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I replaced a connector rod and I think I got everything back where it belongs. Now when I start it up, the oil heats quickly and of course gets real frothy and tries to come up through the dipstick. I drained some oil(not really needing to according to the level), and put on a new head gasket just in case. Now, it still does the same thing. I don't want to let it run too long. There is pressure if I try to unscrew the dipstick, it spews. Somethin ain't right.
I read this in another thread, but I don't understand what it means or how to check it::::
"You need to verify that there is no restriction in the crankcase ventilation system."
Any suggestions??

"the oil heats quickly and of course gets real frothy and tries to come up through the dipstick"

That sounds like a classic blown head gasket. What engine? What did you torque the head bolts to?

I can think of three things which could cause this condition. First, when you installed the piston, did you make sure the ring gaps were 120 degrees apart? Second, breather may be plugged. Third, most common cause is a blown head gasket. Did you check the head to make sure it wasn’t warpped and torque the head bolts properly?

Rivets said:

I can think of three things which could cause this condition. First, when you installed the piston, did you make sure the ring gaps were 120 degrees apart? Second, breather may be plugged. Third, most common cause is a blown head gasket. Did you check the head to make sure it wasn’t warpped and torque the head bolts properly?

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Did not really check the piston rings(was not blowing out any smoke when I started it), don't know how to see if the breather is bad(I did remove it to look at it), I replaced the head gasket and the old one did not have any signs of blowout especially on the valve cover side, but the oil is still trying to get out. How much oil should come out of the valve cover gasket when I remove it to check the valves??

Hammermechanicman said:

"the oil heats quickly and of course gets real frothy and tries to come up through the dipstick"

That sounds like a classic blown head gasket. What engine? What did you torque the head bolts to?

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I did replace the head gasket once and the old one did not show signs of wear on the valve cover side. I did not use a torque wrench to tighten, but I did tighten very good. Don't the head is warped.

If you didn't check cylinder warpage it can be warped. Now as being blown on the valve cover side as most blows next to the cylinder block between the cylinder and push rod galley. Yes the head can warped just did one a couple weeks a\go that was was over .005 warped in the area mention above.

Either you should do a leak down test to verify that either head gasket didn't seal or you have cylinder problems otherwise. These engines do wear the cylinder both taper and oval. Using just a flex hone only makes the problems worst. Many times it is necessary to oversize the cylinder using a ridge hone and instaled a new oversized piston and rings.

Plus the head need to be torque in the sequence in the service manual using three step torque sequence to 21 ft-lbs. IE 7 , 14, and then 21 ft-lbs.

Btw if you are unscrewing the dipstick while running o course oil is going to come out because the piston is moving in and out. It going suck in a lot of air and blow the same back out.

There will be "some" restriction in the crankcase vent hose to carb. It's not a wide open hose. Little baffling going on to slow down oil escaping the sump.

I second piston ring end gap needs to be spaced out far as possible, ring to ring. Also some pistons have a notch that goes up for example.

If you remove the valve cover, only a small oil mess will come out. Raise up the front end or valve cover side of the mower. Will keep the oil inside while adjusting valves.

slomo

Thanks for all the suggestions. Rookie here and this mower is 26 years old. I will have to learn how to check piston wear and how to do leak down tests. There seems to be an inordinate amount of oil coming out of the valve cover when I remove it. After all those years, it probably needs a new breather anyway. I will report back.
Engine is

28N707-0173-01 - Briggs & Stratton Vertical Engine​

theticket said:

Thanks for all the suggestions. Rookie here and this mower is 26 years old. I will have to learn how to check piston wear and how to do leak down tests. There seems to be an inordinate amount of oil coming out of the valve cover when I remove it. After all those years, it probably needs a new breather anyway. I will report back.
Engine is

28N707-0173-01 - Briggs & Stratton Vertical Engine​

Click to expand...

26 YO, I would put a new piston and rings, head gasket and valve adjustment for sure. Probably going to need a valve job and cooling fin cleaning like only MR. Clean can.

theticket said:

Thanks for all the suggestions. Rookie here and this mower is 26 years old. I will have to learn how to check piston wear and how to do leak down tests. There seems to be an inordinate amount of oil coming out of the valve cover when I remove it. After all those years, it probably needs a new breather anyway. I will report back.
Engine is

28N707-0173-01 - Briggs & Stratton Vertical Engine​

Click to expand...

Be sure that the oil is not overfilled and that the Crankcase vent hose and vent are clear.
If that is not the case, park it at the curb. It owes you nothing.

Is this your mower?


slomo

slomo said:

Is this your mower?

http://www.lawnmower-manuals.info/d/Sears-39.pdf

slomo

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Close, mine is a 917.258522. Sorry for the delay. I don't want to dispose of this mower. Still trying to work through it to learn more. thanks a bunch for sticking with me. Still need to do a leak down test. I'm slllloooowwww!!