Done for the season...(Update)

sorry about your bad luck,hope the damage is minimal

Pulled the head tonight and #1 exhaust valve snapped the head off, flipped over in the cylinder and punched a big hole in the head, plus cracked the block. I think the block can be sleeved so if I can find another piston we may go that route as a spare motor (only has about 50 runs on it). The Dick Landy head is toast. The valves were Ferreira stainless versions; not cheap and the guides were bronze-inserts. Everything was checked by my machine shop earlier this year, so the only thing I can think of is component failure or the valve stuck in the guide. We had Teflon seals on the valves and they may limit the amount of oil to the exhaust (just a guess on my part); they may work too well. Piston to valve clearance was more than adequate and there is no evidence of other valves contacting the piston (if anything, the intakes would hit before the exhaust). Major bummer It's all Mr. Yuck's fault. His engine is contagious.

Note in the picture above the new dual sparkplug max wedge head...

This fell on the floor when we pulled the head.

OK, so what is the general consensus on why an engine drops a valve? Guide too tight (sticking)/loose (off-center on seat)? Lack of oil? Material failure? Enquiring minds want to know.

Who does your machine work?

Rockville Ring & Bearing did the heads, Burtonsville did the shortblock. Rockville said the guides were OK; seats were touched up when the new valves were purchased. Guides were new when we got the heads. They were in the trunk of a 63 max wedge Dodge from California that a friend bought. Will probably let Burtonsville do the heads next time...

Steve is a good guy.I dealt with him when he was @ Racing Parts...FWIW Ed Thompson from Thompson Machine does really good work too.Been going to him since 1990.And my junk rolls pretty good.Tom

Sorry about the damage...........as far as teflon seals, I ran em for several thousand street miles and several passes for 5 1/2 years w/out issues. Maybe tight guides?

My guess would be inadequate spring pressure but, if they were the Ferrea 5000 series valve, they are really nothing more than a street replacement.

Springs are Trick Flow with seat/open pressure spec'd for the cam (MP 590). I checked them before installation. Valves are Ferrea 6217 & 6250.

Soon to be between the fenders...once it's painted Hemi Orange of course

what do the say about an intake...lol I was running ISKY 8005A springs "Valve Springs, Dual, 1.530 in. Outside Diameter, 400 lbs./in. Rate, 1.160 in. Coil Bind Height" as advised by the cam maker. I doubt they lacked the spring pressure as mentioned above.

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I don't think the MP 590 needs a lot of spring pressure, but what were the actual installed numbers? (130/330?). Check the spring to see if it is broke, and if not, the current pressures. Since it broke at the finish line, what was the max RPM?

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I'll have to look it up in the log when I get home. We had to shim the springs slightly to get the pressures up to spec. They were far from coil bind. I'll measure some when we get them off to see if they weakened. Ferrea wants the valve, spring, retainer and locks for analysis. Motor was shifted at 6000; through the traps at 6100.