date
Special Coupe Frank
Well-known member
Well, in the original post, Rokkern was looking for a quickie-fix to get him through the summer driving season, then doing a full rebuild over the winter...
Just a few more miles & the crank shaft would have been damaged Pistons are not likely to weigh the same as they are not a matched set.It has been burning a lot of oil as well.If it had modern insert brgs you wouldnt have driven a mile without damaging the crankshaft.One time I drove about 30 miles with a rod brg that looked similar.I grounded the spark plug on the bad cyl,& drove with light throttle & made it home & crank shaft was not damaged or out-of round.Try that with insert brgs!Modern isnt always better.
I just read all the posts, tanks for all the advise. It's burning a lot of oil yes! I'm pretty worried about blocked oil passages. there was alot of bearing material in the pan. There where a lot of oil in the baffles, and If the oil supply to the rods where poor number 1 would let go first right?
I'll answer the other q's later, on my phone now.
Let me know If you wan't any other pics. Going to the workshop later.
I'll answer the other q's later, on my phone now.
Let me know If you wan't any other pics. Going to the workshop later.
Kurt in NJ
Well-known member
If it has original Ford pistons most likely there would be NO worrys with weight when using an original Ford piston , when I first got a good scale I weighed all the rods and pistons I had---any NOS piston --std, .020, .060, centerlonk --endlock all were within 5 grams -----then I weighed aftermarket (badger) sets ---those had as much as 40 grams difference in the set, the boxed sets of Ford pistons and rods were all within 1 gram
I had 1 rod loose it's babbitt, the replacement rod is something like 10 grams different, I had some flywheel balance vibration before, now I have some more vibration, before the rod let go I had 67 as top speed, after it lost some top speed 62-64 mph ---but the has still run for 20 years more, yes there was lots of debris to clean out of the pan, but the debris are 99.9% babbitt, I didn't remove the side cover to clean ---
#1,#2 get first chance at the oil, when the valve chamber fills it overflows the front dam and pours into #1 dipper trough, when the back of the valve chamber is full it flows back the return pipe and onto the dipper tray between #1 and 2 ----most likelt the bond between the rod and the babbitt was somewhat weak and there was some excessive clearance that caused some pounding --not quite a knock you could hear and the babbitt crumbled ---for me it happened all at once, I thought the car ran over a telephone pole when it happened ---then I heard the knock, with the spark retarded and driving slow it hardly knocked, I made it the 5 miles to home and didn't damage the crank
Measure the crank journal, measure the bore, put in a rod, set of cheap rings and drive it for the summer ---the "temporary" rod I used has lead babbitt, I thought I was going to fix it that winter ---quite a few winters have passed and my car still runs --I don't go on 200 mile trips away from home but I think nothing of putting 100 miles on the car locally in a day
If the screen on the oil pump is intact it won't pump any chunks large enough to block passages, and by design the pickup is a ways off the bottom of the pan and the oil feeds for the bearings are higher than the bottom of the valve chamber so debris have a chance to settle out and not have easy acess to the bearings
I had 1 rod loose it's babbitt, the replacement rod is something like 10 grams different, I had some flywheel balance vibration before, now I have some more vibration, before the rod let go I had 67 as top speed, after it lost some top speed 62-64 mph ---but the has still run for 20 years more, yes there was lots of debris to clean out of the pan, but the debris are 99.9% babbitt, I didn't remove the side cover to clean ---
#1,#2 get first chance at the oil, when the valve chamber fills it overflows the front dam and pours into #1 dipper trough, when the back of the valve chamber is full it flows back the return pipe and onto the dipper tray between #1 and 2 ----most likelt the bond between the rod and the babbitt was somewhat weak and there was some excessive clearance that caused some pounding --not quite a knock you could hear and the babbitt crumbled ---for me it happened all at once, I thought the car ran over a telephone pole when it happened ---then I heard the knock, with the spark retarded and driving slow it hardly knocked, I made it the 5 miles to home and didn't damage the crank
Measure the crank journal, measure the bore, put in a rod, set of cheap rings and drive it for the summer ---the "temporary" rod I used has lead babbitt, I thought I was going to fix it that winter ---quite a few winters have passed and my car still runs --I don't go on 200 mile trips away from home but I think nothing of putting 100 miles on the car locally in a day
If the screen on the oil pump is intact it won't pump any chunks large enough to block passages, and by design the pickup is a ways off the bottom of the pan and the oil feeds for the bearings are higher than the bottom of the valve chamber so debris have a chance to settle out and not have easy acess to the bearings
Thanks for all the replies, this is great food for thought. I'm om my phone so will have to get back to the specific q's later. Going up to the garage now. I'm planning to use the foil method, i guess this will be easier with the piston off.
I'm hoping to get the engine thru the summer yes, so this is nothing else than patching it together and hope for the best.. That beeing sad I have not found the cause of why the babbitt let go. Metal fatigue and pushing the ole lady to hard, maybe with too low ignition,
I don't know. Rod cap was not clogged. And if little oil (clogged oil passages) was the reason it's fair to think the number 4 rod would have been the best supplied rod right?
For now I'm leaning towards:
"babbitt was already worn - it had no shims, and the little clearance it had hammered the bearing until it finnally started to give up"
I am worried about not being able to clean all of the oil passages, but knocking on wood and hoping for the best and drive carefully might take me thru the summer. At least now I have a few rods stored.
I'm hoping to get the engine thru the summer yes, so this is nothing else than patching it together and hope for the best.. That beeing sad I have not found the cause of why the babbitt let go. Metal fatigue and pushing the ole lady to hard, maybe with too low ignition,
I don't know. Rod cap was not clogged. And if little oil (clogged oil passages) was the reason it's fair to think the number 4 rod would have been the best supplied rod right?
For now I'm leaning towards:
"babbitt was already worn - it had no shims, and the little clearance it had hammered the bearing until it finnally started to give up"
I am worried about not being able to clean all of the oil passages, but knocking on wood and hoping for the best and drive carefully might take me thru the summer. At least now I have a few rods stored.
The cap is in the same condition as the rod. Shot.
No idea how many miles. Alot would be my best guess. These cars where beaters until 1961, when they opened up for being new cars in Norway. Norway where a really poor country post war and hot a lot of help from US at the time. This car is a sold new in Norway and has all the classic repairs from the time. Patches, brush paint some places etc.
It sat from 64-2011 in a barn.
I don't know the condition of the other rods. There where only one knocking and the others have no play you can feel. Sincethey're not broken, I'd rather not open them.
Ok. Measured the rod babbitts. The one closest to crank looked good.
Here's what I got.
1. No shim no foil. Snug fit, rod and piston where mounted on the underside of crank. Rod would stay in position i left it but move easily. At one point it would centre itself from gravity.
2. Put 3 layers of foil each 0,01mm. Total, 0,03m. Resistance was definetely there all the way round and piston would not centre itself from gravity. Somewhat heavy to move by hand force.
3. 5 layers of foil, 0,05mm total.
Piston was very hard to move and had to hammer the piston (with my hand!) to get it to move. Almost gave up but made it a whole round.
0,03mm is 0,0011".
Innstall with no shim and call it good, or take some off the cap?
Here's what I got.
1. No shim no foil. Snug fit, rod and piston where mounted on the underside of crank. Rod would stay in position i left it but move easily. At one point it would centre itself from gravity.
2. Put 3 layers of foil each 0,01mm. Total, 0,03m. Resistance was definetely there all the way round and piston would not centre itself from gravity. Somewhat heavy to move by hand force.
3. 5 layers of foil, 0,05mm total.
Piston was very hard to move and had to hammer the piston (with my hand!) to get it to move. Almost gave up but made it a whole round.
0,03mm is 0,0011".
Innstall with no shim and call it good, or take some off the cap?
Tom Wesenberg
Well-known member
No shims and call it good.
I wouldn't force the rod to make a full round. As soon as it feels tight, stop. You know you need to remove some foil and check again.
I wouldn't force the rod to make a full round. As soon as it feels tight, stop. You know you need to remove some foil and check again.
Good advise thanks !
As the crank and rod is out of round I wanted to check a whole round. Never done the foil testing before. But yes, I guess you could force it round no matter how many foil layers you put it in, so it really is no point at continuing once it is locked. It did seem tight all round so that´s good.
Will install with no shims.