Farmall Cub Blue Smoke - Part 1, The Investigation
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- Опубліковано 9 лют 2025
- 1949 Farmall Cub; Blue Smoke.
Air fuel mix, fuel additive, oil change, spark plugs fouled, compression test, low compression, valves not seating, valve adjustment check, piston rings, cylinder walls glazed, head gasket check, disassembly, draining the fluids, stuck radiator drain plug, removing the hood, removing the head, oily valves, checking head for warps, original valves w/ IH logo?, two new valves, replace all the valves, valve guides and valve springs, measuring the piston size, measuring crank rod journal, removing the valves, removing the pistons, crank journals are good, antique valve spring compressor.
Looking forward to more on the Cub, I like your approach to problems & troubleshooting.
Thanks 👍
I love your channel and your little video series you do on each project. Just my two cents, I think you're totally on the right track with figuring out the smoking issue. Consider the valve guides as well. I did a valve job and new rings on an engine and didn't address the valve guides. Once I got the engine back together it still smoked, then I had to go back in again... I'll only make that mistake once.
Thanks John. Yep, valve guides are getting done too. New valves, guides, springs, and keepers. I do NOT want to do this twice! ;)
Thanks for that tip
Best way to isolate your blow by problem is do a cylinder leak down test very easy a will pin point where your problem is. Procedure is as follows put cylinder your testing on tdc then install tester to spark plug hole charge cylinder to 100 lbs and read second gage on tester to see difference between charging pressure and cylinder pressure there will be 4 areas for you to check at this point while air is being introduced to cylinder 1 open radiator to see if you have a blow head gasket 2 open throttle fully and listen for air escaping thru carb indicated burned intake valves 3 listen to exhaust for air escaping ie: burned exhaust valve 4 open breather to crankcase for air escaping indicating blow by from rings. Hope that helps
Thanks Terry!
that is the first Flathead valve adjustment I have ever seen
Best thing to do is replace everything rings, valve seats, rod bearings , piston maybe be reused but if I had any doubt I would replace it. The last thing you want to do is have to tear it back apart
Agreed!
with the piston on TDC see if the piston moves from side to side I think Indicating the rings are worn
yes other issues there I didnt think of
I just had to replace my manifold on my cub loboy 154 same engine why did they mold it so tight to the inner bolts
Ring Job and a valve Job yah
Another source for oil burning is the Oil bath air cleaner.
Is there too much oil?
Is the filter media above the oil cup dirty?
That was not the issue in this case but that’s a good reminder to check that. Thanks.
yeah if valve guides are worn it will pump oil out the valve guide
Is that valve compressor for a Model T? 🙂
I have actually seen old tractor engines so worn out you would literally have to pull crank it , then it would die when you let the couch out ( not enough compression to even pull it's own weight.
These engines will run untill there literally dead!
I'll bet your original valves would probably grind out just fine. Those IHC ones will outlast any new valve.
Did you notice any coolant mixing with oil, either in the oil or coolant? I just did everything you did for the same reason (smoke), but on a John Deere H (new pistons, rings, machined head/block, new gaskets on everything). Put it all back together and started right up. No smoke at all any more, but lots of coolant in my oil now and no idea why.
I'm sorry to hear that. Did you have coolant in the oil before the tear down? Are the surfaces of your block and head flat? Did you use any type of coating on the head gasket or did you install it dry?
I'm pretty sure that I didn't have any coolant getting into the oil but I'm still right in the middle of the project.
Sounds like your head gasket is leaking, maybe it moved a little when you tighten the head don't take much movement
Great video of the teardown. I'd recommend measuring the cylinder at the top and bottom to see if there is a taper to the cylinder as well. Yeah those valve seats are a mess. The valves themselves are probably ok. I'd have them ground. They are probably better then the new ones available.
Just for curiosity what is your opinion on the head if it would be warped? I've heard one individual of UA-cam say that Cub heads should NOT be milled. Best yo replace them. It's even debated a lot about not needing to worry about a warped head. They claim it will flatten out when torqued down. I disagree with that. First off I wasn't aware that cast iron flexes?
Thanks. Cylinder #1 has about a .003” taper. I’ll check the others later. I went ahead and ordered new valves. They seem like good quality but I'll definitely keep the old ones just in case. I have heard the same thing about Cub heads. Not sure why they don't "take" to being milled. I've never heard of that on other stuff. It looks like new heads are available for about $250. I agree with you about the warped heads. Why even bother? I wouldn't want to use one. Mine seems to be ok, so that's good.
Did I see a rear combo “white/red” light as a headlight?🤔 I seen the knob.😂
Yes! That's all I had available when I assembled it (one headlight and one rear combo light), and I've never switched it out.
What did you use to clean the head a valve with?
I believe I used brake clean and an sos pad.
Dang! I hate when that happens.
Good morning. Is this your first engine overhaul?
No, but it feels like it. It’s been a while. Good morning ☀️
Hamilton Bob's