Valve replacement

[steveh1155]

What is the intent with the ATF in the cylinders? Confirming if valves or rings are the problem? Or freeing up stuck and carboned-up rings? As you probably know, the way to confirm whether valves or rings are the cause of low compression is to put some oil in the cylinders and check again. If the compression goes up, it's a ring problem. If it stays pretty much the same, it's a valve problem.

Seeing that the numbers went up with ATF in the cylinders and knowing you just had the valves done, it sounds very much like worn or stuck rings. Might be time for a ring/top-end job. But I'd try to get the rings unstuck and get rid of some of the carbon in them first. That might do the trick without more parts and tear-down. But you'll need to let them soak in something thinner and more potent than ATF. And you'll also need to run it for a bit with a load to really clean them up and set the rings. I prefer a good dose of a high quality penetrant in each cylinder. Deep Creep is good. The Delco penetrant GM sells is even better. A mix of ATF and acetone would probably be good too. But ATF alone won't do much apart from confirm where the problem is.

Spray a healthy dose of your penetrant of choice in each cylinder through the plug holes, let soak for a few days, repeat, let soak, then fire it up and run it with a load for an hour or so. With any luck after running for a bit with the penetrant having worked into the rings and broken down any carbon, the rings will free up and help those compression numbers.

The ATF in the cylinders is just to free up the carboned up rings that are stuck in the grooves. I had initially used some MMO and PB Blaster but ran out, I'll have to replenish my supply. Everything in the valve train is new except the valve seats, they were finished with a valve seat cutter and the valve to tappet clearance was adjusted by the book after all the new valve components were installed, much easier to adjust valves with the head off!

 

[steveh1155]

Crack on right is going to continue till it reaches the hole. Drilling a hole at end cracks will eliminate.
Then lock and stitch it .
Link to how that’s performed.

Engine Block & Cylinder Head Crack Repair MA,CT,RI,VT,NH,ME,NY,NJ

Engine Block & Cylidner Head Crack Repair. metal stitching, pinning and welding. MA,CT,RI,VT,NH,ME,NY,NJ. 603-742-8812

www.rlengines.com

Looks like a pretty good system! I may try that when I have things apart again.

 

[used red MN]

The compression numbers were still pretty disappointing,
#1 30lbs
#2 35lbs
#3 30lbs
#4 90lbs
Sounds like stuck rings doesn't it? I poured some ATF in each cylinder and checked it the next day.
#1 50lbs
#2 50lbs
#3 60lbs
#4 90lbs
I gave them the ATF treatment again and let it set another day, and today when I checked compression I got,
#1 60lbs
#2 60lbs
#3 90lbs
#4 90lbs
At least it's going in the right direction!

If all this is done and the engine was not run in between your building on false hope. Pistons, rings, ring grooves and cylinders all interact with each other with specific clearances. Sure carbon or other residue can get in between all these items especially the ring grooves and interfere with sealing. For the most part when you add the oil to the cylinder to see if that raises the compression the oil is just filling in those clearances allowing less compression (air) to pass by them. Valves seal on a metal to metal surface, clearance plays no part in their sealing operation to hold compression. If some part of the circular seal is not contacting, oil in it makes very little difference in the ability of air to pass through that gap. Thus adding oil only identifies the problem is with the valves when the compression doesn’t raise and not the rings as Daniel pointed out.
I don’t know what your history is with this tractor. If you ran it much with 30 lbs of compression on two cylinders my guess is it probably burned quite a bit of oil. Right there would be the indicator that the pistons should have come out to at least look at the rings and most likely replace them.
Your tractor your time, your dime.

 

[soaked]

Its been a few years since I've done the valves on 8ns. The last step was to pour gas or other liquid on the closed valves, so it makes a puddle. A good sealing valve wont pour right through. The gurus here can advise better than me.

 

[steveh1155]

If all this is done and the engine was not run in between your building on false hope. Pistons, rings, ring grooves and cylinders all interact with each other with specific clearances. Sure carbon or other residue can get in between all these items especially the ring grooves and interfere with sealing. For the most part when you add the oil to the cylinder to see if that raises the compression the oil is just filling in those clearances allowing less compression (air) to pass by them. Valves seal on a metal to metal surface, clearance plays no part in their sealing operation to hold compression. If some part of the circular seal is not contacting, oil in it makes very little difference in the ability of air to pass through that gap. Thus adding oil only identifies the problem is with the valves when the compression doesn’t raise and not the rings as Daniel pointed out.
I don’t know what your history is with this tractor. If you ran it much with 30 lbs of compression on two cylinders my guess is it probably burned quite a bit of oil. Right there would be the indicator that the pistons should have come out to at least look at the rings and most likely replace them.
Your tractor your time, your dime.

The tractor ran fine when parked about 6 months ago and I didn't notice excessive oil use then. I checked compression again today and now the cylinders are all near normal compression. I'm going to button everything back up and see if it'll start and go from there. One thing I did notice when I had it apart, there was tons of carbon on the head and around the valves. I spent a fair amount of time cleaning all that off. If it will start and run decent enough now, then late summer I'll tear it all down again and replace rings and sleeves. always had good oil pressure 30 - 35lbs.

 

[steveh1155]

I finally got it started and it smoked like a mosquito fogger for about 20 minutes and then gradually diminished, It still had one cylinder that was missing, so after I shut it off, I sprayed some Sea Foam Deep Creep in each of the cylinders and let it sit overnight. I did this for the next three days, ran it hard and then Deep Creep in the cylinders. When I pulled the plugs each evening cylinders #1, #2 and #3 looked like normal combustion, but #4 was black and oily. Finally, this morning the miss went away, and it started running great! It starts before I can even get my thumb off the starter button and seems to have plenty of power. It hasn't run this well since I got it about 4 years ago! The engine is pretty well smoke free now but maybe a tiny bit from the oil fill cap...I can live with that. Any advice on how to prevent sticking rings in the future? The only thing I can think of is to put deep creep in the cylinders before I put it to bed for the winter in the fall.

 

[Powered By IH]

Another point is when you use it, make it really work once in a while and get the tractor good and warm, otherwise the rings will varnish and gum up from incomplete combustion.

 

[rustred]

I was getting the block cleaned up and saw this crack. This is at the center bolt on the valve side of the block. Is there any chance just some sealer on those head bolt threads would be enough that the crack wouldn't cause any problems?


View attachment 146957

you were getting the block cleaned up ??? , if you are done cleaning it , is a fail. that is a mess, all scratched up like that. a block is a machined surface and should look that way. just posting so u know for next time. and that crack on the bolt threads is not good either. its gonna open up when torqued.

 

[steveh1155]

Yes, I had just begun to get it cleaned up when I saw that crack. I did finish getting it cleaned up. I'm well aware it's no longer a nice, machined surface like it was when it came out of the Ford factory at Highland Park 76 years ago and obviously I have no idea who's worked on it all those years, however the rough block surface isn't attributable to me, it's the first time I've had the head off. I don't have the luxury of time right now or, sure I would just take it to a machine shop, but it is what it is. It's running awful damn good for a fail!

 

[ole fred]

Yes. Not the end of the world.
Next thing to do is buy yourself a brand new. sharp, 12" flat file.
Lay the file on the deck, and WITH YOUR FINGERTIPS, move the file across the deck lightly in all directions.
Don't go all "King Kong", you're not filing the deck, you are locating high spots.
You will begin to notice high spots around bolt holes for sure.
You can measure with a straight edge and feeler gauge if you wish.
Once you are sure of high areas, you can gently lower them, again using minimum force.
Same procedure on the head surface, although you may prefer to just have a machine shop surface grind.
O.K, I'm ready for my whipping.
Let the flames begin....

No flaming from here. I did the same thing on my 961. I used a 16 inch flat file though. It's amazing how "unflat" the top of the deck is/was.

 

[rustred]

No flaming from here. I did the same thing on my 961. I used a 16 inch flat file though. It's amazing how "unflat" the top of the deck is/was.

yes, proper use of a file ,and it will look like a machined surface . there will be no scratches. i have done the same. how is the head gasket to seal with scratches.