Technical Rocker arm refurbishing problem.

I'm finally seeing the end of my engine build after 3 years... It took 2 years to source some of the parts. The joy of building an oddball 4 banger.
Now my problem is the rocker arm part. I was unable to locate new ones and I have at least 3 with too much play in them, and 3 that are borderline. They are shaft mounted, no bushing, the shaft stands are integral part of the head, so I didn't want to overbore the rocker arms and especially the stands.
I'm worried that if I was to bore the rocker arms to insert a bushing that it would weaken them too much.
How could I fix the bore on my rocker arms?
I checked different rocker arms also and couldn't get anything that could match up their geometry and oiling other than the early 390 Cadillac that could get bushed to match my shaft, but I need them to be adjustable and Studebaker are too far off.

 

Surely you not the only one to ever build or refubish what ever 4B it is? tried the clubs that deal with the car it came from? or the rocker arm specialty place in CA that rebuilds them. What about doing what everyone does with cranks, as in go oversized in the shaft stand bushings and also the rockers and have the shaft machined down to that size and then re hardchromed?

There's always a way around a problem, just sometime we don't the the $$ it might cost.

good luck!

 

consult with Rocker Arms Unlimited in CA. They have a web. They can give you some ideas or solutions

 

Everything can be fixed with a big hammer.

 

We rebuild these type rocker arms by plating the shaft end. Buildup of the plating material untill it can be honed to the proper fit to the shaft. GM did it on production connecting rods for all the original V-8 engines.

 

What is the ID dia. of the rocker arm?

 

If you took three years to rebuild the engine then a little more work on the rockers isn't crazy, is it?
The shaft does not (or should not) move in the head stands so unless there is some terrible problem there then move on to the shaft/rocker fitment. Although the rockers may seem a bit thin they will likely withstand an 0.010" oversize hole that you will fill with a pressed fitted bronze liner. The shaft would then be hard chromed and centerless ground to the original OD and the liners honed to match. The hard chrome finish and a bronze liner allow for some pretty snug fits. BTW, this is, and has to be precision work.
Post some photos if you can.

.

 

The shaft is 20mm, my machine guy don't want to put bushings any smaller than 0.1" thick which surely will weaken the arms, if 0.01" can hold up, I'm all for it.
The shaft is already hardchromed and machined.
Unfortunatly people on those cars tend to do half ass job, some parts are impossible to find (pushrods, oil pump, rocker arms, camshaft, camshaft bearings or lifters for example) I found some of my NOS parts in old machine shops who were in business 40 years ago.
I spent in that engine as much as a complete driver and people don't understand why, including the club: simply because I like to drive my cars any distance without worrying about getting stranded.
@ BOBCRMAN, you're saying that it's possible to hard chrome just the inner shaft part of the rocker arm then hone it to size? I thought of that but was not sure if possible.
In that case what would be better? Hardchrome or .01 or so bushing?

 

I agree completely with 73RR above on this.
And as a 49+ yr. as a machinist with the last 24 in aircraft parts rebuild to OEM&FAA specs, I think I can comment and perhaps contribute to this.
You can't just turn those rockers on their side and run a reamer thru them, as the reamer will follow the eccentricity created by the wear on the thrust side of the rocker bore, and although round, it won't have the proper geometry because you will be relocating the hole.
Best to supply the machinist the least worn of the rockers, one of each type if they aren't all the same, so the machinist can build a fixture to properly locate the arm so that it can be bored.
There's going to be more time spent fixturing than machining the arms if you have to get the fixtures built. Unless the 4B is a really obscure one, most likely there's a guy somewhere, and locatable by the internet, already tooled up to do this at a cost lowered by the fact he's already amortized the cost of building the fixtures some time in the past and had other paying jobs covering that aspect.
Trust me, the number of machinists knowledgeable enough to create and build the fixture, and have access to the needed equipment, the time and inclination to do this from scratch accurately are becoming quite scarce and expensive. Find somebody already tooled up and pay their price.

 

http://rockerarms.com/

They did mine...Awesome!

 

Now that's a great link, I put it in my favorites list! Exactly the type of place to which I was referring. and it appears mail order is OK.

 

I would have to see the rockers, but in most cases one could be bushed without destroying it. Sometimes it is a matter of plugging it with brass and then boring it to fit, that way you can take a minimum out of the rocker itself and still come up with your .010 bushing thickness.

Like I said I would have to see the rocker to give a reasonable answer.

Another option is sleeving (sp) the shaft, again without seeing the current application it is an impossible question to answer.

 

1: Bush the rockers undersize. Then make a smaller diameter shaft.
Then make some sleeves to go over the shaft where it clamps in the pedestals

or
2: Offset bush the rockers so the tension side is uncompromised. Then try to find shorter pushrods to get the geometry better

 

Whittle some out of a chunk and heat treat it. They made millions of rockers with less.

 

^^^^^^^^^
As I said earlier, machinists who can/ are properly equipped/ are willing/ are affordable are also scarce.

 

Ahhhh then its a Perfect match for oddball rockers on an oddball engine that has more $ in the engine than an entire driver - right?

 

X 3 on rockerarms.com

 

Yeah I'm starting to regret not to have swapped the engine for something else and more powerful like a Chevy 6, hell I even have on stands a 331 hemi, a 390 Cad and a flathead, they cost about the same to rebuild as my 2600cc crappy engine.
I'll take a picture of the head and rockers, unfortunately this is France, we're not car people and most people who restore mass produced cars calculate the cost of the restoration as such : I paid my car 2g's, it's worth 5, can you restore it for 3? I deal with this shit almost every day... For this Renault in particular people usually throw away the worn out engine and get a "new one"
I know of rockerarm.com but wish to find a solution doable here (cost of shipping, remanufacturing then shipping back with import taxes).
On the pushrod side I got some Comp Cam I have to cut to length, because the head was shaved and this is one of the weakness on this engine, when it rev's up they chatter, I got some custom Manley valves done also and installed Isky flathead valve springs to avoid valve chatter. I searched and I've been into those cars for 23 years, I know the president of the club for 20 and no one ever souped up one of those engine or bother with new parts, they try to find good used parts, most people don't drive their old car, for a lot them as long as the engine makes noise that means it's running, some of them advised me to do like them on the rocker shaft : emery cloth and nothing to the arms...
I like to drive old cars and hard (worst I did was 120 in a 56 vette on bias tires ) my suspended driver license is a testimony to that.

Anyway, there are some real good infos, inserting a bronze bar, I would never have thought of that.

 

I did not say hard chrome plate! Something like copper or softer material is what is used. I use a plater that does a lot of nickle and a material called co-plate. Then I light ream and hone to shaft size. Actually a babbit place could do it, if there are any left. My guy died. Been sending those jobs out to Effingham regrinders.

 

OP, I can do them for you but would need a pic to be sure...Would you want all eight done? $200.00 us as I am in CT, usa..

 

Here's the head and rocker.
I'm planning on following 73RR and porknbeaner advice, having all rockers reamed at the same size then insert bronze, I'm thinking cusn10pb10 or cusn7pb15 depending on what I can find, then get it bored to the correct size.
Oldman this kind of precision work I always give it to my machine guy, even if I have access to the machines this is beyond my capabilities, he already machined for me oversized bearings for the torque converter for the same car (another part that's impossible to get on this car).



Bob, I misunderstood you when you said plating, since we were talking about hard chrome, I thought it was odd to have 2 hard surface in contact, but what do I know I'm a bodyman this is why I ask.
Seb thanks for the offer but I know I will get slammed by the Custom when the rockers will be shipped back, I even asked my in laws not to send any Christmas gift to my daughter for that very reason, they need money and nothing goes through for free anymore, not even a present...

 

Looks to me like you have plenty of wall thickness on the rockers...you could easily go more than 0.010"wall on the bushing.

.

 

Yes plenty of material. Look into automotive connecting rod bushings.. Federal-Mogul, TRW, Mahle (Clevite), King etc. Paper master catalogs at "real" auto parts stores. OD and ID specs.

 

Gary at rocker arm specialties is a sharp cat. I had a similar problem with a set of nailhead rockers made by gotha. I sent the shafts out to gary for hard chrome and had them leave them .0150 over size. Then I took the rockers and honed them to size and allowed .0020 oil clearance.the stands are even easier to open up.
I do my own machine work, so find someone capable locally that has a large selection of honing mandrels. 16 forged rocker arms took less than a hours labor.
The adjusters as shown are a little far out to be effective,a longer pushrod may be in order.
Galling on the pushrods cup is common,to solve that I cut a 360 groove in the center where the pressure feed is and drilled a .0180 hole to squirt on the cup.
Honing picks up the center of a worn hole and will not change the ratio,as long as the ratio is right and the same from rocker to rocker to begin with. If you check your ratios at the valve you may be surprised .
Gary turned me on to smith bros. for push rods and I have to say both places are class acts and very helpful.
Good luck,great project I must say.

 

Update : I finally found bushings I could use. I fabricated a fixture to set my rocker arms in the 3 jaw lathe we have at work and machined away.
Here's the end result:
Hosted on Fotki
They are press fitted, I still need to hone them and regrind the tip.
This is a tremendous amount of work just for those small things. I hope now to get that thing on the road before year's end.
Between the cost of the few available parts and unobtainable parts, I will never do again an engine like that... All this for maybe 100hp

 

...the small victories do add up. Good luck on the remainder of the work.

.

 

I suggested rockerarms.com earlier...but nothing beats doing it yourself!!
Great Work Man!!

 

Thanks for the encouragements.
I thought of using rockerarms.com but with international shipping both ways it was getting really expensive.
This is actually my first engine rebuild and learn as I go, including machining.

 

There's a specific radius on that tip. Suggest making a fixture that has a short shaft of proper OD to fit finished ID of rocker arm, mount short shaft to a flat piece square with short shaft so that rocker will be held so that when you reface tip it will be square to shaft if tip is ground on a fixed disc grinder with a table square to the disc..
Make a template duplicating the constant radius of an unworn section of a tip, and with careful work you should be able to hand finish the tips.
Ad.mittedly a grinding fixture on a tool grinder would be better, but requires a lot of skill to build and set up. This is where the folks that do a lot of these can amotize the cost of a fixture that would be time costly for a single set.

 

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I'd paint the rocker tip or valve stem with permanent marker and install soft springs on the valves so I could move the rocker thru it's arc and confirm the tip is making 100% contact stem tip. There were some rebuilt BMW rocker arms a few decades back that were a mile off.