Unique method for rocket arm adjustment?

One thing to consider when adjusting the valve clearance on old used parts is how much of a notch is worn by the valve stem into the rocker arm face.

Another is that I've found that when setting the valves on my 235 with the engine shut off that the base circle that I would think is the same all the way around a long as a valve is closed, is not. And the clearance can change as the cam is moving thru the base area. It's a Howard's cam and maybe reground? And not new? IDK.

 

Yes, worn parts can give a range of measurements.
I do mine running at 450 rpm idle, which kind a beats up the feeler gauges, but it lasts for several adjusments and they are cheap.

 

Very interesting post and replies. All the solid lifter 235's/216's I've ever worked on seemed to have a little ticking noise when the valves were adjusted by the book. I would be a little nervous driving one adjusted so tight that the noise was gone completely. In my opinion, it's better to be a little too loose than a little too tight.

You mentioned your timing was set right on the ball. I've found that you can get increased performance and economy by advancing that further. I don't know if it's because of the difference in today's fuels or what, but my 235 seems to be happy at several degrees advanced of the ball. An old rule of thumb was to advance the distributor a little, drive it under load and listen for any "spark knock" or pinging, and keep doing that until you start to hear pinging under load, then retard it back to the last setting and bolt it down.

 

I got vacuum gauges permanently mounted on the dash on both my rides.
I look at them more often than any other gauge. Really tells you what the motor is doing.
The little one on my truck is called 'Gasometer'.
If I try to stay above 10 during accelerating, it does help getting a little better mileage on my trips to town, which is a 40+ miles roundtrip.
Today gas was just under $4 for the first time in a long while - What a thrill.


Thanks for the post btw - I never thought of checking the vac. gauge when adjusting rockers.
I Tee it in under the hood next time just to see what happens at various settings and through the rpm range.

And the tip about setting timing to be just below 'pinging' under load, like on a moderate incline in high gear, is right on....about 6 degrees advanced seems ideal for a stock cam, close to sea level.





Btw: I swaped the oil pressure gauge on the coupe for a 60 psi, but mounted the original bezel to keep the look.

 

I made a final adjustment. Two different spec sources say it should be set nominally to .016” for exhausts and .006” for intakes. I’m settling on .018 for exhausts and .007 for intakes. It's a bit noisier than before, but not that bad at all. You all have convinced there is more to this than just making them quiet.

When Intakes are set to .008” it starts getting rough. Most intakes have best vacuum at .005“, so some were loosened a full .002”. (to .007)

Exhausts being opened to .018 is a good thing. The vacuum and coughing threshold is very sensitive when set tighter. Let it be noisy, and everything is far better behaved. A couple were raised a full .003”. (to .018)

Vacuum at 450 RPM dropped to 18 In/Hg. Down a 1/4” point but still at spec.

Check out the cup of water test video! (LOL...I just made it up.) Notice as I raise the idle to ~500 it smoothes right out?

I’ll try that! Others seem agree with you also.

Well I don’t think this motor will be used to do any heavy duty anything. Surely, in those days, when they said heavy duty, they meant it, This motor will probably end up in a weekend cruiser, even if in a truck. I don’t think it will be hauling rocks day after day, or going cross-country any time soon..

However, as you and others so emphasize, better to be safe than sorry. My final adjustment is right in the middle of normal use for intakes according to your data above, and my exhaust is safely above normal use, although not quite set to heavy duty. My shop manual says basically what you say above.

I believe my setting based on input from everyone, the vacuum gauge and my ear to pin it down, It’s pretty good. I’m going with it.

I must thank you for your input!

Very nice! If I owned a Mile-O-Meter I would mount exactly where Road Runner mounts his Gas-O-Meter. It has 4 bands of data! Cool! Mostly useless gobble, but still looks very scientific. Fits the mind set of the day. I think it is awesome!

Those are awesome! That Gas-O-Meter is really something. Yep, 6 deg adv is for me. I get a kick out of how one could deck out their car, with gadgets and gauges, resembling the cockpit of a steam locomotive or Flash Gordon. The gadgetry (Dash Trash as Curbfeeler calls it.) was creative to say the least. Nice gauges you got there.

I just can't thank everyone enough!

 

This is an extremely important point that I'm glad he brought up. If you have that little ridge worn into your rocker arm from the valve stem rubbing against it, it is basically a hole or depression. When you run your feeler gauge under it, the gauge will give you the gap from the unworn rocker arm face to the valve stem. It won't tell you how wide the gap is inside the depression and you are probably going to be setting your valves at a much larger gap because of it.

 

Yes excellent observation. From what I have learned, better to have a slightly larger gap than a smaller gap. Certainly the difference must be very small. (I hope.) I tried to see it or feel it with my fingernail, and I couldn't. I'm not sure I can detect a .001"-.002" without removing the rocker and measuring with gauges?

The trouble, I believe, is this wear will inhibit the gap from being consistent across the board? Should all intakes or exhaust be set exactly the same as the others? I was thinking yes and tried to do that. I will admit, One or two of them set tighter would be better. Obviously, I have wear somewhere.

I suppose, in a time when engines needed a rebuild every 50-60K miles (from what I'm told), the shop would simply set the gap. If it didn't do the trick, you would be expected to have the top-end done. Perhaps places to have that done along with bearing Babbitt-ers were around every corner, and job completed in an afternoon? I can't afford a rebuild right now.

What's the interim solution? Grind the rockers? Replace them? I'm thinking, just go with what I got?

Thanks!

 

I would pull the rocker arms no matter what and inspect them. I do this for any stove bolt engine. The rocker arms shafts have a tendency to clog up with sludge and then the rockers arms starve for oil. The first thing I do before cranking one of these is take them a part, check for wear and clean the hollow rocker arm shafts to insure proper oiling. The ends of the rocker arms can be reground to get them smooth again. If you have a little wear in the rocker arm end, you will never be able to get an accurate setting on your valves.

 

OK, I’m convinced. I’ll definitely go through the drill. But not sure if I want to open a new can of worms just yet. (I’m in the middle of rebuilding the Rochester Carb that was originally on there, and will do it after that.) When I do, I will pull the rocker arms and inspect them. Clean and have reground as needed. When reassembling I will check torques on all manifold, head bolt, rocker shafts, as suggested. And of course, do the whole diagnostic adjustment thing again. I can see this taking many hours.

Anything else?

Questions:

1. I expect to put the exact same ones in back their original position? For instance #1 exhaust will be put back as #1 exhaust exclusively?
2. What do I look for as far as wear on the rocker shaft? Will it be visible? Do I need to check for out of round? Will it need to be gauged?
3. What if the wear is on the end of the valve stem? Will it require a top-end job? What if the wear is on the cam? Complete rebuild?
4. Is solid-lifter wear visible to the eye?

Thanks!

 

This '54 235 is an (extra) motor from my restoration project, I don’t want to spend a ton of money. (How many times have I said that...geeesh!)

Is your engine a 1954 235 truck motor?
From your pics it looks like the rocker/valve cover is earlier.

 

Block: 0143269T54X GM14 CON1 Head: 3835913 GM 21 CON12

I’m not exactly 100% sure if it truck or not?

The number thing is still a bit confusing to me. Perhaps someone could help me out. Especially the 3835911 GM 14 which is also cast on the block. The previous owner tried to say it was a corvette engine? I do know if it was a ’54 Blue-Flame there would be a YG somewhere. Not to mention, the valve-cover bolts down totally different to the head, and the head would have 3836241 on it somewhere. And it don’t.

3835911 GM 14 according to Stovebolt is for a corvette? Either I’m reading it wrong or a mistake. As far as I know, 1954 Corvette was sold only with a 150 HP Blue-Flame that year, and no 115 HP sub-option?

http://1954advance-design.com/Stovebolt-engine/casting-numbers.html

Other than that the previous owner seemed to know nothing about it. The numbers come up as a ’54 235. w/o power-glide as it has solid lifters. (According to Wikipedia) If it was for a truck, it would have hydraulic lifters for that year. However StoveBolt say’s T54 with X after is truck? Weird?

http://en.wikipedia.org/wiki/Chevrolet_Straight-6_engine

http://1954advance-design.com/Stovebolt-engine/casting-numbers.html

Truck: T54 OR F54 FOLLOWED BY: L, LA, M, MA, MB, N, P, Q, R, S, T, TA, U, UA, UB, X, XZ, XB, Y, YE, YG, Z, ZC, ZE, ZH Pass??

StoveBolt also says:?

Block: 3701481, 3702436, 3835911 Powerglide, Pass: 5845363 (PG?), 3835911 (Corvette), (and, maybe 3701488 - Corvette)

----------------------------------
Block 0143269T54X:

http://chevy.oldcarmanualproject.com/models/engine.htm#54eng

Unit No.: = 0143269 T:= Tonawanda, New York 54:= Year 1954
Type Designation Z:= 235Ci 115HP Regular Engine. (Type Designation X? Truck?)
Head 3835913 GM21:

http://1954advance-design.com/Stovebolt-engine/casting-numbers.html

Head: 3835913, 3836241 (Corvette)

BTW: For anyone interested the Rochester is rebuilt and working fine on the 235. (I think)

Thanks!

 

.
Yikes! If it is a Power-Glide, I may have installed the wrong push-rods!

Does your oil pan insides have the "troughs and nozzles"?

The oil pan does not have troughs/nozzles and is a full-pressure-system with solid-lifters. The head does have the alternate valve-cover-hold-downs tapped into it. Also, I think it has aluminum pistons and connecting rods. (See photos) I wonder if 130PSI cold-cranking compression is an indication of high-compression 7.5 :1?

I’m convinced it is a fist-series engine due to the 911 code, and concur it is a truck motor. Obviously, Wikipedia is not the best place for facts! I certainly appreciate your input, and the fantastic 1953 high-compression sales ad!

I will say, the 235 motor had some real umph… compared to the 216ci I replaced it with. The 235 had some noticeable low-RPM torque. Most steep-grades did not require any additional pedal. And, believe it or not, it got essentially the same MPGs as the 216.

If you wonder about it being 1953-54 vette', I would suggest you investigate it with the Corvette collectors.

Is a first-series 115HP Blue-Flame, or a Corvette engine, or a 108 HP Thrift-Master more desirable? Perhaps it is just a Frankenstein? A lot can happen in 58 years.

I say, with only a bit of humor, you have inspired me to seriously find out, as I may have made a terrible error?


Block: 0143269T54X GM14 CON1 (3835911 cast) Head: 3835913 GM 21 CON12