The Ford Barn

Bob Johnson · 07-26-2016, 01:37 PM

Trying to adjust the tappets, see picture below. The nut is split which would indicate that it is self locking. But the top of the tappet just below the nut has flats for a wrench. I tried holding the tappet and backing off the nut. I did not apply a lot of force but the nut did not move. If I hold the nut with a wrench the "bolt" turns with some resistance, but less than I would anticipate for a self locking nut. How are these adjusted? Should I use some thread locking fluid ?

Bob

Russ/40 · 07-26-2016, 03:26 PM

All the locking nut tappets I have seen, do not have a split in the nut. I believe that is a broken nut. You should not be able to turn the bolt with the nut seated on top of the tappet. You put a wrench on the tappet flat, with the second wrench loosen the lock nut and then make the lash adjustment. It is a tedious project with very thin wrenches to get everything done. When you do, they stay the way you left them.

Heck of a photo by the way!

Joe K · 07-26-2016, 04:03 PM

Russ (above) is describing the "3 wrench" tappets. Be aware that there are "2 wrench" tappet (self locking) systems - and that at least one of these has a "slot" similar to what you see in your most excellent pictures.

Opinions vary as to which of the two systems is best. I, familiar with the 3 wrench system asked my engine rebuilder (Knight Automotive of Kettle Cove, MA) to use that. He explained at length that he preferred the 2 wrench system which he felt more reliable, easier to adjust, easier to correct, and half a dozen other reasons to stick with his recommendation.

I ultimately relied on his judgment.

Perhaps you know your engine source and can tap them for further knowledge? Unless somebody here can recognize your lifter?

Joe K

colin1928 · 07-26-2016, 04:26 PM

X2 what Russ said

Chuck Sea/Tac · 07-26-2016, 05:04 PM

Well that's easy to figure out, do the other lifters have a split nut?

Y-Blockhead · 07-26-2016, 05:10 PM

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Quote:

Originally Posted by Chuck Sea/Tac

Well that's easy to figure out, do the other lifters have a split nut?

You're being too logical Chuck

Bob Johnson · 07-26-2016, 06:12 PM

Yes all the nuts are split.

George Miller · 07-26-2016, 06:31 PM

I think that is the locking tappet. It is not just a nut it has a tapper on it that goes in a tapper in the lifter. If you look close you will see where there is a half a hole at the top where they started the split.

glenn in camino · 07-26-2016, 07:29 PM

I set mine at .012 intake and .015 exhaust.

Joe K · 07-26-2016, 08:29 PM

Quote:

Originally Posted by George Miller

I think that is the locking tappet. It is not just a nut it has a tapper on it that goes in a tapper in the lifter. If you look close you will see where there is a half a hole at the top where they started the split.

Thank you George. I saw a 1932 Patent which seemed to incorporate the split seen.

IIRC, the 2 wrench tappets used on my motor were of the "nylock" type. But I have not had occasion to adjust them. They seem fine as they are for now.

Joe K

Russ/40 · 07-26-2016, 09:36 PM

Interesting! Never saw those, but I haven't been in the Model A world for very long.

Jim Brierley · 07-27-2016, 09:56 AM

In the tappets pictured, the split nut is a jamb nut, and may require some torque to loosen. Be sure to tighten firmly. I've only seen one other set like this but they should be good. I set the clearance of a stock cam at .012" and .014".

Bob Johnson · 07-27-2016, 10:15 AM

If it is a jam nut then the tappet must be threaded? Why would the jam nut be split? If the nut is tightened too much would the split open? I was able to adjust the "bolt" without opening up the "jam" nut. Is that normal?

Bob

Keith True · 07-27-2016, 10:57 AM

That's not really a 'jam nut'as we know them.It is more of a hollow bolt,threaded on both the inside and outside.One of the parts has a slight taper,although I can't remember which one.When you get the clearance where you want it,with the top bolt,you hold the top bolt,the tappet,and turn that jam bolt down with your third hand.That taper closes up the split and squeezes against both the adjusting bolt and the tappet.The jam bolts on mine though don't thread in far enough to bottom out on the tappet like the one in the picture.Somebody got carried away tightening,or it was made wrong to begin with.The top of the tappet could also be recessed enough for the hex to drop into a little too.

Y-Blockhead · 07-27-2016, 11:10 AM

Quote:

Originally Posted by Keith True

That's not really a 'jam nut'as we know them.It is more of a hollow bolt,threaded on both the inside and outside.One of the parts has a slight taper,although I can't remember which one.When you get the clearance where you want it,with the top bolt,you hold the top bolt,the tappet,and turn that jam bolt down with your third hand.That taper closes up the split and squeezes against both the adjusting bolt and the tappet.The jam bolts on mine though don't thread in far enough to bottom out on the tappet like the one in the picture.Somebody got carried away tightening,or it was made wrong to begin with.The top of the tappet could also be recessed enough for the hex to drop into a little too.

That makes perfect sense now that it is explained, Thanks Keith

07-26-2016, 01:37 PM	#1
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 977	Tappet adjustment Trying to adjust the tappets, see picture below. The nut is split which would indicate that it is self locking. But the top of the tappet just below the nut has flats for a wrench. I tried holding the tappet and backing off the nut. I did not apply a lot of force but the nut did not move. If I hold the nut with a wrench the "bolt" turns with some resistance, but less than I would anticipate for a self locking nut. How are these adjusted? Should I use some thread locking fluid ? Bob

07-26-2016, 03:26 PM	#2
Russ/40 Senior Member Join Date: May 2010 Location: Santee, California Posts: 3,505	Re: Tappet adjustment All the locking nut tappets I have seen, do not have a split in the nut. I believe that is a broken nut. You should not be able to turn the bolt with the nut seated on top of the tappet. You put a wrench on the tappet flat, with the second wrench loosen the lock nut and then make the lash adjustment. It is a tedious project with very thin wrenches to get everything done. When you do, they stay the way you left them. Heck of a photo by the way!

07-26-2016, 04:03 PM	#3
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Tappet adjustment Russ (above) is describing the "3 wrench" tappets. Be aware that there are "2 wrench" tappet (self locking) systems - and that at least one of these has a "slot" similar to what you see in your most excellent pictures. Opinions vary as to which of the two systems is best. I, familiar with the 3 wrench system asked my engine rebuilder (Knight Automotive of Kettle Cove, MA) to use that. He explained at length that he preferred the 2 wrench system which he felt more reliable, easier to adjust, easier to correct, and half a dozen other reasons to stick with his recommendation. I ultimately relied on his judgment. Perhaps you know your engine source and can tap them for further knowledge? Unless somebody here can recognize your lifter? Joe K __________________ Shudda kept the horse.

07-26-2016, 04:26 PM	#4
colin1928 Senior Member Join Date: Mar 2013 Location: Australa Melbourne Posts: 878	Re: Tappet adjustment X2 what Russ said

07-26-2016, 05:04 PM	#5
Chuck Sea/Tac Senior Member Join Date: May 2010 Location: Between Seattle & Tacoma Posts: 2,354	Re: Tappet adjustment Well that's easy to figure out, do the other lifters have a split nut?

07-26-2016, 06:12 PM	#7
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 977	Re: Tappet adjustment Yes all the nuts are split.

07-26-2016, 06:31 PM	#8
George Miller Senior Member Join Date: May 2010 Location: NC Posts: 2,975	Re: Tappet adjustment I think that is the locking tappet. It is not just a nut it has a tapper on it that goes in a tapper in the lifter. If you look close you will see where there is a half a hole at the top where they started the split.

07-26-2016, 07:29 PM	#9
glenn in camino Senior Member Join Date: May 2010 Location: Camino, CA. Posts: 3,086	Re: Tappet adjustment I set mine at .012 intake and .015 exhaust.

07-26-2016, 09:36 PM	#11
Russ/40 Senior Member Join Date: May 2010 Location: Santee, California Posts: 3,505	Re: Tappet adjustment Interesting! Never saw those, but I haven't been in the Model A world for very long.

07-27-2016, 09:56 AM	#12
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,085	Re: Tappet adjustment In the tappets pictured, the split nut is a jamb nut, and may require some torque to loosen. Be sure to tighten firmly. I've only seen one other set like this but they should be good. I set the clearance of a stock cam at .012" and .014".

07-27-2016, 10:15 AM	#13
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 977	Re: Tappet adjustment If it is a jam nut then the tappet must be threaded? Why would the jam nut be split? If the nut is tightened too much would the split open? I was able to adjust the "bolt" without opening up the "jam" nut. Is that normal? Bob

07-27-2016, 10:57 AM	#14
Keith True Senior Member Join Date: May 2010 Location: Epping N.H. Posts: 2,983	Re: Tappet adjustment That's not really a 'jam nut'as we know them.It is more of a hollow bolt,threaded on both the inside and outside.One of the parts has a slight taper,although I can't remember which one.When you get the clearance where you want it,with the top bolt,you hold the top bolt,the tappet,and turn that jam bolt down with your third hand.That taper closes up the split and squeezes against both the adjusting bolt and the tappet.The jam bolts on mine though don't thread in far enough to bottom out on the tappet like the one in the picture.Somebody got carried away tightening,or it was made wrong to begin with.The top of the tappet could also be recessed enough for the hex to drop into a little too.