The Ford Barn

DonChiotos · 03-15-2026, 04:28 PM

Does anyone know how I can check and if needed adjust the valves on my Model A with the engine in the car and the heads attached. Everywhere I look the information shows the head off, so valves and pistons exposed so you know what the position of the valves.

alexiskai · 03-15-2026, 05:09 PM

If you have a stock head, with the plugs out and a flashlight you can easily look through the spark plug hole and see the positions of the valves and pistons. An endoscope makes the job easier but it's not required.

Big hammer · 03-15-2026, 05:21 PM

With the valve cover off look at the valves and lifters, if you can see more of the lifter it’s on the toe of the cam, use the rule of 9 and keep track and log the gaps . With the spark plugs out have someone turn the engine over by hand studying whats going on !

nkaminar · 03-15-2026, 06:04 PM

To elaborate on what Big Hammer said, When valve 1 is up you can measure valve 8. When valve 2 is up you can measure valve 7. When valve 3 is up you can measure valve 6, etc. In all cases the numbers add up to 9: 1+8=9, 2+7=9, 3+6=9, etc.

Joe K · 03-15-2026, 06:23 PM

The problem is you may have original "non-adjustable" lifters. If that is the case you need to "tear down the engine" and one by one measure and adjust each individual valve. KRW made a nifty "gauge/grinder" for doing this - and getting the adjustment right the first time. Quite ingenious their system. But few and far between either in those who have the tooling - or those who use it.

MOST engines once they have been rebuilt probably have "adjustable" lifters. Yours is most likely to be of this ilk. One of the modern "improvements" over the KRW system which allowed ANYONE with a single or pair of open end wrenches - and a feeler gauge now able to set their own valves. It put valve adjustments into truly "shade-tree mechanics" level.

There are two basic types of adjustable valves. The first and original version involved a lock-nut system where the two adjustment nuts "worked against" each other to "lock" the adjustment in place.

The downside of this system is that the mere act of adjusting tends to "upset" the adjustment as any "free-play" is found in restraining the system and happens as this free play gets taken up. You adjust for the proper clearance, and by the time you've put the lock nut in place and torqued it to value - you've changed the clearance. Very tricky and intricate to use.

The second and only slightly later system involves a single lock-nut - but the nut is designed to be "self-locking" - and can only be moved under the influence of the wrench. Think "Nylalock" nuts which are similar.

When it came to me to make a choice between these two, the rebuilder (Richard Knight) recommended I go with the nylalock system as "easier" and probably (overall) more reliable. Which is where I went and where I remain to this day.

Richard may dial in here and confirm my decision and offer any "since then" improvements to that recommendation. Everything has a tendency to be "Improved upon" given time.

Joe K

JayJay · 03-15-2026, 06:34 PM

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Quote:

Originally Posted by Joe K

The problem is you may have original "non-adjustable" lifters. If that is the case you need to "tear down the engine" and one by one measure and adjust each individual valve. KRW made a nifty "gauge/grinder" for doing this - and getting the adjustment right the first time. Quite ingenious their system. But few and far between either in those who have the system - or those who use it.

MOST engines once they have been rebuilt probably have "adjustable" lifters. Yours is most likely to be of this ilk. One of the modern "improvements" over the KRW system which allowed ANYONE with a single or pair of open end wrenches - and a feeler gauge now able to set their own valves. It put valve adjustments into truly "shade-tree mechanics" level.

There are two basic types of adjustable valves. The first and original version involved a lock-nut system where the two adjustment nuts "worked against" each other to "lock" the adjustment in place.

The downside of this system is that the mere act of adjusting tends to "upset" the adjustment as any "free-play" is found in restraining the system and happens as this free play gets taken up. You adjust for the proper clearance, and by the time you've put the lock nut in place and torqued it to value - you've changed the clearance. Very tricky and intricate to use.

The second and only slightly later system involves a single lock-nut - but the nut is designed to be "self-locking" - and can only be moved under the influence of the wrench. Think "Nylalock" nuts which are similar.

When it came to me to make a choice between these two, the rebuilder (Richard Knight) recommended I go with the nylalock system as "easier" and probably (overall) more reliable. Which is where I went and where I remain to this day.

Richard may dial in here and confirm my decision and offer any "since then" improvements to that recommendation. Everything has a tendency to be "Improved upon" given time.

Joe K

All the overhead valve cars I've owned with solid (adjustable) lifters were the locknut type. After a while you do get a feel for them, but it's not all that easy. The trick I found was to rotate the engine with the starter (but disconnect the coil wire) while you adjust, feeling the resistance on the feeler gauge. You folks of a certain age, remember adjusting the valves in your VW Bug every 3K miles?

The flatheads I've had and reconditioned (mostly Model As), I've always put in the "single nut" type of lifter with the interference in the adjusting bolt. I've never had cause to regret going that way. In fact, I've had more issues with the locknut type opening up than ever with the single bolt type.

Trapdoor2 · 03-15-2026, 08:28 PM

Quote:

Originally Posted by JayJay

You folks of a certain age, remember adjusting the valves in your VW Bug every 3K miles?

LOL, mine (a Type III "Fastback") never made it that far. In High School, I usually tore it down every other weekend. I was making more power than the head studs could handle and, being a teenager...shifting at 6K.

Thankfully, I had a VW dealer in town with a large junkyard. I could buy a used engine for $25 on Saturday, strip off the heads and jugs, etc. and be back on the street Sunday.

old ugly · 03-15-2026, 08:51 PM

take off the manifolds, take off the side cover. take out the spark plugs. have someone turn the engine over by the hand crank slowly. put you thumb on a spark plug hole while they are turning the engine. you will feel the air pressure going past your thumb. now look in that plug hole to see if the piston is at the top. if the valves are closed and the piston at the top use your feeler gauges to check the clearances. do the same for each cylinder.
like said above unless it has adjustable lifters they can not be adjusted unless you tear it down.

nkaminar · 03-16-2026, 05:49 AM

One other modification that is commonly done is to machine off the top of the casting where the valve lifters go through. This allows access to the adjustable valve lifters. If this has not been done you may have to adjust the lifters when the valve is up and measure the clearance when the valve is down.

The rule of nine can be applied to this procedure too. Instead of working on one valve at a time and having to turn the engine over 360 degrees several times for one valve, adjust the valve that is up while measuring the valve that is down. So applying the rule of 9, assuming starting with valve 8 up, measure 1. Record the value. Then rotate the engine until the next valve is up and measure the one that is down. Continue until you have measured and recorded all 8. Then adjust the one that is up. Rotate until the next valve is up and adjust that one. At the same time check the adjustment for the one that is down. Continue until all are adjusted and checked and all have the correct clearance.

By the way, it helps to have the spark plugs out while turning the engine over. But stuff rags in the holes so that you don't accidentally drop something down there.

Randall · 03-16-2026, 06:22 PM

Here's a simple way I adjust, pull the spark plugs.out, put it in hi gear jack up one rear wheel and have someone turn the wheel forward and watch the valve https://youtu.be/07v6AERzVQQ?si=TMX5-vu2eZjBkpTF

03-15-2026, 04:28 PM	#1
DonChiotos Junior Member Join Date: Mar 2026 Posts: 11	Valve adjustment Does anyone know how I can check and if needed adjust the valves on my Model A with the engine in the car and the heads attached. Everywhere I look the information shows the head off, so valves and pistons exposed so you know what the position of the valves.

03-15-2026, 05:09 PM	#2
alexiskai Senior Member Join Date: Apr 2018 Location: Mebane NC Posts: 3,179	Re: Valve adjustment If you have a stock head, with the plugs out and a flashlight you can easily look through the spark plug hole and see the positions of the valves and pistons. An endoscope makes the job easier but it's not required.

03-15-2026, 05:21 PM	#3
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,635	Re: Valve adjustment With the valve cover off look at the valves and lifters, if you can see more of the lifter it’s on the toe of the cam, use the rule of 9 and keep track and log the gaps . With the spark plugs out have someone turn the engine over by hand studying whats going on ! __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

03-15-2026, 06:04 PM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,852	Re: Valve adjustment To elaborate on what Big Hammer said, When valve 1 is up you can measure valve 8. When valve 2 is up you can measure valve 7. When valve 3 is up you can measure valve 6, etc. In all cases the numbers add up to 9: 1+8=9, 2+7=9, 3+6=9, etc. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

03-15-2026, 06:23 PM	#5
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 5,013	Re: Valve adjustment The problem is you may have original "non-adjustable" lifters. If that is the case you need to "tear down the engine" and one by one measure and adjust each individual valve. KRW made a nifty "gauge/grinder" for doing this - and getting the adjustment right the first time. Quite ingenious their system. But few and far between either in those who have the tooling - or those who use it. MOST engines once they have been rebuilt probably have "adjustable" lifters. Yours is most likely to be of this ilk. One of the modern "improvements" over the KRW system which allowed ANYONE with a single or pair of open end wrenches - and a feeler gauge now able to set their own valves. It put valve adjustments into truly "shade-tree mechanics" level. There are two basic types of adjustable valves. The first and original version involved a lock-nut system where the two adjustment nuts "worked against" each other to "lock" the adjustment in place. The downside of this system is that the mere act of adjusting tends to "upset" the adjustment as any "free-play" is found in restraining the system and happens as this free play gets taken up. You adjust for the proper clearance, and by the time you've put the lock nut in place and torqued it to value - you've changed the clearance. Very tricky and intricate to use. The second and only slightly later system involves a single lock-nut - but the nut is designed to be "self-locking" - and can only be moved under the influence of the wrench. Think "Nylalock" nuts which are similar. When it came to me to make a choice between these two, the rebuilder (Richard Knight) recommended I go with the nylalock system as "easier" and probably (overall) more reliable. Which is where I went and where I remain to this day. Richard may dial in here and confirm my decision and offer any "since then" improvements to that recommendation. Everything has a tendency to be "Improved upon" given time. Joe K __________________ Shudda kept the horse. Last edited by Joe K; 03-15-2026 at 06:34 PM.

03-15-2026, 08:51 PM	#8
old ugly Senior Member Join Date: Aug 2021 Location: alberta canada Posts: 865	Re: Valve adjustment take off the manifolds, take off the side cover. take out the spark plugs. have someone turn the engine over by the hand crank slowly. put you thumb on a spark plug hole while they are turning the engine. you will feel the air pressure going past your thumb. now look in that plug hole to see if the piston is at the top. if the valves are closed and the piston at the top use your feeler gauges to check the clearances. do the same for each cylinder. like said above unless it has adjustable lifters they can not be adjusted unless you tear it down. __________________ old ugly my mom would have told me. "these things are here to test us"

03-16-2026, 05:49 AM	#9
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,852	Re: Valve adjustment One other modification that is commonly done is to machine off the top of the casting where the valve lifters go through. This allows access to the adjustable valve lifters. If this has not been done you may have to adjust the lifters when the valve is up and measure the clearance when the valve is down. The rule of nine can be applied to this procedure too. Instead of working on one valve at a time and having to turn the engine over 360 degrees several times for one valve, adjust the valve that is up while measuring the valve that is down. So applying the rule of 9, assuming starting with valve 8 up, measure 1. Record the value. Then rotate the engine until the next valve is up and measure the one that is down. Continue until you have measured and recorded all 8. Then adjust the one that is up. Rotate until the next valve is up and adjust that one. At the same time check the adjustment for the one that is down. Continue until all are adjusted and checked and all have the correct clearance. By the way, it helps to have the spark plugs out while turning the engine over. But stuff rags in the holes so that you don't accidentally drop something down there. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

03-16-2026, 06:22 PM	#10
Randall Senior Member Join Date: Nov 2010 Location: Lambsburg Va Posts: 373	Re: Valve adjustment Here's a simple way I adjust, pull the spark plugs.out, put it in hi gear jack up one rear wheel and have someone turn the wheel forward and watch the valve https://youtu.be/07v6AERzVQQ?si=TMX5-vu2eZjBkpTF