Captain Obvious

You're a Space Cowboy, huh? I wasn't ready for that. Welcome aboard. You know your carb is on the wrong side of the engine, don't you?

Did you check the PCV hose on the underside of the intake manifold? If you've never seen it, you might not even know it's there.

Zed, I agree that both connections should see pretty much about the same thing. What I don't know is if maybe the system was optimized for one direction or the other. I'm pretty sure it will "work under most conditions" in either direction, but not sure about the optimization. If my understanding of how PCV works is correct, then there will already be flow in both directions depending on engine conditions and loading, but the reverse flow might be less common than the default direction. As for the oil separator, I believe there is also supposed to be one stuffed into the hose that comes off the valve cover. Problem is, however, that most people have had to replace that hose because their originals cracked, and they probably didn't know about the separator and chucked it in the trash with the old hose. How effective is the baffling inside the valve cover? I've never seen one with the cover removed. JSM, Just musing at this point... The thought was that if I could connect the rubber nipple on the duct between the AFM and the throttle body to the lower PCV connection (on the block), and then relocate my PCV to a new drilled and tapped hole on the top of the manifold, I could connect the valve cover hose to that. Would eliminate some of the long hoses draped across the intake system and might look cleaner. But the default flow direction would be reversed.

Is there anything magical about the direction of the flow through the PCV system? I think I could clean up the engine compartment and hose scheme if I were to reverse the flow direction of the system. So do we have any engine vent experts in our midst? Currently, under low flow conditions (low blow by and high manifold vacuum), it pulls from the tube in the block, through the PCV and refreshes clean air into the nipple on the top of the valve cover. This direction already reverses under high flow conditions, so is there any issue with reversing this direction for the low flow (default) condition?

Thanks for the pic. So it looks like the sticker is just centered on the top of the booster. I can do that! Really looking forward to this coming spring after all the salt is off the roads. I've made a couple improvements and customizations this off season that I'm anxious to test!

So another project during this off season was to do something better with my brake booster. I took both the newly purchased "rebuilt" unit, and my old failed original boosters apart and reassembled one unit using the best parts from the two, plus a couple new parts I made to replace some rusty bits. Here's the final unit. Reassembled, painted, and ready to put back in the car: Some of the internal parts were really crappy, so I made some stainless replacements. I used stainless steel for everything with the exception of the threaded output shaft tip. I reused the original tip because it's hardened and I didn't feel like dealing with the heat treating. Besides, it doesn't ride against the vacuum seal, so even if it's not perfect, it doesn't affect operation. Here's what I made: Here's a pic of the smooth stainless output shaft sticking through the vacuum seal. This has GOT to seal better than the rusty crusty versions I had from both the boosters. My idle will thank me: As a bonus... My PO had painted the booster that came with the car, and I found the original sticker hiding under a thick coat of paint. Thankfully the paint didn't stick too well to the plastic sticker, and I was able to chip most of it off. It's not perfect, but it looks "appropriate" for the rest of the car. I haven't put it back on yet. Anyone have a good reference pic showing the location of where the sticker should go?

Something else quick. You probably know this already, but just to make sure there's no misunderstanding... All the AAR does is allow air to bypass around the butterfly plate in the throttle body. With the exception that the AAR doesn't affect the TPS switch, it's exactly the same thing as sitting there with your foot on the gas pedal. It has no effect on mixture. So the only difference between opening the throttle plate by pushing the gas pedal down a little and having an opening through the AAR is that if you push the gas pedal down far enough, you will open the TPS idle switch (which would raise the A/F ratio a little). Other than that... No difference. It's just convenient because you don't have to sit there with your foot on the gas as the engine warms up.

Something to think about is that by pulling the hose off the AAR and letting air in, what you are doing is leaning out your mixture more than anything else. So if it sputters and struggles at 400 RPM when cold, but it runs great if you let in some unmetered air (air that did not go through the AFM), I would be looking for a mixture problem, not an AAR problem. It sounds like you're running way rich at idle and drowning the motor. By opening the hose and that letting air in, you're raising your A/F mixture, and apparently your engine likes that.

In my experience, your expectation is not valid. If that thing was completely open, your idle would be at 4000 RPM. That opening you've got on that one should be plenty to raise the idle to a high "cold idle" level. The important part is that it completely closes when hot, or the idle will stay high. Mine went intermittent. Sometimes the idle would slowly creep up to cold idle level even after the engine was warm. And then it would slowly drop back down as connection was made.

Thanks for the link. I'm hoping that I don't need any adhesive at all since the bushings are slip fits on the shaft, but I'm just not sure what's going to happen as things heat up, age, wear, and get dirty from being on the road. I consider the glue "insurance". I did put those adhesive grooves in the bushings and also roughened up the surface with sandpaper before final install. Trying to give the JB weld something to bite onto.

I just had a headergasm.

A while ago, I was looking into an issue where my idle would hang a little because the throttle body butterfly would not always return to fully closed. The puzzling part is that it always closed just fine with the engine off and it only got sticky when manifold vacuum was present with the engine running. Reference old thread about it, but that old thread never really got to the bottom of it: http://www.classiczcars.com/topic/45152-sticky-throttle-body-hanging-idle/#comment-409180 My solution at the time was to simply add an extra turn to the throttle body return spring and that extra spring force overcame whatever was causing the stick. Worked, but not really the right way to fix it and I always wanted something better. So this off-season, I pulled the throttle body off again to do some more investigation. I believe I have traced the sticking issue to worn through chrome plating on the throttle shaft exposing the softer steel beneath, and that softer steel doesn't slide as well against the pressed in bushings pressed of the throttle body. Even though everything seems to move just fine with the engine off, I believe the friction between the worn shaft and the bushings is amplified when the two of them are forced together by manifold vacuum causing the hanging idle. After considering several different approaches to fixing the issye, I decided to try replacing the original steel throttle body bushings with Delrin. The thinking was that Delrin is a naturally slippery material and the hope is that it won't stick to the exposed steel of the shaft. Also, while I was in there, something else I wanted to improve is that with the original design - The only thing locating the throttle butterfly plate within the throttle body bore is the butterfly plate itself (just like the carbs). In other words, when the throttle is closed, the butterfly plate should self center within the throat because the walls of the throttle body bore will contact the brass butterfly and move it into the center. But when the butterfly is opened, the plate is free to move back and forth a little within the bore. This results in scraping against the internal walls and wear on the walls and butterfly. I was thinking that I might be able to come up with a way to incorporate shaft locating into a new bushing design. So with all that as background... I started with this: I ran a tap into the original bushings and pulled them out: Here's the original steel bushing and the new Delrin bushing for the side where the throttle linkage attaches. The larger diameter lip section keeps the throttle butterfly from moving too far in one direction: Here's the linkage side in place. You can see how the lip is sandwiched between the linkage and the body casting to take up the side-to-side slop and acting as a thrust washer in the inward direction. The other end will address the play from the TPS direction, but this is half the battle won: And here's the concept I came up with for the TPS side. I turned a groove on the throttle shaft to accept a spring clip, and made a stainless steel "D" holed thrust washer to run against the outside of the bushing. These features are what prevent the throttle shaft from moving in from this direction. With the combination of the two limiting features, the throttle plate is now locked centered in the middle of the throttle body throat bore. This side was more of a PITA because there is very little room to work with since everything has to be hidden behind the TPS: This is what the TPS side looks like when installed. Spring clip limits motion in the inward direction: Here's the two new bushings on the throttle shaft to show how they work: A little epoxy to keep the bushings from spinning in the throttle body casting (that's what the grooves are for). Not much sticks to Delrin (including epoxy), but it doesn't need to stick well. Just enough to make sure the shaft spins withing the bushing instead of the bushing spinning within the body: And a little blue thread lock on the butterfly screws: It's all put back together and back on the car and I'll post the final results after the salt is off the roads!

Too late now, but forgot to mention it before... I was in HD and Lowes this past weekend and both of them have plenty of muriatic acid on the shelves. I thought of you when I saw it. NJ may not have it, but you can still come across the bridge to get it.

Haha!!! I like it! A friend of mine suggested that I get my wife a new milling machine for Valentine's Day.

Cool. So they moved that hole. Wonder why. Anyway, glad you're back on the road. I've got a couple months to go yet before they stop salting the roads up here.

And before I forget... I'm planning to cut another vent passage into my aluminum spacer as close to 6:00 as I can. I just rebuilt my booster and even remade some of the internal parts out of stainless, but I don't want that thing to ever suck brake fluid again. Getting that thing apart and together again is not something I plan to make a habit out of!

Yup. Just the tip. As for the o-clock positioning of the vent, I was remembering incorrectly and talking earlier as though the vent passage was in the aluminum spacer, and it's not. My vent passage is not in the aluminum spacer, but is stamped into the booster clamshell. Mine points right at the vacuum hose connection which is in the same place as the one in your pic (mine's a 77). So the bottom line is that my vent hole is at maybe 4:00?

I haven't messed with any of that stuff so I don't have any experience, but I agree that seems a little hokey. With a little web searching, however, it does seem that's the "accepted" solution, and I didn't see any records of failures. Do you know if the Timeserts hardened? Other than the obvious (and expensive) solutions of boring and rethreading or sleeving the entire hole, one other idea instead of epoxy would be to turn (and maybe even thread) some aluminum spacers to take up the gap? Loctite to hold them in place in the upper portion of the recess?

Hmmm... Maybe Klingon? SoHvaD Hija Ha'DIbaH. Qapbej maj.

Yup. I got it. I didn't pay attention to the polarity at the time so I don't know if I got it right, but here's what the reluctor output waveform looks like:

I wouldn't be surprised if the cutter is carbide (which is brittle).

My thoughts on the subject... First, I would be careful with lithium grease on the master cylinder output shaft. A very little bit right on the very tip would probably be OK, but you don't want any of that stuff to come in contact with the vacuum seal that rides on that shaft. I wouldn't want to assume that rubber seal is compatible with that grease. I think a better choice would be silicone based brake grease. Something safe for rubber seals. As for sealant on either of the seams between the parts... I don't think sealant is necessary on either of those seams, but a little sealant between the M/C and the backing plate won't hurt anything. And some sealant between the backing plate and the front side of the M/C clamshell won't hurt anything either as long as you don't block the vent passageway. My read on that vent passage is that it does two things: First, it allows for the change in volume in that (otherwise sealed) cavity when the brakes are depressed. If not for that vent, when the volume inside that cavity were to change, the pressure would change as well. That vent keeps everything at atmospheric. Second, that vent acts as a drain for brake fluid out the hole in the event of a rear M/C seal failure. It would be best if it drains before that fluid ends up inside the master cylinder, but clearly from the amount of fluid inside my failed booster, that's not always the case. One last thought... If that vent is to act as a drain, it would be pointed down, not up. I don't know if it's the original position or not, but mine was pointed at the 5:00 position, not the 11:00 position. Do you think yours was stock original position at 11:00?

Wow. Well that really sucks. I've seen your skill in the other work you have done, so I know it's not an ability issue. Thanks for the warning, and thanks for taking the leap so the rest of us didn't have to.

I don't think any 260 used points. I believe all the 260s (both early and late) used the electronic ignition with the reluctor pickup. If you can't find a proper distributor, you should be able to bypass the TIU and connect the points directly up to the coil like they did for 70-73. Another option? I haven't tried it or researched it, but I bet anything from 74-78 would work (as they're all reluctor pickup). The advance curves might not be "right", but I bet they would "work".

I love the look. It's a view of a Z that I've never seen before. Have you considered clear coat only and do the DeLorean thing? Couple (real) questions: 1) Would the paint guys consider the clean metal surfaces "ready to paint" or would there be additional clean-up that would need to be done? Just a wipe down with solvent, or something more labor intensive? 2) How long do you think you have to get paint on there before things start rusting? I know that in my garage it only takes a day or two for surface rust to start on completely clean surfaces. I'm guessing that the pickling solution in the third tank applied a rust preventative coating of sorts? 3) Do you really think the solder melted? Do you think the bath(s) were that hot?