MY '53 compression test

Farmall Cub Forum -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
User avatar
farmergiffIV
5+ Years
5+ Years
Posts: 203
Joined: Sat Aug 17, 2013 8:36 pm
Zip Code: 97526
Tractors Owned: 1948 FCub
1953 FCub
Location: Oregon

MY '53 compression test

Postby farmergiffIV » Thu Jun 28, 2018 8:43 am

So I did a dry test and got 70,50,67, 71

The wet test was: 90,65,90,99.

I might redue the test again, I was hand cranking about 10 strokes for each test and I heard what sounded like air escaping around the o-ring on my compression tester...

Even if these numbers aren't exact does it indicate worn rings and maybe something else near cylinder number 2? I am hoping to get another year or two of farm work before I need to rebuild but maybe sooner than later that number 2 was an odd ball low. and boy I was excited to see a 99 on the 4th, the needle just kept going up!
Sun Spirit Farm Manager



My '53 and '48 Cub Project

User avatar
raystractors
5+ Years
5+ Years
Posts: 334
Joined: Wed Aug 31, 2011 11:55 am
Zip Code: 37058
Tractors Owned: 1950 Cub, 1952 Cub, 1970 Cub, 1975 Cub, 1953 Cub, 1939 A, 1948 super A, 1952 super A, 1950 C demonstrator, 1952 Super C, 1949 H, 1956 farmall 300, 1957 international 350, 1963 Massey Ferguson 35
Circle of Safety: Y
Location: TN Dover

Re: MY '53 compression test

Postby raystractors » Thu Jun 28, 2018 9:09 am

I would check the valve clearance before i got too upset with those readings. Maybe some seafoam and work it some to see what happens.

Matt Kirsch
10+ Years
10+ Years
Posts: 4605
Joined: Tue Jun 08, 2004 3:04 pm
Zip Code: 14559
Circle of Safety: Y
Location: Rochester, NY

Re: MY '53 compression test

Postby Matt Kirsch » Thu Jun 28, 2018 9:50 am

If it's getting the job done now, isn't knocking or completely smoking you out, has serviceable oil pressure, and you keep the oil topped off, you should be able to easily get another year out of it.

I agree though, run the valves, and try half a can of seafoam. Put it straight into the intake; don't mix it with gas or oil. In the oil it really mucks with the viscosity of the oil and makes for low pressure. In the gas its too diluted to do much good.

What I've done is put it in an old windex bottle, and spray as much directly into the intake as the tractor will ingest without stalling. It'll take a while to feed it all in, but once it's in shut it off and let the tractor cool off. Next time you start it up it's going to smoke like a freight train for a while, but after that you should see some improvement, if there's any to be had. A wore out engine is a wore out engine, and no "snake oil" is going to change that.

inairam
501 Club
501 Club
Posts: 967
Joined: Wed Jul 08, 2015 10:24 am
Zip Code: 19342
Tractors Owned: 1948 with international 1000 loader
1949 with kub klipper belly mower.
1957 with c-2 mower & c-54 grader blade
1965 lo-boy with c-3 mower
1975 with homemade mower
Memberships: Rough and Tumble Engineers Historical Association;Chapter 8 IH Collectors; IH Collectors Worldwide
Circle of Safety: Y
Location: Glen Mills PA

Re: MY '53 compression test

Postby inairam » Thu Jun 28, 2018 10:34 am

remove all of the spark plugs and crank it with the starter when you redo the compression test

Like Matt & Ray said seafoam first but I do put it in the oil at recommended levels. If it is a real problem I put is in the spark plug hole and let it sit overnight or for a few days rotating the engine by hand every once in a while, then run it lightly for an about an hour and change the oil. You are trying to get the seafoam to the rings to loosen the crud up so the rings work again.
When you only have 9 horsepower you need to know the names of all of the ponies!

User avatar
farmergiffIV
5+ Years
5+ Years
Posts: 203
Joined: Sat Aug 17, 2013 8:36 pm
Zip Code: 97526
Tractors Owned: 1948 FCub
1953 FCub
Location: Oregon

Re: MY '53 compression test

Postby farmergiffIV » Thu Jun 28, 2018 1:19 pm

I'll pop the valve cover and inspect the gaps. I already set them once and they were waaaay off, but I'll double check my work and see, and share a few photos if I am unsure if anything needs work.
Sun Spirit Farm Manager



My '53 and '48 Cub Project

User avatar
Glen
5+ Years
5+ Years
Posts: 2806
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: MY '53 compression test

Postby Glen » Thu Jun 28, 2018 4:52 pm

Hi,
When doing the compression test, open the throttle so the carburetor throttle valve is fully open, so it can get air.

User avatar
farmergiffIV
5+ Years
5+ Years
Posts: 203
Joined: Sat Aug 17, 2013 8:36 pm
Zip Code: 97526
Tractors Owned: 1948 FCub
1953 FCub
Location: Oregon

Re: MY '53 compression test

Postby farmergiffIV » Sun Jul 01, 2018 12:00 am

The 1,2,3 and 5 valves clearance for the 1st piston at TDC were off noticeably. I must have not set them properly the first time or something in there is loose and moving around during engine operation. I will fire her up tomorrow after I get off the farm for a hike and see if there is any difference.
Sun Spirit Farm Manager



My '53 and '48 Cub Project

inairam
501 Club
501 Club
Posts: 967
Joined: Wed Jul 08, 2015 10:24 am
Zip Code: 19342
Tractors Owned: 1948 with international 1000 loader
1949 with kub klipper belly mower.
1957 with c-2 mower & c-54 grader blade
1965 lo-boy with c-3 mower
1975 with homemade mower
Memberships: Rough and Tumble Engineers Historical Association;Chapter 8 IH Collectors; IH Collectors Worldwide
Circle of Safety: Y
Location: Glen Mills PA

Re: MY '53 compression test

Postby inairam » Sun Jul 01, 2018 8:33 am

as a general rule with the flat head slightly loose is better than slightly tighter.

The manual says .013 but there are many posts where people say 015 is what they use.
When you only have 9 horsepower you need to know the names of all of the ponies!

User avatar
farmergiffIV
5+ Years
5+ Years
Posts: 203
Joined: Sat Aug 17, 2013 8:36 pm
Zip Code: 97526
Tractors Owned: 1948 FCub
1953 FCub
Location: Oregon

Re: MY '53 compression test

Postby farmergiffIV » Tue Jul 24, 2018 10:42 am

Alright, so I redid the compression test. This time all the spark plugs off and I used the starting motor to turn the engine over quit a handful off times.

Dry: 120,117,120,120 ( I was very happy to see the gauge go up this high!)
Wet: 165, 165, 170, 170 (what the heck?)

This is bizzare, the dry numbers indicate I have good compression, but then I did 3-4 squirts of sae 30 in each cylinder and the numbers jumped up to the 165 range. Can anyone explain what this indicates?

I want to reiterate that I am trying to solve the issue of engine power loss so my hunch is timing but I am trying to decide if engine rebuild is necessary to get good results
Sun Spirit Farm Manager



My '53 and '48 Cub Project

xraycajun
Cub Star
Cub Star
Posts: 119
Joined: Sun Aug 20, 2017 11:05 am
Zip Code: 70769

Re: MY '53 compression test

Postby xraycajun » Tue Jul 24, 2018 11:51 am

Your wet compression should be higher due to the oil creating a better seal between the cylinder and the rings. Overall, it sounds like you have tight engine. I wouldn't rebuilt it anytime soon with those #'s. I have mine apart right now. I only went in that deep because all four pistons were down into the '70's. Last rebuild was 1981.

Bob McCarty
Team Cub
Team Cub
Posts: 8990
Joined: Tue May 25, 2004 8:02 pm
Zip Code: 80501
Tractors Owned: Cubs, MH Pony, Shaw, Allis G, 1934 Silver King, JD LA and LI, Gibson D, David Bradley Tri-Trac
Circle of Safety: Y
Location: CO, Longmont

Re: MY '53 compression test

Postby Bob McCarty » Tue Jul 24, 2018 3:19 pm

I question the wet numbers, not sure you could get a Cub to go anywhere near that high.
"We don't need to think more,
we need to think differently."
-Albert Einstein

User avatar
farmergiffIV
5+ Years
5+ Years
Posts: 203
Joined: Sat Aug 17, 2013 8:36 pm
Zip Code: 97526
Tractors Owned: 1948 FCub
1953 FCub
Location: Oregon

Re: MY '53 compression test

Postby farmergiffIV » Sun Jul 29, 2018 10:12 am

https://vimeo.com/user87861297/review/2 ... 175b11ba7b



Here is the video of me getting high compression on cylinder number 1. I already cleared a totally clogged valve vapor manifold, is it possible there is another clog somewhere internal that is causing the pressure to read so high? But each cylinder got 120-140 on this test. I believe my compression tester works fine, its a good quality one. This is really weird. I am totally confused by this compression test. (I did this about 48 hours after I put a tablespoon of seafoam down each spark plug hole.
Sun Spirit Farm Manager



My '53 and '48 Cub Project

tst
5+ Years
5+ Years
Posts: 2980
Joined: Tue Jan 12, 2010 2:08 pm
Zip Code: 12514
Circle of Safety: Y

Re: MY '53 compression test

Postby tst » Sun Jul 29, 2018 10:30 am

the theory is when you add oil to cylinder and the compression rises that much is the oil is sealing the leaking rings raising the compression

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 17089
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: MY '53 compression test

Postby Eugene » Sun Jul 29, 2018 12:20 pm

Hand cranking will produce significantly lower compression reading than using the starter motor.

My opinion. Start the engine and operate for a short period to time to clear the oil out of the compression chambers. Then add SeaFoam to the engine oil and fuel. Work the tractor hard for a couple of weeks.

Let tractor set over night, dead cold engine, don't start the engine. Conduct dry compression tests, again.

If the dry compression readings are satisfactory, call it good. If not satisfactory, wet compression tests, then make a decision.
I have an excuse. CRS.

User avatar
Glen
5+ Years
5+ Years
Posts: 2806
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: MY '53 compression test

Postby Glen » Sun Jul 29, 2018 4:10 pm

Hi,
You could try another compression tester, and see if it reads the same as the one you have.
It's possible your tester doesn't read right.
I think I have read on here that some auto parts stores rent them out to people. :)


  • Similar Topics
    Replies
    Views
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: Mht, mikes5785 and 5 guests