My 71 Duster work in progress

[RUSTY Cuda]

Crap Bob, sad to here that I hope all goes well for you & it does the job.
Jass, we are just trying to keep you on your toes, since I retired the stress level has bottomed out, the car like with Bob mostly just frustrated & pissed me off.
Hope you don't get to bored without my adventures!

 

[b-body-bob]

The rear end ratchets hard, as in it feels like the whole car shifts over. Twice I had the sensation of something rolling from one side of the trunk to the other and bumping into the quarter. There are two towels and a rolled up car cover back there so they weren't the cause. That has to be the ratchet effect too.

I've got a bottle of Ford limited-slip additive, and I remembered I need a backup light switch so I've got that ordered. I'll raise the rear end up high and drop the nose down to maybe keep from a gear oil bath when I pull the speedo cable and the switch out of the trans. At the same time I'll pump a little oil out of the rear end and put that additive in then go do some figure-8s.

The engine still taps too much for my comfort. Younger me would've said just switch to thinner head gaskets, lengthen the effective pushrod, gain CR at the same time. Older me says it's probably worth throwing $100 at it to prevent it snowballing into a problem later.

Also, it detonates, and not under a necessarily big load. Need to correct for that. That could be the cause of the cheap made HF timing light/tach combo that I bought just for the startup. It was set at 15* yesterday. I've got an old dial back craftsman that I will double check things with.

I kind of laid the wood to it going into second, it chirped and I stayed in it. It felt like the tires were spinning until I let off. Or the clutch slipped - it isn't broken in yet so I'm not supposed to do things like that. I'm probably 20 shifts toward the 500 that McLeod wants for break-in ....

 

[b-body-bob]

the car like with Bob mostly just frustrated & pissed me off.

I don't so much get POd at the car as I do at myself for getting into the mess to start with. I'm too old for this crap.

Then something works out and it makes me happy again.

 

[Dr.Jass]

The rear end ratchets hard, as in it feels like the whole car shifts over. Twice I had the sensation of something rolling from one side of the trunk to the other and bumping into the quarter. There are two towels and a rolled up car cover back there so they weren't the cause. That has to be the ratchet effect too.

The only rear axles I've encountered that behave the way you describe are an 8.75" without the wheel bearings adjusted, a GM Gov-Lock without additive, and anything with a Powertrax-style locker in it (the kind that replace the guts of an open diff). My Dad's Delta 88 did that badly when the limited-slip lube wore. It felt like someone kicking the quarter panel in turns. Similarly, my friend's '70 Super Bee with one of those drop-in lockers--I believe a Powertrax Lock-Right--clicked, kicked, and banged in corners so badly he thought it was broken and didn't want to drive it.
Lastly, Agnes behaved like that and I quickly realized I'd fully installed the axles but never did the adjustment procedure. Those bearings didn't have a football field's worth of yardage on 'em, but they're getting replaced anyhow. If you've got a Dana Powr-Lok style diff, make sure the thrust buttons are in place. They can and do fall out.

The wheel bearings need to be re-adjusted any time the axles are removed, period.

Also, it detonates, and not under a necessarily big load. Need to correct for that. That could be the cause of the cheap made HF timing light/tach combo that I bought just for the startup. It was set at 15* yesterday. I've got an old dial back craftsman that I will double check things with.

Have you messed with your idle mixture screws yet? If its lean, it'll ping. I don't think you have enough compression that detonation should be a problem, especially with aluminum heads. The highest-compression "shelf" piston I could find, outside of forged racing stuff, was about 9:1. Even with the closed-chamber Edelbrocks, you shouldn't be much above 10:1. You should--should--be well within normal timing parameters with the aluminum heads.

You may have too much vacuum advance, or more likely it's coming in too fast. You can adjust the rate at which it's applied (but not the total amount) with an allen wrench through the vacuum nipple.

I kind of laid the wood to it going into second, it chirped and I stayed in it. It felt like the tires were spinning until I let off. Or the clutch slipped - it isn't broken in yet so I'm not supposed to do things like that. I'm probably 20 shifts toward the 500 that McLeod wants for break-in ....

500 cycles? I guess you could mount one of these to your clutch pedal to keep track for ya...

Realistically, I would expect 500 shifts to happen in a week's worth of daily driving, at least for those of us not working from home. There'd be roughly 12 shifts from my house to work one way, including backing out of the yard.

 

[b-body-bob]

It's going to be the additive because it's all brand new and adjusted.

I figure the rolling-across-the-trunk feeling was my brain doing the best it could to make sense out of what it was hearing. I had one with an original clutch type in it that would leave black marks at low speed around corners like backing into a parking spot. I got POed with it one day and wheel hopped it until it broke the cross shaft. Then I paid a guy to rebuild it and it came back exactly the same way because MP was selling Dana clutch packs as 8-3/4 and no they are not the same thing. It worked like a new one after I bought the right clutches and did my own damn work. Still have a newish set of Dana clutches in the cabinet I'll use in the A12 when (if) that comes apart.

Have you messed with your idle mixture screws yet? If its lean, it'll ping. I don't think you have enough compression that detonation should be a problem, especially with aluminum heads. The highest-compression "shelf" piston I could find, outside of forged racing stuff, was about 9:1. Even with the closed-chamber Edelbrocks, you shouldn't be much above 10:1. You should--should--be well within normal timing parameters with the aluminum heads.

It should have mid-9s for compression and the head gasket is probably thicker than what I used when computing things, so yeah I was surprised. You're right it's probably way lean. I had forgot about that cause. FWIW the pistons are speed pro h116cp.

for those of us not working from home

I have worked from home for 24 years now.

I'm not going to go any easier on the clutch now than I would if it was broken in. I hadn't planned on any 4k sidestepping or kick to shift action anyway.

 

[Dr.Jass]

Then I paid a guy to rebuild it and it came back exactly the same way because MP was selling Dana clutch packs as 8-3/4 and no they are not the same thing. It worked like a new one after I bought the right clutches and did my own damn work. Still have a newish set of Dana clutches in the cabinet I'll use in the A12 when (if) that comes apart.

MP was selling both, except one was "mild" and one was "aggressive". When I was eBaying for a living, I put a number of 'em together with the "aggressive" clutches and always made note that they would be very harsh in daily-driver type use and were better suited to drag strips. However, I never had anyone get back to me and report the kind of behavior you experienced. Never had any negative feedback either, for that matter. They were definitely tight on my test axle, but I didn't know they were that rowdy.

FWIW the pistons are speed pro h116cp.

Yeah, those are the pistons I bought for my 360. They're pretty near 9:1 on the nail head with a production (70-71cc) chamber and a .028" gasket (which is what I have for that engine), as I recall.

 

[b-body-bob]

MP was selling both, except one was "mild" and one was "aggressive". When I was eBaying for a living, I put a number of 'em together with the "aggressive" clutches and always made note that they would be very harsh in daily-driver type use and were better suited to drag strips. However, I never had anyone get back to me and report the kind of behavior you experienced. Never had any negative feedback either, for that matter. They were definitely tight on my test axle, but I didn't know they were that rowdy.

I remember the sets being identified as for a Dana or for an 8-3/4. I expect they would've come from Mancini's. I don't remember if the saved set is in one of the original boxes or not. I do remember being really PO'd and amused all at once that the guy gave me back exactly the same problem he was supposed to fix.

Yeah, those are the pistons I bought for my 360. They're pretty near 9:1 on the nail head with a production (70-71cc) chamber and a .028" gasket (which is what I have for that engine), as I recall.

I've got more gasket and less chamber, but I remember it measuring out just over 9:1 somewhere in these 100+ pages. Then you recommended the cam with the intention to preserve the dynamic CR. Even so it shouldn't be pinging from that.

 

[Dr.Jass]

Well, I'd written quite the long response here, but the board ate it. It makes me sad, as I'd been working on it for over an hour and had dragged out the FSMs, etc. to try and give you some ideas. Since I can never seem to duplicate my own thought process, I'll just suggest ballpark some shit.

First of all, check for vacuum leaks. Double-check all your bolt torque readings and that there are no open vacuum ports or sources. You can't always hear a vacuum leak, so if all that checks out, resort to the ol' "flammable aerosol" method (I do not recommend ether/starting fluid for this).

Next, set your idle mixture. You've got to get this sorted since Holleys literally run on the idle-mixture and transition circuits of the carburetor until you're well into the throttle. In other words, jetting has no effect on cruise mixture. There's an incredible, if hard to follow, thread about this on the Yellow Bullet forums. If you recall all the drilling and tapping I was doing on my 830, it was a direct result of that thread. Essentially, Holley's idle- and transition-circuit tuning got heavily altered in the '80s and have sucked ever since. I was correcting that, but haven't got the car back together for testing because new cars, etc.

If your vacuum advance is connected to manifold vacuum, you're going to have to remove most of your initial timing, period. This was actually how I was told to run the vacuum on Agnes, but I never did get that method sorted, so I haven't a good play-by-play. The suggestion went something like, "With the vacuum attached, keep advancing the timing, backing the throttle screw down to your desired RPM, until the RPM stops increasing with more advance." After that, it would've been up to me to then limit mechanical advance based on whatever initial I reading the "advance until no RPM increase" method netted me. The problem I encountered was that I ended up with about 60° initial--seriously--and a car that would still start just fine. Obviously I had other issues, but my query to those suggesting this method as to how I would then limit my mechanical advance -25° went unanswered. Another suggestion was locked timing, which seems a bit idiotic to me.

If you have got ported spark vacuum, once your idle-mixture screws are adjusted you'll need to drive it again. If it still detonates, put a 3/32" allen wrench into the advance canister's nipple. Rotate the adjustment one turn counterclockwise and drive it again on the same loop. Repeat until the detonation is gone.

If that doesn't work, you may have to use the "Big Fat Friend" method of timing, which isn't ideal but it does work. Your limiter plate may become a real boon at that point, since that method netted me 26° initial on my RA-III. However, that method is another discussion which I'm sure I've outlined elsewhere on the site. I just don't feel like seeking it out at the moment.

 

[Dr.Jass]

Also, I don't recall recommending a cam per se, as that's something I always suggest leaving to a cam grinder. However, I do remember running several candidates you had in mind and finding one that seemed the best of the bunch in terms of dynamic CR and overall curves. I don't believe I saved those tests, unfortunately, but they did show the suggested timing at various RPM. Then again, there's no guarantee those numbers would prevent detonation, although EAPro does a pretty decent estimation of knock potential.

 

[b-body-bob]

Well, I'd written quite the long response here, but the board ate it. It makes me sad, as I'd been working on it for over an hour and had dragged out the FSMs, etc. to try and give you some ideas. Since I can never seem to duplicate my own thought process, I'll just suggest ballpark some shit.

Thanks. Some of that tuning info is already here in this thread, from back when I was fighting with the 400. You've been a wealth of knowledge.

Essentially, Holley's idle- and transition-circuit tuning got heavily altered in the '80s and have sucked ever since.

This one is a brawler, comes with jets in the air bleeds and etc. so it's going to be an improvement. Brawler is the result of Holley swallowing QFT.

However, I do remember running several candidates you had in mind and finding one that seemed the best of the bunch in terms of dynamic CR and overall curves. I don't believe I saved those tests, unfortunately, but they did show the suggested timing at various RPM. Then again, there's no guarantee those numbers would prevent detonation, although EAPro does a pretty decent estimation of knock potential.

There are traces of all that in this thread too.

I remember it as you started with a Howard's grind you already have for something else, then compared it to at least a Hughes Whiplash, maybe another one. I also contacted Howard's; they recommended a smaller cam both on lift and duration. I went with the one you started with Hydraulic Flat Tappet Camshaft; 1964 - 2003 Chrysler 273, 340, 360 1800 to 5800 Howards Cams 711451-08 | Howards Cams

 

[Dr.Jass]

I still have that cam on the shelf.

Just for fun, I ran a simulation on it with a 9.69:1 CR 360 with Speedmaster heads, which should be close to what you've got in terms of compression ratio and flow. It doesn't love a lot of timing, at least if the program's to be believed. It really doesn't want more than 33° until about 5,000RPM. Those are WOT numbers, though, not part-throttle/partial-load figures. As such, I think your vacuum advance is coming in too quickly, assuming fuel adjustments don't correct the issue.

This one is a brawler, comes with jets in the air bleeds and etc. so it's going to be an improvement. Brawler is the result of Holley swallowing QFT.

Replaceable air bleeds are a beautiful thing, especially since the out-of-box calibration will almost certainly suck goat balls. Off the top of my head, I'm guessing the IFR will be need to be moved (and shrunk) with a corresponding IAB change, and the "emulsion package" will need a bit of reconsidering. These are two areas both Holley and OFT (and Barry Grant, and...) have been screwing up their carbs for decades. I'm not sure what the threads for each are in their factory configuration, but don't buy any overpriced brand-name bleeds. It's easy to make one's own, and I've got literal boxes of blanks here in multiple thread sizes.

 

[b-body-bob]

It really doesn't want more than 33° until about 5,000RPM

That makes me think I might need to juggle springs too.

I think your vacuum advance is coming in too quickly, assuming fuel adjustments don't correct the issue.

It's brand new out of the box so where ever the factory left it is where it's set now.

I'm not sure what the threads for each are in their factory configuration

I think they are just jets in this carb.

 

[Dr.Jass]

That makes me think I might need to juggle springs too.

I wouldn't mess with that yet. I think it's probably too much vacuum too soon.
This next won't really apply until you've got the timing and base idle-mixture setting, but it's probably going to come in handy....

I think they are just jets in this carb.

I'm not sure I understand this.

Replaceable bleeds are usually small threaded orifices. I guess they're like jets, but when you say jets I picture main jets. Air/fuel bleeds are much smaller, usually 6- or 8- machine thread. Instead of paying $6/pr for 'em, they can easily be made with numbered drill bits and brass set screws. I actually drilled and tapped my 830 in several places to be able to replace various bleeds and change (tune) the power-valve restriction.
Looking at the Brawler 750DP page at Holley, I see the replaceable air bleeds but wonder about the emulsion bleeds and idle feed on the metering blocks. Late-model Holleys are notorious for running extremely rich at idle and cruise and part-throttle acceleration, inconsistent cruise AFR, etc. None of that stuff can be cured by jetting, and most of it is caused by a goofy idle/emulsion setup. A quick interwebs search showed this carb, much like most other Holley DPs, usually runs pig rich out of the box--and the mixture screws/main jets ain't gonna help. It definitely needs the IFR moved, for one thing. The problem is that "conventional" (magazine), er, wisdom leads most people to make the situation worse by stressing "emulsion" over proper AFR, and there's a lo of misinformation floating around the web.
The reason I mention making your own bleeds is that tuning them is always a trial-and-error process--often a change of only .002" can make a noticeable difference in how the car runs. It's not hard to end up with $100 or more in tiny, easily-lost bleeds lying around. A set of numbered drill bits, a ton of blank socket-head brass set screws of a couple different sizes, and a few "gun taps" (spiral flute) are probably cheaper in the long run, and you can make your own bleed orifices at will. You may own another Holley someday.*

I could be 100% wrong on the above, but I don't think I am.

I highly doubt you'll get involved in Nth-degree tuning with a wideband or anything, but it'll almost certainly need some love. "Close enough" shouldn't be too hard to achieve. It's a bridge we'll cross when we come to it, but don't spend days wondering why the car makes your eyes water, and why futzing with the mixture screws doesn't seem to help much.

*This stuff doesn't apply to the A12's Six Pack carbs. Those were calibrated for an OE emissions standard that actually gives them very good manners for idle mixture and cruise/light-throttle AFR. Even the Direct Connection mechanical-secondary race carbs are pretty well-mannered in that regard, at least on a 440.

 

[b-body-bob]

I decided I've got enough stuff to worry about and re-ordered the pushrods 1 turn longer so I'm sure to have enough preload. Or more accurately I tried to. Same company as last time, no change.

I swear I just talked to the guy I talked to the first time I called on this go-round and it all started over LOL. The things we will go through to save a few bucks.

They aren't really set up to deal with individuals. Every time I call I get the feeling some guy had to walk away from a machine to get the phone and stop it ringing.

If I had some way to accurately measure/cut them I'd just use a set of Mancini's cut-to-fit but I don't so I can't.

I prepped the front valance to good enough for Bob condition and gave it a good coat of satin black so I'll get that, the bumper, and the grille installed soon enough. I also went ahead and took 1 turn out of the vac advance because yeah that's most likely a part of the detonation.

I also think both floats are too low and that might be causing a lean condition. I tend to set a Holley so fuel sloshes out if you shake the car a little- in other words it's right at the bottom of the sight hole. This carb has a ginormous sight glass, so the level has to be in the middle of hole to achieve the same level as a Holley with its tiny sight hole. Right now it's adjusted like a Holley, so the level is at the bottom of the sight glass and is too low. I'm trying to hold off on starting it until I'm satisfied with the pushrod situation but that needs addressed the next time I fire it up. FWIW this small block Carter pump keeps the pressure in normal range unlike the one I had on the 400 that would hold 9 PSI.

 

[Dr.Jass]

I decided I've got enough stuff to worry about and re-ordered the pushrods 1 turn longer so I'm sure to have enough preload. Or more accurately I tried to. Same company as last time, no change.

I swear I just talked to the guy I talked to the first time I called on this go-round and it all started over LOL. The things we will go through to save a few bucks.

They aren't really set up to deal with individuals. Every time I call I get the feeling some guy had to walk away from a machine to get the phone and stop it ringing.

If I had some way to accurately measure/cut them I'd just use a set of Mancini's cut-to-fit but I don't so I can't.

Unless you're literally against the ends of the threads--meaning you hit a dead stop while turning--I don't think the longer pushrods are going to change anything. Preload's preload; the lifter doesn't care how the adjuster looks.

I also went ahead and took 1 turn out of the vac advance because yeah that's most likely a part of the detonation.

I'd continue to fiddle with that first before I worried too much about fuel (other than potential vacuum leaks). Make one change at a time. If that doesn't work, then try something else. Shotgunning it will only make things harder later since you won't know what change made the difference.

 

[b-body-bob]

you hit a dead stop while turning

Indeed I did - on several of them. I don't seem to be able to order them though. That vendor is the nuttiest thing I've run into for a while.

 

[b-body-bob]

I decided I've got enough stuff to worry about and re-ordered the pushrods 1 turn longer so I'm sure to have enough preload. Or more accurately I tried to. Same company as last time, no change.

... and today I decided I've got enough stuff to worry about as it is, and am going to order a new set of pushrods from Smith Brothers. For crying out loud I've just got a fundamental problem with chasing people around trying to get them to take my money.

I also spent a little time trying to figure out if what is sold for use in an LA hydraulic adjustable system would work for me. Comp has a part that is 7.389 overall length, less .175 for the cup, leaving 7.214 effective length.

My pushrods are 7.080 effective length, and if I add one more turn I have 7.122 as my new length. That means the Comp part is .092 longer than what I'm planning for, which is a little over 2 full turns longer so that takes me from one extreme (not enough preload) to the other (cups too close to the rocker). I was hopeful but I don't think off the shelf parts will work.

I think the Comp pushrods would be more likely to fit if I had Comp rockers.

 

[Dr.Jass]

... and today I decided I've got enough stuff to worry about as it is, and am going to order a new set of pushrods from Smith Brothers. For crying out loud I've just got a fundamental problem with chasing people around trying to get them to take my money.

I also spent a little time trying to figure out if what is sold for use in an LA hydraulic adjustable system would work for me. Comp has a part that is 7.389 overall length, less .175 for the cup, leaving 7.214 effective length.

My pushrods are 7.080 effective length, and if I add one more turn I have 7.122 as my new length. That means the Comp part is .092 longer than what I'm planning for, which is a little over 2 full turns longer so that takes me from one extreme (not enough preload) to the other (cups too close to the rocker). I was hopeful but I don't think off the shelf parts will work.

I think the Comp pushrods would be more likely to fit if I had Comp rockers.

I have a set of the Comp pushrods new in the package. They're too long--the 7.389" is not the overall length to the edge of the cup, it's the length from the bottom of the cup to the tip of the ball. That's how they and nearly everyone else measure cup/ball pushrods, and yes--I checked them. I did some digging quite awhile back and found an original Sealer Power or TRW part number for T/A pushrods, and I'll be damned if I can find that information now, but I was able to find the original length. It might be at home--I'll have to look. I want to say it was very close to, but not exactly, 7.25". By no means is that gospel. 7.060" definitely seems short.

I'm not really certain how much travel there is in the the factory adjusters, but on locknut-style I usually measure with aboot one thread showing. I average the length of four pushrod measurements. On a hydraulic, you'd want to add probably .040"-.060" to your zero-preload measurement.

I literally bought a 12" caliper and a 5/16" individual ball bearing--the latter from the local hardware store--just so I can accurately measure pushrod length. I put the bearing in the cup, measure the OAL including the bearing, then I subtract .3125". That's how cup/ball pushrods have to be measured; as it turns out factory cups have a different depth than Comp, which are different than Smith Brothers, etc. "Overall length" is as useful as a chainsaw in the desert.

If you're going to order from Smith Brothers, you absoposilutively have to call them. They do not check their online orders (ever, it seems), and their actual prices are not-inconsiderably higher than what's posted online. Ax me how I know.

 

[b-body-bob]

Yeah I know the way with Smith Brothers now. Free shipping on on-line orders but you have to put a cc number on the form and email it to them. Sure I will.

They've got a FAX number too. I should've sent a FAX and called to be sure they got it. Then I could've jumped up and down over the free shipping.

I have the number of quarter turns I took on each rocker written down. I will probably start by backing them all off 1 turn since the new pushrods are 1 turn longer. If necessary, dealing with the distributor and priming rod is sort of second nature at this point but I think my records are good enough that I can just revisit them all and have 1 full turn of preload on them without even turning the crank.

 

[b-body-bob]

Also, while I'm thinking of it ... am I correct in assuming I'm going to leak gear oil when I remove the backup light switch? Looking at photos it sure looks like it's below the level of the fill plug.

And is there a good way to draw off about 4 oz of oil from the rear end so I can fit a bottle of additive in it?

I thought of trying to lift the rear end higher than the front but I don't want a lot of hassle that's going to turn into little if any gain.