My 71 Duster work in progress

[RUSTY Cuda]

I'm glad I'm trying my best to follow some of this.
I do not have caps for my rocker shafts, there were none on the old either???
Am I in trouble again?

 

[RUSTY Cuda]

OK maybe not I just pulled down the old shafts (all 3) & the caps are pushed in so you wouldn't notice them, I just hope the ones in the car are the same!

 

[b-body-bob]

I've got a pretty good case of analysis paralysis going on right now trying to figure out what length pushrod to order.

First- need to be sure I have enough threads exposed to keep the pushrod off the rocker.
Second- need to be sure I have enough threads left to preload the lifters.
Third- need to get accurate with the cup depth so I don't chance running out of adjustment in either direction.

1 turn = 1/24 = .042
Preload = 3/4 turn = .042*.75= .032
Thread left = .042*.25= .010

So, if I turn the adjuster all the way out, then back in 1 turn, that should keep the pushrod off the rocker. But that's cutting it close so my ball depth can't be more than .010 off to the deep side or I'll run out of thread. I measured the cup at .1645. I found a FABO thread where a guy made drawings and his cup is .155 deep, so if he's right and we used the same cups, I've got .010 extra to take up with the adjuster and that runs me smack out of threads in the adjuster. So I think I need to go to all the way out then back in 1-1/2 turns, or I can keep screwing around trying to get the cup measured accurately and end up doing it anyway.

This is the FABO post. I think he worked off a factory pushrod just like I did.
Pushrod for hydraulic cam and 273 rocker arms

Going out to measure one more time at lunch.

 

[Dr.Jass]

It all comes down to clearance, Clarence. You can run the adjusters as high as you want, so long as the edge of the cup doesn't hit the rocker arm at maximum lift. That's the only concern. If you can accomplish it with the threads flush, by all means run the threads flush. A lot of what you see regarding this topic and exposed threads, etc. involves aftermarket adjusters (as does your link). There's no hard/fast rule here, only what works for your combination. The pushrods I used on my W2 didn't match any of the lengths I was finding that others used. Go figure.

 

[b-body-bob]

It all comes down to clearance, Clarence

Yep, I got that, and clearance is the unknown, until I have pushrods. Get it wrong and fire up another C note.

I also noted the other guy's adjusters had changed, but I was just using his measured pushrod dimensions.

Also, all the adjusters were pretty much identical to begin with, leading me to think the pushrods will clear at that point.

 

[b-body-bob]

I realized I was over thinking this pushrod deal yesterday. Then I thought about it some more. I think 7.08 is the right length. I could've measured things more accurately but it's not needed. At 1-1/2 turns back from all the way out, I've got room to move in both directions if needed.

I now have a dilemma related to the rockers and heads.



That is #1, Exhaust and Intake. The rocker for #1E doesn't have .024 clearance to the valve. The rocker for #1I has plenty of clearance above .035. When I swap the rockers, I still have the same situation. So the problem is related to the valve/spring, not the rocker. I've got other valves that are too close that look about like #1E does there.

It'll center up once it starts cycling, if it doesn't hit the rocker and pop the retainer first.

I thought of trying to squeeze the spring and get it to center up better but can't find my valve spring tool. Might need to weld one up now that I've got spare LA rocker parts. Any other hare-brained ideas? I'm not inclined to keep grinding.

I can't order pushrods until I get past this. I shouldn't have to buy different rockers, but won't be surprised if that's where this ends up.

 

[Dr.Jass]

The problem is not with the rockers themselves. Swapping them and getting the same results proves that they're consistent.

My first suggestion, based on similar but not identical issues, would be to check the rocker shafts for straightness. Roll 'em on the flattest surface you can find and see if they've any banana-like tendencies. I had two rocker shafts that were hooped, badly, and those were mega-duty Harland Sharp pieces. Swapping them for new shafts (because I had 'em) solved all my inconsistencies during the pushrod-measuring process.

You could also try tap-tap-tapping on the valve stem with a soft-faced hammer (or something to use as a bit of a cushion for the valve stem) to see if that helps. No need to go Big John here; you're not shooting for full lift. You just need to unseat the valve a bit and see if that helps the springs and retainers find center.

Assuming straight shafts, personally I'd just grind all the rockers to clear .035"+ on the problem springs. If the springs find center later, great. If not, also great--you've still got clearance. As long as you're not making horrific grind marks or leaving sharp corners along the edges of the areas you've ground, you'll be fine. It's the lowest-stress area of the rocker, and you're grinding just in the area of the spring, not all the way across. People clearance those rockers for 1.500" valve springs and don't have problems.

If that's not enough, the Mopar Performance/Crane W2 rockers are both die-cast aluminum and thinner in the valve spring area than your ductile-iron parts (I just checked). I've got some of those ground to clear 1.600" springs and none of 'em are broken, despite grinding I find rather primitive.

 

[b-body-bob]

The problem I seem to have is I keep grinding, but I don't seem to get any more clearance, clarence.

I can't afford to grind them to the point of breaking when I should've just given up. That one clears the other valves with room to spare.

Will check for a warped shaft and give the spring a whack to see if that helps.

 

[Dr.Jass]

Make sure you're torquing all five shaft bolts to spec when checking.

 

[b-body-bob]

I just noticed it looks like the spring seat isn't centered over the faced spot. I didn't think that could move around.

 

[Dr.Jass]

I just noticed it looks like the spring seat isn't centered over the faced spot. I didn't think that could move around.

Well, the valve guide can't move in relation to the spot-face for the valve, so that's something with which you have to live. The spring and, I assume the cup on which it sits, can only move so far based on where the valve tip is in relation to the spot-faced area.

In other words, don't tap sideways on anything. Damage is the only thing you'll accomplish, particularly on an alloy head. Anything you'd hit is ultimately connected to the valve tip, and it can't move without some kind of damage.

 

[b-body-bob]

don't tap sideways on anything

Roger that.

the valve guide can't move in relation to the spot-face for the valve

I was thinking maybe the spring's not released straight and cycling it a few times with a compressor might get it to land in its happy place.

I just checked and see that the spring cup being off is an optical delusion. The spring seems square up the sides, and the diameter checks out ~ 1.47, Edelbrock specs 1.46.

 

[b-body-bob]

The shafts are straight.

I still can't find my spring compressor, but I taped up a pair of channel locks and gave that one spring a little CW twist. Yeah, now it's fine. I think it's got to do with me having the springs on and off. Looking at other springs, some are like that, most aren't.

Is there an up side and a down side to a valve spring?

 

[Dr.Jass]

Is there an up side and a down side to a valve spring?

If there is, nobody ever told me about it.

 

[b-body-bob]

All I know is the spring should be squared up top to bottom so there is no part of it that sticks out more than any other part. It shouldn't matter which way the spring is turned because it is centered around the valve stem.

I turned #1E and now I have clearance, so I've got at least one spring that isn't squared up like it should be.

I've got .024 min clearance on all of them. Valve springs turn, they should center up as they're used too. Maybe.

The confusion/concern comes from worrying they can/will move so clearance decreases before it increases and mayhem ensues.

 

[Dr.Jass]

I turned #1E and now I have clearance, so I've got at least one spring that isn't squared up like it should be.

It might be now. Those little float-level squares that come with carburetor kits are good for checking that.

Valve springs turn, they should center up as they're used too. Maybe.

Valve springs generally rotate only if they have rotators installed. Those are the first things tossed in a performance build. I can't say I've ever seen them on an LA engine, but I've always tossed worthless heads (273, 318, anything with air-injection ports) without bothering to inspect how they were equipped.

Tapping on them as I suggested may well help them align themselves, as would running the engine (of course). The latter would not induce any rotation, though. The vibration will cause the spring's tension to force it into a straight, parallel-sided shape. If it fits the retainer as it should, it'll be perfectly parallel to the valve stem.

 

[b-body-bob]

After popping 1 and a half retainers out with a hammer I'm a little leery of tapping around at them again. But I did. It's easy to convince yourself they're moving when you're doing it, but nothing really changed.

I was thinking of compressing the spring less than enough to release the retainer, and trying to rotate it or otherwise straighten it out but I still can't find my valve spring compressor. It's a tool, why isn't in in a TOOL box? Gina has said I hide things from myself.

It might be now. Those little float-level squares that come with carburetor kits are good for checking that.

Good idea, will check that.

 

[Dr.Jass]

I was thinking of compressing the spring less than enough to release the retainer, and trying to rotate it or otherwise straighten it out but I still can't find my valve spring compressor. It's a tool, why isn't in in a TOOL box?

The van is box-shaped. Didst thou leavest it yon?

Gina has said I hide things from myself.

Been married awhile, haven't you?

 

[b-body-bob]

The van is box-shaped. Didst thou leavest it yon?

I wondered if anyone would ask me that. No it's not in there. Need to get back on that thing now that it's cooling off a little. Before I got a chance to fire it up I noticed the accelerator pump wasn't working like it should, then things snowballed on the other projects/tasks.

It's stuck in my head that it's in a specific area of my garage. I've basically moved everything there and still no joy. It will probably turn up on the opposite side of the garage. I've basically moved everything there too.

Been married awhile, haven't you?

Not so long, just 42 years.

The benefit of hiding things from yourself is sometimes you find something you forgot you had put away, like a C-note at page 100 of "Treasure Island". Of course Gina ended up with that in the end so it was a good find, but not a real good find.

 

[b-body-bob]

Started the order process on my pushrods. 5/16 cup and ball, .080 wall, 7.080 length to the bottom of the cup.

OEpushrods is a different kind of place. First, you have to call and they only answer the phone part of the day, they take your info, then call you back with when and how much. I'm at the waiting on the callback part. Kind of can't walk away from the phone. That's what I get for giving them my landline not cell number.

Call Us 7am-3pm ET M-F
phone 1-(586)-463-6520