How often do 2 piece valves come apart?

[NoelChico]

I was gifted a 16 Roadster and 24 Coupe. Neither has run in over 20 years since the owner died. I got both started and running. They both have 26-27 engines in them with what appear to be 2-piece valves. Compression in the 16 is 45 on 2 and 50 in 2. I've been quoted about $600 to put new valves and lifters in (200 miles away), plus the cost of the valves and lifters. It runs well currently. How often do these valves come apart? The machinist I talked to stated it is rare. I'm tempted to run it the way it is. Opinions please.
Noel

[TXGOAT2]

Ford phased out the two-piece valves on some of the late production cars.

[pete eastwood]

Just once .

[Allan]

In the vast population of T's, the valves breaking is rare. That said, we do get to know of the results of those that happen these days, so it appears to be a greater problem than it likely is.
If you are basing your identification of two piece valves on the ones you see, the two holes in the top were also often made in one piece valves and later replacements. You need to remove an inlet manifold and look in the block ports to positively identify a two piece valve.

Allan from down under.

[RVA23T]

Just once .

That made me laugh!

It is possible that they look like 2pc due to someone drilling the 2 holes inorder to use the old hand held lapping tool. You need to look for the press fit of the stem into the valve head to confirm

[got10carz]

I saw a car that had sat for years taken to a national tour. Day 1 one valve lost its head. Cylinder head was pulled and 1 valve replaced. Day 2 another valve lost its head, this time he replaced them all. I think miraculously neither time any major damage was done.

[NoelChico]

Thankyou. I had ASSUMED (there's that bad word again) that the 2 holes in the valve signified them as 2 piece. I'll pull the inlet manifold and take a look. FWIW, the cars had had the radiators and fuel tanks drained and were up on jacks. All tires had zero air pressure but have held 50 lbs for the past week.

[RVA23T]

Two piece valves also have more of a donut, ogee shaped bell flair where the stem goes in the valve head. Modern are more of just a bell flair.

[Wayne Sheldon]

I have over the years known of several people or cars that broke two-piece valves. Most many years ago. Nearly everybody I know will not use those two-piece valves because it happened often enough.
To make matters maybe worse? It is an age related failure. I suspect that running one much today would be much more likely to fail due to age, moisture, and corrosion issues that lead to valves breaking. Fifty years ago it was believed that valves were failing more often due to age. Now they are another fifty years older.

A flip side consideration. If the engines aren't the proper year? Maybe it wouldn't matter so much if a valve broke and destroyed an engine? Onto again the other hand? 1926/'27 blocks are notorious for cracking in the valve chamber, and good blocks are getting more difficult to get. If these blocks are not cracked, you may not want to risk them.
There is also the consideration that things sometimes fail at the worst possible time and place. A breaking valve usually gives no warning whatsoever! Driving along, fat, dumb, and happy - - - and CRUNCH!

[Humblej]

Replacing original Ford 2 piece valves is easily done and can be accessed by just removing the head and valve cover. If your engine is running fine I wouldn't bother with replacing the lifters which is not easily done. Replacing 2 piece valves is cheap insurance.

[TXGOAT2]

All 2 piece valves are very old, and most have been abused and many have very high hours on them. Corrosion can get between the valve head and stem when an engine sits idle for long periods, and when the engine is run again the heat will burn out the corrosion and leave the head loose. I wouldn't trust them in an engine that I meant to use. New one piece valves are lighter and flow better and have superior metallurgy and heat flow characteristics.

[Jerry VanOoteghem]

All 2 piece valves are very old, and most have been abused and many have very high hours on them. Corrosion can get between the valve head and stem when an engine sits idle for long periods, and when the engine is run again the heat will burn out the corrosion and leave the head loose. I wouldn't trust them in an engine that I meant to use. New one piece valves are lighter and flow better and have superior metallurgy and heat flow characteristics.

The head does not typically come loose. The stem breaks off, usually due to being necked down from corrosion. Heads are also known to crack and break off chunks.

[Jerry VanOoteghem]

To answer the original question; too often to trust them.

Or; often enough so that it's a known issue.

[RajoRacer]

This is what can happen ! I found the rest in the muffler !

[Jerry VanOoteghem]

It doesn't just happen to Model T's. A friend of mine had one break in a 1910 Buick. It cracked the top of the piston and ruined the valve cage.

[Steve Jelf]

I have no clue how often it happens, but it has been often enough to cause their troubling reputation.

[Craig Leach]

The two holes in the valve head are a indication they are two piece valves but not a guarantee they are. I had one break in my speedster
sitting @ a red light ( idling ) the valve head ended up vertical and broke a hole in the combustion chamber. Found the valve head in the
water jacket of the head. The valve stem was badly eroded from many hard miles so it was weakened. I would defiantly pull the manifolds
& look to verify they are two piece & look at the stems before just doing a valve job for fear of a valve coming apart. I just sent a set of good
looking two piece valves to a friend to put in a engine that had the worst looking valves I've ever seen that none of broke. He has been
running Model T's for a long time & never had a valve break & has no worries about running them. I know of people that will not run them
( two piece) for fear of them breaking as well as some that remove the magnets for the same reason. I know this doesn't help much if you
are looking for a do it or don't answer. Hope it gives you some info on the subject.
Craig.

[John kuehn]

2 piece valves are among the parts that are really needed that are in a 100 year old car.
Radiators, tires, 2 piece valves and oh yes I forgot one other. Wooden spokes and in no paticular order!

[Erik Barrett]

Only once.

[Erik Barrett]

How often do airplanes crash? Only once.

[TXGOAT2]

Very worn valve guides might contribute to valve stem breakage. Weak springs might, too.

[DHort]

One always breaks on the 1st day of a 7 day tour.

[Dan McEachern]

If the valve head just breaks, that's one thing. It's when the broken piece punches a hole thru the top of a piston that things go downhill quickly.

[DanTreace]

Quite a few photos have been posted on the Forum over the years showing such damage. Those old iron head, steel stem valves should come out, always, if you want to save yourself some grief.


Steel stem burned away by intense exhaust heat, that iron head resisted though, may be because the higher quality iron used for the 2-piece heads, better than the iron used in the blocks?

Another stuck 2-piece, at #4 , cracked off from the grinding recess holes. Also ran a while to ruin the seat. Hot exhaust.

Worn out #4 seat.jpg (56.15 KiB) Viewed 6373 times

Broken two piece .jpg (90.76 KiB) Viewed 6373 times

[TXGOAT2]

I'd guess the valve heads were chilled iron.

[TXGOAT2]

A cylinder running lean for a long time will tend to destroy the exhaust valve and exhaust manifold. A poorly-seating valve in a cylinder that still fires will run extremely hot.

[RVA23T]

Also if you find they are original 2 pc valves, don't trash them, I believe Larry Smith (Original Smith) will take them, since they are original Ford parts, and not modern "crap".

[JohnH]

I had it happen three years after I got my car. It punched a hole in the head when it came loose and started rattling around in the cylinder. Water then poured out the exhaust.

[John Codman]

Ford phased out the two-piece valves on some of the late production cars.

How late?

[TXGOAT2]

Very late, as I recall. There is a service letter or dealer letter somewhere that discusses it. I don't remember all the details. Unusually, Ford advised dealers to return unused stocks of any of the 2 piece valves on hand and to use the new one piece ones for service as soon as they were available.

The info is online, here or the Cimorelli site, or another well-known one.

[DanTreace]

Very late, as I recall. There is a service letter or dealer letter somewhere that discusses it. I don't remember all the details. Unusually, Ford advised dealers to return unused stocks of any of the 2 piece valves on hand and to use the new one piece ones for service as soon as they were available.

The info is online, here or the Cimorelli site, or another well-known one.

Very late indeed . From Bruce's book, documentation

one piece valve.jpg (121.06 KiB) Viewed 6025 times

[J1MGOLDEN]

I recently purchased a 1925 engine that was in dry storage for about or over 100 years and has all the original valves and pistons.

After removing the top and cleaning up the area, I found two intake valves #1 and #4 stuck open.

They released with some cutting oil and Kroil added.

The block top was cleaned, and the head replaced.

To my amazement the engine started right up and runs great!

[thom]

My engine was completely rebuilt but had not been started when we got the '21 Touring in 2016. After about 10-12 hours running time a small pie piece shaped chunk of the #1 exhaust valve head broke off. It made some minor pock marks on the top of the piston and head. The piece(s) apparently went into the exhaust pipe or muffler. I replaced all eight valves with new one piece valves. I had my local machine shop shorten the stems because our engine has been fitted with adjustable tappets. It has ran great for another 8-10 hours.

[NoelChico]

After a week of travel and other duties, I pulled the intake on the 16 with the 26-27 engine and watched the valves as my pretty wife hand cranked the car. DARN! It has the 2-piece valves. Now for more decisions, but nothing solid until after the OCF with the Gumbingers.

[Corey Walker]

The #4 exhaust valve broke in my 1914 right after I’d gotten it running in 1994. I didn’t know this was common so I just replaced the one and made a keychain. I’ve ran it since with the other 7 still there but I’ve got a new set of valves for my speedster engine I’m working on now.

[speedytinc]

Well, do you feel lucky? You never know when or if major damage will occur.
you know, like Russian roulette.

[AndyClary]

If it has 2 piece valves it probably needs a valve job anyway. A set of valves is like 90 bucks, the labor is the same as doing a valve job on what you have. Grind valves, grind seats and set clearance. Cheap insurance.

Andy

[John Codman]

Just once .

[J1MGOLDEN]

I recently purchased a 1925 engine that had been in storage for between 90 and 100 years and it was only used a few months each year to cut ice blocks in the winter season there.

The engine still turned over with the crank and did not have a starter or generator.

That made a compression test difficult to do, but two cylinders seemed to have no compression.

#1 and #4 or # 2 and #3 had the intake valves stuck open, but a little Kriol and some light taps let them move again.

#2 lasted "stuck" a little longer.

The engine started right up again, which was amazing.

A later compression test measured 55, 54, 51, 55 so #2 and #3 may have been the ones stuck open.

[Dan Hatch]

FYI:: If you go back with Ford style valves be sure to use Ford keeper washers. Check out this old thread.
http://www.mtfca.com/discus/messages/50 ... 1450555390
Not sure if this has been fixed. I only use Ford 351 exhaust valves and keepers.

[dykker5502]

Been there - done that. I'll never hessitate to replace the 2 part valves. It costed me a head.