Valve adjustment procedure on a 300 Ford?

[The_Eric]

Hi guys, I've got an 1983 300 that I'm resealing and replacing the cam in. I searched out the valve adjustment procedure as they look to be adjustable, but found that you just torque them down irrespective of their position?

Since it's not entirely clear, I though I'd ask and double check and since this is a side job, I can't really tap into the shop's resources...

 

[OVERKILL]

IIRC, they are just pedestal mount rockers that you torque down as indicated.

 

[oldhp]

Ford-Trucks.com

Ford Truck Enthusiasts Forums> Performance, Engines & Troubleshooting> Ford Inline Six, 200, 250, 4.9L / 300

Check out this site. Type in "how to adjust valves 1983 F-150"

 

[mechanicx]

Yeah I think that's correct. If they are adjustable rockers once you have eliminated the lash turning the nut about one turn tight regardless of the cam/lifter position should be good.

 

[The_Eric]

Originally Posted By: OVERKILL
IIRC, they are just pedestal mount rockers that you torque down as indicated.


What threw me is that there is no stand. Just a stud, pivot ball and nut, much like a Chevy's valve train.

 

[The_Eric]

I read that you just torque them down to 17-23lbs, with some people calling for 25lbs.

 

[mechanicx]

They very could be adjustable if there is a stud and no stand and a self locking.

 

[OVERKILL]

Originally Posted By: The_Eric
Originally Posted By: OVERKILL
IIRC, they are just pedestal mount rockers that you torque down as indicated.


What threw me is that there is no stand. Just a stud, pivot ball and nut, much like a Chevy's valve train.


Funky!

I never had the valve cover off my 300, I just assumed they were the same as the 289, 302, 351...etc, which were pedestal mount.

 

[Clevy]

Originally Posted By: OVERKILL
Originally Posted By: The_Eric
Originally Posted By: OVERKILL
IIRC, they are just pedestal mount rockers that you torque down as indicated.


What threw me is that there is no stand. Just a stud, pivot ball and nut, much like a Chevy's valve train.


Funky!

I never had the valve cover off my 300, I just assumed they were the same as the 289, 302, 351...etc, which were pedestal mount.


They have gear driven timing too. No chain.
It's no wonder those engines were so reliable. They are so very basic,nothing complicated to break or not function properly.
We have one in one of out work vans. Over 300000kms on it and starts first turn.
When I was in high school a friend had one in a 4x4 truck. We were out on the trails and ended up pulling a hose off,lost all the coolant.
We drove it 30kms like that albeit at 800 rpms. Lucky it was winter and we were whiskey warm. Once we got it home we changed the oil and filter. Oil was scorched. His dad is a trucker. He told us to flush it out with kerosene or diesel to try to clean out the cooked oil.
Anyways long story short that truck ran fine,no additional noises after the overheat but it did start consuming oil so he ran whatever his dad used in the rig.
Truck ended up totalled but the motor never quit.
Great engines.

 

[OVERKILL]

Mine had the nylon gears, which failed. Swapped it out for a 302HO

 

[mechanicx]

Originally Posted By: mechanicx
Yeah I think that's correct. If they are adjustable rockers once you have eliminated the lash turning the nut about one turn tight regardless of the cam/lifter position should be good.


Sorry I botched that up. If they are adjustable the cam/lifter position should be on the base circle when adjusting of course and if they're not adjustable then position doesn't usually matter. I'm not sure if '83 are adjustable or not but they might be.

 

[OVERKILL]

Looks like '85 was the year they went non adjustable (pedestal like my beloved Windsors!)

So the procedure would be the same as doing any other stud-mount rocker:

1. Make sure the valve you are adjusting is on the back-side of the lobe. You do this by rotating the engine until the OTHER valve on the cylinder you are adjusting starts to crack open. This means you are on base circle.

2. Using a socket to rotate the nut, spin the pushrod between your thumb and finger while slowly tightening down the nut. As soon as you feel drag on the pushrod STOP. You have hit zero lash.

3. From zero-lash, go 1/2 a turn to set your pre-load.

 

[Brons2]

Originally Posted By: OVERKILL

1. Make sure the valve you are adjusting is on the back-side of the lobe. You do this by rotating the engine until the OTHER valve on the cylinder you are adjusting starts to crack open. This means you are on base circle.

2. Using a socket to rotate the nut, spin the pushrod between your thumb and finger while slowly tightening down the nut. As soon as you feel drag on the pushrod STOP. You have hit zero lash.

3. From zero-lash, go 1/2 a turn to set your pre-load.


That's the way I would always do it when I worked in a machine shop back in the day, except I would do both valves when the cylinder was at TDC on the compression stroke. I always knew where that was because I would set #1 at TDC with a gauge before the head was on, and then mark all the TDC's on the balancer based on degrees from there.

 

[229]

They just torque down.

 

[The_Eric]

Originally Posted By: oldhp
Ford-Trucks.com

Ford Truck Enthusiasts Forums> Performance, Engines & Troubleshooting> Ford Inline Six, 200, 250, 4.9L / 300

Check out this site. Type in "how to adjust valves 1983 F-150"


Thanks to your link, I think that there are two styles used in this era and it looks like mine are indeed adjustable.






Originally Posted By: mechanicx
Originally Posted By: mechanicx
Yeah I think that's correct. If they are adjustable rockers once you have eliminated the lash turning the nut about one turn tight regardless of the cam/lifter position should be good.


Sorry I botched that up. If they are adjustable the cam/lifter position should be on the base circle when adjusting of course and if they're not adjustable then position doesn't usually matter. I'm not sure if '83 are adjustable or not but they might be.

Originally Posted By: OVERKILL
Looks like '85 was the year they went non adjustable (pedestal like my beloved Windsors!)

So the procedure would be the same as doing any other stud-mount rocker:

1. Make sure the valve you are adjusting is on the back-side of the lobe. You do this by rotating the engine until the OTHER valve on the cylinder you are adjusting starts to crack open. This means you are on base circle.

2. Using a socket to rotate the nut, spin the pushrod between your thumb and finger while slowly tightening down the nut. As soon as you feel drag on the pushrod STOP. You have hit zero lash.

3. From zero-lash, go 1/2 a turn to set your pre-load.


Yup, that's typically what I'd do for any valve train that is adjustable, accept in this case, I believe Ford is calling for 1 additional turn after zero lash is achieved.



Originally Posted By: 229
They just torque down.


It looks like the heads that have a pedestal are the ones you torque down and the cylinder heads that have studs get adjusted, unless I've missed something?

 

[Garak]

Originally Posted By: oldhp
Ford Truck Enthusiasts Forums> Performance, Engines & Troubleshooting> Ford Inline Six, 200, 250, 4.9L / 300


That's a great resource, and has helped me a lot over the years.

 

[George7941]

Originally Posted By: OVERKILL

1. Make sure the valve you are adjusting is on the back-side of the lobe. You do this by rotating the engine until the OTHER valve on the cylinder you are adjusting starts to crack open. This means you are on base circle.



I don't quite follow this. If you are adjusting the exhaust valve and the engine is rotated forward till the intake starts to open, the exhaust is just closing and is not on its base circle.

BTW I had the nylon gears fail twice and strand me in the exact same location on the Gardiner Expressway. I switched to aluminium gears and it was not noisy at all and had no more gear problems.

 

[OVERKILL]

Originally Posted By: George7941
Originally Posted By: OVERKILL

1. Make sure the valve you are adjusting is on the back-side of the lobe. You do this by rotating the engine until the OTHER valve on the cylinder you are adjusting starts to crack open. This means you are on base circle.



I don't quite follow this. If you are adjusting the exhaust valve and the engine is rotated forward till the intake starts to open, the exhaust is just closing and is not on its base circle.

BTW I had the nylon gears fail twice and strand me in the exact same location on the Gardiner Expressway. I switched to aluminium gears and it was not noisy at all and had no more gear problems.


The factory cams have no overlap, when the exhaust valve is closed, you are on base circle by the time the intake valve starts to open.

With a long-duration aftermarket stick you'd have to adjust your technique accordingly. This was the advised procedure from a cam grinder I dealt with.

Mine failed on the 401 when I was towing a car trailer with my buddy's Mustang on it. Not a fun experience!

 

[The_Eric]

Alright, as an update, I've got the beast back up and running.

There when scrubbing parts, I saw that the nuts had a conical taper to them, as well as the studs. Like they were meant to be locked together. I tried the usual adjust to zero lash and then go an additional 3/4 to 1 turn, but I just ended up almost on the taper. I talked to a machinist who said to just tighten them down.

So it looks like 229 called it. It fired up and ran fine after a quick adjustment of the distributor. It had one lifter that chattered for about 5 minutes, but it quieted down and now the truck runs like it should.