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08-21-2013, 05:11 PM | #1 |
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Join Date: Jul 2013
Posts: 196
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Two Piece Valves
If you have a choice, don't run two-piece valves.
Here's a nice photo of what happens when the head separates from the stem. We found coolant pouring out of the turbocharger inlet when we arrived. We knew it wasn't going to be a good day. The yellow thing is the engine (1260 hp @ 1400 rpm), gray is BOP gas compressor. |
08-21-2013, 07:44 PM | #2 |
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Re: Two Piece Valves
There are thousands of 2 piece valves out there you will be fine.
R |
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08-21-2013, 07:52 PM | #3 |
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Re: Two Piece Valves
That looks expensive
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08-22-2013, 05:01 AM | #4 |
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Location: Fitzgerald, Georgia
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Re: Two Piece Valves
I have seen similar damage from forged, one piece valves. I would not hesitate to use 2 piece valves. An investigation into the cause of that failure will need to be conducted.
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08-22-2013, 07:38 AM | #5 |
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Re: Two Piece Valves
T fords had two piece valves and aged valve trains were subject to heads popping off.
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08-22-2013, 07:45 AM | #6 |
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Re: Two Piece Valves
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08-22-2013, 04:00 PM | #7 | ||
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Re: Two Piece Valves
Quote:
Quote:
Caterpillar is very close-to-the-vest about their factory problems. I guess if I sold a jillion parts, and had a 1% or 2% failure rate I wouldn't advertise it either. They re-designed both the material and the manufacturing process for new exhaust valves. I had a factory tech I have a good relationship with tell me "off the record" not to order or install any heads or valves carrying certain part numbers. We pulled our cylinder head inventory and R&R'd any suspect valves. So far, no issues with the new parts. That failure took out a power pack (head, piston, rod, and cylinder assembly), a turbocharger, 200 gallons of coolant and about 120 gallons of oil. No, it wasn't cheap, plus our down-time. My other baby, a 351C, is noted for this failure. I don't think anyone would rebuild that engine with two-piece valves (nor would most builders recommend it). |
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08-22-2013, 05:29 PM | #8 |
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Location: Canada Where it snows
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Re: Two Piece Valves
Do you think that you are going to have the option of two piece valves or not for a flathead??No one disbelives the failures that have occured as stated,but in a flathead !!!
R |
08-22-2013, 06:00 PM | #9 |
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Location: San Antonio, Texas
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Re: Two Piece Valves
Charles Thompson (the T in TRW) developed the process back in 1904 or there abouts. Manufacturers have been doing it ever since. I work on Lycoming engines that require sodium filled valves on the exhausts and there is only one way to get the sodium in there. Henry Ford picked up on the steel stems with stainless heads way back in the early V8 days and probably well before when Ford was making Liberty Engines.
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08-22-2013, 06:39 PM | #10 | ||
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Re: Two Piece Valves
Quote:
I haven't done enough research yet to see what is commonly available, but I'm relatively sure someone would make them. I could be wrong. It would not be the first time. Quote:
Again, I just stated my opinion. If there's an option, I don't like two-piece valves. In general, I also prefer forged parts over cast, and parts machined from steel over MIM, and rolled threads over cut threads, when there are options. None of this may be "necessary" in a low BMEP engine like a flathead, but I don't like doing things twice. There are always exceptions. Ford, notably, made very high quality castings and there is usually no reason to upgrade to a forged crank, or third member, in a Ford street car. Other marques are another story. |
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08-22-2013, 08:28 PM | #11 | |
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Re: Two Piece Valves
Quote:
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'52 F-1, EAB flathead |
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08-23-2013, 01:03 PM | #12 |
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Re: Two Piece Valves
The original process from 1904 was electrical resistance welding. Originall it was steel to steel in order to better utilize the raw materials. The heads could be cut from larger stock and the stems from smaller so it didn't take all the whittling to make the large stock small. Thompson products (much later TRW) pioneered welding stainless or high nickel steels to carbon steels. Ford likely consulted Thompson when the welded the water jacked plates on the V8 60 engines but by then it may have been a little more common to weld the dissimilar metals.
Friction welding is a lot newer process but has become a lot more common now days. |
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