Y Block Valve Springs, Rocker Arms &c
 

Given that I'm not too sure about the quality of the rebuild I had done some years and miles ago I've decided to replace the valve springs as they may well have a lot of miles. The rocker arm assembly has to come off for this anyway, and may well find that the rocker arm shafts are buggered. Is it usually the case that the rocker arms themselves are also heavily worn? I can bet the rocker arm tips need resurfacing, but if everything is otherwise OK I'd like to reuse them. Can get kind of spendy real quick, but. Seems to me can probably get away with just rocker shaft replacement, though I see there are rocker arm rebuilding services that will sleeve them. I'm afraid once I get into this much it will be obvious right away whether standard items or assemblies were skipped.

Re: Y Block Valve Springs, Rocker Arms &c
 

I think it is Smith Brothers that will rebuild your assemblies. It is primo work, which is what you would want right? Get a set of new pushrods from them at the same time.If you don't want to spend the money, then why do it at all?

Re: Y Block Valve Springs, Rocker Arms &c
 

The only place I could find that rebuilds them is out in California @rockerarms.com

It may be cheaper to find new rocker arms. I've been reasonably good about oil changes, there's no sludge. There's about 30k miles on it since I got the engine back from this guy. Maybe the rocker shafts, rocker arms are OK, no way to tell till I get them apart. But that's not the way to bet. I agree do it once, do it right.

The problem is, I tend to have a "Might as well replace _____ and better do _____, so long as I'm in there." I could see this snowballing into all kinds of things. Not quite a whole rebuild... lol But maybe a new intake.. camshaft... You see where this is going right?

Re: Y Block Valve Springs, Rocker Arms &c
 

If you have that attitude, it's not all bad. Take a PROPER compression test first, with valves adjusted as close as possible. Maybe you can just replace rocker arm assys, and pushrods. Valve springs and seals also. Maybe that should do it. Also, whats wrong with being a little overboard with your pet?

Re: Y Block Valve Springs, Rocker Arms &c
 

That's the plan, won't know till I look at stuff closer. Can the valve springs be replaced without removing the rocker arm assembly? Then I wouldn't look at all that other stuff, ha ha. It sort of looks like the rocker arms would slide far enough sideways, maybe not.

Re: Y Block Valve Springs, Rocker Arms &c
 

The valve springs can be tested as to the amount of force it takes to depress them. The amount of force should very closely match on all the springs. The way I done it before was to measure the amount of force in each and compare. the spring that has the highest compression force is used as a basis for all the other springs. You can get lots of different thickness washer shims to place under the springs to increase their compression force. Keep the proper thickness washers with the spring being tested to match the spring that has the highest force. Test all springs and add washers as needed to match the highest tested spring.
With rocker arms, you can measure the slop and keep all those that measure within the tolerances given in the specifications at the back of the shop manual. The ones that are greater than the allowable tolerances can have the brass bushing driven out and new bushing pressed in.
I recommend numbering with a paper tag and bread wrapper wire each spring and rocker arm as to it's original position on the rocker shaft so they can be put back in the same place they were removed from, that way, there should be little adjustment required of the rocker arm adjusting screws after assembly.
There's not a whole lot you can do with a worn rocker shaft except to replace it with a new one, but being a tightwad as I was, I measured the riding surfaces with a micrometer to see if there was substantial wear in an attempt to re-use them so I wouldn't need to buy new ones.

Re: Y Block Valve Springs, Rocker Arms &c
 

Right, but my thinking was better to just replace the springs. Stock springs aren't going to have lots of pressure and should last a while, and I don't run it at high revs much. But they probably have a LOT of miles on them. For $36 a set, what the heck. But it's easy to find lots more bad or out of spec parts once everything gets disassembled. Unfortunately we don't have the machine shops around here anymore. So even simple things like rocker faces resurfaced would be a pita. I'll have to dig in the manual and see what the specs are for wear on the rockers and shaft. Not much, I'll bet. New rocker shafts alone would probably go a long way. Rocker arms range in price from $2.89 (they only had 4) to almost $50 per. Then want to ensure push rods are straight.. Maybe some oiling mods etc.

Re: Y Block Valve Springs, Rocker Arms &c
 

OK, pulled one rocker arm assembly so far and found deep scoring and some galling. So rounded up some NOS rocker arms and Melling rocker shafts. It's just great to go through all this stuff and re-do what I thought I paid for 20 years ago. Anyway.

The spring replacement is more complicated than I thought, since the heads are on. It's not a race engine but the installed or assembled spring height is important. If the heads have been reworked - then different shims will (should) be found on every valve correct? And if so, then there is nothing more to be done? Install new spring, move on. This is complicated by the fact that only one cylinder at a time can be worked, i.e. using the "rope trick".

Re: Y Block Valve Springs, Rocker Arms &c
 

Nope. The needed thickness of shims under each valve spring is a combination of at least 2 different things...
1. How deep or shallow the valve sits in the combustion chamber.
2. The actual pressure needed to compress each individual spring.

The existing valve springs may or may not be within specs.
Newer springs should be consistent but don't assume they're all exactly the same.

If you're looking to get all the assembled spring pressures the same on used heads with used valves then the shims under the springs will be slightly different, along with the assembled spring height.

I have no idea what the oem valve to valve seat pressure spec is, but on a stock engine 'more' is usually not better. It creates additional valvetrain wear.
.
Your initial suspicions about the quality of work he did may be confirmed.
Take some time and decide what to do before you go much farther.

.

Re: Y Block Valve Springs, Rocker Arms &c
 

Well I don't want to get down to the granular level here. I'll "assume" that the new, stock type U.S.A. made in Aug. '17 valve springs are "close enough" provided I check or adjust the assembled height for each valve. Since they are stock it shouldn't stress the valve train any, although maybe more than it has been in a long while. It looks to me like the "engine rebuilder" didn't do a damn thing near as I can tell. Just eyeballing right now, I don't see any evidence of shims on any of the valves, they'd be visible wouldn't they?

One site recommends compressing the new springs a few times with a valve spring compressor before installation and measurement. Will a vise work for this purpose? I don't see why not, but ya never know.

Plan on replacing the pushrods so didn't pay much attention when removing them. Found these two on the passenger side. I've read that the wrong intake bolts can cause this, but looking down the holes I can't see any obstruction. Wondering if this was remedied at some time in the past, but the "rebuilder" didn't bother replacing them.

Re: Y Block Valve Springs, Rocker Arms &c
 

Those new springs should be fine. ;)

Any valve spring shims should be between the base of the spring and the head.

Yes, the 2 smaller bolt holes at each end of the heads (4 on each head) are open into the pushrod passages. A bolt that's too long will definitely do that.

http://www.ford-y-block.com/assemblyerrors.htm
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Re: Y Block Valve Springs, Rocker Arms &c
 

If incorrect intake bolts are installed would this would be visible looking down the pushrod hole? I expected to see bolt threads somewhere down there innards.

What I mean is, the shims should be visible undeneath the springs, on the surface of the head. I'm not really setup for this, I don't have a valve spring micrometer. Cool item, but. My tape measure won't cut it here apparently.

Re: Y Block Valve Springs, Rocker Arms &c
 

Yes, if bolts are to long you should see them protruding in the pushrod hole.

On setting your spring pressures here is a suggestion. Have you got a drill press? Have you got a machinist steel ruler (6" version)?
I checked on John Mummerts web site and stock seat pressure is 65# so if you have a drill press , machinist rule, and a bathroom scale you would be in business.
I use a drill press, Vernier calipers, and a spring pressure gauge from Summit for less than 100.00 to do my race heads with no issues. The are 375# on the seat.

Dave

Re: Y Block Valve Springs, Rocker Arms &c
 

Well the problem there is the heads are installed? Of course when heads are removed, and access is a lot easier the trick setup is to measure the opening and closing spring pressure allowing for some variance in the actual assembled height, within the limits. Even springs from the same lot will vary somewhat so this is a cut and try method. I figure these springs are original and may have 100k miles plus. Replacement with fresh springs should make for a better running motor. If I don't screw up anyway.

I'd be happy with getting them all at the low end of the assembled height, this would be the maximum (stock) spring pressure, but since everything is stock, spring binding could never really be an issue? With the heads installed, keep in mind I'm limited to only doing one cylinder at a time. Assembled height spec is 1-3/4" to 1-25/32"

Had no idea valve springs were this complicated! I just figured they would be pretty tired by now and I should swap 'em out. They are an overlooked part of engine tuning, performance, smoothness at idle and fuel economy, ease of cold weather starting &c.

Re: Y Block Valve Springs, Rocker Arms &c
 

Couple more things I was thinking of doing

1. Since plugs all have to be out, and rocker assembly is removed, maybe spin the motor over for 30 seconds or so and ensure adequate oil flow from the gallery at each head. Not sure how much is considered good. Maybe shoot some solvent and shop air down the holes?

2. The instructions for this task recommend assembly grease on the pushrod cups and ball end, rocker tips/valve stem. Something like Lubriplate 105 is the plan. Maybe grease the rocker arm bores themselves and the shaft? And lots of oil, too.

Re: Y Block Valve Springs, Rocker Arms &c
 

With unclear history of the rest of the assembled engine, trying to overthink the valve spring setup may be more trouble than it's worth.
Did you do a compression test on the engine before you took the rocker arms off?

Put the new valve springs on, fix the few rocker arm parts that are obviously bad, put it back together and drive it.
If you really are worried about how the engine was built the other choice is that 'snowball' thing you mentioned earlier.
(been there, done that)

Re: Y Block Valve Springs, Rocker Arms &c
 

It's been a little while. They all ran 140 to 150 cold engine. Spec is 170. Engine vacuum is good too - 20" but the ignition timing has to be goosed pretty good to get there. I think stock ignition timing is 3° or something like that. Y's like a lot of advance, in my opinion.

Not trying to overthink anything, just make sure they are in spec?

Yes only replacing what's needed, that was the plan, but I knew all I would find is junk parts. Both rocker shafts are scrap. So are the rocker arms. It's all on order, just waiting for them to arrive.

So it's safe to say heads from the factory never ran any shims, strictly a rebuild thing? As in the the valve faces get refinished, hardened seats, whatever?

Re: Y Block Valve Springs, Rocker Arms &c
 

That will blow any crud in the oil passage back down to the center cam bearing.

Shims were often to compensate for grinding the valves and valve seats at valve-job time.

"140 to 150 cold." Again, I'll vote for putting the valvetrain back together and driving it.
.

Re: Y Block Valve Springs, Rocker Arms &c
 

By all means, be sure that both sides are receiving oil. The lack thereof, is a very common cause of valvetrain wear on a Y block.

Re: Y Block Valve Springs, Rocker Arms &c
 

I might be able to figure something out, I don't want to make a career out of these valve springs though. So the idea is something like this, install spring on valve. Measure valve spring height. Or measure some other way with proper tools.

Then, determine #s pressure when a spring is compressed to exactly that same height. Maybe mix and match springs as required to get the right pressure.

Didn't realize the valve springs were that precise about height or affect the numbers by being out of spec. The difference between "too high" and "too low" in this example I'm working on is 1/32" of an inch. Now I know why they sell those barrel micrometers.