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Vapour Lock 289 V8

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  • Vapour Lock 289 V8

    I own a 63 GT Hawk, with a rebuilt 289 V8, added high compression pistons, cast iron headers, R1 cam, Carter AFB 4 BBL, triple core rad. I have 2 major problems, when the car heats up to 180 it vapour locks, or rattles until it quits. I have redirected the fuel line from the pump to the carb so it does not pass the header but with no + affect.I just recently added the 4 bbl, (had a 2bbl Stromberg) the problem seems to be worst now.
    Second, since the rebuild I have had to retard the timing greatly to avoid major pinging upon accereration, to the point where I only have 12 to 13lbs vacuum.
    Are these 2 problems related?
    The gent who rebuilt my engine is an experienced Stude Enthusiast, and I believe he rebuilt it correctly, I am open to any and all ideas. I was told that I will need to re curve my distributor, will this help?
    Desperate to drive my car this summer since our summers are so short here, I hate it sitting in the garage on nice days, could some one help me?

    Thanks Ted

  • #2
    Couple of generic responses.
    What do you mean by 'high compression' pistons.
    Anything over 10:1 on the street for general driving is going to require high octane fuel AND octane boost of some sort.
    Retarding the timing to stop ping will only aggravate a hot running problem. Have you tested your fuel pump for both pressure and flow?
    The long, and smallish diameter, of the stock Stude fuel line from the tank makes for a long draw for fuel, and getting todays fuel hot at low pressure is asking for vapor lock.
    Having your distributor recurved (and blueprinted) is an excellent idea. Keeping some stiff advance springs will help the ping problem a bit.
    Just thinking out loud...
    Jeff[8D]




    quote:Originally posted by lube_sales

    I own a 63 GT Hawk, with a rebuilt 289 V8, added high compression pistons, cast iron headers, R1 cam, Carter AFB 4 BBL, triple core rad. I have 2 major problems, when the car heats up to 180 it vapour locks, or rattles until it quits. I have redirected the fuel line from the pump to the carb so it does not pass the header but with no + affect.I just recently added the 4 bbl, (had a 2bbl Stromberg) the problem seems to be worst now.
    Second, since the rebuild I have had to retard the timing greatly to avoid major pinging upon accereration, to the point where I only have 12 to 13lbs vacuum.
    Are these 2 problems related?
    The gent who rebuilt my engine is an experienced Stude Enthusiast, and I believe he rebuilt it correctly, but I am open to any and all ideas. I was told that I will need to re curve my distributor, will this help?
    Desperate to drive my car this summer since our summers are so short here, I hate it sitting in the garage on nice days, could some one help me?

    Thanks Ted
    HTIH (Hope The Info Helps)

    Jeff


    Get your facts first, and then you can distort them as much as you please. Mark Twain



    Note: SDC# 070190 (and earlier...)

    Comment


    • #3
      Jeff, Thanks for the thoughts, the fuel pump is new from Stude International, but had the problem before new pump. I do put in Premium fuel and yes they are 10:1 pistons. I tried adding octance boost but nothing changed.Would placing a larger spacer between the manifold and the carb help? If so where can I find them are they rare or common?

      quote:Originally posted by DEEPNHOCK

      Couple of generic responses.
      What do you mean by 'high compression' pistons.
      Anything over 10:1 on the street for general driving is going to require high octane fuel AND octane boost of some sort.
      Retarding the timing to stop ping will only aggravate a hot running problem. Have you tested your fuel pump for both pressure and flow?
      The long, and smallish diameter, of the stock Stude fuel line from the tank makes for a long draw for fuel, and getting todays fuel hot at low pressure is asking for vapor lock.
      Having your distributor recurved (and blueprinted) is an excellent idea. Keeping some stiff advance springs will help the ping problem a bit.
      Just thinking out loud...
      Jeff[8D]




      quote:Originally posted by lube_sales

      I own a 63 GT Hawk, with a rebuilt 289 V8, added high compression pistons, cast iron headers, R1 cam, Carter AFB 4 BBL, triple core rad. I have 2 major problems, when the car heats up to 180 it vapour locks, or rattles until it quits. I have redirected the fuel line from the pump to the carb so it does not pass the header but with no + affect.I just recently added the 4 bbl, (had a 2bbl Stromberg) the problem seems to be worst now.
      Second, since the rebuild I have had to retard the timing greatly to avoid major pinging upon accereration, to the point where I only have 12 to 13lbs vacuum.
      Are these 2 problems related?
      The gent who rebuilt my engine is an experienced Stude Enthusiast, and I believe he rebuilt it correctly, but I am open to any and all ideas. I was told that I will need to re curve my distributor, will this help?
      Desperate to drive my car this summer since our summers are so short here, I hate it sitting in the garage on nice days, could some one help me?

      Thanks Ted

      Comment


      • #4
        Three words: Electric Fuel Pump. You can mount an electric fuel pump back by the tank to push the gas and eliminate the mechanical pump completely. Or, you can put the electrical pump back by the tank to push the gas up to the mechanical pump and put a switch on the electrical pump to only run it when you need it. Vapor lock was an occasional problem on these cars when they were new, but the modern gas boils at a much lower temperature, and the problem is much worse than it was in the old days.

        Comment


        • #5

          Lots of little things add up.

          1. Agree with going to a low-pressure electric fuel pump. Don't get carried away with some race pump stuff.
          2. Consider moving your PCV to the front of the carb if it is still at the back.
          3. Check your advance curve to confirm it matches the specs in the manual.
          4. Check for vacuum leaks. Any time a manifold is changed, it can happen.
          5. If octane boost didn't make any difference, your compression may be more than the original 10.25. If your builder bored way oversize, used flattop pistons, gave the heads a cleanup mill, and put on thin head gaskets, you could be looking at 11+ compression. No way that is ever going to work today. Know it is a pain, but you might have to pull the heads and cc the chambers to verify where you are. Quick and dirty, run a compression check on all cylinders. If it is over 200psi, it probably won't work on the street any more.

          thnx, jv.

          PackardV8
          PackardV8

          Comment


          • #6
            Great thanks for this, I did a compression check and the cyln ran from 178 to 185, the PCV is still at the back, could look at that. My mech also recommended an electric fuel pump, will do that if all else fails, it may be my only option. I was told that I should use a manifold gasket with the middle hole blocked so hot air does not hit the carb, ever heard of this and where could I get one of those?
            Again Thanks for all of your help.
            Ted


            quote:Originally posted by PackardV8


            Lots of little things add up.

            1. Agree with going to a low-pressure electric fuel pump. Don't get carried away with some race pump stuff.
            2. Consider moving your PCV to the front of the carb if it is still at the back.
            3. Check your advance curve to confirm it matches the specs in the manual.
            4. Check for vacuum leaks. Any time a manifold is changed, it can happen.
            5. If octane boost didn't make any difference, your compression may be more than the original 10.25. If your builder bored way oversize, used flattop pistons, gave the heads a cleanup mill, and put on thin head gaskets, you could be looking at 11+ compression. No way that is ever going to work today. Know it is a pain, but you might have to pull the heads and cc the chambers to verify where you are. Quick and dirty, run a compression check on all cylinders. If it is over 200psi, it probably won't work on the street any more.

            thnx, jv.

            PackardV8

            Comment


            • #7
              Hey Thanks my mechanic also highly reccomend an Electric fuel pump, it seems to be the popular answer. I will discuss it with him. I did not know it was possible to still use the old mech one and simply boost it with a back up pump. Sounds good.
              Thanks Again Ted

              quote:Originally posted by whacker

              Three words: Electric Fuel Pump. You can mount an electric fuel pump back by the tank to push the gas and eliminate the mechanical pump completely. Or, you can put the electrical pump back by the tank to push the gas up to the mechanical pump and put a switch on the electrical pump to only run it when you need it. Vapor lock was an occasional problem on these cars when they were new, but the modern gas boils at a much lower temperature, and the problem is much worse than it was in the old days.

              Comment


              • #8
                If you do not use the electric fuel pump (or even if you do) you may want to consider adding a R1-style inline fuel filter with a return line fitting, and run a return line back to the fuel tank. It might even be worthwhile to change out all the fuel lines to have a 3/8" feed, R1-style, since after all you basically have a R1 just without the windage tray and damper. This will keep the fuel cooler at least while the engine is running.

                Agree on the timing; are you using composition head gaskets? Retarding timing will make the engine run hotter and subsequently exacerbate your vapor lock problem.

                good luck,

                nate

                --
                55 Commander Starlight
                62 Daytona hardtop
                http://home.comcast.net/~njnagel
                --
                55 Commander Starlight
                http://members.cox.net/njnagel

                Comment


                • #9
                  One more thought, I am told that certain 70's Chryslers used an inline, disposable fuel filter with a return fitting, as a less expensive alternative to a real R1 filter. I will probably put one on my '55 when I get it all back together but I just haven't gotten that far with my project yet, so I don't have a part number to give you.

                  nate

                  --
                  55 Commander Starlight
                  62 Daytona hardtop
                  http://home.comcast.net/~njnagel
                  --
                  55 Commander Starlight
                  http://members.cox.net/njnagel

                  Comment


                  • #10
                    Your compression is on the low side of R1 specs, so that is not your problem.

                    All that is needed to block off your exhaust heat riser is a couple of thin pieces of stainless steel about .030". Just slide them between the intake manifold and the gasket and retighten the clamps.

                    After you are certain you have no vacuum leaks and the PCV valve is in the front and functioning correctly, another possibility, the carb may be jetted too lean. Lean pings before rich, so get someone who has a chassis dyno to read your exhaust at the rpms and loads you are having the most pinging.

                    Nate's idea of adding a return line is a most excellent one and you should definitely try it. An electric pump with a return line should solve the vapor lock problem.

                    thnx, jv.

                    PackardV8
                    PackardV8

                    Comment


                    • #11
                      I you elect to run both the electric and the mechanical pumps, be sure to switch the electrical pump. Only use the electrical to start the car, and once it is running, switch it off. It is not good to run them both continuously.

                      Comment


                      • #12
                        quote:Originally posted by whacker

                        I you elect to run both the electric and the mechanical pumps, be sure to switch the electrical pump. Only use the electrical to start the car, and once it is running, switch it off. It is not good to run them both continuously.
                        Gotta add a little here wacker...

                        If you're gonna run that electric pump, (and that's exactly what I'd suggest), I would not run it in conjunction with the mechanical pump. If the mechanical pump diaphragm goes bad, it WILL fill the crankcase with fuel. Remove and block off the mechanical pump hole, (Chebby plate will work with trimming), and run the electric pump only.

                        Also, watch which electric pump that you use, choose with care. The little, round, universal, 4 psi pumps sold in most FLAPS are junk in my experience, (can't keep the filter full on long fuel line runs and fail every few months). I would get, (and this is what I did), the 5 to 8 psi pump, works MUCH better, lasts longer, both old Ford and Stude carbs love it.

                        One very important note to using an electric fuel pump, DO wire it through a low oil pressure switch, meaning..... You can buy a switch that looks something like the old-style brake light switch, but with three terminals on top. What you want to do is screw the pressure switch into one of the extra oil pressure holes in the heads, put a push button switch in the dash somewhere, and wire it so you can push the button to "prime" the carb. if needed, but it will kill the pump in the event of an accident or loss of engine oil pressure.

                        Also, one LARGE problem we Stude guys have, and was well covered by Jack earlier..... If you don't do ANYthing else, COVER THE INTAKE CROSSOVER HOLES! Jeff Rice makes/sells the super thin, stainless plates in a very reasonable kit, get one. That frappin' huge hole with exhaust running thru it at all times under your carb. is absolutely unnecessary! Heat from the intake turns the carb. into a pressure cooker and evaporates the alcohol based, chitt fuel that we're stuck with, right in the fuel lines! Hell, if the ambient temperature is hot enough and you don't have the crossover blocked, using the stock mechanical pump, fuel never even GETS to the filter! You can now buy the 12 volt replacement choke caps OR, (better yet), put a hand choke on it!

                        One last tip, (and this is actually more for "parade duty", but works very well at any time and gives more benefits than just stopping vapor lock), pour a quart of diesel fuel in the tank with every fillup. Yep, that's right, diesel fuel, trust me, it works.

                        Good luck....




                        Sonny
                        http://RacingStudebakers.com
                        Sonny
                        http://RacingStudebakers.com

                        Comment


                        • #13
                          The diesel remedy was discussed in a previous thread, and somebody provided a very precise answer why the diesel "additive" was a simple but effective solution.
                          / H

                          Comment


                          • #14
                            lube, it sounds like this has been pretty well covered, i just went through this same battle before i left for deployment. a few things that might help, for your carb i highly advise getting a phenolic spacer, even just a 1/4 incher will help. also another thing that might be going on is if you recently had a rebuild you might have to re-adjust your valves, which is a pain sometimes and makes a pretty good mess of smoke and oil, but with a fresh re-build like that your valves are going to tighten up more then enough to when your engine heats up your intake and exhaust will be fighting each other, causing it to bog down and die. those were the problems i had and once they were addressed it fixed it right up. by the way summit sells phenolic spacers for a edelbrock carb(if thats what you have) for about 20 bucks or less. if you have something that a edelbrock spaceer wouldn't work with you can ask around and try to get a piece of phenolic, trace your gasket on it and cut it out yourself. be sure to wear a respirator!!!! good luck hope this helped out.

                            p.s. miss all you guys, can't wait to get back to the states, back to my stude and a chance to get on the forum. benny.

                            notsoslow64
                            1964 lark daytona
                            bd_marks@yahoo.com

                            Comment


                            • #15
                              I want to thank all of you for your suggestions and help. I will block the cross over first and see how that works, then I will try the 3 outlet filter, and if all fails I will try an electric fuel pump. Reason is I am trying to keep the unit looking as original as possible. But also fast to show all the other makes that Studes are not to be triffled with.
                              I will keep you up to date with my progress.
                              Thanks Again Ted

                              Comment

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