Anyone know what could have caused this???

This is a G head off of a 71 455 that I bought as an almost complete motor. No oil pan, brackets, exhaust manifolds and rod cap for #7 rod. It did come with a complete engine stand though. Motor and stand for $75.
The widow I got it from said her husband had been working on the motor but did not know anything about it, just needed it gone since she sold the house and was moving. I assumed he must have had a problem with #7 since the rod cap was off. The heads and intake were still bolted on. I pulled the head and found his #7 problem. I am just curious as to what would have caused it. Had he kept using the motor, I am sure it would have eventually lost the keeper as the valve recessed. Could it be unleaded fuel in a non hardened seat??? The other valves look to be OK, just this one is bad. Struck out on a forged crank but it is Nodular.

 

It took a bunch of heat to do that, rebuild that set of heads.
Replace the whole #7 rod.
Do NOT just put another cap on it.

 

HOLY SHYT! I have never seen a exhust valve do that before!!!!!!!

I would redo the heads youll need a valve job and some replacments.........I have used valves from another set of heads with doing much to them but if your looking for a motor with some longevity I would break down and get them magged cleaned and have the block checked also,That motor has some issues........Great price even for a core tho......................Jerr

 

Oh yeah, no doubt. I don't take short cuts building motors. I will get a complete rod. I was actually going to use a rod cap off a 425 rod and have the rod reconned, but to no avail. The caps are differant so I will find another rod. On the heads, without doubt, they will be going to the machine shop to be done properly. I am leaning toward my small valve C heads instead of these G's and grinding the A I R bumps out of them, triple angle, resurface, new guides, hardened exhaust seats etc etc. I had never seen a valve that way either and just wondered if anyone had an idea of what caused that. I have seen heads with unleaded fuel recess before and they did not even look like that. Maybe an excessive lean carb adjustment condition, or no water in that back corner of the block or what. I did not know and new to Olds and not sure of whats common and whats not. Sure want to avoid that issue in the future if I can.

 

Since you need machine work done and you live in OKC you should check out Buddy Rice Machine Shop. They are in the phone book.

They did my 455 and C heads. I was pleased with their work.

 

I had heard he did good work, but I am thinking he has passed on and other in his shop do the work. Or am I thinking of someone else. He's a pretty common name around here. I live in between OKC and Noble, OK where the Thunder Valley racetrack is. I try to go at least 2x a month in the open season, but lucky if I can make it to the track once a month. I really hope to get a BBO built for one of my trucks and have a good reason to go more often.

 

Correct. Buddy Rice passed away; however, his son Skip is the owner now. Actually, it was Skip and his machinists that did the work on my engine. It took awhile but they have good customer service and are great craftsmen.

 

Hey; Valves that burn up like that are usually the result from a seating issue (bad seat or bad guide) also cam lobe failure can be the cause. Around the time leaded fuel was being phased out this was a common problem with cast iron heads, fuel & material compatability issues.

 

I had a valve do that in a '67 Pontiac OHC-6. The cam was fine, and the valve seat was fine (fortunately). The machine shop that did the head believed that it was possibly a bad valve (hairline crack/weakness) that just eroded as in the picture, from continued combustion and use until the miss or dead cylinder became too noticeable to live with. The other 11 valves were all in good shape and responded well to a standard valve job and head reconditioning.

 

Thanks for the responses. Just so long as the head is still probably good, I'll be happy. Its a G head and I believe those are supposed to have hardened seats already even in 71. If I do use the head, I will probably have hardened exhaust seats installed anyway, and replace some vavles.

 

Imagine how long it was like that and they kept driving it ...

 

Is wasn't a day or two, thats for sure. Whenever the problem came to a head and they decided to yank the motor, they obviously thought the problem was bottom end. I bought the motor for $75 and the oil pan was missing and so was #2 main cap. Heads and intake were still on it. But that problem is #2 exhaust valve. I may have said in a previous post. I was looking at the wrong end of the motor. At any rate, the Nodular crank and bearings looked good and the cylinders are not scored, but I do believe its time for a bore job to revive this one.