Question on connecting rods

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Model T Ford Forum: Forum 2014: Question on connecting rods
Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary London, Camarillo, CA on Saturday, February 01, 2014 - 07:41 pm:

I am going through a '15 engine soon that is completely original and turns over freely. There is some pitting in one cylinder from when the previous owner stored it with one plug out, the others all are smooth and there is no ridge at the top of any cylinders. The pistons are original and standard size...... Other than a whole lot of dirt it looks really good and unmolested. Based on the standard size pistons and lack of any ridge at all it does not seem to have lots of miles on it. It has an early narrow nose pan with a broken off mounting ear.... It's like someone removed it and put it in the barn when the ear broke and ignored it. It still has the original timer and cable.

I am hoping to rehab this as a decent spare engine, not to completely rebuild it. I'd prefer not have to send it out for babbit. I will have the cylinders honed and bored if necessary, and modern valves and seats installed. I'll measure all the journals for round and have the crank checked for cracks. When I tear it down if the babbit is good and there are still shims when the clearances are set would there be any reason to replace it?

I am sure I will find the original heavy style rods. If the babbit, crank journals and clearances are good I'd prefer to use them then have to fit new ones.... It's for a spare engine, I want it reliable, if I need to use it for a year or two I want to count on it, but it will never be a high mile, high speed engine.

I've always been told to use the lighter rods, but I don't really understand what he problems are with the heavier ones other than weight. I would have them balanced along with aluminum pistons. And the crankshaft.

Can someone explain what the issues are with using the heavier rods, and explain to me any concerns about the babbit?

ThanksI


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Saturday, February 01, 2014 - 08:37 pm:

I have found many blocks that still have good Babbitt, as long as it is not worn badly or coming loose I would use it. KGB


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steven Thum on Saturday, February 01, 2014 - 08:49 pm:

Model T's do not get a ridge as the top ring goes all the way to the top of the cylinder. As long as you have good babbit I would do no more than refresh the engine. I would also not worry about the heavy rods if the babbit is good on them, but that's just my thoughts

Steven


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steven Thum on Saturday, February 01, 2014 - 08:52 pm:

The one thing I would do is to replace the original 2 piece valve with modern valves. You do not need to replace the seats unless they are worn. Again, just my thoughts.

Steven


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Saturday, February 01, 2014 - 09:32 pm:

Agree with Steven. You be surprised what a ring and valve job will do for a tired engine. By valve job, I mean cutting or grinding the seats and valve faces, not just lapping them. I personally have never had problems using the old valves, and the faces can be resurfaced easily. But I can't argue with replacing them with modern values.
There is a way to equalize the weight of the old pistons without removing stock or changing the pistons in any way. If interested, email me.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Putnam, Bluffton, Ohio on Saturday, February 01, 2014 - 10:28 pm:

There is nothing wrong with the old style rods. They will run fine if the Babbitt is good. I have rebabbitted many of the heavy style rods. I suspect they are rejected because they may not fit some of the "modern" jigs used to rebabbitt them. Weight is another factor.
The T-100 1914 engines were built with the heavy weight rods. They run 7 day a week, 9(?) months a year.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary London, Camarillo, CA on Saturday, February 01, 2014 - 10:57 pm:

This is lots of good information, thanks! Great to hear about the heavy rods. I should be able to start on this in about a month, now I'm really looking forward to it.

Richard, I do want to hear what you're suggesting with the balance.

I figured I will need to have it honed or bored for the one cylinder, so while it's at the shop I'd go with valve seats and modern valves... If I'm going to do it that's the time.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Sunday, February 02, 2014 - 01:46 am:

Gary,
Really depends on the amount of pitting--it may only provide more oil reservoir surface! Have someone look at it who is familiar with our kind of engines (as opposed to modern, high speed engines).


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Swanson on Sunday, February 02, 2014 - 09:57 am:

as stated by steven there will be no ring ridge so you have to check the bore in many places for taper and out of round. pistons are cheep, just bore it. heavy rods and pistons worked fine but the light weight new style with aluminum pistons give the poor 100 year old, weak from the start, crank shaft less weight to throw back and forth which may help to keep it in one piece.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Sunday, February 02, 2014 - 10:05 am:

If the valve seats are good, I wouldn't even think of putting hard seats in your block.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Brancaccio - Calgary Alberta on Sunday, February 02, 2014 - 12:35 pm:

I have been working on an original 1920 engine disassembly/rebuild and have been looking to share some of the things I have found.

It had the heavy rods & cast iron pistons, stock bore.

The biggest weight difference is the pistons, the cast pistons are almost twice the weight of the aluminum, 1400 grams vs 700.

The heavy rods are 740 vs 640 grams.

My new replacement rods with insert bearings are 664 grams.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Sunday, February 02, 2014 - 12:43 pm:

Agree with Larry wholeheartedly. Use the money you would have spent on hard seats and purchase Neway cutters and a pilot on eBay sized for job. The tools are user friendly. You'll need one combination cutter 30 and 45 degrees and one 60 degrees. You'll need an adjustable pilot that will fit your reamed valve guide. Neway sales reps are very helpful guiding you. If you want to recut the valve face, its really easy to do on a lathe by setting the compound at 45 degrees. Its important to have a chuck that centers the valve stem accurately. You should ream the guides first so the pilot is stable during the cutting. Get the pilot that fits the reamed guide. Its all hand done, easy, enjoyable and makes a big difference in performance. The biggest plus is that the job is done right. I could tell you some stories about valve jobs I hired out. When you set your valves, assemble all the pieces with the springs and retainers in place, then remove one spring at a time and then set the lash. By keeping spring tension on the cam you'll get the correct amount of lash the same as when the car is running.
My cars never ran so good as when I started doing my own valve jobs.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, February 03, 2014 - 11:53 am:

Check the bore for roundness and taper. The old pistons and rods can be reused if in good condition, and if the crank is round. The valve seats do not need to be replaced unless severely pitted, cracked or ground down so the valve head drops below the surface of the block. However if you have the original two piece valves, they should be replaced. The heads of the original valves can come off and when they get between the piston and the head, cause bad damage which would cost a lot more to repair than the cost of a new set of valves.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, February 04, 2014 - 07:49 am:

The heavy rods are fine if you are content to putter along at 20 MPH like the cars at the Henry Ford. The heavier weight causes a lot of stress on the crankshaft and bearings because the rod must accelerate from a dead stop and decelerate to a dead stop twice for each revolution of the engine. The faster you go, the more the stress.

All that accelerating and decelerating of the heavy parts is lost power. Make the parts lighter and you get "free" horsepower, because that power is no longer wasted.

Lighter pistons and rods make everything last longer. Babbitt is expensive to replace. So are crankshafts. If the engine has good Babbitt, it is worth the few hundred bucks to install new light rods and aluminum pistons. The performance will be markedly better too. Vibration will be less.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Tuesday, February 04, 2014 - 10:51 am:

Royce, your last paragraph contradicted itself! Half the babbit is in the rod bearings. So if you replace the rods, you will also replace the babbit!

Gary is asking if he can use the old rods. I say yes if the crankshaft and babbit is good. If he needs to replace the babbit, he should then look for the newer lighter rods.

Likewise, I would say if the bore is still useable and the pistons are not cracked, they can also be reused. If they need replacement, then go to aluminum.

He only want's this as a spare engine, not for long time use.

Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Tuesday, February 04, 2014 - 12:43 pm:

Royce is correct, of course. Less vibration, less stress on the crankshaft. But there is historical value in using original parts, at least for some. I took a lot of care with my former 1910 touring car to keep it original, including, machining the ring lands to accept a spacer. Its a trade off, originality vs performance. Each of us draws the line differently. And it depends on the car.
The original 19 I have been working on has all the original engine components, except new babbitt on the original rods, new rings and NOS Ford valves and lifters. My 26 pickup has alum pistons, modern valves, new crank gears, a Stipe cam, etc. etc.
The 19 has value because its an original, pretty much untouched car, the 26 was made up from parts with a new wood body.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Tuesday, February 04, 2014 - 12:47 pm:

Heavy rods!






Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary London, Camarillo, CA on Tuesday, February 04, 2014 - 02:02 pm:

My intent is to use aluminum pistons, it's only the rods I am interested in reusing if the babbit is good. I would also have them balanced.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Brancaccio - Calgary Alberta on Tuesday, February 04, 2014 - 03:01 pm:

Per my posting above the weight of rod & piston together are

Heavy Rod, Cast Piston 2133 gr

Light Rod, Aluminum Piston 1349 gr
New Rod, Aluminum Piston 1371 gr

Heavy Rod, Aluminum Piston 1440 gr

So not much heavier with the old style rod and aluminum piston.


Top of pagePrevious messageNext messageBottom of page Link to this message  By joe bell on Tuesday, February 04, 2014 - 09:23 pm:

When you rebabbitt the heavy rods they use more babbitt and more babbitt is not always a good thing why do you think Ford uses less as the years progress? The A's have about 1/16 in them.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Tuesday, February 04, 2014 - 11:00 pm:

All I can say about this is that my 24 with the cast Iron pistons and worn out rings(smoked like a tar kettle) had a good bit more lugging power before I replaced them with aluminum. That is a fact and not an assumption. KGB


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