rodneybeauchamp Posted October 31, 2020 Share Posted October 31, 2020 Hi all, 1962 Valiant SV1 with 225 slant six engine, manual transmission. When cranking the motor we noticed that the distributor rotor was not turning. We were also able to rotate the distributor rotor and shaft by hand. No wonder it would not fire! Removing the distributor we noted that the horizontal drive pin on the distributor shaft was fine but could not work out what should drive it from inside the motor. Can forum members shed some light and perhaps some photos of what may be the issue here? Rodney 😀😀😀😀😀😀 Link to comment Share on other sites More sharing options...
broker-len Posted October 31, 2020 Share Posted October 31, 2020 the other end of distributor shaft has a gear that is driven by cam shaft first make sure the rotor is not slipping on shaft if shaft is not turning maybe the gear has come lose from the shaft or stripped drain oil pull pan so you can look up into motor and see what is going on Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 31, 2020 Share Posted October 31, 2020 (edited) Is there a plastic or nylon gear at the bottom of the distributor shaft? Is it intact, not stripped or worn? Was the distributor all the way down? The distributor is driven by a gear on the camshaft which is part of the camshaft. The chance of it going wrong is practically nil. The fault must be in the distributor . You can see how it is driven off the camshaft in this illustration. You can't see the drive gear on the cam, but it is a spiral type gear that drives the distributor and oil pump. Edited October 31, 2020 by Rusty_OToole (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 31, 2020 Share Posted October 31, 2020 (edited) The top of the shaft is free to turn on the lower part but only to a limited degree, for the centrifugal advance. I don't see how but it is conceivable that the advance mechanism is broken. If you take out the distributor, first turn the engine to top dead center with the #1 cylinder on compression. This will make it easier to time the distributor when you put it back in, or when you get a rebuilt distributor. Edited October 31, 2020 by Rusty_OToole (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 31, 2020 Share Posted October 31, 2020 The only other thing I can think of, is failure of the camshaft drive. If the engine turns over but the valves do not move, the cam drive has stripped. This is not the end of the world, a new cam chain and sprockets can be installed without removing the engine but you must be careful to clean out any debris. Link to comment Share on other sites More sharing options...
MikeC5 Posted October 31, 2020 Share Posted October 31, 2020 (edited) Could timing chain be broken? Cam would not turn. If I remember correctly, if you remove the oil filler cap, you can see one of the rocker arms on the head. Rotate the motor and verify that the rocker moves up & down. If it doesn't move, cam is not rotating. If I'm wrong about being able to see a rocker arm, remove the distributor and rotate engine and try to look in the distributor hole with a flashlight to verify cam gear is turning. Edited October 31, 2020 by MikeC5 (see edit history) Link to comment Share on other sites More sharing options...
c49er Posted October 31, 2020 Share Posted October 31, 2020 Back in the day I used to replace those stripped out plastic distributor drive gears on the slant sixes. Most all parts stores even carried them as it was a common problem on higher mileage engines. 1 Link to comment Share on other sites More sharing options...
Oldtech Posted November 1, 2020 Share Posted November 1, 2020 Yes, if the gear looks good it's likely the timing chain. If it were me.. I'd pull the valve cover and crank it over to see what is happening. Link to comment Share on other sites More sharing options...
Frank DuVal Posted November 1, 2020 Share Posted November 1, 2020 OP said the drive pin iis OK. Is there a plastic gear on it? I speak from experience, the plastic gear CAN break! Used to be a common parts store item, so I guess they failed often enough to be a stock item.😉 Oh, I see Bob has already said this. 😄 Link to comment Share on other sites More sharing options...
rodneybeauchamp Posted November 1, 2020 Author Share Posted November 1, 2020 OK from what we saw, it appears the plastic gear is broken as part of it went in the sump as we tried to fish it out. Didn’t know they had that sort of drive but makes sense. I will pass this on to the new owner who is a Valiant guy. many thanks to all! Rodney 😀😀😀😀😀😀😀 Link to comment Share on other sites More sharing options...
RussJagoau Posted November 1, 2020 Share Posted November 1, 2020 Hello I did my Mechanics apprenticeship on those old slants and the timing gear failure is a common problem. So i would suggest you pull the sump off and clean the oil pump pickup as well - reason being 9 times out of 10 the fibre gear remnants will block or partially block the oil pickup. Holden 6 cyl Red Motors used to suffer the same fate also. More than one suffered catastrophic failure due to the blocked oil pump pickup not long after the timing gear failure had been repaired as to replace the gear itself is only half the job done !!!. Link to comment Share on other sites More sharing options...
hchris Posted November 1, 2020 Share Posted November 1, 2020 17 minutes ago, rodneybeauchamp said: OK from what we saw, it appears the plastic gear is broken as part of it went in the sump as we tried to fish it out. Didn’t know they had that sort of drive but makes sense. I will pass this on to the new owner who is a Valiant guy. many thanks to all! Rodney 😀😀😀😀😀😀😀 Yep that'll do it, one more thing to consider when sourcing the drive gear, there were 2 different distributors used here and you've guessed it, they had different size gears Link to comment Share on other sites More sharing options...
rodneybeauchamp Posted November 1, 2020 Author Share Posted November 1, 2020 Thanks for your input, will pass it on! cheers Rodney 😀😀😀😀😀 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted November 1, 2020 Share Posted November 1, 2020 Plastic timing chain sprockets and plastic distributor drive gears often fail on very old cars because they are weakened and made brittle by age. GM V8s used to be patsies for this, with the cam drive sprocket failing anytime after 10 years. I haven't seen this on Chrysler products but no reason they should be immune. 1 Link to comment Share on other sites More sharing options...
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