MTFCA Forum

Did all T motors have two piece valves or did some come from Ford with one piece

I am fairly certain that nearly all (if not actually all) Ford model Ts left the factory with two-piece valves. If not, I would very much like to hear the details, when, why, and so forth. The two-piece valves were a choice, made in the interest of building the best car "for the money" that would be affordable to the masses. The cost of the valves reduced the cost of the car many times the difference in actual valve cost. And, the simple fact is, when they were new, the two-piece valves were good. Failures of the valves in the first years and thousands of miles were quite rare. It is only with the passage of many years, that the two-piece valves have become too risky to chance running any significant amount. Age, moisture incursion, corrosion, and the wear from being hammered millions of times by running for many years, have made breakage a thousand times more likely.

Higher quality so-called one-piece valves have been available since before the T model first came to market. After-market sellers were offering them as replacements for the model T almost as soon as the T model hit the market. Original era replacement valves in the one-piece style can be found with the two holes, or the long slot, to engage a valve lapping tool. They also were made smooth on top during the T Ford's day. I have opened several model T engines over the years that had such valves inside (so simply looking for the two holes in the head does not identify valve type!). And if I have some, I reuse those to this day.

It is interesting to note, that many so-called one piece valves are actually two-piece valves. While some actual "one-piece" valves are actually a forged head on the end of a machined stem, many so-called "one-piece" valves are actually a steel head welded onto a steel stem. So although they may appear to be one piece, they are actually made from two pieces. And those do on occasion break. Not often, not to be unreasonably worried about, but it does happen. It happened many years ago to my dad in his modern-ish pickup. What a mess!

As desirable as original technology is, I have to draw the line at two piece valves. My car no longer has the original cylinder head, as a result of a hole punched through it when the #4 exhaust valve separated into its two parts. The engine was actually running quite well as I was driving down the freeway, but I could hear something rattling. I couldn't see anything when I pulled over to have a look, but when I restarted, that was the end of it - water started pouring out the exhaust pipe.

My valve separated and punched a hole in my piston, glad that was all it did.

Customer got lucky when this one let go - it stayed put !

I had #4 stretch on me last spring replaced with a solid one, ran all summer and fall and developed a miss back in December a compression check shows nothing on number 3 I'm guessing I stretched another one. The first one did not come completely apart and I can see both valve heads when I look down the plug hole thus my thinking it stretched. Will be put back together with one piece valves. Jim

Nearly fifty years ago, when I was just a kid in this hobby, I remember people debating whether or not it was a wise/good thing to do to run the original two-piece valves. While I was wanting to keep as era correct as I could even then, most of the hobbyists I liked best were in favor of replacing ALL two-piece valves with the one-piece types. I listened, and followed their lead. I also knew several people by 1970 that had two-piece valves separate inside their engine while driving. Most, were fortunate that no serious damage had been done. One totally destroyed his model T''s engine.
Ever since then, I have put replacing two-piece valves as second ONLY to replacing the Babbitt thrust washers as necessary upgrades for any model T that is intended to be driven.

Same here
When I first bought the coupe in 1976 I sure didn’t know any better. One failed on a trip to Vista. I drove it back to the bottom of the hill out of Poway but there was no way it was going to climb over 1000 feet in two miles with one exhaust valve rattling around in the muffler.

Late 26-27 engines that were intended for use in TT truck chassis used 1-piece all steel valves.

Respectfully submitted,

Trent Boggess

Thank you Trent B! I will try to remember that.

What do you expect using old valves been banging away for miles or would say hours
I used them not worrying about it but know risks

To be clear, can anyone explain how I can tell if a valve is two piece or one? I just have the head off the motor and replaced three valves and would replace all eight if I have two piece valves. Thanks. Pictures would help. Frank

This is the one I removed last spring. It stretched on me and would not seat at all, I now have another that I believe has done the same thing, no compression on number 3 cylinder. When I say stretched I think the valve is in it's last days and is about to blow it's top and it starts to separate the stem from the head resulting in the loss of any gap that was between the valve stem and the lifter thus not letting the valve close fully. The turning you see is from me trying to face off the top to see if I could get it apart, it was to hard near center to cut with high speed tool. Jim

Simplest way, 2 piece valves have a steel stem and a cast iron head.

My TT has a replacement engine that dates to 1929. It was stock bore when I got it and it had 1 piece valves that I believe were original.