Adjusting U20 Valves

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Rutty
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Adjusting U20 Valves

Post by Rutty » Sat Oct 05, 2019 3:28 pm

Hi all,

I was adjusting the valves on my U20 for the first time and ran into an unexpected issue.
So from what I see there are three nuts under the rocker arm. The top one is the adjusting nut as far as I can tell. The one under that is the lock nut. The largest one on the bottom is where I'm having trouble.
The first valve everything went fine but the second one when going to loosen up the lock nut I found it was already loose. Upon further inspection I saw that it was the nut on the bottom that was loose. This nut isn't loose on any other valve.
The problem I'm having is I can't get a wrench on it as the head bolt is in the way and I can't get it tightened back up or the lock nut loosened without getting a wrench on it. Do I need to disassemble it till I can get a socket on it?
Any help would be greatly appreciated.

Thanks,
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Matt
'68 1600 (L20b)
'69 2000
Minnesota

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Re: Adjusting U20 Valves

Post by JT68 » Sat Oct 05, 2019 3:52 pm

The largest "nut" as you describe (the threaded base of the adjuster) should always be tight in the head. Remove the rocker arm and tighten it (tightly) with a deep socket. You don't want that nut loose. Once it is tight, hold the 14mm pivot stationary and turn the 19mm jam nut to loosen.

Alternatively, once you remove the rocker, reomove the adjuster completely, put it in a vice (the flats) and loosen the 19mm nut.
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Rutty
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Re: Adjusting U20 Valves

Post by Rutty » Sat Oct 05, 2019 5:30 pm

Thank you. Do you know, is the base of the adjuster 27mm? I don't have a socket that fits and it seems 27mm would be close. Also, to get the rocker off do I need to remove the cam?
Matt
'68 1600 (L20b)
'69 2000
Minnesota

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redroadster
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Re: Adjusting U20 Valves

Post by redroadster » Sat Oct 05, 2019 6:03 pm

Rutty wrote:
Sat Oct 05, 2019 5:30 pm
Thank you. Do you know, is the base of the adjuster 27mm? I don't have a socket that fits and it seems 27mm would be close. Also, to get the rocker off do I need to remove the cam?
No with the piston down. 1/ 2. way in the cly ,pry down the valve. , unclip the rocker spring Or you can pry the heal of the rocker off w bent screwdriver
This allows you to use a boxed end wrench to tighten down the base nut. and if the lock nut is tightly jammed
Replacing the rocker by doing the reverse as it was removed

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Rutty
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Re: Adjusting U20 Valves

Post by Rutty » Sat Oct 05, 2019 7:56 pm

Great! I'll try that tomorrow.

Thanks,
Matt
'68 1600 (L20b)
'69 2000
Minnesota

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Rutty
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Re: Adjusting U20 Valves

Post by Rutty » Tue Oct 08, 2019 8:29 pm

That worked great. Got the adjuster base tightened back down and adjusted to what another one of the exhaust valves is when cold. Figured that will be close enough to start it and get it warmed up so I can finish adjusting them when hot.
Another question. Has anyone had much luck reusing the cam cover gasket? Mine was leaking a bit before. I was going to order a new one since I have it apart but it looks like they're $125. Yikes! Can I use some sort of RTV to seal it?

Thanks,
Matt
'68 1600 (L20b)
'69 2000
Minnesota

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redroadster
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Re: Adjusting U20 Valves

Post by redroadster » Tue Oct 08, 2019 9:07 pm

Yes or avaition sealer if you get the oil off it enough where the rtv or other will grab it.
What size was it 24mm?
Last edited by redroadster on Wed Oct 09, 2019 7:45 pm, edited 1 time in total.

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Gregs672000
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Re: Adjusting U20 Valves

Post by Gregs672000 » Wed Oct 09, 2019 1:21 pm

You can adjust the lash cold. Contrary to the manual, they actually LOOSEN when hot. If you go 8in and 10ex cold, they'll be 10 and 12 hot. I personally run mine about 6-7 intake and 8-9 exhaust hot.

Regarding the cam cover gasket, assuming it's still good, how well it seals is influenced by how tight the bolts are... don't over tighten them! Not only will it not seal, you can break the cam cover. I can't give you a torque spec... I do mine by feel that comes from 30+ years of ownership, but it's snug. Try slowly tightening the bolts while watching the gasket to make sure it doesn't bulge etc. It may take some trial and error before you find and develop the feel. But know that going over tight will not fix it! Also, wipe the oil off mating surfaces.
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Re: Adjusting U20 Valves

Post by theunz » Wed Oct 09, 2019 7:43 pm

I believe the cam cover bolts only tighten to about 5 foot pounds. That's just a little past snug.
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Rutty
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Re: Adjusting U20 Valves

Post by Rutty » Wed Oct 09, 2019 9:02 pm

Thanks for the tips guys. I'll make sure to not over tighten the cam cover bolts. FYI, I used a 27mm deep socket on the base of the adjuster. I tried a 26mm first but it was too small.
Matt
'68 1600 (L20b)
'69 2000
Minnesota