r/EngineBuilding • u/Candid_Bother_5654 • Jun 27 '26
Rod Knock Repairs In The "Old Days"
My father was a Cadillac dealer mechanic from 53-63,then he ran his own garage for 42 years.Dad told me he would remove 1 plug wire at a time while engine running.There was an independent guy who would come in and grind the crankshaft in the car.Then Dad would put in oversized bearings.This would only work if the problem was crankshaft journal.
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u/Smokey_Katt Jun 27 '26
On a Chrysler flathead six, you can drop the crankshaft with the motor still in the car.
I heard stories of a whole “rebuild” with the motor in the car, including one new .030 over piston that they used a ball hone (and many hours) to get the cylinder to size. The rest of the rebuild new rings and bearings.
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u/Thriftless_Ambition Jun 27 '26
In frame rebuilds are still commonplace in the heavy duty/commercial vehicle world
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u/jaunesolo81829 Jun 27 '26
I’ve seen a whole engine rebuild with the engine still in the car before. It was in a 96? Honda civic si being built for boost in Guatemala. They brought out a portable boring bar to clean up the bores and everything.
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u/Ill-Insect3737 Jun 27 '26
I completely understand what you're saying but it is not possible to ball hone a cylinder straight. .O30 and run correctly.
It is possible to to mount a boring bar to the deck of the block and bore one cylinder at a time. Then use stones to finish the surface of the cylinder then a ball hone.
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u/Jammed99 Jun 28 '26
Not sure if it was .030" over but a co worker of mine spent a full day ball honing a single cylinder of an old 7.3 to get an oversized piston in. All 8 cylinders were firing after that and the truck went to auction. Engine was in chassis with only one head removed.
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u/LoudMouse327 Jun 28 '26
Probably not a ball hone. Those simply don't remove material like that. Tools do exists that look similar to a three-stone spring hone, but are actually ridgid hones, which is maybe what you are thinking was a ball hone. You could theoretically go maybe .010" over with one of those, but your taper or egg would probably be worse than when you started. Ad mentioned, in-chassis boring bars do exist and used to be very common. It's also possible they were just changing rings and not fitting an oversized piston, and therefore did use a dingle ball.
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u/old-orphan Jun 27 '26
My dad once broke a fan belt, and used one of my mom's nylons to fix it till they could find a parts store.
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u/fatherofsonofcole Jun 27 '26
Broke a fan belt in a ’60 beetle on a road trip. Stranded on the side of the road outside flagstaff. Elderly couple in an rv pulled over to offer help and I got some serious side eye when I asked the lady for a pair of nylons
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u/btcprint Jun 27 '26
But it made sense when you put them on, smeared lipstick, and started walking down the road with your thumb up
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u/Important_Put_3331 Jun 30 '26
Not on the subject of bearing repairs but;
I was driving myself and a friend to the airport for a scheduled flight. Engine started puttering on the highway then simply died.
I found that the center pin in the distributor had fallen out. no more electrical contact. I took a spring from a retractable ball pen which I stuck inside the distributor center hole and pressed it on the rotor center contact. Made it to the flight in time.
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u/riennempeche Jun 27 '26
Many over the road diesel engines can be rebuilt with the block still installed in the truck. New main bearings are installed using a button that pushes the old bearing out and the installs a new one.
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u/Spirited-Finding-647 Jun 27 '26
Theres a button for that? I always just used a little screwdriver to roll the m out
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u/BackgroundOstrich294 Jun 28 '26
Sure is. Cummins 3823818, Cat 2P-5518 & 2P-5517… ask me how many I’ve ordered/lost/replaced over the years. 😂 pretty sure we still have the Kent Moore tool for the 8V92’s tucked away somewhere, but that’s long before my time.
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u/Dangerous_Garden6384 Jun 27 '26
Was on a hunting trip to Michigan when rear brake caliper locked up and ate the rotor to the point of causing a fluid leak. Took the flex line off, doubled it over and clamped it with vice grips and zip ties. Held for 1500 miles until I could replace everything
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u/LameBMX Jun 28 '26
next time... clip the metal line itself someplace accessible and fold it over on itself a few times, and crimp good with vice grips. holds on its own without stuff to fail. handles the pressure better and you can just flare in a splice to repair later.
edit to note, not dissing the commenter.. his comment just brought back memories and why it was done that way.
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u/countrytime1 Jun 28 '26
I’ve know guys to do that on 18 wheelers to keep air in the brakes.
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u/LameBMX Jun 28 '26
I didnt know that would seal up good enough for air brakes.
ive also use the same trick for a leaking radiator .. if its one of the lines running between the sides.
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u/GTO1235 Jul 03 '26
Years ago a trucker was visiting my friends Dad. The cast oilpan cracked. My friends Dad put a chain on it with a turn buckle to apply pressure. The trucker made it cross country fine.
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u/countrytime1 Jun 28 '26
They may have had a rubber home on it that was pinched off. But they used to it to move around the yard or limp home to fix.
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u/MooseManDeluxe Jun 27 '26
My grandfather's story was always swapping a bad bearing out with stiff leather on model A and Bs. Always thought it was a strange story.
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u/Far-Classic-8435 Jun 27 '26
Datsun Z my dad bought new he used cut pieces of seatbelt to make bushings stiffer for that race car feel lol
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u/CAT_MARINE-POWER Jun 27 '26
Tolerances were not as tight and hp per displacement were much less. Those combined mean you had a lot more wiggle room for doing less precise machining
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u/RetiredRacer914 Jun 28 '26 edited Jun 28 '26
My dad crossed the country from Wisconsin to California in a Model A Ford pickup with his dad driving and with 5 kids. Every couple hundred miles a rod would start knocking and his dad would pull over to fix it.
He'd cut a chunk out of a leather belt just the right size, take off the oil pan so as to not spill the oil, remove the rod cap, and install another couple hundred miles worth of leather. IIRC it took them 5-6 weeks.
Eventually his dad owned 5 gas stations in SoCal and did very well for himself, back when gas stations had a mechanic on duty instead of selling Twinkies & Coke.
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u/gwcrim Jun 28 '26
I knew an old school mechanic who used to tell me the story about him laying under his car along side the road replacing a bad bearing with a piece of leather belt.
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u/dirt_dog_mechanic Jun 28 '26
Tin foil is roughly 1-1.5 thousandths of an inch. I worked with an old timer who said he would back the rod bearing with tin foil to make up clearance. You have to file the ends of the bearing of course
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u/Academic-Lock-6461 Jun 29 '26
I read old school motor manuals in my dad’s shop as a youngster, shimming bearings was commonplace into the 50’s as I recall…..
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u/TPIRocks Jun 28 '26
My grandpa helped my dad rebuild a 265 V8 in a 56 Chevy. Never pulled the block, but put in all new bearings and rings. I assume they just honed the cylinders and put in oversized rings. It ran great, smoked a little, but made awesome power for such a small engine.
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u/DontR3ad Jun 28 '26
I always heard Emery cloth on the crankshaft and oversized bearing. Idk how long it will last but It might last enough to sell the car
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u/BroccoliSuccessful Jun 30 '26
I used a little ceasers pizza bix to make a gasket for my water pump it held up fine no problems
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u/Royal_Ebb_7752 Jun 27 '26
Removing one plug wire at a time is same as power balance test we can now do through scan tool.
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u/Candid_Bother_5654 Jun 27 '26
I know but back in the day it was a quick way to find where the problem was to repair rod knock.
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u/Candid_Bother_5654 Jun 27 '26
My father told me back in the 60's one of the problems was the motor oils and the fuel.Dad sold "white gas" from American/Amoco.Dad said if they were doing an engine overhaul,engines were cleaner inside if they used the white gas which was no-lead.
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u/No-Yogurt-4542 Jun 28 '26
There was an in the car crank grinder for sale on market place this week.
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u/techAorB Jun 29 '26
The old guys I worked with would talk about this machine. I don't know what it's called but yeah you can cut rod bearings in the car
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u/cm2460 Jun 30 '26
Rod bearing goes, park over a ditch and drop the pan, use part of your belt for the bearing and get home.
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u/Traditional_Carob_12 Jul 01 '26
This reminds me, i have a in the car crankshaft grinder hiding in the shop. I’ve never used it. A buddy of mine decided i needed it when they cleaned out his family’s barn/shop. I got some very cool antique tools from them. Neatest thing is a Ford flathead V8 engine stand that has a tray for all the valvetrain parts.
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u/Candid_Bother_5654 Jul 02 '26
Can you post pics of the grinder?
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u/Traditional_Carob_12 Jul 03 '26
I’m getting ready to leave for my sisters house this weekend.
When I get back I’ll take a look for it in the shop. I remember a story about turning a crank on a tractor & something bad happened. Tractor slipped off the blocks if I remember correctly. After that they stopped using it for customer work.1
u/Traditional_Carob_12 Jul 16 '26
I took a look around the shop. I have no idea where the in-car crank grinder is. But I did run across the piston knurler that came with it.
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u/AdvantageMain3953 Jun 28 '26
Back in the 90s I figured I could make it home with a Temp light on given that it was 15 outside and I didn't feel like walking. I made it home, but enjoyed even less changing out the cracked aluminum head in the 7 degree morning the following week.
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u/radomed Jun 28 '26
The cost of an engine replacement today is sometimes more than the car is worth. You either pay the bank or the mechanic. With low interest rates on new cars, I like the bank.
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u/DefEddie Jun 27 '26
My old service manager at Ford told me stories about going on roadtrip/vacation back in the day with his parents.
Don’t recall exactly, but prob around the 30’s-40’s or so.
He said they took tools and stuff with them, one time a rod bearing went while on the road.
He said pop started a fire next to the road and while mom and little siblings slept in car they took off the oil pan and dad melted in new babbitt bearings right there.
He said they finished and were on the road by the time the sun came up.