LouMercado
Junior Member
I sometimes have some grinding while I shift. Is this normal? I have a 1930 model a
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Gears 1930 model A
- Thread starter LouMercado
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Mike Peters
Well-known member
Use the heavy 600W gear oil as well for the best shifting.
First understand what is grinding. The gears are not modern synchro-mesh so they have to slide into each other. Try to keep this in mind...the purpose of first gear is to get to second and the purpose of second is to get to third! In other words don't rev it up like a modern car, shift quickly at like 5MPH into second and at 10-15 MPG into third. YES 600 oil in trans to help slow them down when the clutch is in, here's a big one for me...when going into second and third hold that shifter HARD to the right it really helps for some reason, BE SURE THE IDLE is slow, in other words have the right side throttle arm as slow as possible to let the gears slow down as you shift. A high idle will always cause grinding.
Patrick L.
Well-known member
Good info above.
Take your time. These old monsters are not in a hurry to do anything.
As said, shift 1-2 while just moving. 2-3 at about 12-15mph. Nice and slow and feel the shifter slip along. No need to double clutch.
Down shifts are different. Double clutch. Until used to it, its better to raise the engine speed a bit too high then leave it a bit too low. Take your time, you'll get used to it.
Like most things, its a learned skill.
Take your time. These old monsters are not in a hurry to do anything.
As said, shift 1-2 while just moving. 2-3 at about 12-15mph. Nice and slow and feel the shifter slip along. No need to double clutch.
Down shifts are different. Double clutch. Until used to it, its better to raise the engine speed a bit too high then leave it a bit too low. Take your time, you'll get used to it.
Like most things, its a learned skill.
Y-Blockhead
Well-known member
I'm so used to double clutching I even double clutch my Mitchell O/D. In fact I'm so used to double clutching I sometimes find myself double clutching my F-150... and it's an automajic.
Big hammer
Well-known member
A nice slow engine idle is needed when shifting like what's stated in the owners manual or double clutching ! I shift both ways 1-2 @5-8 mph,2-3@12-15 mph or if I'am in a hurry double clutch
Patrick L.
Well-known member
I'm so used to double clutching I even double clutch my Mitchell O/D. In fact I'm so used to double clutching I sometimes find myself double clutching my F-150... and it's an automajic.
LOL. It does become a habit doesn't it !
rotorwrench
Well-known member
Shifting a non synchronized transmission is an acquired skill that gets better with understanding and time. Double clutching can help but it's also a lot about getting used to the rpms matching for the different gear selections. First off, it's important to have good hearing and recognition of the sound of the various rpms that a particular gear likes to start out at. Just letting off the throttle allows the countershaft cluster to slow down but you don't really need to let it stop turning. It just needs to be allowed to slow enough to match the rpm that the next gear needs to match it.
I know that this may not make much sense to folks but a smooth shift will only happen when the cluster is going the same speed as the main output shaft. I learned to drive in an old 1952 F3 pickup with the non-syncho 4-speed and I was able to anticipate the correct rpms for upshift and downshift after I got used to it. Low gear was the only one that I seldom ever tried to downshift to because it wasn't practical If I was coming to a stop anyway.
I know that this may not make much sense to folks but a smooth shift will only happen when the cluster is going the same speed as the main output shaft. I learned to drive in an old 1952 F3 pickup with the non-syncho 4-speed and I was able to anticipate the correct rpms for upshift and downshift after I got used to it. Low gear was the only one that I seldom ever tried to downshift to because it wasn't practical If I was coming to a stop anyway.
1928Mik
Senior Member
My Dad put his car away and it sat for 30 yrs. I resurrected it and had to learn all over again how to shift. I ground some gears til I figured out the timing. Patrick L. is correct on the method. My Dad always had a truck with a manual transmission, and always shifted them the same way, just get up to 5-10 mph and then shift to 2nd. The engines would lug along at slow speed and practically stall, but since he had grown up in the Model A era, he just thought that's how you do it! He ruined an '89 Chevy dump truck motor doing that!
Purdy Swoft
Well-known member
Lugging the model A engine can-will beat up the babbit .
Patrick L.
Well-known member
So, just what is lugging ? I'd like to know, been hearing it my whole life.
Henry says to shift our old monsters from 1-2 at 5-8 and 2-3 at 12-15. So what are the engine speeds while we're doing this ?
As long as there is an oil cushion and no metal to metal contact,,,,,,,
Henry says to shift our old monsters from 1-2 at 5-8 and 2-3 at 12-15. So what are the engine speeds while we're doing this ?
As long as there is an oil cushion and no metal to metal contact,,,,,,,
Mister Moose
Senior Member
I would define lugging as too high an intake manifold pressure for the current RPM. Combustion impulse forces get transmitted down to bearings much more when lugging. It's not just oil film, it's the beating. Just like detonation can ruin an engine even though lubrication is adequate.
It's going to be a function of shift speed, yes, but also load. How steep is the hill you're on? But it's hard to quantify with x rpm at x grade at x speed with x weight in the car.
However, if you step further on the gas and you get an immediate increase in speed, you are not lugging. If you step further on the gas and get no increase in speed, or the increase is painfully slow, you just might be lugging.
It's going to be a function of shift speed, yes, but also load. How steep is the hill you're on? But it's hard to quantify with x rpm at x grade at x speed with x weight in the car.
However, if you step further on the gas and you get an immediate increase in speed, you are not lugging. If you step further on the gas and get no increase in speed, or the increase is painfully slow, you just might be lugging.
Y-Blockhead
Well-known member
Yes, I see low vacuum on my "Motor Minder" when in too low of a speed for throttle position (as when in too low of a gear or when going up hill). A quick downshift cures it.
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Patrick L.
Well-known member
I agree in part.
I've been flying over 50 years and a lot of it is done operating over-square. [ manifold pressure v rpm] [ also lean of peak]. Doesn't hurt anything when done correctly.
However, some think lugging is what causes or can cause detonation. I suppose its a fine point or a matter of terminology. Detonation/ping/spark knock [ not pre-ignition] can be somewhat hard on an engine and is caused by too much load [ combustion temps and pressure] along with too much ignition advance.
Mister Moose
Senior Member
I don't think lugging in a car bears any resemblance to 23/25 in an airplane. Go feather a Continental IO-520 at cruise power if you want to hear lugging. And there really isn't an automotive equivalent to operating over-square.
I think its more than terminology. Lugging is still controlled burning, but the cylinder charge is too much for the RPM/load. Detonation is uncontrolled too rapid burning which is too close to an explosion inside your engine. That's what octane does, it slows down the burn rate. This is also different than pinging from pre-ignition from carbon or retarded timing.
What do you fly?