SB rockers hitting springs and retainers

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kevinh

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I just did a teardown of a [apparently] good running engine to check condition, clearances and to replace all the gaskets and seals due the to fact that their age was causing numerous oil leaks. I was surprised (because I put 5000 miles on the engine) to find evidence that the stock stamped rockets were hitting the spring and or retainers. I attached a picture. It looks like the damaged area could have been caused by a grinder, but the rounding of one intake cam lope and heavy lifter base wear suggests the spring/retainer and rockers were making improper contact and binding. To give a little more background the rockers shaft was shimmed previous to me owning the car.

I need some advice and have several questions. I will summarize here that I am looking at the possible replacement of the stock retainers and rocker shaft and of course the cam and lifters. I am willing to spend money, but am on a budget.

1) I have read that this was a common problem is small blocks. True or false?
2) I noticed the "step" inside the retainer allows the spring to be pushed laterally. I would estimate the top of the spring can be pushed laterally about .125" when pushed to the furthest extreme away from the rocker shaft to the opposite extreme when pushed toward the rocker shaft. There in no play in the valve guide and the measurement of the inside retainer step revealed that all this slot is by design. Unless the is a reason, which I happen to be ignorant of, that level of slop seems unnecessary. If there is an aftermarket retainer with a larger diameter step it could retain the spring as much as .60" more away from the rockers which may be enough to stop the contact. Does any one know if this slop is necessary or has anyone used a aftermarket retainer to take up all this slop?
3) I am looking at Speedmaster's Stainless Rockers, part number PCE261.1181 because rocker shaft spacers were shaped like narrow washers and the small contact area probably allowed the rocker shaft to shift toward the springs over time. I am looking to get a new rocker assembly that will allow me to dump the spacers. Anyone used this item before?

If you've read to this point, thank you for your patience. Any advice is greatly appreciated.
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PCE261.1181#sthash.1igeUZw1.dpuf
PCE261.1181#sthash.1igeUZw1.dpuf
PCE261.1181#sthash.1igeUZw1.dpuf
 
The problem is more than likely not going to be solved by new rockers... Shaft rocker systems with the as-cast rocker stands have only two variables when it comes to valvetrain geometry: the valve job, and the rocker manufacturing. I agree that the clearancing was done purposefully by a hand grinder. But the inclusion of shims means they were compensating for something. Probably sunken valve and or seats from a crappy valve job. That's where teh stem heights are set - during the valve job. If it was me, I would pull the heads and have them checked by a competant performance shop first. Following that inspection (and an anticipated valve job, probably with either new guides, seats, and/or valves) then replace the rockers with the stamped steelies (new ones - not the ones weakend by grinding through. The only problem the previous owner (and you) had with those rockers was the vlave job on the heads they got bolted to.
 
Sound like the retainers are the wrong ones for the springs. They should fit with little or no movement against the bottom. I solved my clearance issues by using beehive springs with the necessary spring rates/pressures for the cam/application. That's a common problem.
 
"3) I am looking at Speedmaster's Stainless Rockers, part number PCE261.1181 because rocker shaft spacers were shaped like narrow washers and the small contact area probably allowed the rocker shaft to shift toward the springs over time. I am looking to get a new rocker assembly that will allow me to dump the spacers. Anyone used this item before? "

Stay away from cheap rockers, or anything speed master IMO. I would run 273 adjustable rockers before them.
 
Lay a straight edge across the top od the valve tips to see if they are all the same length. I had a set of 440 heads done at a local shop years ago, they didn't cut the valves to the correct length after grinding them. When it warmed up there was a pop in the intake, I found that some of the valves being held open because the installed height was wrong. There is a spec for valve length measuring from the spring seat to the valve tip.
 
I probably put the wrong springs on when I did my 273 and had the same problem. The spring od was too big and hit the rockers. I had to grind away a little to make them work. The iron adjustables for the 273 can be clearanced though. The stamped non adjustables should not. tmm
 

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You have geometry issues.

Call Mike at B3 racing engines and tell him what is going on. Switching rockers won't fix a geometry problem. May make it worse.


Google B3 and talk to Mike.

Easy fix really.
 
Retainers and/or springs are wrong for a stock rocker arm...if you can move the retainer back n forth....it is the wrong retainer for the spring...

can you measure the diameter of the retainer?

most/some aftermarket rockers are clearance for bigger retainers and springs...
 
Gtsdude, I read a post on this site saying the 273 rockers quickly and constantly fall out of adjustment. Any truth to that? That is why I was thinking about the Speedmaster part. I am not a person who thinks inexpensive automatically means bad. I'd be interested in hearing stories about defects, design flaws and parts failures in Speedmaster parts. It it helpful to know why to avoid a manufacturer. Have you had any bad Speedmaster experiences or heard about any?
 
273 rockers need adjusters with jam nuts.....
 
The shimming would have been done to get the rocker to wipe more evenly across the valve stem, not to necessarily address any contact with the springs..... well, that is if it was done with any knowledge on the matter! We recently put stock stamped rockers, 273 adjustables, and PRW's on a new Edelbrock head. Both the stamped and the 273 adjustables had some interference to the springs/retainers; it was not on all rockers in either case, just some of them. So I would expect neither to fix you problem with these springs.

As said, the retainers seem to not match the springs.

Answering the question on the valve lift that you have is important. After checking the 3 rocker sets as above, I would be looking at aftermarket roller tipped rockers if going to .500" lift or more; the stock types looked to be at their limit of contact on one edge of the valve stem or the other at that level of lift; remember, the stock systems were designed for lifts in no more than the low-mid .400" range. (Again these valve stem contact checks were on Edelbrock heads; I have not repeated the checks on stock heads.)

I read several very negative experiences about the Speedmasters used in multiple engine brands and decided to stay away from them. I am OK with cheap but adequate, but these do not seem to qualify for that category.

If you grind the 273 rockers, I would do so with the axis of the grinding stone parallel with the rocker shaft hole. That would put the grind lines in an orientation to be less likely to cause any cracks to start; the grind lines will be parallel to the strain in the material.
 
someone could of put longer valves in a .100 longer is common replacement
 
yellow rose said:
You have geometry issues.

Call Mike at B3 racing engines and tell him what is going on. Switching rockers won't fix a geometry problem. May make it worse.


Google B3 and talk to Mike.

Easy fix really.
Click to expand...

^X2 ^this is your answer , if you really want to understand rocker geometry go to his site and read his three part series on it then call and ask him your questions , I will be getting a kit from him as soon as I start my refresh , it's at the top of the parts list .
 
Bought a set of the speedmaster stainless steel rockers at very good reduced price....

Here they are on a 360 with stock eddy heads, 1.6 rocker ratio. hughes 230/237 cam, lift is 540/558 with eddy stock valve springs..

Duster has been up and down the drag strip shifting at 6200 rpm ...been using them for the last 6 races..with about 30 passes on them....
 

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Common problem on SB engines. Last several SB engines I've worked on we just used beehive springs. The beehives are better anyway so it is a double win.
 

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Original Stock 340 rockers came clearanced from the factory, so they must have been close. Deviation from stock must always be checked carefully. 273 mechanical rockers almost never need readjustment, over 100K miles, if up to spec. with up to .470 lift. Higher lift than that, I have little experience. I'm looking at beehive springs and retainers for my next build also.
 
AndyF said:
Common problem on SB engines. Last several SB engines I've worked on we just used beehive springs. The beehives are better anyway so it is a double win.
Click to expand...


To make the broad statement that beehives are better any is just not true.

Started with beehives that comp said were the cats behind and had nothing but issues.

Called PAC and they said, who are the idiots that sold you beehives?

Ditched the beehives, same rate, less pressure and still going.
 
So 70 AARCuda, are you happy with the Speedmaster rockers?

Thanks for all the help. To answer some questions, I don't know what my lift is off hand because I did not build the engine, but the teardown revealed it was balanced at some point and there was a lot of work put into this engine, so I suspect the cam is not stock. I was going to put a dial indicator on the cam itself to check lift (head are off), but had considered that the evidence of binding may have caused lobe wear on other lobes that are not as obvious as it is on the #1 intake lifter/lobe, still that might be the best way to get a lift figure, unless there are some casting markings on the cam itself that will help me identify it.

As for the spring and retainer dimensions I have a set of stock x-head buried in the garage I bought about 20 years ago. I will dig them out and check the spring/retainer dimensions and let you know what I find out. I too assumed the spring were replaced with wider-than-stock spring, but they measure in at stock diameter.

I have no problem using 273 gear if I can find it. What is a good price?
 
I used stock 273 adjustable rocker arms on a cam with .580 lift. These rocker arms had jam nuts, not those locking nuts which are a big pain. I checked by valve clearance frequently, and seldom, if ever, did they need re-adjusting. This was street driven (weekends) bracket racer.
 

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AndyF said:
Common problem on SB engines. Last several SB engines I've worked on we just used beehive springs. The beehives are better anyway so it is a double win.
Click to expand...


Oh, behive.... I mean behave....

[ame]https://youtu.be/F1lJFlB-89Q[/ame]
 
sold my last set of 273 rockers for $200.
 
Well I compared a stock 340 spring with one from the engine I am working on. Definitely not stock: Spring dimensions (approx) of the unknown springs are:
Surprisingly, the unknown spring has a slightly smaller diameter of 1.406 (vs stock)
Free length 2.375 (vs appromimately 2.0 stock)
Wire diameter 1.8 (vs 2.06 stock).

I wish I knew what brand and model springs these are so I could look up the bind height.

Retainers are stock and even in the stock spring there is a lot of lateral slop between the inside retainer step and inside diameter of spring. Valves are stock and correct length.

I will pull the cam in the next few days.
 
Someone said that the stock 340 rockers were factory-clearanced. Did you catch that? Post#18
They may or may not help you. It depends on your geometry.Order an adjustable pushrod, and have atR.
 
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