MTFCA Forum

I got careless (stupid) when adjusting my rods, putting oil in the caps but neglecting to fill the rod dips before starting. At about 30 seconds a loud knocking occurred. Pulling the inspection pan revealed #3 rod was loose and had damaged babbit. The journal looks pristine, and the other rods are tight. The engine is now out of the car. Due to the difficulty getting head gaskets, as well as wondering if it is difficult, I ask if the rod can be replaced through the inspection pan without pulling the head or should I just pull the head?

The number 3 rodcan be changed through the bottom. Be careful to not bend the rod when wrenching the wrist pin bolt
Art Mirtes

noelchico wrote: ↑

Fri Oct 28, 2022 7:16 pm

I got careless (stupid) when adjusting my rods, putting oil in the caps but neglecting to fill the rod dips before starting. At about 30 seconds a loud knocking occurred. Pulling the inspection pan revealed #3 rod was loose and had damaged babbit. The journal looks pristine, and the other rods are tight. The engine is now out of the car. Due to the difficulty getting head gaskets, as well as wondering if it is difficult, I ask if the rod can be replaced through the inspection pan without pulling the head or should I just pull the head?

"... neglecting to fill the rod dips before starting..."

I can pretty much promise you, that had nothing to do with it. Best luck in your repairs

Hey Doc - I don't think it had anything to do with "not filling the dips" which would defy gravity ! Something else must be amiss. Even though it "could" be possible, I've been into enough engine repair to not recommend it.

I replaced the #1 rod in the car in a motel parking lot. Not fun and don't let the bottom ring come out of the cylinder but it can be done. Do be careful tightening the wrist pin bolt.

Thank you, gentlemen, for your comments. I may try to pull the rod through the bottom. If it doesn't work, I'll pull the head. The crank looks pristine, measuring 1.235, so it must have had a regrind when overhauled 15 years ago. Since all the other rods look good, I assumed the problem was my not pouring half a quart of oil in the front to put oil in the dips before the stock internal line, mag post filler, and Horlick style filler on the hogshead could get oil there.

Don't use heavy oil in a Model T. That's especially important with tight bearings, and when starting the engine in cool or cold weather. 5W20 or 10W30 synthetic oils work very well in Model Ts. In cold weather, a 0W20 gives excellent results.

If you get into trouble Doc, drop me a note - I'd send you a new copper head gasket - do it the correct way !

Someone enlighten me on just how do you hold the piston tight to tighten the wrist pin bolt ?????

I tried to replace one with the head on once. Bottom ring popped out and piston was jammed against the center main bearing.
Norm

Let that be a lesson to others.
After replacing the dipper/inspection cover, put in a Quart of oil, or @ start up the engine is dry.

RajoRacer wrote: ↑

Sat Oct 29, 2022 10:52 am

If you get into trouble Doc, drop me a note - I'd send you a new copper head gasket - do it the correct way !

Someone enlighten me on just how do you hold the piston tight to tighten the wrist pin bolt ?????

Been a while since I did a rod change like this.(during a national tour, day 1. There's a whole story there.)
I believe I turned the piston to where I could put a long bolt thru the wrist pin to hold for tightening the wrist pin cinch bolt.

I'd want to take the head off. When done adjusting rods or mains, I'd add fresh 5W20 synthetic oil. Adding oil at the filler cap ought to flood the troughs with clean oil. I'd put in 3 quarts, then hand crank the engine with the ignition off for a dozen rounds or so, then add another 1/2 quart of oil and immediately start it, keeping speed below 1200 to 1500 RPM until the engine is hot. Once warmed up, if everything sounds good, drive away, taking it easy for 30 miles or so.

That sounds plausible John - I wouldn't attempt that task under the car.

And while you have the head off the engine clean out all the water cooling holes in the head and the block. Sometimes it’s necessary to use a drill to drill out the small holes in the head and block. They get scaled and grow smaller over many years. Of course be careful and take your time. A Model T needs all the cooling it can get and cleaning out all the coolant holes can only help.

RajoRacer wrote: ↑

Sat Oct 29, 2022 11:55 am

That sounds plausible John - I wouldn't attempt that task under the car.

I would not either under normal circumstances. Its no fun & I was much younger then. But, it was quite satisfying to get my T back into the game overnite for the rest of the tour.

I replaced no 1 rod in Henrietta, through the inspection pan. It was done on a hoist to make it easier. I did not want to disturb her any more than is essential, so pulling the head was ruled out.
A used rod with sound Babbitt, was filed, scraped and lapped with timesheet. The wrist pin was held in place with a piece of rod inserted, which registered on the web in the block. The only tricky bit wad compressing the bottom ring on the cast iron piston enough to get the piston back up the block.
I repeat, the whole job was done in this manner just to preserve the original appearance of the car. Otherwise, pulling the head is the way to go.

Allan from down under.

In my view there's no reason to take the piston and rod out the top if all you want to do is replace the rod. It's easily and more quickly achieved out the bottom, and you won't require a new head gasket - and as long as you only cemented one side of the pan gasket you shouldn't need a new one of those either.

In doing this I'd expect the bottom ring to escape, you can get slim 'clip' style ring compressors but I have simply used a large jubilee clip (hose clamp) with good (and inexpensive) results. Unless something untoward occurred you should be able to get the job done within an hour.

Probably not a bad idea to make up a small kit of spare rod, jubilee clip and requisite split pins to have sitting under the seat/in the boot or wherever, ready for the next time. Perhaps the best thing about this is that if you do have the spares handy in the car you'll never need to use them

Luke.

In follow up, I was able to remove the #3 rod through the inspection port fairly easily. I put a bolt through the wrist pin and rotated the piston so that the bolt contacted the block to avoid twisting the rod, and removed the wrist pin bolt. I slid the wrist pin partially out with a long L shaped allen wrench, and removed the rod. With the engine out and the inspection pan out, I don't think it took 15 minutes. Unfortunately, the replacement rod I ordered and received today is non-Ford and is 83 grams heavier, so I am awaiting getting my Ford script rod re-babitted and bored to my .015 under rod journals. I checked the other 3 rods and they are all Ford script. Oh well, this gives me time to fix the axle I broke on the Ohio tour.

With T model Fords? The fun never ends!
Fortunately, overcoming occasional breakdowns is part of the fun!

Am I crazy yet?

What Pat said if you remove and replace the head about oiling and warm up. I would add, however, after you warm up the engine, before you drive it, that you re-torque the head bolts. They tend to loosen up and the gasket compresses a bit so if you have a steel head, torque it after it cools again, then you can warm it up and drive it. If you have an aluminum head, let it cool completely before you torque again. Then warm it up and drive it. After you 30 mile run at slower speeds, torque again as above. If it holds torque after being driven you are ready to drive as you normally would drive the T.
Norm

You will find that most gasket sets and tech information on any engine with cast iron head, bolts or nuts, will require re-torquing when engine is at operating temperature.