Valve clearance adjustment - image

[rigspelt]

You're likely simply not turning the upper nut (at the top of the adjustable part of the assembly) with enough force while holding the top of the tappet. The lower 1/2" wrench position is actually the top of the tappet, not a locking nut, as you're calling it. You can turn the tappet freely with a 1/2" wrench as long as you're not holding the upper nut with a second wrench.Don

Thanks for helping Don.

UPDATED: In the image below:
A - a smooth round metal part that "taps" the base of the valve stem and pushes the valve up. A, B and C are all one part: the adjusting nut.
B - adjusting nut that takes a 7/16" inch wrench.
C - These threads are part of adjusting nut B. They turn into the top of the tappet D.
D - The top of the tappet, fits a 1/2" wrench.

This whole unit spins freely if no wrenches are attached.

Hold D with a 1/2" wrench and then turn B with a 7/16" wrench with enough force to move it. First time I did it, I was surprised by the force it took to move the adjusting nut.

[rigspelt]

Wait - I think I see it.

I had a good look through the images I took yesterday. This one shows a valve being pushed up by the tappet. The clearance of course is zero. Now I can see the part under D, labelled E in this image. It is the tappet, and I can see that D is a part of E, shaped to take a 1/2" wrench. So, of course the tappet would spin freely as it rides on the cam. Since this arrangement has no locking nut mechanism, and then of course it would take some force to turn adjusting nut B in order to change the clearance. A, B and C must be one part, and D and E the second part, correct?

I'll go back and edit the images above to change the name from "locking nut" to "top of tappet", but I would like confirmation that my penny finally dropped, and the amount of force it takes to turn adjusting nut B while holding top of tappet D is indeed fairly high. (UPDATED: Confirmed.)

[Don Moyer]

The tappet is built in two parts: the tappet itself with flat spots on each side of the top to accommodate a 1/2" open-end wrench and a threaded part (we've been calling it the adjusting part) which has a hex-headed top. To adjust the clearance between the top of the tappet assembly and the bottom of the valve stem, you hold the top of the tappet with one wrench while turning the hex-headed adjusting nut at the top of the threaded part of the tappet assembly with a second wrench.

The threaded part of the assembly is designed to fit tightly (self-locking) into the top of the tappet so there is no lock nut required. You only have to turn the threaded (or adjusting part) up or down within the tappet to make an adjustment. I still believe that you simply aren't putting enough muscle on the wrenches. Sometimes the threaded part of the assembly turns quite tightly within the tappet.

Don

[rigspelt]

I still believe that you simply aren't putting enough muscle on the wrenches. Sometimes the threaded part of the assembly turns quite tightly within the tappet.

Don, that explains it. Thank you for your patience.

UPODATE: All 8 done and double checked. Thanks all.

[roadnsky]

COLD or HOT?

I'm resurrecting Rigs' old thread to ask...

Should the valve clearances be adjusted COLD or "WARM"? (at operating temp)
I'm about to dive in to the adjustment.
The engine runs fine, but I have no idea when this was last done and that gasket sure looks old!

[67c&ccorv]

I'm resurrecting Rigs' old thread to ask...

Should the valve clearances be adjusted COLD or "WARM"? (at operating temp)
I'm about to dive in to the adjustment.
The engine runs fine, but I have no idea when this was last done and that gasket sure looks old!

I would go with the cold specs myself - mainly due to what one man thinks (or due differences in operating tempuratures of various engines) is "warm" enough.

Plus, it is a lot harder to get burned this way!

[roadnsky]

I would go with the cold specs myself - mainly due to what one man thinks (or due differences in operating tempuratures of various engines) is "warm" enough.

Plus, it is a lot harder to get burned this way!

Thanks 67...
When pulling the carb and cables today to get to the cover, I realized the answer to my own question.
COLD...
Because I won't have a way to run the engine with the carb off!
DUH!

[Dave Neptune]

Oil splash??

Don, I am definately an old school mechanic as I grew up adjusting all sort of valvetrains, some adjusted hot some cold and quite a few running. I always prefered the results on older engines when adjusting while running which brings me to this question.
How messy (spray & splash) is it if you attempt to run with the cover off to check the "running clearance"? I have always had a copuple of extra noises in my valvetrain (not to worried it's been there for 25 years for me @ 3 valve adjustments) that I think I could possibly eliminate if I could check while running.

Dave Neptune

[roadnsky]

Dave-
So, obviously, you have good access to the valves without removing the carb?
There's no way I can on my boat. Between the Indigo PVC and the carb.
(Plus my Shift Cable)

I'm going after mine mainly to change that very old looking gasket.
I'd think trying to do the clearances while the engine was humming along would really get messy.

[Don Moyer]

Dave,

There's hardly any splash at all when running the engine with the valve cover removed. However, if you go that route, you might consider using the 1/4" - 20 studs in our online catalog (product number OVAL_14_418 in overhaul/valves) to replace your 1/4" - 20 bolts. It's much easier to install the valve cover over the ends of the studs than to find the holes in the block when reinstalling bolts through the valve cover.

The warm clearance for the valves are: .008" for intake and .010" for exhaust valves.

Regards,

Don

[roadnsky]

Don-
Is there a torque setting for those bolts?

[Don Moyer]

Jerry,

Assuming you're talking about the 1/4" - 20 bolts which are used to secure the valve cover in place, there is no official torque setting from Universal, but Google suggests 10 ft/lbs (115 in/lbs) as a generic value for standard grade 5 1/4" - 20 bolts (or for nuts). I would definitely err on the low side of these values when using the original bolts. Twisting off a bolt in the block can create a real nightmare in terms of drilling out the remnant with the engine installed in a boat.

This is a good place to point out another booby trap when replacing a valve cover. If you experience a leak when reinstalling a cover on a late model engine, it's usually unproductive to pull harder on the bolts to stop the leak. The uneven surface at each end of the valve chamber on late model blocks frequently requires that a slight bow be placed in the valve cover so that the ends of the cover pull in slightly at each end.

Don

[Dave Neptune]

Oil splash.

Don, thanx for the heads-up. I'll R&R the carb to get the plate off and try from there if I get the ambition. If I get it set running I'll advise as to the results.

Dave Neptune

[roadnsky]

Thanx Don. Good info on the bolts. I'll err on the caution side.
In fact, I might think about getting those bolts...
That plate is pretty stiff! Gonna have to bring it home to get any kind of a bend in it.
I should have this done by the weekend and will report back with results and maybe some pics too...

[rigspelt]

That plate is pretty stiff! Gonna have to bring it home to get any kind of a bend in it.

I took it to a motorhead shop with a big old dog lying all over the step to the door (actually he was just thinking about getting a dog, so I exagerrate, but it's that kind of friendly place). They put it on a hydraulic press and made a perfect little bend in seconds. Refused to charge me for it.