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Fiat 702 Tractor

Phil Johnson

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07/12/2019
I've got a Fiat 702 tractor of one of my customers in the shop for some repairs. Mainly to get it running and repair the cracks in the block. This engine is a headless design and has been badly frozen at some time (I suspect more than once due to and old braze!) There are a lot of cracks in this, but Cal is pretty sure he can fix it!
I have stripped the block and removed it, and taken to Edmonton Cast Iron Repair who have done other major cast iron repairs that have been documented here on the Stak. They did the repair on the Longfender Allis heads a couple of years ago and more recently welded together a manifold for my 17-28 TC.

Here are a few pics of the engine as it was stripped down and the block removed from the crankcase. The water jacket has an extreme amount of rust and corrosion but most of what I haven't removed will hopefully"cook" out in the pre-heat furnace.
 

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Phil Johnson

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07/12/2019
After removing the valve port plugs, the valves were all removed and surprisingly, they are in very good shape and the seats look excellent.

The fun part was getting the nuts removed that fasten the block to the crankcase. This tractor seems to have a mixture of nut sizes on it. Some seem to be a metric size, but most are Whitworth. Fortunately, I had an odd old Whitworth wrench in my Whitworth/ BSF wrench drawer that fit most of the nuts. Needed a very thin wall on the box end as there is very little clearance between the nut and cylinder wall.

The block was carefully lifted off of the pistons which will be removed from the crankshaft later to check bearings. Number three seems to have a tight spot on the crank bearing which will have to be looked at.
 

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Phil Johnson

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Last Subscription Date
07/12/2019
These last few pics show the cracks in the block which are pretty extensive. We decided to weld them as I believe it would be difficult to find a replacement block for this tractor.

The open top of the block is capped by a cover and gasket and the upper water pipe, comes off the front and has a short hose connection to the radiator.

I'll try to continue this thread as work progresses. It's a repair job for a local collector and not a restoration.
 

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Tim Colwell

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gratis
I heard somewhere that somebody in Canada traded a Mogul 8-16 or 10-20 for 2 Fiat tractors. Is this one of those? If so that would make 3 Fiats in North America. Absolutely one of my favorite tractors. Please keep us updated and maybe share a video once it's running!!
 

Phil Johnson

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Last Subscription Date
07/12/2019
Tim I don't know if this is one of the ones you are referring to or not. I do know that this one came from Australia. If the freeze damage was done there, it must have come from the south of Oz.

I've had it running briefly before taking it apart. The cracks had been filled with some type of filler, but as the engine started to warm up, the cracks opened up and water was running out everywhere!
 

typak

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Last Subscription Date
07/30/2019
We had one in the past and it didn't have the reduction hubs? always thought the 703 had the reduction hubs?
 

Molinegb

Registered
Odd it has Whitworth bolts. Tell it has been apart before. My Norton motorcycle had Whitworth wrench set in toolbox.
 

Phil Johnson

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Last Subscription Date
07/12/2019
Got an e-mail from David Parfitt regarding the model of this tractor and it appears to be indeed the later model 703. The radiator tag states 703 7230113. The engine tag is 302A 7130113 and the tag on the rear casting is 703 7430113. I suspect the recurring number 30113 is the actual tractor number.

Thanks, David.
 

Norm Johnston

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Last Subscription Date
08/13/2019
Phill when I restored my Swedish AVANCE tractor from the mid 1920's The nut sizes had me confused for awhile. they were all whitworth threads and some appeared to be sae nuts and some metric nuts. It was only when reading the parts book I found that in the tool kit originally was supplied spanners in 32nds ie 19/32 etc. maybe it is the same with that Fiat.
Good luck with the block repair, it sure has its fair share of cracks.
 

AultmanTaylor

Registered
Hi guys,

A lot of the very early European tractors use withworth treads. Our 1913 Pavesi does, as do a lot of the early Lanz, ...
 

Phil Johnson

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Last Subscription Date
07/12/2019
The fuel tank was beyond repair so it is now over at the Robb McCollum's shop so he can make a replacement.

The block is still out for repair so I had a look at the rods and pistons. Rings all look good and are all a nice fit in their grooves, but #3 rod bearing seemed to be binding on it's journal, so I removed it and measured it and the journal and the side to side measurement was fine at about .003 clearance, but the top to bottom was the same as the shaft. The rod also had a slight bend in it. After straightening and a little careful hand scraping the clearance was adjusted to .003 and it now fits nice on the shaft. There are no shims on these bearings.

Number two had a tight spot on the wrist pin bush so it was taken apart and the bush was not centered in the rod so it was pressed in to where it belonged and a very light hone cleaned that up.
I didn't like the rod bolt assembly on #2 as the bolts had been replaced and the castellated nuts were too short so were spaced out with a stack of three lock washers under each nut! I'll replace these with deeper castellated nuts when it goes back together.
 

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Stuart Landry

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Last Subscription Date
07/12/2019
Phil,
Good to see another old FIAT tractor , I have a 703 model ,
The clutch pedal works the opposite way on my 703 ,
You push & lock the pedal down to drive ,
Thus compressing the clutch spring , Which in turn can put added end thrust on the crankshaft?
Might be a good idea to check the end float on the crankshaft ,
As there is not much room for the conrods in the crankcase cut out ,
 

Tony Thompson

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Last Subscription Date
09/18/2019
Threads like this are very valuable!
Many of us will never work on something as unusual as you often do. Documenting your skill-set with your frequent unique projects allows all of us old iron hounds to learn as you go. Very entertaining and educating at the same time for lots of enthusiasts :)

Thank you very much Phil :salute:

Are you going to arc-n-nickle or employ the spray transfer?
Tony
 

Phil Johnson

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Last Subscription Date
07/12/2019
Stuart, the tractor is a 703 (see post #12). Clutch works as you said. I'm not sure how to change the title.:shrug:

Tony, the block is at Cal Blakeney's Edmonton Cast Iron Repair, a specialty shop here. They did extensive repairs on the 20-35 Allis heads that went to Jacob in Wi., and have done other cast repairs for myself and others on the Stak. They are using the cast iron fusion welding process which entails heating the block to red heat and welding the cracks while hot with the oxy-acetylene process using cast iron filler material.
It's and expensive process, but the best way to repair cast. Cal is going to do this one himself.
He was one of my students many years ago when I taught welding at the tech school!
 

Brasherman

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Last Subscription Date
07/12/2019
Great looking project! Nice that you know the guy welding it learned from a great instructor! ;) That will be a heck of a job for him!
 
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