Rods

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Model T Ford Forum: Forum 2012: Rods
Top of pagePrevious messageNext messageBottom of page Link to this message  By ken bechtel on Monday, March 05, 2012 - 08:15 pm:

I am getting ready for my engine rebuild. X'ed rods or non X'ed rods? X'ed rods should keep more oil but are they dependable? thanks. Ken


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Or on Monday, March 05, 2012 - 09:04 pm:

X'ed and dippers would be my choice. I believe I read on the forum here that the dipper going through the oil trough was about the equivalent of 35 LBS of oil pressure. In the old days when we might be traveling at 20-25 MPS most of the time the splash system worked great (Ok it still does but I want that extra bit of splash at 35 to 40 in traffic).
As an extra bonus, the dippers splash even more oil.
Some might argue that X'ing the rods reduces the surface area of the babbitt. If everything is working correctly, the rod or main is riding on a layer of oil including the oil in the recess. An engine without oil, too tight, or any high area in the rod or main, the babbett will be riding directly on the crank.


Top of pagePrevious messageNext messageBottom of page Link to this message  By clayton swanson on Monday, March 05, 2012 - 09:12 pm:

some like to x the cap only, and some x both and put a hole thru the bottom of the beam like a model a rod, for oil to get out, cause your new dipper is pumping in, it needs an exit


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Monday, March 05, 2012 - 09:47 pm:

Why don't you put in two rods with X's and dippers and two rods without X's or dippers and let us know 10 years from now which holds up the best.

As you might guess I don't think it matters.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dean Yoder on Monday, March 05, 2012 - 09:57 pm:

I ran 3 xed rods with dippers and one not Xed rod 37,000 miles the non xed no dippered rod was the best.
Dean


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Monday, March 05, 2012 - 10:03 pm:

I ran across this book in my library. If you are seriously interested in journal bearing design and performance you might want to get a copy.

Bearing Lubrication Analysis


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money, Braidwood, IL on Tuesday, March 06, 2012 - 05:48 am:

Just to confuse things, if you run dippers, where do you drill the hole? In the middle of the cap or offset?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Tuesday, March 06, 2012 - 06:56 am:

Why not just put the dipper on without the hole :-)
Non drilled rod caps may get hard to find if everyone drills them when it's not clear there's any benefit by drilling - see long distance test by Dean Yoder above.

Stovebolt Chxxys had a stream of oil directed towards the dippers for some angle of the rod's travels. The most cost efficient improvement of the Model T's oil system is probably Texas T's high volume hogshead oiler kit they got from Terry Horlick's mountain oiling system:
oiler
A flood of oil to the front of the crankcase that gets churned up into a fog by the rods (perhaps with dippers to add churning action) will give you the best oiling all the plain bearings can get without a multi $$ full pressure bottom end modification.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Tuesday, March 06, 2012 - 11:12 am:

Suggest you buy a book called Audels Millwrights and Mechanics Guide. Amazon has used ones.

It explains in simple terms plain bearing design T engines are all plain bearings.

On a well designed plain bearing 600 psi pressure is not unusual developed with the rotation of the crank. Its called hydromatic action creating hydrodynamic lubrication.

With about 1 1/2 square inches of load area on the loaded or top side of a rod bearing that pressure keeps the the parts separated.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Tuesday, March 06, 2012 - 11:07 pm:

I ran 3 xed rods with dippers and one not Xed rod 37,000 miles the non xed no dippered rod was the best.
Dean

Where did you get the x grooved rods Dean? And do you have any pictures? What is the best referring to, as in what way? How many ways did you conclude, that the smooth rod was the best?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Hylen- Central Minnesota on Wednesday, March 07, 2012 - 10:38 am:

Let the fighting begin!:-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Hylen- Central Minnesota on Wednesday, March 07, 2012 - 10:41 am:

This question, along with ones about which oil to use and coils vs. distributers, is as dangerous as "honey, doe this dress make my butt look big?"


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, March 07, 2012 - 11:52 am:

Impossible to test unless a large sample of T's equally divided between Xed and non Xed rods and driven at the same speeds along the same course for many thousands of miles and then pulled down and checked. Of course the T's would also need to be the same weight with the same gear ratio and all have exactly the same oiling system. Even then the position of the spark advance could be a factor. The operating temperatures of the engines could also be a factor. Even running 3 Xed rods and one non Xed in the same engine will not be conclusive, because it might be the position of the rod rather than the Xed vs non Xed that made the difference.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Dysart on Wednesday, March 07, 2012 - 12:28 pm:

I'm with you, Norm. Maybe a fleet of 18 engines, each with 2 Xed and 2 plain rods. With only 6 possible combinations of 2 and 2, 18 engines would give 3 data points for each layout. If this was done, I would think that the data collected would be fairly reliable.

The installations should be consistent, no need to bring in variables like beam holes, cap hole position, or dippers on only some. Just go with the most common configuration, full Xed with dippers, no beam hole.

What's the minimum mileage that you would figure it would take to see any difference?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Wednesday, March 07, 2012 - 06:49 pm:

Here is a thread from 2010 where Dean explains more about his rod experiment: http://www.mtfca.com/discus/messages/118802/178702.html?1293469567

He put the non Xed rod in the front position after one of the four Xed rods failed there - it's the position where most rods fails due to insufficient oiling.

Adam Doleshal also has some very interesting posts in that thread.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Wednesday, March 07, 2012 - 09:10 pm:

I find it interesting both Herm and Adam have posted rod alignment issues, I will pay very close attention to that next time.
Reading the description in Audel's for proper oiling is very close to Fords original except if they were not drilled for oil pickup through the cap.
The top or loaded side of the rod needs the most support, by drilling the center at the top side you are sticking a hole exactly where it needs hydrodynamic oiling releasing pressure. Book says that pressure is the highest in the center and falls off at each end with end leakage.

The information was tested by an engineer who did trouble shooting and other engineers back to railway car axels

I notice Seth posted grooving the cap but not top that's what the book says and the modern engines do not groove the loaded side of mains or rods. Forty pounds of oil pressure in a few square inches of loaded area is not even close to 600 psi developed with hydrodynamic
lubrication.

Obviously both splash and pressure oiling needs hydrodynamic pressure to survive.
Lots of other good information in that book.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Sunday, March 11, 2012 - 06:37 pm:

Again Paul, no grooves in the top part of the rod, is for oil Pressure engines. Splash engines, are completely a different story, you can't mix the two, as they are different. Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank Harris on Sunday, March 11, 2012 - 08:03 pm:

We are running X rods with a full pressure Steel Billet crank . . . it is the best of all worlds and that's the name of that tune.


X rods


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Sunday, March 11, 2012 - 08:07 pm:

I will go with tested engineered data. The information provided was without a pump.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Sunday, March 11, 2012 - 08:15 pm:

I will tend to go with Dean on this one as his case is proven by the miles he drives, I don't think many of us drive the miles he does with the exception of a couple other guys I know. KB


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack J. Cole on Sunday, March 11, 2012 - 08:33 pm:

Uh,lets look at a modern rod on a modern car.Are the journals Xéd? I dont think so but they run oil pressure to get oil in there.Intresting discussion as this was something I have been wondering about for my speedster engine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Sunday, March 11, 2012 - 08:57 pm:

Can Les or another engineer do the do the math on a stock T engine with 45 pounds or so compression just turning the engine over without the pressure of the power stroke? There is about 1 1/2 square inches of load area on the top of the crank. Bet its way up there for pressure.


Top of pagePrevious messageNext messageBottom of page Link to this message  By les schubert on Sunday, March 11, 2012 - 09:44 pm:

Paul
Sorry I will not get sucked into this!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Sunday, March 11, 2012 - 10:30 pm:

I will go with tested engineered data. The information provided was without a pump.((End Quote))

Your information is Misinterpreted!

The only pressure you have on the top side of the block, is the rod pushing down, trying to push the oil out.

Model T's all, Don't have grooves, and Ford rectified that with the Model A, and Model B. Did the book say Ford was all wrong?

Chevys, all smooth in the 4 cylinders, 1929, then they seen the light, as 1929, to 1936 were all X Grooved, and again had dippers, 1937 to 1953 they were full circle oil groove, two oil wells, and 1 oil entrance pocket, all had dippers, and the Web drilled. They did not have oil pressure, but a timed oil Squirt system into the Tin Dipper. and I could go on and on, and so could you if you would have had any experience with bearings. The best oil system in a splash rod, is dipper, and X grooving, all the good engines had it.

Look what Ford did with main bearings, He went from a worthless horizontal line in the block, and a smooth cap, to a full oil well, and Diagonal grooves, on the top and bottom of each bearing, and so did Chevy.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Sunday, March 11, 2012 - 10:32 pm:

Oil supplied under pressure provides oil flow to cool the bearing. As Paul stated the load is supported by hydrodynamic forces generated by the rotation of the journal.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Sunday, March 11, 2012 - 10:39 pm:

Frank, what is the story on the picture, rod, and piston? I can see it is the late Model T rod, and maybe Jahn's Piston.

It looks to me that the Rod is out of alignment, or the crank in not centered in the block, or is it something you took down to rebuild. Thanks Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Sunday, March 11, 2012 - 11:49 pm:

Oil supplied under pressure provides oil flow to cool the bearing. As Paul stated the load is supported by hydrodynamic forces generated by the rotation of the journal. ((End Quote))

Well, Ted and Paul, thanks for backing up what I have always said, the more oil you get in a bearing, the better off you are!

So Ted, as you were talking about oil supplied under pressure, in which on a Model T we Don't have a pump with pressure, we can do it with an X groove, and a dipper. So with out oil pressure, Hydrodynamic forces are at their lowest point, and all the shaft does in support the rod bearing, unless the shaft is out of round, which is a debate, by it's self.

But you can put a lot more of the cooling oil in an X Grooved bearing, and that is a fact, Jack! With out Grooves, drilling of the web, and cap, and a dipper, all you have is a rod getting splashed on, and a rod slinging oil off from centrifugal force.

You also remove heat by conduction through the rod bearing to cooler parts of the crankcase, or rod.

That brings us back to oil, the more oil you can get to a bearing, the longer it will last, and the cooler it will run. Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Monday, March 12, 2012 - 01:57 am:

Sorry Les its only because I trust your knowledge. Wish Seth was posting.
You used the logic Herm that drilling a hole through the top of the rod and the top of the Babbitt was to release air, then would it be logical to drill a hole through the cap in the main be the same thing?
If I do my feeble math after a four beer show tonight A- T piston is about 3 3/4" in diameter with about 5.88 square inches times 45psi compression equals 265 pounds of pressure on the top of the journal, thats without the power stroke . It takes a three stage air compressor to get those pounds how does an oil pickup do it through the cap ? It explains that the weight of a shaft slowly pushes out the oil until the shaft and the bearing are in contact when the engine is stopped.The shaft has to be lifted with pressure created with hydrodynamic lubrication, its a tested fact.
Now add in the power stroke, don't have a clue how much more pressure but it has to be several times greater then 45lbs compression.
I will admit when I am wrong been wrong lots of times.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Monday, March 12, 2012 - 11:51 pm:

You used the logic Herm that drilling a hole through the top of the rod and the top of the Babbitt was to release air, then would it be logical to drill a hole through the cap in the main be the same thing? End Quote

I know you are not very Mechanical Paul, but I'll try again. Drilling a hole in the top of a Model T rod, does let air out, and oil in. But Not a stock Model T Rod. We are talking an X grooved rod. Putting a hole in a main cap, will loose oil, as the cap is gravity fed, from the top, and you want to let the oil out the ends of the bearing.

You are trying to hard Paul, your getting all tied up in Math, and you can leave that out.

A Model T rod with an X groove top and bottom bearing, is fed by the dipper, through the hole in the cap, into the X groove that is in the cap. It is filled with new oil, at each Revolution. The oil then leaves the cap X Groove to the top X groove, and fills that X groove, and is pushed out from the oil in back of it, and centrifugal force, also some oil goes out the part line. So the X grooved rod which is about 250, to 300 thousandths from the out side of the rod, and as the grooves have oil in them, they keep a continuous wipe of oil on the shaft.

It explains that the weight of a shaft slowly pushes out the oil until the shaft and the bearing are in contact when the engine is stopped.The shaft has to be lifted with pressure created with hydrodynamic lubrication, its a tested. ((END QUOTE))

Paul, it does not matter how much pressure is on the shaft, if that is what it was built for.

((Hydrodynamic Lubrication)), is a cool two words, but all it means, is when the rod comes off of REST, It has to have all the oil Molecule to ride on, that it can get, as not to ever touch the shaft.

Here is something else, a T Rod bearing with out oil Grooves, will run with larger clearances, than a X Grooved T Rod! An oil pressure Rod will run with consistently tighter clearance then a non pressure Rod! Why?

Herm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Tuesday, March 13, 2012 - 06:36 am:

Your last post is a classic, I can easily see your thinking with oil flow and lack of hydrodynamic design, and I am known as someone who can fix a tractor with a piece of string.
Throw out the math, throw out the engineering, throw out part of hydrodynamic design and do it Herms way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank Harris on Tuesday, March 13, 2012 - 09:36 am:

Herm, The X rods are in a go fast engine with a full oil pressure steel billet crank and cam with .411" lift on both the intake and exhaust. The pistons may very well be Jahn's. The oil pressure comes from a typical pump mounted on the rear of the cam shaft. The lower ends of the rods are trapped by the crank with substantial babbet facings which hold the rods in position. You are correct, there is room for the piston to slide fore and aft on the pin but the cylinder keeps it in position.


crank


Detail showing both ends of X rods.

flat head


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Tuesday, March 13, 2012 - 12:04 pm:

Ya, Paul, that is what I have always gotten from your post's, a one book, string, and Bailing wire kind of fixer.

The fact is you have no experience in bearings, but have read a book!

I have in 44 years, built over 30,000 Spun poured Model T Rods, not counting all other Brands of cars, and tractors. I have spent my life studying bearings in ways you would never think of. Your just another case of, (I read a book, I haven't done it, but I know! Good Luck With That!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Tuesday, March 13, 2012 - 03:02 pm:

You have to be among the best with babbitt Herm Just because I don't agree with the oiling method is So What!
There is a ton of information on the web that unless you are an engineer its not understandable. The book was designed for non engineer type people with the same information.
In my business you have to guarantee structure for ten years. The building department will not even look at many plans without an engineers stamp. Every thing is designed for safety, and structural integrity. You learn to respect good engineers when a 40 foot fink truss supported at each end made from 2x4 on 2 foot centers will hold up sheathing, sheet rock, insulation, roofing and some snow load without sagging.
And every thing starts from a foundation with weights and measures calculated to do the job, much like a T in my opinion.
.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joe on Sunday, May 20, 2012 - 11:21 am:

I thought oil in the Ts were not under pressure just dribbled up and dribbled back down and got splashed wherever.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, May 20, 2012 - 12:03 pm:

Herm,

People would respect your opinion a little more if you didn't resort to insulting and degrading other people. It must be hell to have no more self esteem than to have to put down other people in order to feel good about one's self.:-(


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Sunday, May 20, 2012 - 12:30 pm:

Thanks for your Concern, Hal, I even feel better today May 20 2012, then I did my last post on March 13 2012!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, May 20, 2012 - 12:36 pm:

Well, I will have to admit I hadn't paid any attention to the dates. If I had, I would not have posted. I just can't believe I didn't post something similar on March 13. Must have missed the thread. Glad to know you are feeling better.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Aaron Griffey, Hayward Ca. on Sunday, May 20, 2012 - 01:05 pm:

I don't worry about any of it.
When I rebuild the engine of a T or an A I just order a set of rods from Ron's Machine.
They get here quickly and are very reasonably priced. easy place to do business with.
However Ron Miller does them is the way they will last for a long time.
There are too many that swear by his work so I will not ever wonder which way is best.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kerry van Ekeren (Australia) on Sunday, May 20, 2012 - 10:45 pm:

I'm curious on something that Ford did while sorting things out in the first 2500 T's, we all know the water bump was dropped but diving into the engine, the big end oil dipper con rod was also done away with.
For the next 15+ million he must have thought the hydodynamic system was good enough.

The last engine I had in for rebuild had drilled rods and caps for dippers, I have nothing against dippers but I can't see the point in giving oil an easy way out half way in doing it's job, with a hole drilled in the rod, needless to say the crank in this engine was beyond repair.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cecil Paoletti -- Rrnton WA on Sunday, May 20, 2012 - 11:35 pm:

Perhaps I shouldn't comment on this subject. I sort of feel like I brought a water pistol to a gun fight but here goes.
A question was raised about where the hydrodynamic oil pressure came from since the T hasn't an oil pump. The oil has a property we call viscosity. It also "wets" metal. The oil is drug around the rotating bearing by both this viscosity property and the wetting property. From my very limited education in bearing lubrication a peak hydrodynamic pressure of 650 psi is rather low and likely due to a low rotation speed. The oil is retained in the bearing by the close clearance of a properly fit bearing and the viscosity of the oil. For the best hydrodynamic action the bearing should be just slightly elliptical. The T rod, with shims, provides this very slight ellipticity when a shim or two is removed. This deviation from a perfect cylinder provides both a path and a reservoir for the oil to feed into the bearing. There is plenty of side clearance between the rod and the crank journal for oil to enter. The rod cap bearing is lightly loaded so drilling a small hole in the cap and babbit to facilitate a dipper pumping oil into the bearing is likely a good idea to improve lubrication. In my humble opinion grooving the rod end of the con rod may be beneficial since it would provide both a path for oil to get to the bearing and a reservoir for oil in the bearing so long as the groove doesn't extend the full width of the bearing. The most benefit for this grooving would be for a bearing with a "large" width to diameter ratio. But don't ever discount the years of experience both Herm and Paul have since experience is the best teacher.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Monday, May 21, 2012 - 12:23 am:

Kerry, Ford used dipper rods in 1909 and 10. The dippers were cast into the caps. In 1910 the dippers were ground down but the hole in the cap was still present. No grooves in the babbitt at least as I recall. I figure Ford concluded the dippers weren't necessary so he eliminated them, about the same time the dam in the pan was discontinued. Interestingly earlier 2 cylinder Fords had grooves in the rod babbitt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Monday, May 21, 2012 - 01:13 am:

OK, the first thing, early 1909 rod dippers made into the rods were an ineffective design, as the rod bolt, and nut sat up as high as the dipper, and carved a path ahead of the dipper, leaving it useless, and they were heavy. In my opinion, cost was the other reason they were dropped.

Kerry, we have rebuilt many motors, that when taken apart with stock rods, that the cranks were used up, that is not Unique to any one rod. The more experience you get with engines, the more you will see that.

Rods being what they were with no grooves for the most part of production, in my opinion was a cost move, rather then anything else.

So now we come to the last of Model T rods in production. they were the X beam rods, the same as the 1928 model A Ford. A bare rod forging has a dipper that sticks up above the rod bolts, and has X groove tracks in the Forging so the X grooves in the Babbitt don't bottom out. they are also drilled in the web on both sides, and the bolts, like the Model A are made right in the rod. The wrist pin end also has a bushing in it, rather then a pinch bolt. These X beam, or Star Rods are hard to grab, with bending tools for alignment, they only lasted a few months in the 1928 Model A, as they went back to a web design rod, and also for the Model B, through 1934, so those nasty X groove Rods, what was the reason Ford went with them latter, when he knew they were no good, Mmmmm!

So, the more oil you can keep in a bearing, the less wear you get. The X groove wipes a fresh oil wipe two times per Revolution on a Crank Pin.

The last thing is, I have heard many times, well I set my Model T Rod clearance from .001, to .001-50, and when I rechecked after so many miles, the Clearance was .002-50, to .003-00. That is the way it works, the bearing will open up to where it wants to be, by how much oil it gets, and the R.P.M's it runs, and how much the Crank Pin swells from the engine heat in any given engine, and there is nothing you can do about it, unless you change something


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