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3.0 carbureted engine stalls while in closed loop

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    #31
    "We put it in the maintenance manual - therefore if it fails after this amount of miles or years, it's the owners fault due to neglected maintenance."

    I had no idea that they did that! I figured it was a dirty little secret, like the V8s, just a lot less durable. What a way to drive buyers away. Timing belts were considered normal for 'cheaper' cars, but not something like this for a Buick, et al.
    Jerry

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      #32
      Originally posted by KH990j View Post
      rebuilt carburetor
      What we don't know is when it was rebuilt, and what kit was placed within it.

      On a different animal, on a farm truck with 366 GMC engine, its Holley 4 barrel was rebuilt, several years ago at a rebuild shop....it leaked fuel after first year, so I took it back. The seals on fuel "rails" were leaking out fuel, so he replaced them with the right seals.

      RE: plunger works fine

      So, how was this evaluated?

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        #33
        Originally posted by turbokinetic View Post
        I think that one of the ways GM justified this shitty design was by claiming it was already "industry standard." In other words, other manufacturers had timing system maintenance requirements at less than 100,000 miles. Others were coming on the market with rubber timing belts that had 50 - 60,000 mile replacement intervals; so GM figured that specifying the cam sprocket to be a maintenance item it was OK. They operated on the principle that "We put it in the maintenance manual - therefore if it fails after this amount of miles or years, it's the owners fault due to neglected maintenance." The problem here is, the timing belt engines were designed from the ground-up with some thought for access to the belt area; whereas the GM V6 / V8 engines were originally designed for a timing chain setup that would not require regular maintenance. Therefore it is unexpected to need this job; and the job its self it more invasive to the engine than a belt replacement on the competition's engines.



        That Sealed Power timing set is a good one. I know that on the newer Buick engines, there is a tensioner device as well. I am not sure if the 3.0 has this or not. If so, it goes on the front of the block under the timing cover, with a hard plastic "shoe" keeping the slack side of the chain from flailing and whipping. If you see this in the engine, it's important to replace it at the same time.

        Also; thanks so much Jerry and to Ken (and others) for your vote of confidence in my advice. That means a lot and I really need / appreciate it at this time.

        Sincerely,
        David
        You're proven David! Your works speaks for itself, and your generosity through the years makes it easy to heap on the accolades. Credit to you for not letting it all get to your head. And, again thanks for helping those along your way! The knowledge you have shared and the inspiration you've given has helped keep my '96 Century out of the salvage yard. I'm hanging on to her until so I can get that tranny done, and I can enjoy her again. I guess we are all fortunate here that you share the same love for this car platform.

        Had GM known what the future would bring, they might have been a bit less arrogant in their approach to timing gears during that era. Both the Duke and the Buick mills were victims. I'm not sure but, I think in those days, the divisions still had some autonomy with their engine programs. ...so, maybe they were trying to save money for fear of it slipping away. In those days it seems that Chevy avoided these foibles.

        Ken T.

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          #34
          Originally posted by Century7667 View Post
          You're proven David! Your works speaks for itself, and your generosity through the years makes it easy to heap on the accolades. Credit to you for not letting it all get to your head. And, again thanks for helping those along your way! The knowledge you have shared and the inspiration you've given has helped keep my '96 Century out of the salvage yard. I'm hanging on to her until so I can get that tranny done, and I can enjoy her again. I guess we are all fortunate here that you share the same love for this car platform.

          Had GM known what the future would bring, they might have been a bit less arrogant in their approach to timing gears during that era. Both the Duke and the Buick mills were victims. I'm not sure but, I think in those days, the divisions still had some autonomy with their engine programs. ...so, maybe they were trying to save money for fear of it slipping away. In those days it seems that Chevy avoided these foibles.

          Ken T.
          Thanks again Ken. Remember talking about the trans - make time and we'll fix that and make it a learning experience!

          Interestingly, my 72 Chevy Nova had the plastic timing gear failure in its original engine. It ruined the engine in a similar manner to the LG3. It was my mom's car at the time. She took it to a mechanic and he replaced the timing set, but left 7 bent valves in place. The engine ran awful and it made it home from his shop one last time and then was not driven for about 3 years until I was old enough to drive. Then it was correctly repaired, and became my car.

          Look me up on Facebook

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            #35
            Originally posted by Century7667 View Post
            Had GM known what the future would bring, they might have been a bit less arrogant in their approach to timing gears during that era.
            I think GM was fully aware of how to sabotage an engine. EPA increased mileage requirements over the years, and I believe GM designed engines to fail. Nylon based teeth on cam gear was one way with interference engines. A predictable failure...

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              #36
              Originally posted by turbokinetic View Post
              Thanks again Ken. Remember talking about the trans - make time and we'll fix that and make it a learning experience!

              Interestingly, my 72 Chevy Nova had the plastic timing gear failure in its original engine. It ruined the engine in a similar manner to the LG3. It was my mom's car at the time. She took it to a mechanic and he replaced the timing set, but left 7 bent valves in place. The engine ran awful and it made it home from his shop one last time and then was not driven for about 3 years until I was old enough to drive. Then it was correctly repaired, and became my car.
              We'll definitely get her done!

              Wow, the old nova had plastic (phenolic?) even then? My '76 250 Inline has all aluminum gears, I thought the plastic came after that!

              Ken T.

              Comment


                #37
                Originally posted by 85_Ciera_Rebuild View Post
                I think GM was fully aware of how to sabotage an engine. EPA increased mileage requirements over the years, and I believe GM designed engines to fail. Nylon based teeth on cam gear was one way with interference engines. A predictable failure...
                I am not convinced of their motives then, but I believe ALL car makers today incorporate or engineer "planned obsolescence" into their vehicles now. One of my co-workers had to walk away from an otherwise fine 2007 Altima (yuck) because Nissan put the screws to him financially to keep it on the road.

                Ken T.

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                  #38
                  Yuck is right. Yuck.

                  Comment


                    #39
                    Originally posted by Skip View Post
                    Yuck is right. Yuck.
                    Yeah, I don't really like to talk about it. It's not mine at least!

                    Ken T.

                    Comment


                      #40
                      Originally posted by Century7667 View Post
                      I am not convinced of their motives....
                      General Motors streetcar conspiracy - Between 1938 and 1950, National City Lines and its subsidiaries, American City Lines and Pacific City Lines—with investment from GM, Firestone Tire, Standard Oil of California through a subsidiary, Federal Engineering, Phillips Petroleum, and Mack Trucks—gained control of additional transit systems in about 25 cities.[3] Systems included St. Louis, Baltimore, Los Angeles, and Oakland. NCL often converted streetcars to bus operations in that period, although electric traction was preserved or expanded in some locations. Other systems, such as San Diego's, were converted by outgrowths of the City Lines. Most companies involved were convicted in 1949 of conspiracy to monopolize interstate commerce in the sale of buses, fuel, and supplies to NCL subsidiaries, but were acquitted of conspiring to monopolize the transit industry.

                      Comment


                        #41
                        Originally posted by Century7667 View Post
                        I am not convinced of their motives then, but I believe ALL car makers today incorporate or engineer "planned obsolescence" into their vehicles now. One of my co-workers had to walk away from an otherwise fine 2007 Altima (yuck) because Nissan put the screws to him financially to keep it on the road.

                        Ken T.
                        The big three (and probably AMC too) were fond of the gears in V8s for decades, as well as the fiber/phenolic gears in inline engines. The Model T had a fiber timing gear!
                        Jerry

                        Comment


                          #42
                          Originally posted by CorvairGeek View Post
                          The big three (and probably AMC too) were fond of the gears in V8s for decades, as well as the fiber/phenolic gears in inline engines.
                          On a non-interference engine, there is generally not an issue when the chain slips a tooth or two. IIRC, these nylon teeth (nylon over metal teeth) started around late 1960s, or earlier 1970s.

                          Ford's 390 V8 had this by 1972....it was suppose to quiet engine noise....but I understand GM did away with this feature, somewhere in 1990s....thousands and thousands of good GM engines bit the dust, due to nylon bits falling off, with timing chain slipping position, and kaboom, a piston hits a valve.

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                            #43
                            Update: not much to say. I still haven't been able to solve the hesitation issue and I didn't really get the carb dialed in right. I believe the map sensor vacuum hose was connected to the wrong port so I connected it to the large port on the base of the carb. I'm not 100% sure if that's right. The next cold start ran very rich so I made some adjustments with the idle mixture, however, the screws are barely off their seats. It is possible that the float is not set properly. I need to get myself a float gauge and a DDouble driver for the stop screws although I want to make sure I get the right size. I should be able to borrow a dwell meter. I did notice the air horn gasket has tears but I do have a spare. I do have some help from a Delco manual from 1982 on how to set the mixture properly.

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                              #44
                              I forgot to add that the max vacuum I was getting today was 16" hg. Not very good

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                                #45
                                Originally posted by KH990j View Post
                                I forgot to add that the max vacuum I was getting today was 16" hg. Not very good
                                Yeah, I'd like to see 18-20" at idle with a stock camshaft.

                                Ken T.

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