1957 chevy 235 truck engine in my 1949 3100 p/u. I just installed new pistons & rings 200 miles ago. The head is a rebuilt (3836848) one I bought off ebay (6000 mi ago). I am burning m***ive amounts of oil so I checked the cylinders with my camera and seen the puddles of oil on pistons. I compressed the valve springs to see there were no o-rings on the second valve stem indentions. It does have the umbrella types on from rebuilder. So I just added the o-rings and started again to still burn oil. From looking at the pictures does it look like I need to do more valve seal work or can this be coming from head gasket? Every cylinder is similar with obvious oil running down walls. Is it better to go with new umbrella type or put o-ring type on stem? View attachment 6118633 View attachment 6118634 View attachment 6118635 View attachment 6118636
or see what's wrong with the rings? Head gaskets don't seal oil, they seal coolant and compression, so that's not your problem. if it has a badly set up PCV system, that could be the issue too.
I thought it had at least one port for oil to travel to head but it must get it all from that little steel tube next to push rods hey? It seems like too much oil for a valve seal issue. Could it be getting too much oil in head for some reason?
Do a compression check. Did you crosshatch hone the bore? What was your bore taper? Did you thoroughly clean the ring grooves of the pistons? What type of rings? Was your ring gap in spec? Did you offset the ring gaps? Sometimes it takes new rings a while to seat. Chrome and cast iron rings take the longest to seat. 200 miles? That’s not much. I would run it a while to see if that makes a difference. It’s been many years since I fooled with a 235 but on some engines, you use either umbrella or o ring seals, not both. I would research that. Another thing to research and possibly inspect is the oiling system. Review the rocker oil supply and return from the manual. Is something missing there? Is there a compatibility issue? Were the supply and return tubes and galleries clean? Do the cylinders closest to the supply or return show more oil?
A leak down test will only tell you how well your compression ring seals , it doesn't show anything to do with second ring ( mainly oil control ) or oil rings . Sounds like second rings installed upside down and/or lousy hone job . How tight are the valve guides ?
You won't find this helpful, but somebody might enjoy it: In 1973, during my senior year of high school, I bought a 1957 Chevy 3100 short bed/w small back window, 235, and 3-speed on the column. It wasn't running, needed a windshield, but the body, brakes, etc were all good. It also hadn't been registered in years (CA), but a paper trail was included. I paid $300. My stepfather and uncle honed the cylinders and installed new rings. Although it ran well, it burned and leaked lots of oil. I was constantly adding oil & STP. One night, while coming home from a Halloween party, I pushed it too hard, threw a rod, and the cam broke into several pieces. I ended up selling the truck to my roommate, who put a rebuilt engine in it. I wonder where the truck is today.
If you end up removing the head I would change to better seals. When I had the heads off my Y-block for another problem, I bought a tool from Summit to cut down the guides and install positive seals. Cost less than $100. I cleaned the valves and lapped them. It is actually possible if you put the 2nd ring upside down and this would definitely cause your symptoms.
Another vote in the "second ring upside down in the groove" group, turns them into oil pumpers. Second ring is not a compression control ring, it is the final oil prep ring to leave the proper amount of oil for the top ring to ride on and seal with. The oil rail rings and oil expander set is the bulk oil s****er. I agree the crosshatch looks pretty poor, unless that is just a camera focus issue.
If the umbrella seals are to long, they can act as a pump at lift as well. Would even be worse if the guides were knurled. Worth a look to see what they are doing at full lift before pulling apart.
I have a bad feeling I put 2nd ring upside down. I understand that I took a short cut trying to replace them without rebuilding whole thing but I was trying to put that off for a year or two. If it was just a burning a little oil I would leave it til then but it's too much. The picture is of the old ring under the new ring. The new ring gap is out of spec by a lot with new one but I thought would be better than what I had. Also had 2 broken rings. Can I use .020" over rings and grind down til I get to spec? .020" is too big for my bore size. I went with stock size 3.562" pistons and rings. My bore size was 3.567" to 3.572". I understand just putting in new pistons isn't the "Right" way. Just trying to buy a little time til after I pay for medical issue and a Ruckstell axle for my 26 Model T Roadster. I really thank you guys for the help.
I will take apet and put in all new seals. But which ones? Umbrella or the o-ring on 2nd groove on stem? I just seems like the oil is coming from the top. I don't want to pull pistons if it's a head issue
I did this with engine in truck. It did have a good cross hatching with a couple grooves still visible. Comp test with old pistons & rings was 90 to 110 psi. Now it's 135 to 140psi. It seems like the oil is coming from the top of cylinder for it to be an upside down ring or bad ring gap.
Not the o-ring or umbrellas. Positive seals press on to the correct size valve guides. The tool mentioned comes with a shaft and cutter. Any drill can operate the cutter. I do mine with my battery operated one. A supplier like Compe***ion Products offers many styles all for your valve diameter which is 7/32”. I personally use the metal covered ones where the metal cap makes contact with the guide and the “nylon” rubs the valve. After I “ machine” them I press the seal on with a long socket that fits over the seal ledge and a hammer.its not rocket science….
The Cylinder pictured has no cross hatch , did you mic anything , bore piston size? If the rings are in wrong , fix that , your wasting time & money with valve seals , if you want a good price on valve seals , find " Alex's parts"
If that third pic is really the new ring on top of the old one (and the old one has MUCH less gap) then your new rings are not correct. Way too much gap. No way are you getting that much oil past the valve guides either,unless you have no drainback at all under the valve cover. Oh, and the honing and lack of crosshatch isn't the problem either, although it isn't right.
If those measurements are accurate, you have 5 to 10 thousandths of piston-to-bore clearance. No good on a cast piston, that's between 4 and 10 times too much, stock would be about 1.5 to 2 thousandths at most, and 5 thousandths would be considered worn completely out and need rebore to the next oversize. That's the reason for the broken rings. Piston is too loose in the bore, rocks too much. You probably will never get it to seal up.....the compression ring may seal up and give you good compression test readings but the oil rings will never hold with that much piston clearance, since they rely on just ring tension to do their job.
I've never seen .010 variance in bore size in an engine unless the larger bore(s) had oversize pistons in them ?
^^^^^^^^^^ Anything is possible. Our Olds agency got a new Toro once with the 4 center holes .040 over & 8 std. pistons.
The Jalopy Journal
