Newbie with connecting rod problems

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Model T Ford Forum: Forum 2010: Newbie with connecting rod problems
Top of pagePrevious messageNext messageBottom of page Link to this message  By patrick j wegelin on Sunday, June 06, 2010 - 03:03 pm:

I was going along happily yesterday when all of a sudden a jackhammer noise started up, luckily though abt a mile from home.
I dropped the bottom axcess cover this morning to find babbit chunks from #3 rod.
I'm guessing that i should probably
1) examine the mains while i'm in there and readjust if needed
2) pull the head and examine the cylinder walls
3)replace rods with a new set if above seem ok

Unfortunately i just got this a couple months ago and believed it was rebuilt, but wondering as I'm not seeing shims in some places, mains and rods.

am I proceeding ok?
tnx Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, June 06, 2010 - 03:21 pm:

You can check the rods easily without pulling anything else than what you have already pulled. With the crankshaft journal all the way down, try pulling up and down on the rod. and try twisting it as though you would be turning the piston round and round. You should not feel any movement in those directions. However it is normal to have some front to back movement in the rod bearings.

One at a time remove the cap from each rod and buy a strip of "plastigauge" from your friendly auto parts store. place a strip from front to back along the rod cap and install the cap in the same direction you removed it. Place exactly the same number of shims back in place and tighten down. Then remove the cap and check the width of the plastigauge. There is a scale on the package that shows the various widths indicating the amount of clearance. Then remove some of the shims. Normally they are laminated and each lamination is one thousandth. So you want to remove enough shims to get .0015 inch clearance. That is 1 and 1/2 thousandths.

While the cap is off, inspect the babbit and look for cracks of piecies of babbit missing. This will show up on the rod rather than the cap. If all looks good, put oil in and tighten up. You might want to leave each one a turn loose until you have checked and adjusted all 4. Then when they are all adjusted, tighten and put in the cotter pins. If you have a 3 dip pan, the 4th rod will be harder to reach than the others. Be careful not to drop anything in the crankcase behind the 4th rod.

If you need to work on the mains, it is much easier to pull the engine and the entire crankcase to get to the main bearings. The center main can be reached by pulling off the valve cover, but you cannot remove the cap from the front main and the rear main cannot be reached from a 3 dip pan it is also very hard to work on the rear main from a 4 dip pan.

If your worn bearing is the number one rod, you could have an oil problem. There is an oil pipe running between the rear of the engine between the flywheel and magneto to the front of the engine behind the timing gear. If that pipe gets clogged you will not get enough oil to the front of the engine.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Christopher Lang on Sunday, June 06, 2010 - 04:21 pm:

So, while we are talking about looking up through the bottom dip cover... Here's my dumb question. Should you be able to see the oil line inside there easily? When I first got my car, I took the dip cover off, to clean it out, I don't remember seeing the oil line, but I didn't really look too hard either, as I was so gung-ho to go for a drive. I need to go back under there to check the rods with plasti-gauge anyway.

Thanks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon on Sunday, June 06, 2010 - 04:56 pm:

Yes, the oil line can be easily seen. It can also be easily not seen. It should be angled down towards the front and below the camshaft.
W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By patrick j wegelin on Sunday, June 06, 2010 - 05:27 pm:

Norm,
i'm not sure if i made clear,
I removed the rod cap and the #3 rod babbit is completely disintegrated.
so thats' why i'm thinking that I will probably need to install a new set of 4 rods,
and thats' why i think i will have to pull head anyway for that.
and since there's lots of babbit crumbs in crankcase near that cylinder, i figured i will have to check cylinders for scoring.
does that sound right?
tnx patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenny Edmondson on Sunday, June 06, 2010 - 06:31 pm:

Pat, Everyone has a different definition of "rebuild". Unfortunately to some it means new rings or other partial repairs. You need to mic the rod and main bearing journals on the crank to see if they're round and what size they are compared to std. journal size. You need to make sure the oil line isn't plugged with band lint. You should also drop #1 main and rod caps to see what they look like since they are the furthest from the oil supply. Let that stuff be your guide to what approach to take next. Putting it back together "as is" could result in the same failure.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, June 07, 2010 - 12:15 pm:

Patrick,
you will have to do at least pull off the head and repour the rod bearing, or find another rod with good babbit and straight. Someone in your local club should know of a person who can align the rod and pour the bearing.

While it is down check all the other bearings and mike the crankshaft for out of round and size of the bearing. If it is within tolerance .002 inch taper or .002 out of round. Measure horizontally and vertically and subtract. The difference is the out of round. Then measure front and back of bearing surface on crankshaft. difference is taper. If it is within .002, you can repour the rod and use the crankshaft.
you can replace the rod and go back on the road. If not, you will need to regrind or replace the crankshaft. Since you caught this early the crank might be ok. There might have been a flaw in the babbit which caused this and not caused by normal wear. I.E. the babbit had a bubble in it or was not bonded to the rod. It is not normal for it to break unless it had been quite loose and knocking for some time. Overheating would cause the babbit to melt rather than to crack in pieces.

You can check the oil line if you still have oil in the crankcase, by turning over the crank a few times and oil should flow out in the front of the engine around the timing gears. Put a pan there to catch the oil! If it does flow your oil line is working.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By patrick j wegelin on Monday, June 07, 2010 - 12:30 pm:

good info Norm and others and tnx.
I was sitting here going thru archives and head was spinning.
What you're suggesting makes clear sense to me, I'll proceed on this route
tnx pjw


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stan Howe on Monday, June 07, 2010 - 03:31 pm:

Take a look, also, at the babbit in the bottom of the pan. Is it gray and grainy looking or is it shiny pieces??? If it is gray and grainy it probably is very old babbit and may have lead in it. You probably should pull all the rods and at the very least look them over. You may just want to pull the engine and check the whole thing out. "Rebuilt" varies a lot. I could tell you of some that were a can of spray paint and a shot of WD-40 down each cylinder. Others are top quality all the way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Monday, June 07, 2010 - 04:15 pm:

Yeah, there's about 40 brands of "Miracle in a Can", right Stan? Remember "Motor Honey"? (not rally that much of a "miracle")


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Monday, June 07, 2010 - 04:16 pm:

Sheesh,.....fat fingers; I meant "REALLY"


Top of pagePrevious messageNext messageBottom of page Link to this message  By patrick j wegelin on Wednesday, June 09, 2010 - 09:17 am:

Ok, i got a little further into it last nite,
the rod journal is at 1.244-1.246 both round and taper.
also I pulled the head and it appears this engine has never been rebored, a quick measure at top was 3.744.
i still have to check all the bearing caps
If the other caps seem ok, i'll just have this one rod repoured.
Since it was running well before the #3 rod bearing blew,I'm wondering how far i should go?
for instance should I put in a new set of rings since i'm in there?
should i go as far as putting in new alum pistons or just leave it alone.
Even if I do need main caps, is this crank a candidate for putting in the repoured/bored to original like Macs sells?
any advice appreciated
tnx patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson on Wednesday, June 09, 2010 - 09:46 am:

The cylinder measure is odd? Perhaps you should check again? From the 1923 Ford Dealers data book, http://www.mtfca.com/books/ford.htm#mot : "The cylinder bores (-) after the boring and reaming operations vary in diameter from 3.748" to 3.749". They are then rolled to a diameter of 3.750 with a special power-driven rolling tool."


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, June 09, 2010 - 11:18 am:

If it were mine, and I checked the cylinders for taper and out of round and found them within tolerance, I would lightly hone the cylinders to a crosshatch pattern, and install new rings. I would put the same pistons in the same cylinders facing in the same direction they came out. To do this, mark the front and cylinder number at the top of each piston before removing. This can be done with a center punch putting a small dot at the front of #1 and two small dots front of #2 etc. The original pistons will fit best into the unbored cylinders. If you choose to rebore, get the pistons first and bore to fit each individual piston.

Same way with rods, same rod in same position facing the same direction with cap in same direction it came off, except for the rod you re-pour or replace.

Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money on Wednesday, June 09, 2010 - 11:24 am:

If everything else checks out ok, I'd change the rod in #3 and put it back together as it seemed fine before the problem. Others will tell you to completely overhaul it anytime you pull it apart.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Sosnoski on Wednesday, June 09, 2010 - 11:45 am:

You have two options here. The first is to simply replace the rod and put it back together. The second is to rebuild the entire engine/transmission and possibly more. You are starting down a slippery slope, the one where "I have it this far apart I may as well do that while it's apart." Before you know it you are going to be into everything. My general rule is "If your not going to fix it - don't look at it".

My recommendation would be to buy a set of four new rods. Balance the rods end for end, then install on the pistons. Adjust the weight of each piston/rod assembly so they are the same, then put it back together. Make sure to put the same piston in the same cylinder facing the same way.

The reason I say this is because I had a rod bearing go three years ago - the #2 bearing. The engine was running fine at the time and we never could figure out why that one rod suddenly let go. I simply fit a new rod, made sure the oil line was free and put it back together. It's still running fine. The only issue I have is that it has a vibration at speed which I didn't notice before. I think that is because the replacement rod is not the same weight as the other ones which makes things out of balance. I had bought a complete set of four rods even though I only needed one, and at some point I will probably pull it apart and do as I recommended above. While I'm in there I'll probably replace the original 1 piece valves. While I'm doing that I'll probably also replace the lifters and install a new cam. Since it's that far apart I may as well bore it and install some aluminum pistons. Of course I won't put it back together without installing a new field coil and recharging the magnets. Oh, and the transmission should be rebushed, the pan straightened and a new fourth main installed.

Or, maybe I'll just drive it the way it is.

Dave S.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Weir on Wednesday, June 09, 2010 - 04:59 pm:

Stan Howe; Around here we call it a Sherwin-Williams overhaul

Sincerely

Jim Weir


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