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Thread: ford 4600 engine trouble

  1. #61
    MrNoo
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by essexpete View Post
    Am I unsderstanding correctly that the high point of lobe flattens as wear accelarates bcause that is where the loading occurs?? (rather than uniform wear around the whole cam)
    Correct, wear starts at the tip, goes through the surface hardening, a fairly rapid deteriation then occurs. Seen it a lot in race engines, high lift cams and high rpm, road cars so would assume the same for tractors!

  2. #62
    Right-arm fast
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by MrNoo View Post
    Correct, wear starts at the tip, goes through the surface hardening, a fairly rapid deteriation then occurs. Seen it a lot in race engines, high lift cams and high rpm, road cars so would assume the same for tractors!
    It will be interesting to see where this all stems from and how worn the cam is. Even with the cam rotating at half the crank speed multiplying it up, the timing is still a long way out.

  3. #63
    Pryderi
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by Colhonk View Post
    looks like you have the wrong cam fitted upside down, inside out and back to front
    Maybe it's a four cylinder one cut shorter or even half a six cylinder one!!!!

  4. #64
    scoobyjim
    Guest

    Re: ford 4600 engine trouble

    didnt have much chance to do much today but increased clearences on tappets and improved no2 slightly but made 3 worse. Will be next week before i get another chance but cam is coming out next so will let you know what happens next week.

    THANKS EVERYONE SO FAR

  5. #65
    Julian_P
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    came across something interesting today

    with a degree dial fitted crankshaft is within a degree of being correct

    valves on the other hand should be

    intake opening 14 btdc
    intake closing 38 abdc

    exhaust opening 41 bbdc
    exhaust closing 11 atdc

    actually

    intake opening 48 btdc
    intake closing 82 abdc


    exhaust opening 64 bbdc
    exhaust closing 42 atdc

    in other words opening early and closing late

    WORN CAMSHAFT???
    Certainly not a worn camshaft. I used to come across this on Lycoming aircraft engines in the past and a worn cam gives LATE opening and EARLY closing of valves. This stands to reason if you imagine a 'model' in your mind's eye. The easy way to spot a worn cam, ie one with the lobes worn down is to measure maximum valve lift, obviously it'll be much reduced

    I'm perplexed by the valve events that you recorded. Having a fair few years of BTDT on American big blocks etc I can only think that the method you used to measure differs from that of the factory. For instance the factory may use valve timing figures measured with 25 thou lift observed of the valve from the seat.

    Once you start getting in at the 'deep-end' then a healthy respect for the devil being in the detail pays dividends

    Julian.

  6. #66
    Julian_P
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    but cam is coming out next so will let you know what happens next week.

    THANKS EVERYONE SO FAR
    If the cam was so worn as to create problems like you describe then it would have been obvious, by a country mile, when you did the rebuild.

    Julian.

  7. #67
    agrimax
    Guest

    Re: ford 4600 engine trouble

    Will take a guess that the camshaft is twisted or the timing is out.Interesting to hear the outcome.

  8. #68
    Pryderi
    Guest

    Re: ford 4600 engine trouble

    What's the possibility of the camshaft gear not in the correct position on cam? Can it actually move or been fitted wrong previously? I've got some vision in my mind of the timing gear fitting on a key onto the cam or am I thinking of a different engine? Did you mention you brought it not running? Any evidence of spannering before?

  9. #69
    Right-arm fast
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by Pryderi View Post
    What's the possibility of the camshaft gear not in the correct position on cam? Can it actually move or been fitted wrong previously? I've got some vision in my mind of the timing gear fitting on a key onto the cam or am I thinking of a different engine? Did you mention you brought it not running? Any evidence of spannering before?
    IME some have a woodruf key and some dont, even if they have a keyway - just taper fit. If the gear was on the cam in the wrong position the valve timing for intakes and exhaust would all be either advanced or retarded depending on the the position of the gear.

    At the moment the timing is both advanced and retarded. So with the greatest respect possible to scoobyjim his measurements might be a little out or someones been fiddling with the engine because of a cam problem perhaps and fitted the wrong cam which they already had to get it going to flog it, or they didnt realise they had bought or been given the the wrong one. Could be wrong though obviously.

  10. #70
    essexpete
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by Right-arm fast View Post
    IME some have a woodruf key and some dont, even if they have a keyway - just taper fit. If the gear was on the cam in the wrong position the valve timing for intakes and exhaust would all be either advanced or retarded depending on the the position of the gear.

    At the moment the timing is both advanced and retarded. So with the greatest respect possible to scoobyjim his measurements might be a little out or someones been fiddling with the engine because of a cam problem perhaps and fitted the wrong cam which they already had to get it going to flog it, or they didnt realise they had bought or been given the the wrong one. Could be wrong though obviously.
    Yes I am reading it with the timing approximately in the right place but the window/envelope of valve lift being widened??

  11. #71
    suffolksmallholder
    Guest

    Re: ford 4600 engine trouble

    As an aside to timing marks;
    We have an elderly little Skoda for the youngest children to drive and learn in.
    Timing chain was getting quite rattly so I did some internet research to see about the what, whys and wherefores. There was a warning out about the genuine Skoda repair kits, in that one of the timing marks was one tooth out. A picture followed, just for information, as some had been fitted perfectly aligned but resulting in the engine running really badly...... Strip down again and reset this either one tooth back or forward and presto a purrrfect runner.
    SS

  12. #72
    scoobyjim
    Guest

    Re: ford 4600 engine trouble

    i stand to be corrected but the method used was to reduce tappet gap to 2thou, degree gauge on the crank and a dial test indicator on top of the valve cap. As the piston is coming to top centre, watch the dial and as soon as the valve starts to open and the guage moves, look at the degree gauge and should read 14 degrees.

    Is this correct.

  13. #73
    Right-arm fast
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by essexpete View Post
    Yes I am reading it with the timing approximately in the right place but the window/envelope of valve lift being widened??
    I honestly dont know, but that seems to be the case/possible.

    Quote Originally Posted by scoobyjim View Post
    i stand to be corrected but the method used was to reduce tappet gap to 2thou, degree gauge on the crank and a dial test indicator on top of the valve cap. As the piston is coming to top centre, watch the dial and as soon as the valve starts to open and the guage moves, look at the degree gauge and should read 14 degrees.

    Is this correct.
    The method varies as does for example setting tappet clearances.
    You need to check the service manual as to the correct way of doing it as you may need to check crank position/tappet clearances and/or valve lift etc to get it right. If you have the manual it should explain how to do it for this engine, as i dont know. You could check maximum valve lift by putting your dti on the pushrod side of the tappet while your at it and compare to the specs this will give you cam lobe wear.

  14. #74
    Julian_P
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    i stand to be corrected but the method used was to reduce tappet gap to 2thou, degree gauge on the crank and a dial test indicator on top of the valve cap. As the piston is coming to top centre, watch the dial and as soon as the valve starts to open and the guage moves, look at the degree gauge and should read 14 degrees.

    Is this correct.
    Mopar cams specs generally referenced to 50 thou lift.

    Julian.

  15. #75
    Julian_P
    Guest

    Re: ford 4600 engine trouble

    Just out of curiosity I've found the specs on a camshaft that I happen to have the literature to hand on. (albeit for a petrol engine but it's irrelevant as it's the principal that I'm demonstrating.)

    Two sets of figures here, one measured at 4 thou lift and one measured at 50 thou lift. [1]

    @ 4 thou lift

    Intake opens 26 BTDC closes 72 ABDC
    Exhaust 80 BBDC closes 30 ATDC

    @ 50 thou lift

    Intake opens 2 BTDC closes 40 ABDC
    Exhaust 56 BBDC closes 2 BTDC

    [1] lift measured with rocker arm ratio of 1.5

    A monster difference depending on the datum you use to make measurements. And of course there's no standard so the engine manufacturer may quote figures entirely different from the cam manufacturer!

    Julian.

  16. #76
    genesis
    Guest

    Re: ford 4600 engine trouble

    just came across this post ,you say 4600 but is it a 4600 or 4000 engine ? reason I ask is pisotn bowl shape was different & if you fitted the later pistons in a 4000 or fitted 4600 short motor you would get similar symptoms too yours only way too fix was too change inj pump , what height were your pistons above block ? 4600 only used the thick head gasket pistons will hit head with thin gasket seen & heard it. I would have given it some work or checked power on dyno.

  17. #77
    Right-arm fast
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by genesis View Post
    just came across this post ,you say 4600 but is it a 4600 or 4000 engine ? reason I ask is pisotn bowl shape was different & if you fitted the later pistons in a 4000 or fitted 4600 short motor you would get similar symptoms too yours only way too fix was too change inj pump , what height were your pistons above block ? 4600 only used the thick head gasket pistons will hit head with thin gasket seen & heard it. I would have given it some work or checked power on dyno.
    Interesting about the piston height.

    I remembered i have the service manual for the tw5 -35 6 cyl tractors. The valve timing is identical to the figures quoted for the 4600 engine so if its the same as the tw engine - No1 piston should be at TDC compression when installing the timing gears and lining up timing marks. The cam drive gear is keyed to the cam shaft so can only go on one way. So in theory if all that is correct scoobyjim your timing should be right. Once all is in place if you turn the engine backwards 45 degrees and then in the correct DOR when the no1 piston is at TDC the timing marks should all be perfectly aligned again. I cant find anything about methods of checking the cam timing once everything is back together for this engine so i guess theres no need to if all is right as above.

  18. #78
    scoobyjim
    Guest

    Re: ford 4600 engine trouble

    Everything is exactly as you say about the timing.

    Took cam out and there is 10thou wear compared to a new one and setting it up on vee blocks on the bench with a dti, from the lobes lowest to maximum lift is 306 thou even across the whole cam, soit doesnt appear to be that bad.

  19. #79
    5020man
    Guest

    Re: ford 4600 engine trouble

    Hi.

    Had similar symptons with a new Force 4000 back in 1968.

    Turned out to be faulty non return valves in the hollow bolts that fix the

    injector pipes to injector pump.

    Hope this helps.

    5020 man

  20. #80
    Julian_P
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    Everything is exactly as you say about the timing.

    Took cam out and there is 10thou wear compared to a new one .
    I'm a bit doubtful if you have 10 thou wear. I'm not saying you're necessarily wrong, but I tend to suspect that you're within the tolerances on the cam specs in your comparison between old and new.

    10 thou of wear (I suspect) would have taken you through the case hardening (on cam and follower underside) and the consequential wear would be noticeable as a rough(ish) surface on lobe peak and follower underside....

    However, as I'm sure you've sussed out, it has little to do with your main problem.

    Julian

  21. #81
    Richard
    Guest

    Re: ford 4600 engine trouble

    If its not really that worn and the clearances are correct, but still the valve timing is so out.. both ways.. are we sure its the right cam then?

  22. #82
    genesis
    Guest

    Re: ford 4600 engine trouble

    Ive got a spare 4610 engine with only 850 hrs on came out of a wood chipper .

  23. #83
    behive
    Guest

    Red face Re: ford 4600 engine trouble

    Not quite your issue but once had outfit recon 3 cyl petrol DB, motor pinged badly, they had fitted a diesel crank.

  24. #84
    scoobyjim
    Guest

    Re: ford 4600 engine trouble

    well jobs stopped now till after christmas, here is where im at now

    valves opening as they should now - no change

    changed fuel pump from another tractor - no change

    i can get her to rum better if i retard the timing of the pump to the extremities of the mounting slots (will not run if i retard a tooth on the gear)

    Thinking back to when i stripped the engine, the exhaust ports of 2 and 3 were so carboned up you could bearly get a screwdriver into the port, surgesting that she was throwing fuel out the exhaust of 2 and 3 for a long time.

  25. #85
    pjj
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    well jobs stopped now till after christmas, here is where im at now

    valves opening as they should now - no change

    changed fuel pump from another tractor - no change

    i can get her to rum better if i retard the timing of the pump to the extremities of the mounting slots (will not run if i retard a tooth on the gear)

    Thinking back to when i stripped the engine, the exhaust ports of 2 and 3 were so carboned up you could bearly get a screwdriver into the port, surgesting that she was throwing fuel out the exhaust of 2 and 3 for a long time.
    If injectors 2 and 3 had two copper washers under them by mistake it could cause these symptoms.

  26. #86
    Right-arm fast
    Guest

    Re: ford 4600 engine trouble

    Quote Originally Posted by scoobyjim View Post
    well jobs stopped now till after christmas, here is where im at now

    valves opening as they should now - no change

    changed fuel pump from another tractor - no change

    i can get her to rum better if i retard the timing of the pump to the extremities of the mounting slots (will not run if i retard a tooth on the gear)

    Thinking back to when i stripped the engine, the exhaust ports of 2 and 3 were so carboned up you could bearly get a screwdriver into the port, surgesting that she was throwing fuel out the exhaust of 2 and 3 for a long time.
    If the engine is ok, possibly air in the fuel, poor lift pump oeration/pressure not supplying enough fuel to the last two pumping elements to charge them fully retarding the timing - (lift pump blocked with crud/brocken spring etc),
    FIP pump internal phasing incorrect on elements 2 and 3, delivery valves not functioning properly will retard injection timing alot (ATDC) or prevent it altogether, injector nozzles worn or incorrect opening pressure. As mentioned above i would have thought all three injectors should have copper washers. If it has a cold start/excess fuel button on the pump throttle lever, is it clicking out when the engine has fired up, Check you have the correct injector pipe going to the right injector (i made that mistake on a 6cyl, made me scratch my head for 15 minutes).

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