Excessive valve lash

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
bobt
Posts: 228
Joined: Tue Aug 13, 2019 5:43 am
First Name: Robert
Last Name: Thompson
* REQUIRED* Type and Year of Model Ts owned: 1915 touring 1926 roadster
Location: virginia

Excessive valve lash

Post by bobt » Wed May 12, 2021 7:40 am

My friend has a true barn find 1913 touring. We got it running a while back and have done a lot of work on it. We had a stuck exhaust valve on #3 cylinder and finally got it unstuck the valve is now going up and down and the cylinder now has 40-45 pounds of pressure (all are 40-45#) we noticed that # 3 exhaust has about .064" lash where all the others have about .015. What do you think? worn cam? lifter? valve? Thanks, bobt

User avatar

John Warren
Posts: 1069
Joined: Sun Jan 06, 2019 12:18 pm
First Name: John
Last Name: Warren
* REQUIRED* Type and Year of Model Ts owned: 14 Roadster, 25 Pickup , 26 Canadian Touring , and a 24-28 TA race car
Location: Henderson, Nevada

Re: Excessive valve lash

Post by John Warren » Wed May 12, 2021 8:22 am

That is excessive, the way the model t valves are adjusted in the manual will leave the valves with many different clearances. I use the more modern way and actually adjust them to a clearance. .010 to .015 is good to strive for. Sounds like you need a longer valve unless it has adjustable lifters.
24-28 TA race car, 26 Canadian touring, 25 Roadster pickup, 14 Roadster, and 11AB Maxwell runabout
Keep it simple and keep a good junk pile if you want to invent something :P


Allan
Posts: 5201
Joined: Sun Jan 06, 2019 7:21 pm
First Name: Allan
Last Name: Bennett
* REQUIRED* Type and Year of Model Ts owned: 1912 van, 1917 shooting brake, 1929 roadster buckboard, 1924 tourer, 1925 barn find buckboard, 1925 D &F wide body roadster, 1927LHD Tudor sedan.
Location: Gawler, Australia

Re: Excessive valve lash

Post by Allan » Wed May 12, 2021 9:26 pm

If a barn find car performs well on the road, I would leave it well alone. My take is you do the work such cars require to keep them in good operating condition. Safety needs to be paramount. Brakes need to be as good as you can make them, the front axle needs to be rebuilt, good tyres and wheels are needed and then just get out and enjoy the experience.

On my barn find Henrietta, it was not long before she needed new bands. Then she ran number one rod bearing and I replaced that in the car, through the bottom of the pan, to save having to disturb everything. I fixed the windscreen hand wiper so that it worked. She gets fuel and oil as needed, and a windscreen clean when I remember. She just runs better the more I use her.

Allan from down under.

Post Reply Previous topicNext topic