#1 cylinder not doing it's share

[thom]

I drove our '21 Touring yesterday for the first time in about six weeks. It ran good for about a mile on the way to the local store but not so good on the way home. I found, by grounding the plugs with a screwdriver, one at a time, that # 1 was not up to par with the rest. The spark looks strong and with the plug out I can feel, by sticking my gloved thumb in the plug hole, and can hear compression, with the engine running on the other three. I don't have an adapter for my gauge to measure it. The engine is still a fresh rebuild with only 30-40 hours max on it. I suppose now is the time to make myself an adapter for my compression gauge or at least run it with another plug out and compare the compression between the cylinders. I tried a newly cleaned, spare plug in # 1 with no change. I guess the plug(s) in #1 could be firing/buzzing when lying on top of the head but not when under compression? I have not yet tried moving the coils around to see if the problem moves with the coil. There is no sign of water or coolant in the #1 cylinder, and #2 seems fine, so I doubt that the gasket has failed.Any other suggestions? Thanks.

[Rich Eagle]

Join the club. I drove 3 cylinder model Ts for hundreds of miles. I finally graduated to a 2 cylinder car which I also enjoy. I hope you get the appropriate advice to make the proper corrections. They do run sweet on all four.
Rich

[Mark Gregush]

While yours seems to more of an issue, I have found that even with swapping coils around, that often at idle No1 does not seem to have the same power as the rest when I hold down the points for each cylinder. By that I mean, holding down the points for 2, 3 and 4 there is a marked change in how the engine runs, often No 1 not so much. You might have a weak coil as you suggested, fires good without compression but not so good under it.
Try a different coil in that slot and see if that helps or swap them around and see if the problem follows that coil.
If it was a vacuum leak, 2 which shares the same port would be low in power too.
How is the humidity/temperature in your area? Do you have any frost on the intake? You may need to add a heat stove if you don't have one, so the fuel will be more atomized, pre warmed and a little dryer when it enters the cylinders.

[Scott_Conger]

Not nearly enough information to help the OP, but Mark, I'll say that a small vacuum leak can really wreak havoc on #1 and have seemingly no effect on #2. I've experienced it myself repairing a car that had an upside down intake and a vaporizer exhaust...the front port just barely fouled the exhaust and was the devil to detect. A quick grind on the manifold and new manifold rings and she was as good as new. Similarly I've had several cars brought to me that had intake work done on them by their owners and had the same issue. New gaskets and a more careful assembly took care of the problem. In each instance, so far, it was #1 either weak or not firing at all...and it was an intake leak...#2 was happy as a clam.

Go figure.

[Norman Kling]

You really cannot check compression by listening to it run with a plug out. If you don't have a gauge, remove all plugs and use your thumb. Have someone crank over the engine and compare the feeling of compression in each cylinder. You could have a burnt valve or sticking valve on number 1. That would make a difference but with the plug out, and nothing in the hole, all the compression would go out the spark plug hole.

Another possible cause would be cold weather. With number one in the direct path for water coming in the inlet and going out to the radiator, number 1 could be running colder than the other 3. Try enriching the fuel mixture about 1/8 turn and see if it helps. Also a heat tube from the exhaust manifold to the intake of the carburetor could help.

Other causes could be dirty timer or grounded wire between timer and coil box or poor contact with coil box and coil. Even carbon path burnt inside the coil box.

It is also possible for the head gasket to leak without drawing in coolant. Try torquing the bolts on the head starting in the center and working outward they should be 50 ft lbs. Also tighten the bolts holding on the manifold.

Check things one at a time. Don't do all at once. When you find the cause of the problem, stop.

Norm

[thom]

I took time to move a couple of coils around today. No change still strong spark on all cylinders but grounding out # 1 makes no difference. More checking tomorrow.

[Will_Vanderburg]

I'm running a two cylinder Model T right now. I've got nothing but spark on 3 and 4

[Henry K. Lee]

Check all terminals especially down by the timer. It has to be something simple being over looked. Been there, done that many times!

Hope you find It!

Hank

[Henry K. Lee]

How's the roller spring tension and contact?

[George Mills]

I’ll get a ton of pushback...however, put a real “X” plug in number 1 gapped at 0.030” and you have an even chance #1 might come alive.

I can’t explain the science behind it other than I’ve tried it on misfire/underfire that defies resolution on more than a few cars at #1 when equipped with “A25” plugs or others...and most of the time the old wives tale actually works. One of the reasons I think that eventually all of my own cars now run full sets of “X” gapped at 0.030...lol

[thom]

I found the reason for #1 not working. I removed the front side cover and turned the engine thru a few revolutions, with the hand crank, and found that the #1 exhaust valve is not closing. The engine is a fresh rebuild with 50 hours or less on it and has never given any hint of such trouble, until now. I'm pretty sure the valve is new. I haven't removed the head yet but the spring doesn't appear to be broken and the keepers are in place. I have a new/old head gasket so I suppose I will order a new valve and a new spring, from Lang's and prepare to fix the problem. I hope the valve seat is in place where it belongs. I heard no noise when the running bad began and hear none now with it running on three cylinders so I' hoping for the best.

[Scott_Conger]

You don't need a new valve or spring (at least not yet, you don't). That valve will tap closed with a wood dowel and small hammer through the spark plug hole. Your engine is too new to have accumulated too much crud.

I will suggest either a small amount of spindle oil into the valve through the spark plug hole and let it sit overnight. If you don't have such oil, then buy some Marvel Mystery oil and put a little in there instead.

Next morning, tap closed. Start car

repeat as necessary...as it may take a couple times to get oil down along the length of the valve.

The petrolium distilates are what will work along the valve stem to help free it up, and the TCP (Tricresyl Phosphate) will (hopefully) aid in it's continued freedom, as it is an anti-wear, high-pressure boundary lubricant. It is ideal for this condition, where valve-to-hole diameters may be a tad too close.

read lable on container and dope the fuel with recommended amount and drive the car. Hopefully, this will fully resolve itself within a tankful, and then you're done with it. Do not add to the oil...ever...fuel only.

I rarely use this stuff, but can state from experience that this stuff freed up an exhaust valve that was absolutely insistent on sticking open on #4 cylinder on my runabout. Many repeated bouts of sticking with each drive. Finally used some MMO and it was fixed. It has it's uses.

I will happily sit back silently while I'm excoriorated for this advice by people who have not used it for this purpose, but KNOW it will not work. So be it; now have at it.

[Dallas Landers]

Scott I totally agree about MMO . After my valve job this spring, It suffered sticking valves. The stuff does work. After the treatment it has ran great all summer.

[thom]

I guess I'm gonna need a bigger bottle of MMO. Here is the #1 exhaust valve out of our T. I'm ordering a new valve from Lang's today.

[RajoRacer]

I believe I'd be questioning the "fresh rebuild" back to whomever did the work. I've not seen "new" valves with the 2 dimples for the old timey valve grinders - appear to be 2 pc. ?

[Fordwright]

I'm no expert on the steel that went into those valves, but some of the steel in those days could be quite brittle due to the way it was manufactured.

[Scott_Conger]

HOLY MOLEY!

2X what Steve said!

[Ruxstel24]

Yep, sure looks like a 2 piece (well, maybe 3 or 4 pieces) valve to me.
I would consider replacing ALL the valves if they have the holes in the top like that one.

[thom]

There is no way I can "go back" on the rebuilder. I bought the car as-is about three years ago. The price was right enough and I did not get receipts for the engine rebuild on any of the other parts that were obviously new on the car. The seller was selling the car for the widow of the late owner who had been restoring the car for quite a while. It came from middle Tennessee and the engine was rebuilt by someone in the Knoxville area, I was told. The engine had never been started when I got the car and actually was missing a few small parts that I had to find before the first start up. There was no timer and no crank pulley.The head had not been "torqued" down and the bolts were only finger tight, so I removed the head to look at the pistons and valves. The pistons were obviously new, oversize and the valves appeared to be new, maybe NOS (?). I removed the inspection cover on the oil pan and looked up inside and everything inside looked new , the rods, cam, everything that I could see. I will wait until the one new valve arrives to see how it fits them maybe order seven more with new keepers and replace them all.

[AndreFordT]

Thom,

As the engine is open I should go for all 8 valves, new springs new keepers and new valves spring seats.

Good luck
Andre
Belgium

[thom]

I have heard/read that the pin style keepers (as original) that are offered by suppliers now are not hard enough and prone to fail so old ones should be reused. Can anyone confirm this info? Or, will replacement valves with split keepers directly replace my old valves? If I replace all the valves, and I probably will, I hope that my adjustable lifters will allow me to do the conversion without grinding the stems. It will be interesting to see how the new replacements fit the guides too.

[Mark Gregush]

If you are using the original style valves the stems will need to be ground to fit no matter the style lifter. I think the modern style are shorter but the hole in the block needs to be reamed out for them to fit. The information should be in the valve section in Lang's catalog re the new style. If you are replacing all the valves, which if the rest are the same style you should and everything is in good shape, reuse the springs, cups and pins that you have. You will have to check the stem size before you just go out and buy new valves. They could be oversized. When I got my 21 that had been sitting for a very long time, the valve stems were already first oversize. The guide holes were worn so I went to next oversize stock type valve. If and when I need to redo it at some point, I will ether need inserts to bring back to standard or go with the modern style. Point is, don't just order a valve without knowing which stem size you need first.

[thom]

I will grind the stems if necessary but I don't have a liquid cooled grinder. I will buy a new stone for my bench grinder if that will get the job done. What kind of stone do I need to buy?
Meantime, can someone show me a good pic of valve seats, without any valves in them. I want to see if mine look as they should.

[Mark Gregush]

Just go slow on the stem grind and keep a can of water close by to cool. You need to keep the stems at right angle to the grinder. In a pinch, V out a piece of wood for them to ride in. I know the stones say not to grind from the side but it is the only way to keep the ends flat and use a fine grind stone. If the face of the valve is level or below the deck it needs to be fixed, the face of the valve should be just above the deck.

[AndreFordT]

Thom

here some photos.

Andre
Belgium

[Fordwright]

My Dad talked about all the valve grinding they had to do in the old days. They used a type of tool that looked like an old crank drill.

https://www.youtube.com/watch?v=YJoJC2gkjFE

[Scott_Conger]

Thom

My older Dayton 1 x 42 belt grinder works well for me:

1 set table square to belt platten using machinist's square
2 clamp aluminum "C" channel to the bed at right angle to belt platten
3 set machinist's V-Block against channel and lay valve in the "V"
4 press stem into belt while slowly rotating valve

I use 320 grit belt for this. Material removal is surprisingly quick; part stays much cooler whan with a wheel, and the face is all but dead flat

if you try this and are unsure of flatness, simply smear Prussian blue on the end, bring another square block up to the end of the "V", press the end of the valve on the block and rotate the valve...you should see essentially 100% coverage if done right.

[thom]

My new valve has not arrived yet but I found my micrometer and the stem "mikes" .312 so I should be able to use seven more like the one I have ordered. I have misplaced the keeper/pin that came out of the damaged valve and I don't really want to use the available replacements after what I've heard about them.
Anybody got 2 or 3 originals that I can buy?
The valve seats in my engine have very little angle but seem to contact the valves in the correct area. I'm trying to decide whether I should grind the seats or not.

[Scott_Conger]

You can check seat width, contact continuity, and location on the valve with Prussian Blue. Though that is the way it was done "in the day", lapping is a great way to ruin valves and sink seats into the block.

You said the car ran great before your valve went to pieces, so the seats can't be that bad.

If you're absolutely committed to messing with this, find someone with a Neway cutter kit for a Model T and barely kiss the seats, and set the seat on the valve where it belongs using the raising and lowering cutters. None of this is possible by simply lapping the valves. And after using the Neway cutter, if you're still tempted to "kiss" the valves with compound. Don't.

Andre's post above shows a Neway cutter in use with what appears to be a custom handle. Magnifying his photos to the max, shows the 3 angle cut, and the correct width of the sealing seat.

Also, on the new valves (or old), do not rely on them being perfect. For a very small fee, have each kissed on a facing machine and be SURE they are concentric to the stems and completely without blemish.

[thom]

My new (one) valve finally arrived today. It fits the guide fine. I believe the tappet will take up enough so I won't have to grind the stem.

[modeltbarn]

Concerning your compression check.... This may have been mentioned, I only skimmed the thread because it's gotten long.

The vendors sell adapters to use modern plugs in a stock head; all you need is one of those, and you can use your compression gauge. They may only come in a set of four; share them with the guys in your local club!

[thom]

I got all eight new , replacement valves and found that, I believe, the stem to guide fit is good, but as-is with the lifters adjusted all the way "down" I had little or no clearance on some. Today I took all eight new valves to the machine shop and left them with him to get .025 ground off each stem. If that's not enough I'll take 'em back as needed. Anybody know how much adjustment is usually built into adjustable lifters?

[Allan]

Tommy, there is at least 1/4" of adjustment.I discovered this when I mistakenly cut the stems on some modern replacement valves to the wrong groove on the two piece collets. There was enough length in the adjusting bolts to compensate, but I wouldn't recommend winding them out that far.

Allan from down under.

[thom]

I just rewatched Mike Bender's video on installing valves and he said the norm is to have .100 taken off of new valve stems. Maybe I should call my machine shop guy in the morning and tell him to go .100?

[AndreFordT]

Tommy,
I grind mine always to 125mm = 4.92" . This made the clearance you need to adjust the gap with the adjustable tappers and left 4mm under the hole.

Andre
Belgium