using used piston question

I am restoring my "51 B back to allfuel status, (I know, some go for more horsepower, I am going for less.)

I have located a pair of used, late B, cast iron, allfuel pistons, standard bore.

They look OK to me, but I am not an expert. The piston pins move easily and seem very tight(no detectable slop). What should I look for or measure to evaluate the reuseability of these pistons?

I do not have the engine apart yet, but I was thinking I would most likely need to sleeve the block to use these standard pistons.

What would be the measurement of excess cylinder clearance that would necessitate a rebore or sleeve?

Thanks,

Kurt

I'll have you over when I tear the engine down. I'm really looking forward to it.

Kurt

Thanks,

Kurt

You certainly don't need a machine shop to tell you what to do - but nothing wrong with that if you don't mind spending (perhaps wasting) the extra money.

Two main things to check for are top ring side clearance, and cylinder-wall taper. I'd mention the piston-pin bore, but you already stated your's is OK.

Pistons with worn ring grooves can be easily - and cheaply repaired with ring-shims. Hastings sells them - they cost about $2-$3 per piston.
The nice thing about Hastings is - they will sell you whatever you want in any quantity and don't force you to buy sets.

For a quick check of piston skirt clearance - check with a feeler gauge at the near top of the cylinder, half-way down, and near the bottom.
Go by the book since clearances are totally different depending on split-skirt cast-iron pistons or cam-ground aluminum.

A easy way to check for cylinder taper is to just stick a piston ring in the bore and measure end-gap with a feeler gauge. Do it in several places and measure with feeler gauges.

High RPM and high compression engines are much less tolerant of imperfections - but not a problem with your B.

30-40 years ago, many shops still rebuilt their own pistons - we did. Skirts got knurled, piston-pin holes bushed or bored oversize, and ring-grooves recut and shimmed. Then, new parts got so cheap it wasn't worth the labor to reclaim used parts. Now - it's gone the other way again.

Thanks for your comments. I particularly like the method you reference for measuring cylinder taper. I will certainly take your advice for making these measurements, (and may also waste some money on a machinist LOL) I remember now that you mention it, about the trick of knurling the pistons. I wonder if anyone is still doing that?

The spacers you mention will also be of great value, was it standard practice to recut the ring groove to some standard dimension, or to find the best fit with a feeler gauge?

Thanks,

Kurt

If you go to the Hastings website - they have a few webpages that describe it and will show you two types of shims. One type works best with using a special cutter - but the other does not and anybody with basic machining skills could do it for you. My last set was done by a retired machinist who lives near me and does light machining out of his garage. He did a great job and charged me $8 per piston.

By the way - I also called two professional automotive machine shops - and both told me that nobody made piston-ring shims anymore and repairing pistons was an obsolete process that died a long time ago.

So - in regard to machine shops - I tried the only two within 50 miles of me - and both gave me incorrect information. Granted, I am in a rural area - but - years back when farming was more active around here - the machines shops were much better to deal with.

Rather, a waste of money is plowing forth on half-knowledge. The "Oh, tolerances for those old two-bangers are not that critical" notion is not what made John Deere one of the two or three longest lasting tractor companies in the USA. "Not that critical" isn't a descriptor this man can deal with. Service literature contains values. Are you telling this forum not to be concerned with those values?

I for one do not want to make light of the task of good measurements in the early going -- by a person who knows how to use micro-measuring tools, and "yes", if the initial poster can lay hand on these tools and knows how to use, them -- by all means -- he is wise to do so.

Beyond the initial "kick in the pants" for using an engine rebuilder, you go on to offer great points, and we all appreciate that. BTW, I do not mean to imply an ordinary machine shop will do here either! I better go. (PatB)

First - in reply to your comment "to rely on a engine rebuilder is certainly not a waste of money! " . . .

I never said is WAS. I said: ". . . nothing wrong with that if you don't mind spending (perhaps wasting) the extra money."
Note my inclusion of the word "perhaps" - which meant to mean sometimes - not always.

In regard to tolerances and what made John Deere famous. John Deere originally sold those tractors to be used, all day, everyday in many cases. Their intention was not to produce collector's tractors that led a life of "semi-retirement" which many of these old tractors do.

I've got 40 years experience working on Deeres - and have had the occasion to see many last a long, long, time when put together in a worn, but useable condition. I was working on the two-cylinder Deeres when they were used daily on the farm and Deere Co. still gave parts support for them. I don't think you're going to tell me very much new about them that I don't already know.

As to your comment/complaint: "Not that critical" isn't a descriptor this man can deal with. Service literature contains values. Are you telling this forum not to be concerned with those values?"

More reading comp. problems on your part? I said - and I quote myself: "Go by the book since clearances are totally different depending on split-skirt cast-iron pistons or cam-ground aluminum."

Note the word "book."

And - about your comment about me giving a "kick in the pants" to engine rebuilders?

No, I did not. I alluded to the idea that the guy many not need one (again, note the word "perhaps).
I don't know what this person's skill level is. I will also add, that in many occasions, I've seen people pay a lot of money for work they could of done themselves. That's fine for some. But, considering the context of this forum, some people strive to be more than "parts changers."

Many of these tractors, with reasonable wear, certainly can be put back together with a minimum of parts and run well for years. And yes - a low compression engine that runs at low speeds is more tolerant of cylinder wall imperfections than other, more modern engines.

And - now I will give a slight "kick in the pants" to some engine shops (note, not all!).
At the last two Deere dealerships I worked at - we had our own diesel injection pump shop (Stanadyne and CAV certified), we did our own cylinder head rebuilding, rod resizing, etc. Towards the tail end of my working there, the popular trend got to be more of sending stuff out to the machine shops. The cost to the customer got much higher, not lower and the quality of repairs was no better.

I sold my own Sunnen honing machine about five years ago since parts - even stones were too expensive. Last year, I was rebuilding an IH diesel engine and sent all four rods to the local automotive machine shop to get checked for roundness and resizing if necessary. The guy charged me $80 and subsequently ruined all four rods. Ends up his hadn't calibrated his mike recently and he claimed someone must of dropped it. That led to a hunt to find four used rods somewhere for a 1959 tractor. When he finally did - he tried to charge me for them - which I did not. So - I'm sure that sort of thing does not happen often - but it taught to continue to do all I can, myself - when possible.

‘Interesting task set before you! I urge you to find an engine rebuilder kind of a machinist to help you. This is the kind of fellow you would contract to rebore your cylinder block and sleeve as needed, or to examine the cylinder head and perform needed restoration activity. He will have both the tooling and knowledge of the over-bore trigger point.

The first thing to do is to have that engine rebuilder examine those pistons for bore size, roundness and for ring groove wear, and go from there. Determine they are worthy before charting forth. As for cast iron pistons, if you run into a need that cannot be fulfilled with the pair you have in your sights, make contact with Russ @ Paul’s Rod & Bearing (816) 587-4747 and see what relief he can point you too.

And to give you an idea of criteria of some of the parts involved here, I enclose some data (below) that I’ve excerpted from the JD-H Restoration Guide, 3rd Edition. While all the values are for a Model “H” tractor, I’ve also included some values from SM2004 in raw form. (PatB)

PISTON PINS & BUSHINGS -- You should have a thumb push fit in the unbushed piston, and have a clearance of between 0.0002 and 0.002 inch in the connecting rod bushing. (SM2004 says 0.001-inch oil clearance, piston pin to bushing, and a “thumb-press fit”, piston pin to piston).

PISTON RNG SIDE CLEARANCE – This is the clearance between the piston ring and the ring land, and relates to the difference between ring thickness and the groove width in the piston. A new ring in a new groove will have approximately 0.0015” clearance. The old Instructions and Parts Lists (IPL) (Dir. No. 214, 248, and 276) state the following: “When the piston is held in a horizontal position and revolved slowly, piston rings should fit snugly, yet be free enough to fall of their own weight.” The SM states the suggested side clearance should not exceed 0.005” for compression rings, and should not exceed 0.004” for oil rings. The IPLs also state, “When ring grooves in pistons become worn excessively, loss of compression and high oil consumption will result. The pistons and rings should be replaced.” (SM2004 says this clearance should be from 0.002 to 0.0045-inch for the top compression ring, and for all other rings it should be from 0.001 to 0.0035-inch).

REUSING OLD PISTONS! BEWARE –Ring groove wear is but one factor. Next, look at the caliper measurement of the sample piston. Usually, you will see that it is oval-shaped. Pistons are oval shaped from side-forces caused when the piston pushes back on the connecting rod, which is always at an angle during the power stroke. (SM2004 says standard bore is from 1.4172 up to 1.4182-inches). ++++

• Restoration Site, JD H

This gives me a place to start. I believe the top ring grove may be worn beyond the specs you quote. Perhaps I can use a spacer. I will also check with Russ, as you suggested. I would be happy to buy new pistons, however, these are rather oddball pistons, and I have not ever seen a place where you could buy allfuel pistons for a late styled B.

I am friendly with the owner of a speedshop near where I work who may be willing to look at these pistons for me. He is a builder of race car engines, and won"t take on any tractor work, but will give me his opinion, I"m sure.

Thanks again,

Kurt

No offense meant at all,but a builder of race car engines is not going to have a clue what is needed or what you can get away with or expect from an old 2 cyl. His engines idle faster than yours runs wide open. Race cars are a whole diffent ball game ! You do not want a 2cyl. anywhere near as tight as he is used to working with. Or at least I hope he is used to working with. LOL ! I would ask his opinion anyhow as he may just play with old tractors too ? There may also be an option of using gas pistons and having some turned off the top to match your all-fuel ones height ? Providing they are solid enough down far enough.

He is a very practical fellow who literally grew up in an automotive machine shop. He does race car engines now because that's where the money is. Worth a shot anyway.

These pistons are pretty interesting. The top is concave. looks like a softball could fit partway down in them. Also has two small cutouts which I guess are for the valves? Be hard to duplicate that dish.

If I knew how, I would post a picture.

Thanks again,

Kurt

For sure seek out any local free advice and tricks of the trade. And for sure he made a smart move by getting into racing as that's where the BIG money is now. Just go in with an open mind and remember to keep perspective open to as this guy is used to working with tolerances 2cyl. JD's never saw. This guy may well know this ! My local shops don't !

I pause here to wonder how many folks out there know that the person behind Paul's Rod & Bearing (Russ) was once into auto racing big time! And Mike, I would trust him with your engine -- and guarantee the result in a heartbeat.

Now -- I will agree that if you tote a job to a fellow that is "used" to working on something like a race car and takes your job on just because you decided to drop it off there -- that could turn out bad. I always prepare a written statement of work (SOW), carry my tech manual with me, and during the interview, we tweak the SOW as needed and have a pretty good mutual understanding of what will be done before I leave. Now, if this is the first time with this dude & he balks at the SOW, the interview and relationship are both over!

One other key to success is that -- as you mentioned -- antique tractor work is something they do not do every day, and more often than not, a high-tech kind of guy may want to "fit the job in" which translates into it may be a week or two, or more before he does the work. So plan ahead and allow him that time -- one should not screw around until the last minute and then expect others to jump through hoops to meet his or her schedule.

I am blessed to have two race car engine rebuilders to fall back on, Wade Jankowski here in San Antonio and Russ Schworer of Paul's Rod & Bearing in Parkville, Missouri. Both enjoy this old tractor work, and both have performed flawlessly for me! And I am hard to please!

One final thought and I will stop. There is a boatload of folks working a tractor in their garage, and they live in a town or city. These guys don't have much in the way of equipment or an area to house it in. These are the folks that need to carry cylinder blocks and heads out for overhaul. They don't have facility, tooling, and generally don't even want to take that deep an interest in the tractor's come-back, but they do want it done right. A commercial engine rebuilder becomes his only choice! (PatB)

• Restoration Site, JD H

Hey, good idea about getting my own mics. Wait till I tell my wife!!

Kurt

If you aren't going to run it hard you should be able to get away with up to .010" or maybe even .015" of cyl. wear. The most wear usually occurs on the top side of about 1" of the top ring travel. Make sure to blend in any ridge. A dremal with a sanding disk works well. Ridge reamers you can buy are made for auto engines where the piston comes clear up to the top and they don't reach down in enough for these. Hone them really well too.

The piston pins should float in the pistons with no noticable wear. Make sure to check the bushing in the rods too.

I have to commend you for putting back to original. As much of a stickler for being original that I am I'm not sure even I would do that ? If just showing or parades you will be happy. If you are planing on doing any work with it than it's hard to beat the power they make on gas or high altitude pistons.

The hardest work this old girl will likely do is driving up and down hills. Maybe a plow day or two. I never intended to get this into a complete/accurate restoration when I got the B, but the more I do the more interesting it is to me.

I really appreciate the original engineering that went into these tractors,and I figure that a few of them at least, ought to be restored to complete original mechanical condition.

At least thats the goal.

Kurt

At the last Deere dealership I worked at - I began in 1979 in a chicken and dairy farming area.
Many local Deere dealerships got their start by farmers being allowed to sell new Deere tractors right from their own farms. Often "dealer support" amounted to one farmer going over to another guy's farm and lending a hand - and perhpaps buying a few beers. My nextdoor neighbor was a dealer and still has two "leftovers" that did not sell - a 530 and a 620. That sort of thing ended late 1950s when small dealers disappeared, and big dealers got more centralized. Deere tractors suceeded in-part possible because the tractors were designed to be owner-maintained. Also - in regard to wear in these engines - as compared to newer equipment. Engines ran very slow, had low compression, and piston rings were soft cast-iron. The rings were designed to wear first - instead of the cylinder walls - which is the opposite of modern engines.
The Deeres were kind of the "Ford Model T" of the tractor world. At least as judged by Deere owners. Many other tractor companies made good simple tractors also. A retired farmer up the road from me sill rakes hay every summer with his Deere B. Twenty years ago, he had a rod start knocking. He pulled the head - brought it down to my house and I did a "30 minute" valve job for him and took a dozen bales of hay as payment. No new parts - just reground the seats and valve faces. He bought a rebuilt rod, shimmed it to fit, put in .002" oversize piston rings along with a quick hone-job, new head gasket and lead washers - and has been using it every summer since. Like I said - this was done 20 years ago.
Does it run as good as new? Probably not. Has the cheap patch-job served him well? Absolutely.

Deere used to have great dealer and product support. Back late 70s - a Deere rep. came to our place and said Deere Co. would warranty any part they ever made - if it could be proven to be defective - regardless of age. I had an old Deere BO orchard tractor with a sand-casting hole in the block. Deere sent me over a new block from Syracuse - free of charge for a 1937 tractor! Boy - try that now- things have really changed.

My boss at the last Deere dealership was an ex-chicken farmer who got his start selling Deere tractors from two of his farms. He was a rare bird - since he felt no deal was worth making unless everyone involved benefitted. Come early 1990s - Deere tried to put him out of business. They bullied him - and threatened to take away his Deere franchise for foresty, industrial, ag. and consumer - unless he built two new buildings - one for industrial and foresty, and the other for ag and consumer. He was 80 years old and refused. He told Deere they needed him - more then he needed them. He finally shut down the business in 1991 and died shortly after. In regard to your engine and lowering compression. I know of a few people that installed double head-gaskets and said if worked fine. I personally haven't tried it. I did many converions in the other direction. We updated many old Deeres to high compression - either from all-fuel to gasoline only - and also a few standard gas engines - to "high altitude" pistons. I assume you still have the all-fuel carb, switch-over valve, etc.? Also - don't get me wrong. I've got nothing against someone who wants their engine absolutely perfect - and perhaps better than new. But - that's certainly not necessary and not for everyone.

Certainly one of the things that I admire about these old JD tractors is the simplity and economy of the design. It took me a while to appreciate the really fine and sophisticated engineering and metallurgy that is behind this design. But the bottom line is that they are robust and for the most part, easy to work on. I completetly rebuilt the transmission last winter, was amazed at all the parts I could still get from JD. Not cheap, but still available.

My tractor had a 70's era replacement carb on it when I bought it, a DLTX 107U. I have located an original allfuel carb for the tractor, which still has the original allfuel nozzel in it. This would be the DLTX-73. I have also located the allfuel manifold, three way valve, and the various fuel lines as well as a decent pair of shutters.

So I think I am ready to go.

I am assuming that I could run the tractor on Kereoscene anfter I get it good and warmed up on gas?

Kurt