Valve adjustment advice needed

[Bruce_MO]

I have a rebuilt engine done about 5 years ago by one of the best regarded rebuilders on this site. It only has 260 miles on it since then. The valves always seemed noisy to me (I've posted the issue here previously), and the rebuilder was not much help. So I had some other folks listen and concur that the valves needed adjustment, and I finally got around to doing it over the long weekend. They were all over the place... "worst" was 0.019 or 0.0120. So I set all of them to 0.013 for intakes and 0.015 for exhaust, and checked each one 2-3 times. Buttoned it up and started the engine, and it sounded beautiful... absolutely quiet, with no tap, tap, tap noise. Went out a day later and started it, hoping to enjoy the sound of a problem fixed for good. Instead, after about a minute, the tap, tap, tap returned, albeit a bit softer. And after about 2 minutes, it went away and it sounded good. Checked it again the next day and it's noisy for a while, and then the tapping goes away. So I'm assuming that the adjustable tappet on a valve has "slipped". Would that happen so quickly? Is there a way to secure the adjustment? I was assuming I could run the adjuster "up" to expose some threads and apply some locktite, and then run it down and adjust to the setting I need, but I'm not sure that's feasible or advisable. Any ideas? Thanks in advance.

[29spcoupe]

I'm new to Model A's, but it sounds to me like the tappets are dry and when the oil is pumped up the oil quiets them down. I might look at the oil pump. Possibly others on this site that know more than me might chime in. John

[BILL WILLIAMSON]

I would "guess" you have an ever so slight sticking valve, that frees up some, after warm. Rev it up & spray some MMO or such, in the carb intake, to help "lube" the valve stems. Your adjusters are NOT backing off, or it would NOT quiet down.---- P.M. me if I can help more.
Bill W.

[jetmek]

I usually set mine tighter .010/.012

[Synchro909]

Originally Posted by jetmek

I usually set mine tighter .010/.012

I generally go the other way and set them a little wider (by about 2 thou) than what the books say. With the crappy fuel we get these days and how we drive the cars harder, they run hotter so the extra clearance is desirable. If I can't hear the tappets when cold, I worry that the motor will burn valves.

[Russ/40]

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Some will laugh, but I have been doing this for a long time with perfect results. If you identify a tappet that moves, you can readjust it and then hit the threads with some brake cleaner or carb cleaner from an aerosol can to clean the threads. Mix up a small bit of JB weld, and put it on the lifter threads right at the lifter thread junction. Just a dab will do it. It will stay there, and that adjustment is set until you break the bond with a wrench. Lifters never unscrew, they only turn in. The JB will not let the bolt turn in.
I use the Carburetor cleaner from Walmart, $1.79 a can. Works good for cleaning paint guns too.

[PC/SR]

IMHO you have a touch too much clearance. I would go .011 intake, .013 exhaust. Right now I think your exhaust is a little wide and heat expands it. I assume you have a stock of close to stock cam?

[TinCup]

I have single nut lifters that have give me fits with loss of adjustment. I have done the same thing to keep them in spec.

Originally Posted by Russ/40

Some will laugh, but I have been doing this for a long time with perfect results. If you identify a tappet that moves, you can readjust it and then hit the threads with some brake cleaner or carb cleaner from an aerosol can to clean the threads. Mix up a small bit of JB weld, and put it on the lifter threads right at the lifter thread junction. Just a dab will do it. It will stay there, and that adjustment is set until you break the bond with a wrench. Lifters never unscrew, they only turn in. The JB will not let the bolt turn in.
I use the Carburetor cleaner from Walmart, $1.79 a can. Works good for cleaning paint guns too.

[Pinesdune]

Originally Posted by Bruce_MO

I have a rebuilt engine done about 5 years ago by one of the best regarded rebuilders on this site. It only has 260 miles on it since then. The valves always seemed noisy to me (I've posted the issue here previously), and the rebuilder was not much help. So I had some other folks listen and concur that the valves needed adjustment, and I finally got around to doing it over the long weekend. They were all over the place... "worst" was 0.019 or 0.0120. So I set all of them to 0.013 for intakes and 0.015 for exhaust, and checked each one 2-3 times. Buttoned it up and started the engine, and it sounded beautiful... absolutely quiet, with no tap, tap, tap noise. Went out a day later and started it, hoping to enjoy the sound of a problem fixed for good. Instead, after about a minute, the tap, tap, tap returned, albeit a bit softer. And after about 2 minutes, it went away and it sounded good. Checked it again the next day and it's noisy for a while, and then the tapping goes away. So I'm assuming that the adjustable tappet on a valve has "slipped". Would that happen so quickly? Is there a way to secure the adjustment? I was assuming I could run the adjuster "up" to expose some threads and apply some locktite, and then run it down and adjust to the setting I need, but I'm not sure that's feasible or advisable. Any ideas? Thanks in advance.

I agree with Bill, I've done several tractor engines and if they don't get run enough after a rebuild (like 260 miles in 5 years) the valves stick. Spray some cleaner in the carb and drive her a bit, then repeat. Old iron needs to be run a bit once in a while. The worst I had to deal with was a Case SC, ran fine one fall, next spring, bent 2 pushrods like pretzels.

[H. L. Chauvin]

Hi Bruce,

Sounds like you hit the Jackpot.

John's Reply # 2: Engine not run often, maybe temporary dry valve guides and stems.

Bill's #3: Engine laid up, maybe sticky valve guides and valve stems .... MMO.

#4 & #5, maybe less ticking with smaller gaps.

Russ's #6: Lifters only turn & screw in, not out ..... JB Weld always works ... but, only on "clean" metal threads.

# 7: .011" & 0.013" always a winner with either original or SS valves.

#8: Echoes #6.

#9: Suggested future caution.

#10 Echoes #3.

Just one (1) inexpensive can of MMO or carb cleaner, one (1) inexpensive pair of JB Weld Tubes.

Try this with a modern car.

[James Rogers]

If the engine has modern valves, you should set the lash at .011. The modern valves expand less than originals so, the lash can be less. This is how I adjust all my valves in engines I build and they are all quiet. Sounds like the oil is all draining out of the valve chamber while sitting so, you might need to check the rear main clearance to make sure it is correct and not letting the oil drain too fast when sitting.

[BILL WILLIAMSON]

If a car will be stored for awhile, squirt oil in the cylinders & crank it over for a few turns.
Bill W.

[Mikeinnj]

What make and grind is your camshaft ?

[Bruce_MO]

Folks,

Thanks for all the great feedback! I will indeed start with the MMO approach, and then move to the JB Weld method & careful cleaning. Will also go with the 0.011 clearance, as they are indeed new valves.

The car actually gets fairly frequent trips, but they're pretty short... 3-5 mile circuit I make. I have several other cars that get the majority of my driving time. But yeah, it can sit long enough for bad things to happen.

I didn't mention the rebuilder because he was sympathetic, but what was he realistically to do? I wasn't expecting to pull the engine to send to him. But I was hoping that he could have confirmed that he has a standard gap he uses, he knew the engine was "right" when I picked it up, never had any adjustable lifters fail to hold a setting, etc. He didn't really offer suggestions and I got off the phone neither satisfied nor angry. I definitely would buy another engine from him, but I will check the valves to see what I got.

I have a flathead that has adjustable lifters, and they "loosened up" after a few thousand miles from "whisper quiet" to "sewing machine" now. And I have a couple others that have always been very quiet. Just trying to learn something.

Thanks again for taking the time to help!

[Patrick L.]

I'm wondering if you may have 2 problems. You seem to say the engine is initially quiet then becomes noisy for a time before quieting up again.

I agree with Bill, new engines sometimes tend to have tight valve guides. A little upper cylinder lube [ I like ATF] can be squirted thru the hole on the valve stems and a qt can be mixed with the fuel. It amy take awhile for the guides to 'loosen up'.

You could also have an adjuster that doesn't want to hold, but, it shouldn't loosen that quickly.

I don't have a problem with your valve lash settings, especially depending on the cam grind used. I don't expect mechanical lifters to be perfectly quiet. But, of course, everyone has an opinion on this.

[burner31]

If you had the engine rebuilt 5 years ago and you now have 260 miles on it...I think I see your problem.

[JamesAC]

I have a recent engine rebuild (1930 coupe) prior to my acquisition of the car and best info I have on the person doing the rebuild is good/reputable. The car runs strong and no internal engine problems I can tell. On my particular rebuild the single nut adjusted tappets were used and just for the fun of tinkering with it when I first got it a year ago I ran through the adjustment and it was simple and the single nut adjusters seemed to "hold" very well. I set the clearances at 0.013 and 0.015 as usual for what I could read about those engines and I have no problems, hear no valve or other loose sounds.

I have a 1950 Plymouth Special Deluxe (flathead 6) owned by a great aunt from new with all service records from new on the car and the engine has never been gone into and it has the same style single nut adjustment on the valves (interestingly approached by jacking up and removing the right front wheel and removing a fender panel plate designed for the purpose) and they "hold" just fine too and only 8000 miles have been put on that car over the past 35 years. Also have a 1970 Mercedes with the single adjusting nut on the overhead chain driven cam set up and they hold well too.

Not clear there would be a relationship between how little driven and coming out of adjustment, least in my limited experience. And it's so rewarding to have your valves set just right on old engines instead of having hydraulic lifters.

[H. L. Chauvin]

FWIW:

Here is one way to look at asking WHY.

My Dad had a bar. I was of pre-teen age when I started helping him to mix drinks.

Many customers drank whiskey highballs served with same brand Early Times Whiskey back then.

At an early age, I began to notice that after about 3 - 4 hours, even though different guys were all drinking from the "same" Early Time's bottles, one (1) particular guy became sleepy, the next guy started to get happy and laughed a lot, another guy became depressed and teary eyed, one (1) particular guy even became a bit controversial and wanted to argue.

Never tried to figure out WHY ............... but after reading Model A Forum questions and replies, I often thought Model A's were not too much different from Bar Customers.

[Bruce_MO]

Just to clarify... There is only ONE noisy lifter. All others have been quiet, and have always been pretty quiet. I guess that's why I'm now tending to agree that it's a sticky valve guide issue, maybe made worse by excessive clearance.

[daveymc29]

Put some ATF or MMO in the gas tank and run it. I'll bet it quits ticking soon and if it doesn't you may have to pul the valve and polish the stem a bit. JMHO