Adjusting Tappets without Gauges

I think they are just discussing how it can be done w/o feelers as an informational exercise. There isn't any significant benefit to doing it w/o and for the cost of a set of feelers 2-3 bucks, I wouldn't do it w/o the gauges, but it is interesting to to see how one can figure the measurements with thread pattern and turns of the adjusters. The question it brings to mind for me is how can you be sure you are in tolerance to a couple thousandths and I think it would be difficult to get the clearances even by eye or turns if the threads or adjusters are worn.

caddy chris said:

When the tops of the valves are worn by the to rockers, which appears to be common on these contraptions, a feeler guage wont work.

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Chris, I have 15K miles on my current top end, maybe more including valves and see no problems with measuring valve clearances once a year with feelers. I am guessing unless your top end is nearly a total loss one isn't going to have problems at least that has been my experience.

A long time ago, when I had my first Norton, I didn't know that the tops of the valves got dished and concave. Nor did I know that the ends of the adjusting screws would get flat spots.

It was too easy for me, young and dumb as I was, to miss the fact that the tops of my valves were dimpled.

And I scratched my head when the clearance tightened after I just loosened an adjusteer by an eighth. When the adjusting screws have flat spots . . . . . well it's nigh impossible to get the clearance right as a slight turn puts the screw's point of contact "up on edge."

Later, when I bought a 350 Ducati Sebring, I was amazed to find that it had "elephant foot" adjusting screws, similar to the pad on the screw end of a C clamp. What a deal. Heavier but better for a non-race engine.

So go the joys of vintage vehicle ownership. This is my 2nd classic bike and my 6th classic/ antique vehicle, they all have shortcomings that need working around. I'll let you'all know when that magic wand I ordered comes in. :lol:

You can always use a dial gauge to adjust the tappets. Doesn't matter then if the valves ends are dimpled. Just a pain to set up.

Dave
69S

If a feeler gauge isn't accurate enough due to stem dimpling, does anyone believe you can figure out the turns out more closely?

What would be wrong with doing a HOT SET (apart from burning your fingers) Set the clearances with slight movement when all is at max engine temp?

Foxy said:

What would be wrong with doing a HOT SET (apart from burning your fingers) Set the clearances with slight movement when all is at max engine temp?

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The clearances would loosen up once everything has cooled down, it would take a lot of experimentation to figure out the difference between the hot and cold figures, so I'd say it's not really worth the aggravation.

Webby

I have done the hot set on large diesel engines with cast iron heads that hold their heat and are liquid cooled so that the operating temp is pretty constant. On an air cooled head of aluminum it is hard to get the job done while the temp is high enough to be anywhere near close.

Now, as to the reason for this thread. I should have just asked what the thread size was on the adjusters and figured the math out from there. This was in no way intended to convince people to throw away their feeler gauges. The topic came up elsewhere and when I looked I couldn't find the information. Simple as that. My memory was that the thread was actually finer than it is, which would make it easier to use this method.

I think the only conlusion we can take from this is that if you gotta adjust 'em and you don't have gauges or a dial indicator then you are only going to be in the ballpark. So by all means, please do not think that this thread is intended to propose a superior method. It isn't, but it probably beats guessing.

Now, lets go ride...well crap, actually I have to go shovel snow, but my new Ikon shocks arrived yesterday, I have some new swingarm clamps from Windy to install and the rebuild kits for my forks are sitting on the bench. Whoohoo! Happy wrenching to all...

Russ

Oh, and btw the topic title was choosen so it could be found at a later date using the search function. Feel free to put it on ignore!

rvich said:

I have read about using the thread count on the adjusters to get the tappets gapped correctly but can't seem to find the information now that I want it.

Anybody know how many thousandths per turn? Where is this trivia best found?

Thanks,
Russ

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Sorry not a method I would recommend..............IMHO

The reason for setting a clearance cold, is to allow for valve train expansion when hot. As previously stated here, feeler gauges are of little help if you have worn/dimpled valve ends, so to not use any gauges, a hot set would be the way to go. The best way to do worn valve clearances would be to use the Dial Gauge method. I use this method to do injector sets on my Cummins diesel engines. If you know the figures you can detect cam wear as well.
Foxy

Foxy. Have you replaced you Norton engine with a CUM"A"LONG .I Had a 335 small cam from a trans Con, Did some work,Big Turbo 6" Zorst ,up the Cab back Etc,

I had the pump tweaked...85 with 28 ton on the trailer,,,Not bad for 1970, But these modern rigs are pushing 600 BHP!
Men, Bikes and Trucks...lovely!! and not forgetting the shelia's and Beer,

Gday John, seems like Ive traded to much work for the Norton! Ive got 6 Cummins motors in tractors,trucks and a Harvester. All good so far. The older truck ford Loui has a 903 V8 @ 350 HP and sounds mean as with a straight through exhaust! Trouble is you can still hear it in your ears ringing when in bed! Later truck is a Mack @ 435 Hp so Im looking up a dogs bum when driving that! I'm no trucky, once you've worked through 18 gears and into top gear, the thrills over (unless you pick up a nice hitchhiker) :mrgreen:
Foxy

Hey foxy,... Nothing wrong with the old 903T. Looked up a dogs bum for a while myself... AC.