NTX5467

Make sure the condenser is NOS rather than "new", as others have discovered the new ones delaminate internally and cause problems in performance and such. NTX5467

Is that price inline with what local shops charge for fabric? Is it the same "weight" as the OEM fabric appears to be? Just curious, NTX5467

In one respect, which side it's on might be more of a convenience for the engine plant engine dressers. Plus related material costs. As long as the valve sees manifold vacuum, that's all that matters. Chrysler (which used the AFBs OEM) chose to use an intake manifold runner for their power brake vac source, which is probably why Carters have the front pcv port on them? That's my theory on the vac source issue. Where the power brake vac tap was and if it was combined with the hvac/cruise control vacuum tap "trees", tended to be a carline engineering decision, I suspect. Which could vary a bit by the model year and platform. NOT to forget air cleaner clearance of such trees, too! Sometimes, "real estate" back there could be tight, vertically and horizontally!! NTX5467

If any of the rubber fuel lines have been there a long time, time to replace them with new hose, tank to engine.

In the 1990s, when we suddenly started to have oil consumption issues on Chevy V-8s, "Engineering" sent us some pcv valves to try on our customer's vehicles. They were modified pcv valves, cut apart and gutted, with a small hole in the bottom. Probably about .060" or so? I think that helped some, but did not fix the issue. I wondered about the fixed orifice rather than a variable orifice, but figured the EFI was compensating for the differences. At that time, I think the ultimate issue was "ring flutter", with the thinner (low drag) rings of the time. Chevy even bought back some vehicles to use in their testing. One Corvette I read about could be made to have 1000miles/qt or 3000+miles/qt depending upon how it was driven. If the driver drove around town with the manual transmission in one gear, using the throttle to vary rpm and road speed, not upshifting, then under low load, high-vacuum conditions, more oil consumption. Highway cruising, steady rpms and low loads, much less consumption. Adjustments to ease upward the spring tension slightly, plus a change to the bottom/scraper area of the oil rings, was supposed to have fixed that issue. Apparently things which were not around in the 1960s when wider rings were used. Enjoy! NTX5467

Thank you very much for that information, @carbking ! Very informative for comparisons! Might the "Idle Jet" be termed "Low Speed Jet" (hidden in the bottom of the brass idle fuel feed tube)? I've always felt that a metering rod carburetor could be tuned a bit finer with the metering rod diameters rather than a fixed jet. Interesting that the metering rods became a fine-tuning device when they became basically "straight" rather than stepped. Thanks again, @carbking, much appreciated information. NTX5467

"Lean misfires" are hard to notice, unless you know what you're seeing. I once had the Camaro hooked to a big Sunn machine and was trying to get to the low percentage of CO that was best for emissions. I could adjust the idle mixture leaner and leaner, to get to that low percentage of CO, but when I got to a certain point, as the CO digital display still decreased, the HC display went wild. Jumping from one reading to another with each new number, as fast as it could respond. THAT was lean misfire, but the engine did not act like a misfire from a fouled spark plug, it just quivered a bit more than normal. So as i richened things back up, the CO went up and the HC readings went back to normal. The engine idled a bit smoother, too, as normal. Just my experiences, NTX5467

In the research I just finished doing via Google, it appears the CA vehicles started to use them in 1960, with national use starting about 1963. Many GM lines, as Pontiac, apparently phased them in in 1961 model year. Not everybody at once, apparently, but voluntarily prior to the federal requirement I know our '61 Chevy BelAir 6-cyl did not have one. Fram FV112 and FV112DP, via the Fram website, indicates that part number to fit the vast majority of GM cars built between 1961 and 1975. From 3.8L inline sixes to '75 455s. Which tends to indicate two things . . . 1) that the flow needed to keep sludge accumulation (from short trips and such in cold weather) minimized is not necessarily engine displacement-related, 2) that the amount of flow related to engine size might not be as critical as suspected. Which means that any flow is better than no flow. Looks like the "big end" is the same hose size as the bolt-on fitting that went in place of the draft tube, too. Which would then mean the "place of flow compensation" would be in the carburetor calibrations, YET none of the discussions I found mentioned carb issues after installation. I found a good discussion in the CLC forum about 1955 Cadillacs, using a carb base spacer/gasket with a flattened tube going into it, which the pcv hose would attach to. A mention of the MEWagner item mentioned in these forums recently. Plus the amount of information on their website as to pcv valves and such. I found one aftermarket kit which referenced a Fram pcv valve which fit 4.6L V-8s to 5.8L V-8s, in a Ford-related forum. There was also a discussion about Tri-Five Chevy V-8s and adding pcv systems to them in H.A.M.B., noting the different length of the internal "ventilators" on particular model year V-8s and their interaction with factory and aftermarket intake manifolds. Y'all enjoy! NTX5467

@carbking, thanks for verifying a point of curiosity on the Carter aluminum power pistons. I had always wondered about their wear and related vac loss through them, but figured a lighter spring under them would do the trick. Yet the OEMs never did offer replacement springs, but they were in the Carter Strip Kits (for both the AFB/AVS and TQuad) and the later Edelbrock kits. Regarding the QJet secondary cams . . . the Chevy parts book did not mention them anywhere, but I knew they were on the carburetors and could be a wear item. As it turned out, some of the GM carlines had them in the parts illustrations with a ref number for them, which related to the parts list, but not consistently from model year to model year. Never did find them in the parts lists in the Chevy parts book, though, unless they were hiding them somewhere else. The OEM replacements were thinner than the production ones, too, as if they wanted them to wear. Many techs did not know of their existence, either. I remember when the primary throttle shaft wear issues surfaced and the first kits for DIY use (after the ones where a machine shop was needed). I had noticed some such issues on older carburetors, at that time, but never worried about it unless it was "a lot". In a Holley carb seminar I went to in the earlier 1980s, the Holley engineer claimed there should be some "looseness" in the shaft/throttle body interface. Plus that such looseness was figured into the carb's metering characteristics. As if "Don't worry about it. If you do, we sell new throttle bodies." Seems like Rochester sold new ones, too, but by the time they would be needed, they'd be "Obsolete" and/or "Discontinued" items. Perhaps what is needed is for a dyno operator of repute, to test a stock Nailhead on the dyno, but only at hot base idle speeds. With "a hat" on the carburetor to measure air flow into the carburetor. Then do a comparison air flow check with the pcv valve open and compare it to when the pcv valve is closed, to determine just how much air flow goes through the valve when it is hooked up. Maybe even test a clean OEM NOS valve against a newer replacement for the same application? Checking and adjusting the air/fuel ratio at idle each time at the factory hot base idle speed. Then see what idle mixture screw adjustment changes might be needed to maintain a 13.5 or so AFR? A side issue might be that as most of the idle systems were oriented toward a smooooth idle, they would be richer than the later emissions settings. Might be that the 1955 V-8 might automatically get a leaner idle setting, for lower emissions, as a result, too? Things to find: The SAE Transaction I mentioned on the GM testing and decision on their early pcv systems. As to flow rates of what was tolerable. The earlier CARB test papers on their retro-fit systems and how they affected the vehicles they were installed onto. As to which pcv valve applications they used. The comparison of carb main jetting on the pre-pcv carburetors and the pcv carburetors, for several applicable applications. Thanks, @carbking for your input on the carburetor issues! Y'all enjoy! NTX5467

Over the years, I have run into situations were the carburetor became insensitive to whatever I did to it. Mainly on idle screw sensitivity in adjusting them. One side works and the other one did not. Disassembly found nothing more than a clogged pcv circuit in the carb base plate. Clearing it out did not help the situation. So, a new carburetor was sourced and things were good again. BUT, it seems that the "window" for OEM calibrations is a bit small, as the window for "Works Dang Good" being much wider. To me, as long as the spark plugs burn "in the window" of "good", the main system mixture is not too rich to deliver good highway fuel economy, and the idle can be set to work well (mixture and hot base idle speed), then you are near the top of the "works well" window. Even with aftermarket parts. As to the "smell", if the smell is not from excess fuel (which should be blackening the spark plug terminals and possibly putting similar smells in the motor oil), then I highly suspect it is a "Fuel Issue". One day, back in the middle 1980s, I was driving around one Saturday afternoon in the metro area and bought gas from a Ci___ station (new to this region at the time, which had a refinery in Louisiana at the time). No big deal, but as the day progressed, I noticed that I needed to throttle into the engine to get the car to idle in gear at traffic lights. On revving it, the exhaust has a hollow sound to it. It took a bit longer to start when cold, but still ran with some help. The closer I got to Empty, the worse it seemed to get, so I went on a mission to get to "E" sooner than later. New gas fixed it. Last time I bought that brand of gas. A few years later, that brand vanished from the region, for one reason or another. Used to be that each major brand of gas had their own tank truck fleets to deliver was from THEIR tank farms to THEIR dealers. That distribution model has ceased to exist, it seems. Generic gas arrives at a distribution point. As it is loaded into the tank truck, the defining additives and such (for each brand) is added to the batch at that time, "Splash blended". Not unlike the middle 1960s when generic gasoline was loaded and the additives the customer desired was added at that time, "blended" on the way to the customer. BTAIM I FULLY agree with @carbkingon OEM calibrations being the best, BUT they were also designed around gasoline that was leaded and "more real" than what we have now. Designed for carburetor use rather than EFI, too. Much less consideration of 10-15% ethanol! Especially the ethanol to the amount we now have!!! OEMs have much greater instrumentation of their emissions work projects, then as now. Unfortunately, to get to some of those "numbers" is one thing, as numbers a little bit more to the "rich" side of things will not be felt, but only indicated by "the instruments", typically. I also have observed that with newer carburetors, the reaction to off-idle can be sharper than the OEM carbs could ever produce. Even when using a newer OEM carb to replace an earlier one of a different manufacturer. Some things DO get better, the "younger" they are, from my experiences. In that respect, I'm not afraid to use a newer carb to replace an earlier one in an OEM application. With the AVS2 being one of those situations. Or a Street Demon to mix the best attributes of a square-bore and spread-bore carb in a package that will bolt onto anything 4bbl for many years. When I happened onto that early-1970s Exxon Tune-Up Manual, with the flow rates of pcv valves listed by application, I was surprised how close they all were. As to flow rates, there is an SAE Transaction which GM presented back in the early 1960s, where they installed a few different flow rate systems on a few of their security service cars, which were 1961 Chevy Biscayne (or BelAir) 235CID 6-cyl cars. They had one with the draft tube, as produced OEM. One with a low-flow rate system. One with a system twice the flow as the low-flow system. As the cars idled for long periods and always drove slowly, these were good guinea pigs for "worst case scenarios". The lower-flow system did better than the draft tube engine, as expected, decreasing sludge by a good bit. The higher-flow system did even better than expected in keeping the crankcase clean. Proving the benefits of having a pcv system on the engine. Atr the time I found this in the Texas Tech University library, I was not specifically concerned with related carburetor calibrations on the systems. Knowing that if any additional air would be needed to get to the hot base idle speed, that would be just a tweak away. Same on any issues with idle mixture, too. Nor did I later notice that carbs in the Holley Variable Spec Manual were rated for pcv systems or not, or different for years when pcv systems were factory installed. Nor later when the CARB required the retro-fit of pcv systems to 1955-era vehicles. To me, these things mean that a few minor tweaks to a carburetor can be made (idle speed screw, base timing) to accommodate a pcv system where one was not there OEM. I also consider "factory specs" to be a starting point from which "optimum" tuning can be achieved. Some engines are more responsive to such things than others, but "lean best idle" works for everything. As some idle systems are much more sensitive to mixture screw adjustments at different idle rpm levels, for example. Some "windows" are wider than others. Whenever adding a new/different carburetor, always look at the factory jetting specs for the main and secondary systems. Compare and then see how the new carb works before changing anything. You might discover the new carb's calibrations are pretty close to the OEM calibration. Unfortunately, there are other "hidden" calibrations in the venturi cluster or metering blocks that we do not know about or how to change, in some cases. Making the jetting a "rough comparison" of sorts. In the mean time, hope for an earlier Spring season so you can get our and drive the cars! From my experiences and observations, NTX5467

Which would decrease the plenum volume and possibly cause other drivability issues or move the power band upward. There apparently is a dimension between the base of the carburetor and the bottom of the plenum that is important for best performance off-idle and WOT. A thick OEM-style insulator/spacer can make a difference, as I discovered. Going .25" the other way would make things worse. Lots of little things go into the manifold designs. Recently, I've seen a few videos about presenters cutting out the pad holes to make them larger and connected frt to rr. Plus how much better the changes made the cars run afterward. Even allowing a square bore carb on an original, modified, spreadbore manifold. Even connecting the "holes" on a 2bbl intake! NTX5467

I went in search of a parts diagram of the pcv system. First on a '65 Corvette 396 and then on a '65 Impala 327. The 327 V-8 was the item I remembered, but it was a little bit different. There was the metal tube which attached to the road draft tube location, but that was the INTAKE for the air, so the rubber hose went to the air cleaner base. The pcv valve screwed into a bung on the front oil filler tube, with a hose going to the carburetor base. Basically reversing the direction of air flow into the engine. There are also some oil filler/sealed breather caps which have a nipple on them. Those could be adapted to use an inline pcv valve situation, I suspect. Most are chrome, if that matters. NTX5467

When I looked in the 1946-1972 Buick Parts Manual, it listed only ONE pcv valve for 1963-1971 All V-8s. 6478503, which replaces 6421972 Looking in Rock Auto for 1963 Riviera 401 . . . ACDelco 19310783 Looks like it is designed to plug into a grommet on the LH valve cover, two different size end fittings. RA showed grommets for such. For 1965 Corvette 396: Standard Motor Parts V100, which is a screw-iin valve with a hose attachment on the other end. No sizes listed as to fitting it screws into or the hose size that attaches to it. These items are listed in Group 1.745 of the GM/Buick parts book. Probably have to find a '63 or so factory service manual which can detail the crankcase vent system. Similar for a 1965 Corvette parts book, but I recall the illustration of the early pcv system in a 1972 printing of the Chevy car parts book. The "Ventilator" (which fits in the lifter valley) and attaches to the road draft tube, for the closed crankcase vent systems, the road draft tube is replaced with a cap (with a bolt going through it to the anchor for the road draft tube and bracket, plus a seal under the bolt head), with a nipple on the cap to which a rubber hose attaches that goes to the valve, which screws into a brass fitting that screws into the rear throttle body of the carburetor. Or an inline valve with hose attachments on both ends. THESE would be the things to look at in the Corvette repro vendor catalogs. A simple system to adapt to an older car, it seems to me. Enjoy! NTX5467

The first Chevy pcv valves were screw-in, circa 1964 or 1965. The "attachment" to the block replaced the prior road draft tube at the back. One longer screw held it in place. Then a rubber hose between that item and the screw-in pcv valve on a fitting for the rear of the carburetor. Probably can find them in the Corvette or Impala repro websites? NTX5467

One winter when the weather was very cold, a C-30 with a utility bed was towed in. Complaint was "No start". Our tune-up tech got the job and started investigating. He found a completely missing carbon contact between the coil and the rotor. Yet it ran when it was parked, when it was warmer. Replaced the cap, button, and rotor with OEM GM items, considering it was at the dealership. Plugs were also checked and they were wide-gap too. New ACDelco spark plugs. THEN it started and ran as it should. The GM HEI, with the standard coil, is designed to fire spark plugs with a .100" plug gap, but it was also noted that plug wire condition became an issue past about .080" plug gap. Some mid-'80s Olds engines had a .060" to .080" plug gap OEM. THESE things prove the power of the standard coil! Perhaps MSD's quality is better now that the Holley group owns it? After a multitude of ownership changes over the past 20 years. The electronics of the GM HEI module are supposed to be pretty trick, from what I've read. Some replacement companies talk about them in the dialogue for THEIR products, neglecting to say the stock GM HEI module has the same attributes. Be SURE to use the heat sink paste with the module, between the module and the distributor housing! PLUS that the coil is grounded too! Those two areas, other than the noted wear areas, are the "common" things about HEIs not working as designed. IF you buy quality parts, should be no worries about having to change them on the side of the road. Which is why making sure the coil is grounded and the heat sink paste is under the module. Enjoy! NTX5467

1968s did not have the Switch Pitch for less transmission fluid heat build-up and greater durability, as a result.

The current E10 fuels have less "heat" potential in then, due to the addition of ethanol. I understand the optimum air/fuel ratio is about 14.2 to 1, whereas all of the older cars were calibrated for 14.7 to 1 in days past. Which means the calibration can stand some richening of sorts. Using that proportion, about 4% richer to optimize the mixture, most likely. Of course, EFI optimizes for such things (using an oxygen sensor) AND letting the system also control spark timing also helps (in a coordinated fashion), too. The "accelerates well, then bogs past that" sounds like a "power system" that is not working as designed. On a metering rod carburetor, that can be a broken or missing spring under the power piston. On a fixed-jet carburetor, a failed-closed power valve? NTX5467

Greetings! A gentleman has just created an informational thread on GM THM400 and its variants at www.NastyZ28.com. It was created on 01/20/2024 so it might come up under the "What's New" icon or in the dedicated forum for automatic transmissions. I mention this for information only. Enjoy! NTX5467

I mistakenly put "1967 Buick LeSabre model listings" into Google and it found a Team Buick website page for the 1967 Buicks. Prices, production figures, and the order codes they used in 1967. In 1967, the codes were a letter and number, compared to what is on your build sheet, but I suspect they can loosely correspond. I did not find such a page in the 1968 Buick page in Team Buick. There is even a link to get into the factory service manual or download the file with one for a small amount of money, if desired. Team Buick is at www.teambuick.com, but can also be accessed from these Buick forums, at the bottom of the forum list. Quicker to just go to the bottom of the list of Buick Forums on this AACA website to get to the "Home" page and all of the listings it has on it. In the General Information section of the service manual, it has enough pages to detail the various cut levels of the keys, which removes a lot of the mystery of how to cut keys! Enjoy! NTX5467

DFIIERENT generation of Buick V-6, period! The engine in those cars was the first crude, very crude, version of turbos and electronics to control such. They were "famous" for the turbo seal on the exhaust side wearing/failing and suctioning the crankcase of oil as the car was running. The first detonation limiters allowed for "clattering" on mild acceleration, too. Other than the engine issues, they were nice cars. The BEST way to upgrade the car would be with a Buick 350 and a beefed THM200-4R automatic replacing the turbo motor, to me. Maybe going farther with a full self-learning/timing control EFI system? Then do some upgrades to the rear suspension to handle the extra torque, probably using Chevy Malibu or Gen III Camaro items. Would make a very nice daily driver/sleeper car! A later model GN or Turbo T it is NOT. NTX5467

Of all of the pcv valves on my vehicles, I have never had one to fail or get so completely gunked-up that it would not "clean" by flushing it with spray Berryman's B-12 carb cleaner. In the few new ones I've bought, NO difference in performance. Yes, the pcv is a variable vacuum bleed situation. Little flow at high vacuum, more flow at low vacuum. It should rattle, which is the main criteria I used to judge if they needed bi-directional cleaning. Plugging one end with a finger, filling it with B-12 cleaner, plugging the other end with a different finger, then shaking it back and forth to move the plunger around. Then drain and flush in both directions. Usually not much needed before the cleaner came out clear. There should be NO rubber in the valves to facilitate a tight seal between the plunger and the valve's body. Hence what you found, machined surface against smooth metal or plastic surface. Yes, there are flow ratings for the valves. The ONLY place I've ever seen them was in a 1970s-era Exxon Tune-Up Manual, in the back. In the realm of Chevy engines, the L82/LT-1/Gen I and II Z/28 engines had a higher-flow valve (had a purple dye on the metal/bottom portion) than the normal valves. Apparently to help with the higher idle air requirements of the bigger-cam motors? I tried both in my '77 Camaro 305 after I upgraded to a "more cam" situation, but could really not tell a significant difference in hot base idle speed. The only thing that might fail in a pcv valve is the spring. If it should break, there will still be some spring pressure to resist the valve closing all of the way, with the air passing through it being restricted more of the time. Pretty fool-proof, it seems. To me, the best valves to have would be the older OEM ones, cleaned, of course. PCV is needed to decrease crankcase gunk and sludge from happening, especially in cold weather. More reliable than the prior road draft tubes, which needed vehicle road speed to work well. Only about 10 weeks to April 1st! NTX5467

The options of the vehicle are detailed in the center section, with the option codes. The upper section will detail the particular components the car was built with, standard equipment and optional items. Either as an option code (i.e., L77 Engine) or by the letter codes on the parts tags attached to some components. Springs, wiring harnesses, etc. What vehicle is this sheet for? Enjoy! NTX5467

The "heavier fabric" is more related to the higher GM carline than specifically "wagons", I suspect. In the 1980s, we needed to get the seat fabric replaced on one of our cars. I had decided the "velour" in the downsized Caprices seemed to be long-lasting and there was a color which ended up matching dead-on, so we went to the upholstery shop the dealership used for their warranty work. There was a very experienced upholsterer there, too. I told him which fabric I was thinking about and showed him the color. He immediately said "there's something better" and went to pull out a bolt of fabric in the same identical color, but of heavier weight. He said "This is for a Pontiac", which is why it was twice as heavy in the weave. So that's what we used as he had it in stock. Cost about $1.00 more a yard. That fabric "wore like iron". Putting them side by side, there was NO comparison of which one was best. Just my experiences, NTX5467

The original GM ACDelco filter number might now be different than it used to be, back then. Check the ACDelco website for their latest part number, for good measure. Might even find it at WalMart or similar? Just buy a "normal" name-brand filter. Normal pricing. It'll be good enough. Many people dislike Fram filters for their internal use of "cardboard" end caps on the filter media, as others use metal. You can probably find some filter comparisons on YouTube so you can see what they are talking about. Most of these videos are done by non-professionals and some of their dialogue might not be completely accurate, but the visual depictions should be accurate. NONE of them talk about filter media ratings or efficiency, it seems, just the construction orientations. You can also check out the oil filter area of www.bobistheoilguy.com to become more "educated". Enjoy! NTX5467

In your quest, you need to first find a durometer gauge. They do exist and a friend who used to be in the left-hand turn dirt racing had one. I borrowed it years ago to check durometer readings on various tires, in prep for trhe first Muscle Car Club Shootouts (sponsored by Comp Cams in the 1980s, and Muscle Car Review magazine). I went to the new Super Shops nearby my shadetree shop and checked tires they had laying on the showroom floor. Interestingly, the Mickey Thompson tires they had were just harder than their minimum hardness spec. At 51 or 52 rather than the spec of 50. At the time, that was the stickiest street tire around. The other interesting fact was that I checked the tires on some C70 cab/chassis trucks we had on the lot and they checked "50". So, look in the dirt track racer magazines and seek out a durometer gauge. Then start checking tire treads, sway bar mount bushings, sway bar link grommets, and other body mount rubber items. I suspect the most common-to-find "in the wild" will be for Chevrolets. As the body mounts on muy '68 LeSabre have Chevrolet casting and part numbers, that would be a good place to start. When I had the subframe mounts on my '77 Camaro replaced, I also upgraded to Grade 8 OEM bolts. Body bolts can also deteriorate/rust in their hidden location, so the corrosion-resistant, MIL-spec coating helped there. In body design, there are places designed to flex and tolerate flexing and vibration, as others are designed to not tolerate such. Which can mean that as one part of the combination is strengthened, that just transfers those forces to places which were not designed to deal with them. Certainly, a 10% additional flex-resistance might not hurt, but there is a limit which will reveal itself over time. Enjoy the project! NTX5467