641 bad blow by

[Alpine Cheesehead]

I just got this tractor. I adjusted valve clearance to .017 cold, all new wiring, new 12v coil, cleaned carb, new belts, fresh coolant, oil/filter change and new alternator.
When I first got it it seemed to have a fair amount of blow by. I checked compression and I have 120ish in all cylinders cold and dry and 125ish with some oil in the heads so I think my rings are okay. A few valves were a couple thousands off. I was hopeful the valve adjustment would fix the problem.

As soon as I touch the starter button she starts and sounds great. It seems to run great at all RPM's.
I am still getting a lot of blow by from the valve cover vent and oil fill vent. Maybe even more than before. Even after the motor is off it continues to smoke from the valve cover for a while. I took the valve cover off while it was still hot and there is smoke/steam coming from push rod holes. Also I noticed 2 small spots of white/oil spots on roof of the valve cover above number 1 and 2 cylinders.

When I changed oil I did not notice any milky oil. Also the tail pipe is running clear.

What do I have going on? Head gasket??

Jason

 

[souNdguy]

Run her with rad cap off, look for bubbles, if nine, and not loosing water, or making oil, or getting emulsified oil, I'd just keep watching.

120 psi and east starts are good.

In the end if you have son blow by and little to no smoke, and no SIGns if a head gasket issue, I'd let it ride.

On a new machine, add some ATF to the oil.. Won't hurt, remote chance it might help.. Something . Cheap and easy too.

 

[showcrop]

For how long have you been running it? It takes a little while at operating temp to drive the moisture out of the motor.

 

[sotxbill]

water!!!!

 

[Alpine Cheesehead]

I've ran the tractor for about an hour. I dumped some sea foam in the crank case to try to get rid of any water vapor in the oil. What's strange is that I don't get any smoke out the tail pipe. Most the smoke I see comes out the valve cover vent. My latest thought was that maybe my muffler/exhaust is blocked somehow from maybe a mouse or something crawled up in there. I put my hand over the tail pipe and I have a good flow of exhaust so I don't think that is the problem. I'm going to try switching to 15W-30 instead of 10W-30.

Thanks for the reply's!

 

[Keith Williams]

15W40 Diesel grade oil is best.

 

[Sean in PA]

(quoted from post at 12:57:37 03/01/16) I've ran the tractor for about an hour. I dumped some sea foam in the crank case to try to get rid of any water vapor in the oil.

Seafoam does not remove water from the crankcase, but running at temperature for an hour should. Sounds like you might have a leak in the head gasket.

 

[Alpine Cheesehead]

I ran the tractor good and hot yesterday to see if I can drive the moisture out. No luck. I've got no apparent bubbles in the radiator. It was 20 degrees in the garage and it started before I even had time to take my finger off the starter button. I think I will pull the head off - replace the gasket- and put everything back on. It runs so well I don't really want to mess with valve lapping or replacing valves. The exhaust system is severely rusted, I know I'm going to have a hard time removing the muffler/elbow from the manifold.
Wish me luck!

Thanks for the advice.

 

[M-Farm]

That's not a bad idea. I had a leak between two cylinders on my head gasket, at first it did not produce much exhaust steam but it did eventually. Had to replace twice, second time I finally did it right with copper coating, running a tap down the stud holes, proper torquing etc. Pay attention to details, these head gaskets are getting real finicky, I think there are lots of topics on this if you do a search.

 

[showcrop]

(quoted from post at 08:14:09 03/02/16) I ran the tractor good and hot yesterday to see if I can drive the moisture out. No luck. I've got no apparent bubbles in the radiator. It was 20 degrees in the garage and it started before I even had time to take my finger off the starter button. I think I will pull the head off - replace the gasket- and put everything back on. It runs so well I don't really want to mess with valve lapping or replacing valves. The exhaust system is severely rusted, I know I'm going to have a hard time removing the muffler/elbow from the manifold.
Wish me luck!

Thanks for the advice.

What did you do to load the engine so that it got good and hot?

 

[Alpine Cheesehead]

I moved some snow around with it. I probably didn't load it too much but the temperature gauge was on the green/red edge for quite a while. I took the manifold off and
found that where the elbow meets the manifold there is a lot of metal missing where the gasket lies. Also the bolt hole closest to the valve cover was completely worn
through - I'm guessing from the exhaust leak at the elbow. So I'm pretty sure I'm in the market for a new manifold which is a bummer because the rest of it looks great. I
think it would take a lot of work to weld back enough material - grind flat and retap.
Well at least I'm learning a lot about my tractor right? trying to stay positive

 

[showcrop]

(quoted from post at 19:11:59 03/02/16) I moved some snow around with it. I probably didn't load it too much but the temperature gauge was on the green/red edge for quite a while. I took the manifold off and
found that where the elbow meets the manifold there is a lot of metal missing where the gasket lies. Also the bolt hole closest to the valve cover was completely worn
through - I'm guessing from the exhaust leak at the elbow. So I'm pretty sure I'm in the market for a new manifold which is a bummer because the rest of it looks great. I
think it would take a lot of work to weld back enough material - grind flat and retap.
Well at least I'm learning a lot about my tractor right? trying to stay positive

While the exhaust problems are a setback they are a common and relatively minor one. I have a 1969 Yale forklift with a big flat head six in it. Soon after I got it in 1989, I noticed milky oil and foam in the breather, and I was concerned. I happened to know a fellow who at the time was a longtime lift truck mechanic. When I saw him I asked him about it and he told me not to worry about it because all of those trucks with the big motors were that way. Over the 25 years that I have had this Yale, it has been rare to work it hard enough for long enough to heat the oil enough to clear it up. I would unload a truck load of around 30,000-35,000 lbs every four weeks or so. This included putting many of the pallets up on pallet storage racks. It was only when I had one of the larger loads that the truck would be at operating temp for long enough to drive the moisture out. The 8N motor doesn't take as long but I am sure that you have not done enough work with it yet to drive normal moisture out. Always eliminate the easy things first!