Engine condition from piston top and valve photos

pburchett · Feb 12, 2021

I am rebuilding a HF TO-20 for my wife. It was her pappys tractor.
What can anyone tell me about the condition of the engine from these photos.
The light patches on the piston tops are from the flash. The pistons were uniformly coated with carbon.
I have other questions to ask but they are specific to that model and not as general in nature as this question if anyone is an expert.

tomturkey · Feb 12, 2021

I don't have any answers for you, but will add a few questions. Was it running before tear down? If yes, was it producing a lot of
black smoke? using a lot of fuel for the time used? Looks like the head gasket was compromised at number 1 and 4. I am anxious to
hear what others have to say. I do not have enough experience getting into engines to analyze what was happening, I have some
suspicions but unsure. wishing you the best, nothing ventured, nothing gained. goble

Janicholson · Feb 12, 2021

All 4 exhaust valves should be the tan color of three of them. Using your finger nail, feel upward on the side of each cylinder in multiple
places. If you can catch your nail on a ridge easily where the top ring stops on its upward travel, it really needs rebuilt at the piston/sleeve
replacement level. Checking the crank for size and new bearings is also needed if the replacement of the pistons and sleeves is warranted.
This site sells good kits. Jim

casecollectorsc · Feb 12, 2021

Looks like the head needs to be serviced. Plane it and grind the valves. Check valve guides also. Did you take a compression test before
teardown?

super99 · Feb 12, 2021

Rub your finger up and down the cylinder walls, can you feel a
ridge where the top of the pistons stop? With the pistons at
the top can you push them side to side? That will give you
some idea as to how much wear there is.

pburchett · Feb 12, 2021

The tractor was running. It caught on fire due to a fuel leak and since it needed some work I thought I would just rework everything I could. It was not blowing smoking out the exhaust as I can remember but did have some blow-by as the valve cover vent puffed it out.

The sleeves were in surprisingly good shape but I need to take some measurements to verify. I hope I can get by with just some rings and bearings.

I purchased everything possible from YT for my Ford 640 when I re-did it and was not disappointed with the parts so I will get the TO20 parts from here also.

Steve@Advance · Feb 12, 2021

Nothing looks unusual, a typical well used engine.

What are your intentions? A complete rebuild, or rings, bearings, and a valve job?

If you are not replacing or removing the cylinder liners, best secure them down with a couple washers and bolts, otherwise they will ride up, breaking the seal at the bottom.

If there was mystery coolant in the oil, the liners need to come out anyway to replace the aging orings.

Areas of concern, cracks in the block webbing between the cylinders, oil pump problems (disassemble and inspect for wear and failing drive screw), failing/fatigued governor weight plate.

If you don't have a shop manual, it would be a valuable investment. It will pay for itself in mistakes not made!

pburchett · Feb 12, 2021

I should have done a compression test before I tore it down but since it had blow-by I figured it needed rings at least.

I will definitely have the head redone.

pburchett · Feb 12, 2021

Steve:
I plan on rings, bearings, and a valve job, but it will probably turn into a complete rebuild..

There was no coolant in the oil and I checked the webbing between the cylinders and thank goodness there were no cracks.

Thanks for the tip about the liners riding up. I did not know that would happen.

I have not gotten to the oil pump or the governor yet, but I did get a Ferguson Dealer Shop Manual and Parts Book. I would not attempt much without those.

rustred · Feb 12, 2021

it amazes me that people start tearing down an engine for just" because". you want to know about your engine then check the compression! and
monitor the oil consumption and thats all there is to it. from thos epicture you cant tell a thing. the valves need to come out of the head
for inspection. the pistons need to be pulled then an inspection done . the same with the brgs and the rest of the engine. its just a waste
of time posting those kind of pictures cause they show nothing. well maybe the carbon i can see, which would be normal for any engine not
worked. the most important thing is compression checking and it is unbelievable on here that is the most ignored step. and i always say that
too. just like couple days ago on a post everyone posting ideas about a page long , first thing i said check the compression. turns out the
compression is low, go figure.

Steve@Advance · Feb 12, 2021

Just remembered, the 20's also had problems with the fiber crank thrust washers failing. Be sure to check the crank end play.

It was a goofy set up, I'm thinking there is a flanged replacement bearing to upgrade it.

You can also post on the Ferguson board, some good experience there.

Indiana Ken · Feb 12, 2021

(quoted from post at 18:00:45 02/12/21) I am rebuilding a HF TO-20 for my wife. It was her pappys tractor.
What can anyone tell me about the condition of the engine from these photos.

I am assuming the crankshaft is still in the engine. If you purchase a head gasket and install the head you can do a leak down test. Install the head without the push rods or omit the rocker arms so all the valves are held closed by the valve springs. The pistons are typically positioned two at TDC and two at BDC. The leak down tester outlet is threaded into the spark plug hole and compressed air is introduced the cylinder you wish to test. The inlet of the tester is connected to an air compressor.
There are two pressure gauges on the tester. One gauge is used to set the test pressure and the other gauge reads the air leakage of the cylinder. If you have leakage, listen at the inlet or exhaust port to determine which valve is leaking. Leakage past the piston can sometimes can be hear by listening at the crankcase breather. In my opinion, the leak down test can actually give you more information about engine condition than a compression check.

rustred · Feb 12, 2021

all you need to do is check for blowby. the beginners dont understand leakdown tests. if you have an engine using oil and low compression
blowing out the breather , you dont need a leakdown test as it was just done in front of you.

M-MAN · Feb 13, 2021

Looks like a normal tired old engine to
me. Neither end cylinder was firing good
but one is much worse. Lots of
oil/carbon build up indicates it's time
for an overhaul.

Really don't understand all these guys
hammering you about a leak down or
compression test. Unless you're a patch
artist or it's an almost new engine it's
a waste of time. If you tear down an
engine to rebuild it the head is
automatically going to the machine shop
for the valve work. At a minimum the
pistons will get new rings. These two
things make both tests a waste of time.

I would advise you to remember what your
working on and how much it will be used
to determine how far you want to go with
rebuilding it. It doesn't have to be
factory perfect to do what you need it
to.

showcrop · Feb 13, 2021

(quoted from post at 19:02:09 02/12/21) it amazes me that people start tearing down an engine for just" because". you want to know about your engine then check the compression! and
monitor the oil consumption and thats all there is to it. from thos epicture you cant tell a thing. the valves need to come out of the head
for inspection. the pistons need to be pulled then an inspection done . the same with the brgs and the rest of the engine. its just a waste
of time posting those kind of pictures cause they show nothing. well maybe the carbon i can see, which would be normal for any engine not
worked. the most important thing is compression checking and it is unbelievable on here that is the most ignored step. and i always say that
too. just like couple days ago on a post everyone posting ideas about a page long , first thing i said check the compression. turns out the
compression is low, go figure.

The sort of post that shows that other posts in the thread were not read.

rustred · Feb 13, 2021

i post what i see here. these picture show nothing about engine wear , other than it is carboned up and giving it a good work out might have
been all that was needed. and if the poster is asking about the condition of the engine then something wrong with the big picture. and why is
he redoing the engine? still amazed why tear it down for the sake of tear down. the only thing that jumped out at me is the left cyl. exhaust
valve is carboned up could be low compression on that cyl? , the other 3 cyl's. look more normal. so compression check was due before tear
down.

rustred · Feb 13, 2021

if you would have posted what you have been replying to in others posts then things would make a whole lot more sense, not just throwing out
a picture with no explanation. there was no other posts when i posted.

roaddevil49 · Feb 13, 2021

What year,a Continental or a Standard (British) engine?

pburchett · Feb 13, 2021

(quoted from post at 14:23:51 02/13/21) What year,a Continental or a Standard (British) engine?

Its a 1950 TO20, Continental Z120

Yep, I should have done a compression test to just see what the numbers were, but I got carried away taking stuff off and planning my next move and had the head off before I remembered it. I don't guess it matters much as it had some blow-by so I am sure the numbers would have been on the low end of the spectrum.

Good to also know about the fiber crank thrust washers.

I do believe the engine was always idled along and never really worked hard as I have been around her pappy since 1990 and he always just putters along. He had the tractor since 1976 and it caught fire last year.

Any tips are appreciated as this thing was made 19 years before I was born.

SVcummins · Feb 14, 2021

New pistons rings send the head off get it checked and rebuilt

Engine condition from piston top and valve photos

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