Technical The world's worst valve job?

Some genius decided to install the top ring with a piece missing (must have broken it when putting it on the piston). The motor ran fine for a while (it was in the car when I bought it), then it started missing. Nothing in the cylinder or the sump, so the missing piece is probably on the floor in the previous owners shed.

 

more likely out the exhaust port, that's damage from detonation, doesn't look like that engine received any love recent to its demise.

 

I always figured that running the carburetor dangerously lean for smog purposes had something to do with it. On non smog engines if you keep the valves below a critical temperature they don't suffer unusual wear. In other words if you puppy the car around town. Hard driving builds up heat to the critical point.

You can add some upper cylinder lube like Redex, Bardahl, Marvel Mystery Oil etc to protect the valves on older (pre 1970) engines.

 

That makes sense. Thanks for explaining.

 

I've also seen .100" exhaust valve recession in a 60's vintage Chev six cylinder.
A friend has run a 302 Jimmy on unleaded premium for decades and many thousands of miles. He adds a small amount of two stroke oil to every tank of gas. He hasn't had the motor apart since he built it, still runs really strong, I doubt it's lost any compression due to exhaust valve sinkage.

 

I run a lot of the older engines. And I burn ethanol gas. What I do is add a pint of diesel fuel or 2 cycle oil to every ten gallons of gas. The 250 in my 66 GMC gets hard use hauling wood and pulling my trailers ect. I have a old motor minder vacuum guage and try to drive in a manner that keeps the guage in the green zone. I had a 250 in a 65 chev Pk that recessed the valves and burnt a piston. It developed a vacuum leak on a trip to Dallas Tex. I think vibration caused the manifold bolts to get loose. I first noticed it wasn't idling properly. Then It started smoking. I found the loose bolts and tightened them. However the damage was already done. Probably less than a 100 miles of driving with a vacuum leak. The old engine made it home. However It was really puffing smoke and had plenty of blow by.

 

That's a burnt piston . It can be caused by lean fuel mixture or incorrect timing. The burnt part of the piston and the missing part of the piston ring went out the exhaust

 

I could go on for days about stuff that I have found when tearing one down. The 394 I got had a big ass Water Roach ( call them Oak Roaches here in Missouri)stuck in the oil pump pickup, and a mouse next in one piston.

My favorite is one that happened to a friend and I. I have a younger friend that I have raced with for about 20 years give or take. he's about 5 years older than my daughter. he has a big block dart (OT car) that is his first car. He hasn't driven it for probably 10 or 12 years. He had a 440 in it when we first met and one Friday night he decided that we should change the cm shaft so he could go street racin' on Saturday night. So we stated early in the evening. In the very late evening or very early morning we were getting ready to throw the intake back on and a big assed June Bug came flying in the shop and right down into the lifter valley. We didn't manage to catch it and just left it, figured that it wouldn't hurt much and we were tired (and a little loopy).After we laughed for a while we buttoned it up.

So there is the back story. fast forward to about the turn of the century we swapped a low deck motor in and were going to pull the 440 down for a freshening. pulled the pan and low and behold there was that damned June Bug stuck to the pickup, intact. He has it in a jar on his dresser to this day.

@Old wolf I just use top oil in my old engines what ever is on sale. Bardahl is still available here (probably in your neck of the woods too) and can usually be had cheap. Diesel is probably as good an idea as anything all you need is something to cushion the valves.

 

You can easily fix those heads with oversize exh valves. Not expensive and quite simple.I once had a customer bring me a BSA A-10 for a top end overhaul.Got it done,ran the engine,test rode,checked oil pressure and circulation( dry sump) gave the bike back.About two weeks later he comes back with a seized engine.I pulled it back apart wondering what on earth I had done wrong.rebored (again) fitted new pistons,etc.Drained the oil and it didnt want to drain properly.Looked in the tank,fished around and there was a well taped up plastic bag of pot in the oil tank!As the oil circulated it would work its way down and block the feed line-------I had cleaned the oil tank the first time and it hadnt been there.I got the guy into the shop and handed him the bag.He said "Wow! I thought I had lost that".Turned out he had hidden it during an emergency and didnt remember where the next day-------

 

That's rich.

 

That's always a great feeling, isn't it?

I remember when I inherited my buddy's truck that never ran well. It had been sitting for years at that point, and I decided that some basic maintenance was called for. I rebuilt the carb and adjusted the valves, and suddenly that poor-running truck purred for the first time in decades. It put a huge smile on my face, that comes back every time I turn the key.

 

That story makes me glad I live where pot is legal.

 

fixed it fer' ya

 

That's what I thought too, but I figured that that those bits of ring would make their mark on the top of the piston, and on the valve and seat, but they were all un damaged.
I had a chemical engineer at work have a look at some "valve saver" upper cyl lube stuff, and he said it was mostly diesel, so that's what I stick in the drip feed which goes to the carb.
Works fine so far.

 

cowboyted when that incident occurred it wasnt legal in Colorado----it was around 1965.

 

The thing that kills seats is lugging them around. My uncle owned a machine shop,and we had this old man that was bragging about how his Datsun had never been over 50 mph, he wasn't a hot rodder blah blah blahand low and behold the seats were hammered. They looked way worse than your pics.

Btw, I have never owned a car with hardened seats.

 

Years ago I bought an LS6 454 short block new from our local Chevy dealer. When I took it apart to add blower pistons, there were a bunch of moths and some kind of dirt nests in it. Glad I took it apart.
As for the old truck, I really thought that they had done all the updates to those heads based on the fact that it had been rebuilt long after they took the lead out of the gas here in Ca. Had I known, I would have used some kind of additive, especially when I was towing.
Roothawg, I always heard that lugging engines was hard on bearings too. My dear ol' Dad was a world class lugger with his '49 Ford and later his '51 Stude. He was in 3rd gear before he passed the neighbor's yard.