Tappet adjustment on new rebuild flat 6- when and how?

['41 Fat Bottom Girl]

This poses some questions and I sure can use some help.

My newly rebuilt 218 L has about 240 miles on it and will be due for tappet adjustment at some point. Maybe now? Later?

1) I need to talk to the machine shop, they have a generic engine break-in sheet that says "rocker/valve lash" has to be checked and readjusted if necessary at around 200 miles and again at 500 miles. But these are solids of course, no rockers- rockers are easy. Maybe adjusting once is enough for solids? and at what mileage point? I will ask them, because they have to agree to preserve my warranty- but comments from you as well would be appreciated.

2) The shop manual states that valve tappets be adjusted with engine running, at idle speed, at normal operating temperature.

Hoo boy. The access covers are behind the exhaust manifold. The only access going under the manifold seems to be through the front fender well (lower skirt panel and wheel removed), looking in above the frame rail. Towards the back, that cover is 12 inches from the rail. At the front cover, it's about 18" because you'd have to work around the drum and control arm. Is it expected that you extend a wrench and feeler gauge through there to make the adjustment?

3) Shop manual is sketchy on how to do it, but I suppose the method was common practice back in the day. Can someone explain how you would use the feeler gauge when the engine is running? Do you slip the feeler gauge in while it is running and then back off the adjustment nut until you hear it clacking? Then tighten until it is quiet and then remove the gauge? There's a technique there I would like to understand.

4) This might be too easy- Are there "cold" clearance values (say at 75 Deg F. ambient/block temp) that are corrected to correlate to the "hot" values?  Then could make the adjustments at TDC for each cylinder without the engine running? 

Thanx much!

 

FYI-

Machine shop settings were at .008" intake valves and .010" exhausts at rebuild.

My D19 shop manual says .008" intake and .012" exhaust, hot.

 

"You can educate the ignorant, but you can't fix stupid"  Ron White

 

 

 

[Sharps40]

Set cold to get the rebuild running,  after 20 minute break on set lash hot with engine off (rotate crank by hand do front3 button up and reheat then engine off for back 3) and change oil.

 

At 500 miles I check lash hot (engine off/same as above) and change oil.

 

Same at 1000 miles.  Then I just go with Normal service intervals.

 

Feeler gauge running is a pain in the hand.   Much easier engine off and at least inner fender removed. 

 

Better yet just remove right fender, only takes 10 minutes after the first try. 

Edited October 4, 2020 by Sharps40

[Sam Buchanan]

Valve adjustment tips on the Tech Section of this forum:

 

https://p15-d24.com/page/p15d24/tech/tech_tips.html/

 

The Chrysler Master Tech service film on valves:

 

https://www.youtube.com/watch?v=tCj0XktYuM0

[keithb7]

I have a couple of old Mopar cars. I too had to get in there and deal with valve adjustments. I read and heard what people had to say. I researched to understand what exactly was going on with the valves and why.  I went further and performed a valve grind myself. The old way, by hand. Then I followed up with lapping and checked for valve sealing. It was indeed fun. I learned a ton. 

 

I wanted to try my hand at setting the valves when running.  I had the car hot at full running temperature. I inserted the feeler gauges while the car was running. I had the RF wheel off and the inner fender window removed. I could tell when a valve needed adjustment. I'd shut off the engine, make the adjustment, fire the engine back up and re-check the clearance. I was not able to confidently insert two wrenches in the engine while I was running to adjust a tappet. So this is why I shut the engine off. Due to siamese casting design of the block, and the L-head design, the valves do not all run at the same temperatures. A hotter running valve stem may elongate .001" longer than an adjacent valve.  This is why they want you to get the engine hot....So I set them hot, and it seemed to be a success. That was 3 years ago on my 53 Chrysler.

 

This year I replicated the valve set process in my 38 Plymouth. It was more difficult for some reason. Maybe a tighter engine bay? I struggled a bit to get good firm confident settings. After my face way black, my back was aching, and I figured I'd inhaled enough crankcase gasses, I was done. I reassembled the engine. I had a couple of noisy valves. Hmm.. I did not experience this when I set my 53 Chrysler valves. I drove it for a bit, and scheduled to go back in. This time, I decided to set the clearances when the engine was cold. I added .002" to the specs for both intake and exhaust. I did find 3 or so that were too loose.  I set them cold and flashed up the engine....Perfect. Nice and smooth and quiet. I picked up some noticeable horsepower too. 

 

So I've tried both ways and had success with both hot and cold valve settings. Cold was easier, I must admit. Easier on my back, lungs and face. LOL.

 

A few tips for the cold method: Blow out any dirt around the spark plug holes. Remove all spark plugs and #6 cylinder timing plug access hole in the head. Get a small piece of oak wood dowel from your local building supply store. Use it to find TDC on #6 and #1. Then start at #1 cylinder. Set the valves. Watch a fan blade and turn it 120 degrees.  (1/3rd of a full revolution) Then set #5. Repeat going through all cylinders. Firing order is 1,5,3,6,2,4. When you are on TDC of any particular cylinder, grab the respective tappets. You should be able to move both the intake and the matching exhaust valve tappets up and down slightly. Then you know for sure that cylinder is on TDC. You'll easily be able to back up or roll forward the crank slightly as needed by simply rotating the fan blade. It will take two complete revolutions of the fan blade to get all 6 cylinders set to TDC.  Get a piece of paper and draw out the valve positions. They are not simple. They are E, I, I, E, E, I, I, E, E, I, I, E.  Mating up pairs per cylinder it starts to become clear. You may find yourself referencing your paper with valve locations many times when your face is down in the wheel wheel setting the lash.

 

In many of todays engines in my field of work, after a rebuild, an initial valve set is done at about the 250 hour mark of the engine. The break in period. Everything settles in. Then the valves can be left alone for quite some time. Proper valve lash is indeed important. I was quite surprised at how much performance I gained in my old flathead, after setting the valves right.

 

 

[knuckleharley]

3 hours ago, Sam Buchanan said:

Valve adjustment tips on the Tech Section of this forum:

 

https://p15-d24.com/page/p15d24/tech/tech_tips.html/

 

The Chrysler Master Tech service film on valves:

 

https://www.youtube.com/watch?v=tCj0XktYuM0

 

[knuckleharley]

Just now, knuckleharley said:

 

Those two tips above need to be preserved in the "how to" archives,IMHO.

[Young Ed]

I've got about 20k miles on my rebuild and they've never been touched. I think the guy that set them knew what he was doing. My 48 was a new engine to him! I keep thinking someday I should check them... 

[tom'sB2B]

Here is another how to video.

 

[Ward Duffield]

The valve adjustment tips on this site are wrong.

If you follow the Step A/Step B scenario as written, you will be setting some tappets that are NOT on the base circle of the cam.

Note the duplications between step A and Step B; if one step is correct for a given tappet, the other cannot be, and vice versa.

Make sure you can rotate the tappet you are going to be adjusting, by hand, before you start.

That way, you will be certain that the tappet is on the base circle on the heel of the cam, and not on either ramp.

[keithb7]

My take on it. 

[allbizz49]

I lay under mine with it running and check/adjust them. I'm 5'8 130 lbs though. Never had a problem. Get a set of go no go gauges.