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Blow by.

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  • #16
    Ok. A few questions;

    Does it smoke on start up (out of the exhaust pipes)?
    If so, does it do it hot or cold (or both)

    If you nail it, does it lay down a smokescreen?
    Does it smoke more under acceleration or decelleration?
    Same Q with what comes out of your blowby tube.
    Speaking of which, where does the hose from your oil cap attach? the outer air cleaner housing (outside of the filter?)

    Let me know, but it sounds like you have even more serious issues than rings not seated. If you see smoke coming in the car . . . Don't drive it (much) until you get this resolved.
    John Byers
    1960 Convertible (Orig owner)


    • #17
      * what do your plugs look like if you pull a couple?
      * how much oil (i.e. a quart every XXX miles) are you using?
      * have you checked that nothing is leaking onto an exhaust component ? (like the valve covers)

      A leak down tester might provide some interesting information with not alot of work.
      1958 Hardtop
      #8452 TBird Registry



      • #18
        Regarding smoke out the exhaust pipes: the only times I've seen smoke out the pipes have been when 1. the engine has been tuned rich and 2. I'm starting the car for the first time in several weeks (and even then, it hasn't always smoked). Over the last several days, when I've been driving it all the time, I have not seen any evidence of exhaust smoke at all, even when accelerating relatively briskly. And I have been checking for it fairly often.

        The smoke out the filler tube happens most liberally when the engine is maintained at moderate or high RPMS. The faster it spins, and the longer, the more gas it makes. I can only see it out the hood when I'm stopped, but as I said, if I leave the a/c vents open, cruising at 60 mph I can see the same gases blowing into the passenger compartment through the vents. I take this to mean that there's enough gas building up under the hood that it can find its way through the a/c ducts, which are obviously not sealing very well. Avoiding the highway helps. I suppose the pcv is able to do a better job keeping up with the blowby at lower speeds so I don't see much of it coming into the car. I've been riding always with the windows open so I don't have to breath that stuff.

        I don't have a hose coming from the oil cap. I'm using the stock, original oil cap.

        I pulled all my plugs and checked each one just a few days ago. Most of them were very clean, healthy looking normal plugs with a light dusting of tannish color, and a couple of them were immaculate, looking almost like they were new out of the box.

        I don't know that I'm using any oil. I used to leak some out of my pcv setup because it wasn't sealed properly; it dripped down onto the bellhousing. If it is using oil, it's doing so at maybe 1 quart every 1000 miles. that's a really rough estimate and it's almost worthless; I'll try to monitor it from here out.

        There may be some leakage of trans fluid on the exhaust pipes below the pass. compartment. If this is happening in any significant amount (which I doubt) it would blow back underneath the car, not out the front.

        Thanks so much for all of you guys' input so far! This is really puzzling me and I want to get to the bottom of it.


        • #19
          Do you suppose I could be using the wrong pcv valve? The one I'm using looks just like the one pictured at the bottom of the Squarebirds Technical article page. Maybe its spring is too weak or too strong?

          Just seems strange that the blow by gets sucked in at idle in park/neutral but not in other situations.


          • #20
            The PCV valve is most restrictive, though not totally closed, when the engine is at idle (the engine develops the most vacuum at idle). At wide open throttle, there is little engine vacuum, so the blow by gases would not flow through it, but would go mostly through the oil cap as you describe.

            There are countless PCV valves. They all work in a similar fashion. There is a spring towards the carburetor that rests against a tapered insert. It is impossible for the PCV valve to completely close completely in the direction of the spring. The other side of the insert is flat, so that if there is backfire it can close.

            To what vacuum source did you hook up the PCV valve?
            1959 Hard Top
            1960 Golde Top


            • #21
              I have a single rubber hose coming off of a fitting in the stock location on the intake manifold. A T-fitting in the hose splits off to go to the fuel/vacuum pump; another t-fitting farther down the hose splits off to go to the brake vacuum booster on one side and the pcv valve on the other.


              • #22

                The pcv line is installed on it's own into the intake manifold. The vacuum suction created through the combustion process draws the blowby gases back into the engine. The pcv valve flows in one direction only, similar to a check valve. If there is clearance for a carb spacer, that is what I would install. The pcv valve could be in backwards, too. Good Luck



                • #23
                  That's how the original Ford kit came. It was installed on mine in the early 70's when pops put the hi-po 390 in there.
                  Ftg @ Rr of Int/manif w/90 deg bend. then a 3/8 hi pres hose (not fuel line) so it won't collaps, then pcv to 3/8 fitting at the rear of the carb spacer plate (part of kit).
                  Part 2 is an oil cap with a 1/2" outlet. There was a fitting popped into the side of the air filter hsg with a 1/2 inl. Aprox 1 ft of hose connecting them. Walla . . . Poss crank case ventalation. When I installed the 62 air cleaner, I moved the hose ftg to the under side out of sight.
                  John Byers
                  1960 Convertible (Orig owner)


                  • #24
                    Do you suppose that installing the oil cap breather with the hose to the air cleaner would take care of my problems? At least then the extra gases would go back into the engine rather than breathing out all over everywhere....


                    • #25
                      Well, that's the bandaid to find out where all this blowby is coming from. Do you have the pcv backwards? That would sure do it.
                      Thats too goofy. no smoke out of the exh but excessive blowby??!!! Something is bass ackwards somewhere
                      John Byers
                      1960 Convertible (Orig owner)


                      • #26
                        I really don't think it's in there backwards... the larger end is towards the crankcase and the smaller end is towards the vacuum source.

                        Really, it is strange. It demonstrates no other unhappy symptoms but the blowby. I'm using the valve labelled pcv1134 sold at AUtozone; it's the one they say to use for '61 birds and most other early Fords.

                        Any other ideas? Things to try?


                        • #27
                          Something to do with the intake and how the oil from the rocker arms drain. I remember some wierd thing FE motors were notorious for.
                          I'll check with a couple of my old time Ford buddies. Might be 1st part of next week until I get ahold of them. If there's no smoke in the exhaust, it's a top end oiling problem.

                          If you're running the pcv, you also need to run the breather into the air cleaner. That's not the fix for your problem, but it will put the excess back into the engine.
                          John Byers
                          1960 Convertible (Orig owner)


                          • #28

                            Can you take a couple of photos of how it's hooked up. It might help someone to be able to spot something.

                            Where do you have the large end of the PVC valve going to?
                            1960 Hard Top/430
                            Thunderbird Registry Number 1231


                            • #29
                              A top end oiling problem? Very interesting!! I know it has those strange oil baffles under the rocker shaft mounts. I had to buy them used because mine were missing. I didn't install the large central baffle; everyone told me it wasn't needed.

                              I checked the pcv for suction at idle earlier. It was sucking hard! As soon as I pulled the valve out blow by gasses started pouring out of the hose I had pulled the valve from. Like I said, though, nothing come out the breather with the valve installed and the car idling in park.

                              Here are some pictures of my setup.

                              This one shows the manifold connection and the first t-fitting, which goes to the fuel pump.

                              This one shows the hose at the other t-junction. The right split goes to the brake booster. You can also see the valve and my "custom" pcv adaptor. It's just copper tube with a plastic cap sealed with silicone and a brass hose fitting threaded into a hole in the copper tube. The fitting sticks into the tube maybe a half inch or so.

                              Here's another view of the valve. Big end is at the bottom.


                              • #30
                                ...and in drive with the brake on the blow-by billows out from the hood scoop and breather tube. Hmm.

                                peeeot, how are you making out with seating the rings ?

                                I am not sure if this thread is your log of engine modifications or what ?

                                I am anxious to read what you discover.