Dropped a valve seat...what's the verdict? Options

[billh1963]

Way back in August 2013 I went to start my 914 and heard a funky noise. I immediately shut it down. Using my limited mechanical knowledge (and a tremendous amount of luck) I postulated that I had dropped a valve seat.

Three years later I decide it's time to get this 914 back on the road. Pulled the heads and, sure enough, a dropped valve seat. Prior to the issue the car was running good...no smoking, seemingly good oil pressure, etc.

I'm hoping I can get by with just rebuilding the head (if possible). Anyone see anything that would cause me to deviate from this plan of action?

[Mike D.]

I did the same thing back in 2000. Had the head rebuilt, didn't touch anything else. Put it back together ran fine for years after. Sold the motor in another car when I did my conversion in '06. Never heard from new owner so I guess it was just fine for him too.

Depends on if the engine was running fine before?

[ConeDodger]

I see at least two and maybe three cracks in that chamber alone... (IMG:style_emoticons/default/blink.gif)

[billh1963]

I see at least two and maybe three cracks in that chamber alone... (IMG:style_emoticons/default/blink.gif)

I figure the head may be toast.

The engine was running good before this "incident". I'm hoping I can just change the head and get back on the road..

[porschetub]

Oh dear the head is scrap ,not worth the repair cost,have seen worse,broken valve hits piston bends rod etc old story total carnage at high RPM,yes good move on the quick shutdown.
That piston will clean up,a WTB could yield a good core head to rebuild be I would be checking the other head,honestly not worth the gamble IMO.
Hope all goes well.

[porschetub]

I see at least two and maybe three cracks in that chamber alone... (IMG:style_emoticons/default/blink.gif)

Yes there are a few (IMG:style_emoticons/default/agree.gif) funny it didn't drop the exhaust seat first judging by one of those cracks.

[billh1963]

Oh dear the head is scrap ,not worth the repair cost,have seen worse,broken valve hits piston bends rod etc old story total carnage at high RPM,yes good move on the quick shutdown.
That piston will clean up,a WTB could yield a good core head to rebuild be I would be checking the other head,honestly not worth the gamble IMO.
Hope all goes well.

Other head looks good.

This event occurred after driving on a hot day where the oil temperature got up to around 230+.

I started it up the next day and the valve dropped as soon as it started. I shut down the engine while it was idling and after it only ran a few seconds. I'm hoping the piston is okay.

[r_towle]

Depending upon your finances I would suggest you buy a new pair of heads, based upon new castings.
You could sell the good head to someone who needs it.

Or, hunt downs used head.

[76-914]

Is that piston cracked above the indentation?

[billh1963]

Is that piston cracked above the indentation?

I saw that. I'm going to scrape it clean and see.

I'm hoping not. Will find out more tomorrow (IMG:style_emoticons/default/dry.gif)

[HAM Inc]

The seat drop repair alone is not so bad, as far as consequences to the casting's integrity. But the crack out the exhaust port is a real killer for the T4. It can be repaired, (done it countless times over the past 20 years) but the casting will never be the same.

Time to stick a fork in that one.

BTW, those cracks were really common on smog heads. Is your head one of them? Just curious.

[billh1963]

The seat drop repair alone is not so bad, as far as consequences to the casting's integrity. But the crack out the exhaust port is a real killer for the T4. It can be repaired, (done it countless times over the past 20 years) but the casting will never be the same.

Time to stick a fork in that one.

BTW, those cracks were really common on smog heads. Is your head one of them? Just curious.

It's from a '74 2.0. I don't know if the heads are original or not.

[ConeDodger]

The seat drop repair alone is not so bad, as far as consequences to the casting's integrity. But the crack out the exhaust port is a real killer for the T4. It can be repaired, (done it countless times over the past 20 years) but the casting will never be the same.

Time to stick a fork in that one.

BTW, those cracks were really common on smog heads. Is your head one of them? Just curious.

Len is of course one of the few people you could trust with a repair of this sort. The problem is, it has become economically unfeasible to do this repair. The valve seats aren't a big deal as Len said. In fact they should be done on any rebuild of a Type IV head. Len puts the heads in an oven without valves in place and many of the seats fall out just due to the heat. The welding needed to repair the cracks, and if I can see three? There are at least a couple more is the killer. It becomes pretty quickly cheaper to just buy a set of the LE200 heads and cook yourself up a 2056 or 2270.
Sorry...

[DRPHIL914]

Looks like you will be building that 2056 --- you had one before so you know how they compare to a stock 2.0
I'd say get the new heads- match them up with some nice new p&c's and back on the road in no time!

[Toast]

I've had a valve seat embedded in a head before. Just replace the head.

[cwpeden]

And don't use head gaskets. I used them for the first time in 25 years and 50 hours later I'm taking the engine apart. (IMG:style_emoticons/default/slap.gif)
Just look how far away you were from a failed gasket.

[HAM Inc]

The seat drop repair alone is not so bad, as far as consequences to the casting's integrity. But the crack out the exhaust port is a real killer for the T4. It can be repaired, (done it countless times over the past 20 years) but the casting will never be the same.

Time to stick a fork in that one.

BTW, those cracks were really common on smog heads. Is your head one of them? Just curious.

Len is of course one of the few people you could trust with a repair of this sort. The problem is, it has become economically unfeasible to do this repair. The valve seats aren't a big deal as Len said. In fact they should be done on any rebuild of a Type IV head. Len puts the heads in an oven without valves in place and many of the seats fall out just due to the heat. The welding needed to repair the cracks, and if I can see three? There are at least a couple more is the killer. It becomes pretty quickly cheaper to just buy a set of the LE200 heads and cook yourself up a 2056 or 2270.
Sorry...

Thanks for the plug Rob. How's your ride doing these days? Still good, I hope.

The LE200's would be too much head for a typical street 2056. The RS+ heads would be a better fit, unless peak power is what you're after, like for a track car.