Knock developed....bearing question

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Model T Ford Forum: Forum 2015: Knock developed....bearing question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Brian Mettling - Dayton OH on Saturday, September 19, 2015 - 08:38 pm:

hi all,

I recently developed a nasty knock in my '22 motor, and sounds like it's coming from #1 piston area. I checked the fan pulley and the timing seems okay, so I'm thinking it could be a connecting rod bearing. I've never dived deep into a motor to investigate anything like this before. So my question is, can I order a new babbited bearing and rod and can it be hooked right back up? Seems like it wouldn't be too bad, but never done it before. does it just bolt right up?

thanks!
https://www.modeltford.com/item/3024RXSTD.aspx


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Saturday, September 19, 2015 - 09:31 pm:

You would be lucky if you can, first you need to establish what has been done to the crank in it's life, ground or worn etc, basically it's a job for someone who knows what they are doing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, September 19, 2015 - 10:06 pm:

Brian

Suggest you pull the pan cover and check that bearing. That's a relatively easy job, especially on #1. Connecting rod should be hard to push front and rear on the crankshaft with your fingers, but should move easily with a light tap with a small hammer. Check them all while you have the pan cover off.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Saturday, September 19, 2015 - 10:27 pm:

Short each cylinder out one at a time with screwdriver placed on plug to ground on head. Noise should quit if it is that particular shorted out cylinder.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Saturday, September 19, 2015 - 10:27 pm:

You can do it. You will need to drop the inspection cover on the oil pan and determine which rod it is. You should start by shorting out each spark plug one at a time. If the knock goes away then that is the likely cylinder. Rods will clatter if you speed up the engine then close the throttle quickly. Main bearings knock under a heavy pull. You will need a 1-2 inch micrometer to determine the crankshaft bearing size. A Chinese mike will get the job done.

Before you tear anything apart, buy a reprint copy of the Original Ford Model T shop manual and the MTFCA engine manual.

You will likely be buying a rebabbited rod to fit your crankshaft.
To take the wrist bolt loose put a punch in a vise and slip the piston and wrist pin over it. Then loosen the bolt. If you grip the rod on a vise and loosen the bolt you will likely put a twist in the rod.

Everyone has a first time in the guts of the engine. Model T owners have been doing this for a 100 years. You can too. Take your time and don't force anything.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Wilson - Omaha NE on Saturday, September 19, 2015 - 10:29 pm:

Pulling tie pan cover is not a hard job, but it is a nasty dirty job. Plan ahead and protect your floor with at least one layer of cardboard, 2 layers are better than one, and a couple of layers of newspaper on top of that is even better. Have a fair amount of wipers or shop towels near by, and expect a lot of oily mess. disposable nitrile gloves are very good too. You will have 3 or 4 oil dips full of oil to contend with. I doubt it even amounts to a cup of oil, but it will seem like a gallon as it makes it's mess. I have pulled my cover 3 times this summer, first my new engine was too tight, and I had to loosen the rod nuts a flat to get it loosened up to run. Number one ended up too loose and I had to go back and tighten it.
The fist time I removed the cover, it stuck, and I had to pry it off. Of course all of the best laid plans on how to handle the oil went out the window when one side dropped and the other side stuck.
The next time I pulled all of the bolts, it seemed stuck, so I went to get the scraper I use to pry it open, and as I was crawling out from under the car, it dropped on it's own. Oil everywhere.
The last time it was more cooperative, but with oily fingers, it slipped, again oil every where. Thank goodness for cardboard.
Each time I was in and out in maybe an hour and a half. Point is, is it really is not hard, just messy and tedious, with all of the bolts you have to wrench in and out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Saturday, September 19, 2015 - 10:38 pm:

Check the pulley and pin on the crankshaft, they can make a knocking noise sometimes.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Brian Mettling - Dayton OH on Sunday, September 20, 2015 - 07:28 am:

Wow, thanks all. Especially to plan for the oil pan mess. Didn't even think if that! My wife would kill me! Thx


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Sunday, September 20, 2015 - 10:59 am:

Did I miss it or didn't anyone mention that there might be some shim left that can be removed to tighten up the rod if that is what is causing the knock. That would be a simple fix if you are lucky enough to find that the rod is shimmed or you could always take the easy way out and file the cap if the babbit is still good. I don't suggest that as a long term fix but it will keep you going for a reasonable amount of time and is a good temporary solution if you are planning to do the motor over not to far down the line!
Doug your oil mess can be reduced a bit if you jack the front of the car up fairly high so most of the oil in the dips drains back into the sump. If you get it high enough and then drop the pan what little oil that is left will stay in the dips and can be poured out. I usually don't even drain the oil when I drop the pan if it has been changed recently because with the front raised all the oil is back in the sum anyway and it is easier to work under the car if the front is jacked up and securely blocked. I don't know if anyone else does that but it works for me.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, September 20, 2015 - 11:14 am:

What WAS skipped over, in case the OP doesn't realize it, is that to remove the rod, the whole piston has to come out and that is done by removing the head. In order to replace the rod, you need to know if the crank has ever been ground. That is what the mic is for. If it has been ground, you will have to order a rod with undersized babbit. Hopefully, there are shims left and removing one will tighten it all up. Easy fix. Bad thing is, if the crank journal is not round (The mic comes into play again here), the 'fix' won't last for long. It will be time for a crank grinding. That is what happened to my wife's Touring. It developed a knock. No shims left. Filed the cap of the offending rod. It fixed it for about 6 months, but came back. Pulled the engine that time.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, September 20, 2015 - 11:22 am:

You didn't describe the knock. When is it present? A rod knock tends to be worse when you are going at a steady speed or slightly decreasing your speed. A main knock will be worse when pulling. A main knock will also decrease when you slightly retard the spark. A piston slap can sound very similar to a main knock. Other knocks toward the front of the engine are timing gear, either very worn or loose on the camshaft. Front cam bearing or the pin which is used to engage the hand crank to the flywheel. If it is that pin it tends to be worse at idle and disappear with speed.

I would suggest that you find someone in your local area who is familiar with Model T's to help you. A new rod won't help you unless you know what size the crank journal is. Almost all T cranks have been turn down and not the same original size, but sometimes the crankshaft has been replaced by one with standard size. There are also some cars with chevy crankshafts or Model A crankshafts. Besides knowing what size the crankshaft is, you also need to know if it is flat on one side or tapered from front to back. If it is out of round, a new rod bearing won't last long.

After you determine whether the knock is a rod knock, take off the inspection plate and check for shims between the bearing cap and the rod. If there are shims, remove one. Go to your auto parts store and buy some plastigauge. put a strip on the crankshaft lengthways to the crankshaft and tighten the cap. The plastiguage will crush. On the package is a measurement of the width of the plastiguage after it is crushed. Aim for .0015. If more than that, remove a shim from the other side and try again. When you get the clearance correct put on the cap and torque to 25 ft lbs and insert the cotter pin. If the pin won't go in tighten just a little to the next notch and put in the cotter pin. It's a good idea to check all the rods while you have the inspection plate off. If you still have the 3 dip crankcase, the rod #4 can be harder to adjust, but it can be don if you turn the crankshaft to a point where the wrench can be used. You will have to turn slightly for each nut in order to get the cap off.

If you need to replace the rod, it will be easier to do so by pulling the head and taking out the piston when you do so.

Anyway, best to get a little help before you start taking things apart. If you lived in the San Diego area, I would volunteer to help you free, but Ohio is a long way to go for me.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Sunday, September 20, 2015 - 02:45 pm:

Brian - I just replaced the #4 rod and cap in my speedster last month after finding the Babbitt had chipped away around the edges of both. It had started knocking, and dropping the pan and inspecting thongs quickly revealed the problem.

Having just done this, if you need some help, let me know. BTW, if it is the #1, it's a lot easier than the #4.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Sunday, September 20, 2015 - 02:50 pm:

Excuse me, that should have said inspecting "things", not thongs. Though they can fun to inspect also.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les VonNordheim on Sunday, September 20, 2015 - 10:48 pm:

I have R&R #1 rod from underneath with out taking off the head or draining the coolant. Remove lower inspection cover, rotate crankshaft to position piston BDC, pull wrist pin cotter key and remove bolt, next remove lower rod cap and bolts, push piston up slightly allowing connecting rod to swing away from crank throw, pull piston down slightly until the wrist pin can be slid to one side allowing connecting rod to drop out. Be careful not to allow the piston to slide down enough allowing rings to pop out. The force of the rings in the cylinder kept the piston in place. Having an extra connection rod with the bearing bored to size can be a big asset on tours that last several days.
It can be done....I know it sounds tricky but it was not difficult. It worked out great as only #1 rod bearing was bad.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, September 21, 2015 - 12:49 pm:

What Les said is true if you have the modern aluminum pistons. I tried to do it on #3 rod on one of my cars but the piston got cocked and the ring came out. I tried but couldn't get it out without pulling the engine. Easier to pull the head than the engine. Just a word of caution. Also if you have the original cast iron pistons, the bottom ring is below the wrist pin, so you cannot pull it down to take out the wristpin without popping out the ring.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By James Michael Rogers on Tuesday, September 22, 2015 - 07:09 am:

Just a bit of help to those who try this and let a ring slip out of the cylinder. When this happens, you can use a screw type hose clamp to compress the ring and push the piston back up into the cylinder. Have done this on many motorcycle pistons and it is the only way to do most motorcycle and Volkswagon piston/cylinders.


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