Valve seat shrapnel (1 Viewer)

[Terry Lindsey]

Last week I drove my 76 Fj40 to breakfast (DD) and it ran perfect. Came home for a few hours and went out to start it. Sounded like someone drop marbles in the motor. Pulled the plugs and the insulator in #5 was gone. Installed new plugs and still sounded bad. Pulled plug #5 and tip was crushed.

I used a scope and ended up fishing a few pieces of metal out of the cylinder. I ultimately pulled the head and later, all of the pistons. Pictures show all 6 pistons, left to right. As you can see in pic of the bottom of the head, the valve seat is no longer visible and I ultimately removed the remnants from 2 other cylinders (pic#3).

The head is toast but a buddy has a rebuildable one for me. I plan on ordering new pistons, rings and rod bearings. I’m praying that I only have to hone the cylinders as I’d refer not to actually pull the motor. Any thoughts? I do believe the engine has ever been rebuilt so hopefully standard sized pistons with new rings will suffice.

 

[Dizzy]

What make of spark plugs?

Sorry to hear the news.

 

[Helipilot]

Ouch! Had the same thing happen to one of my aircraft, the valve got into the pistons and it was a $30 K rebuild. Hope you don't have the same issues and it is a minor rebuild.

 

[Pin_Head]

If the head has been peened that badly, chances are the cylinder bore has too. Most likely you will need to bore it for oversize pistons.

 

[Terry Lindsey]

What make of spark plugs?

Sorry to hear the news.

Denso W14EXR-U are you thinking too hot of plugs?

 

[SteveH]

I bought a stock '83 engine in which one valve seat was completely gone and the PO drove it until that entire cylinder was hammered to death. Engine had 150K on it. No indication of why it ever failed.

 

[3_puppies]

could have been more obvious like this one.

 

[Pin_Head]

Impressive carnage!
Thanks for sharing.

 

[Terry Lindsey]

Any comments on this idea?.... what about buying 1 or 2 used domed pistons with all news rings? Is that even doable?

 

[Dizzy]

Not all of your valves say Teq. I have a Feb '75 head with what looks like replaced valves on two cylinders.

I once heard that the later heads will work, you just use flat pistons to match - that might allow you to expand your options. Does your block indicate any scoring? Using telescoping gauges will give you a sense of cylinder wear, but they take practice to get accurate numbers. The block that went with head, pictured above, has much of the original cross-hatching, and the factory-diameter bore, but I assume that the valves were once serviced

 

[Terry Lindsey]

Actually the cylinders look good. I may have sourced a decent set of used pistons. I’ll know further later. If so, I’ll get them balanced,re-ringed and install a rebuilt head.

 

[Terry Lindsey]

A quick update. The head needed replacement and a good friend up the street (Robfj40) had a reconditioned head for me. Thanks buddy. All the cylinders were fine but did discover, after removing some carbon from the pistons, that it had previously been rebuilt and bored out +.030. The crank bearings were +.020. Glad I discovered that. I ordered a set of ITM pistons, rings and bearings. Once delivered I’ll get them balanced. I did have difficulty in locating the proper head gasket though. The gasket that was on it was the wrong one as it did not have a hole for the oil passage to feed the rockers. That explains why the PO plumbed an exterior oil tube to the head plug from the oil cooler. It worked fine but now it will be corrected. Drove it like that for 10 years. Lastly, I checked with Toyota and the factory head gaskets, 11115-16010, are not available. He said one was enroute to a customer and 2 were on back order which could be months away. By the way, Toyota’s price....$200. I finally settled on a Felpro gasket, most other gaskets, for some reason don’t depict the oil galley hole in their photos.