hi it is normal for timing to change as you tighten distributor ,-- IF it is somehow moving the oil pump drive gear up and down inside the motor .Down , in this case ? Was the motor rebuilt? an error in that assembly work around the length and position of the oil pump drive shaft / gear on pump drive or precision of assembly of those parts may cause this . If this diagnosis is right . The drive gear for the pump and distributor that mates with the cam is machined at an angle -- so any vertical motion of the internal gear parts makes them rotate slightly . That said, when you set timing, keep mount tab tight enough it is not easy to turn . Not " loose" But the drive to the distributor itself is a slot and tab , inherently designed to keep timing right independent of amount of vertical engagement ( more on that in a second) It is, or should be totally insensitive to tightness in the timing sense There is no way ( as an engineer) that I can see that this fault is in the distributor? even if the distributer shaft had badly worn thrust washers , vertical movement rises and lowers point rubbing block , not much else .I believe there is a cross pin in didt shaft in a collar , locking height ? Unless ridiculous amount due say to leaving out the special shaped washer under the advance assembly or in upside down etc . All that is extremely remote , infact so unlikely , as to just discount it . Even then the timing wont change? At very high mileage , supposedly the bushings holding shaft can wear wobbling the cam block . I have never seen that, except in total junk aluminum mopar " performance " distributors which have no provision to oil those bushings and , unbelievably , mine was put together dry in china or where ever they came from , wiped itself out in 1000 miles , no oil ---- ram cars have a beautiful grease oiler , cast iron case The reason I respond to this, is I have a37 packard six business coupe I restored . The engine had already been rebuilt . Twice on start after using it a bit I had a really violent backfire, cracked the bell housing , bent the starter shaft destroyed the bendix ( 500 $ starters 6 v rewound to 12 ) cracked the starter nose casting too . All this is unobtanium in 2026 . = big $! And a lot of work , trans , clutch, flywheel , bell housing has to come out , a bear in a packard Distributor obviously checked , top to bottom 15 times, replaced with another etc All was perfect To make a long painful expensive journey short ( disappointing the 12 armchair experts) , the reason was the distributor tang barely engaged the oil pump drive gear and Packard has a 45 taper on tip on the tang sides to help engage it at assembly despite very close fit . Someone had apparently done something wrong at rebuild -- the slot was too far in ,from the block surface -- but still drove the distributor by hitting the angled portion (!) .( on one-side of taper , but --- could be the other ) So there were two stable drive positions . one correct ( almost, where it was timed) , one was out xx degrees where xx landed it way advanced ( maybe in another cylinder ) driving the engine backwards on all 6 with starter engaged ( for 1/1000 sec?) blowing up everything !! Sharing this ( not your issue , but very related) I decided to machine .1" off distributor bottom plate that touched block letting tab go in further , to untapered part , ran ok then thinking more , I measured the slot depth , with just a shaft pulled out of one of the others -- I found I could go another .1 . Tab on all dist is maybe 3/8-1/2 " long Did that . Not opening motor to find out why ... Point of all this , diagnosis that distributor is at fault is probably incorrect ? Given how all this functions ? School of very hard knocks .. Hope info helps you... PS -- RB had major problems in 61-62 with drive gear / oil pump drive engagement ,at oil pump drive hex end , ( like an allen wrench) . The hex end would shear off, especially 426 max wedge at high rpm , high oil pump loads . Boom . There were / probably still are, many after market " better parts" but I wonder if one was supplied somehow wrong ? the gear rests on a machined surface in a pocket near cam , the bottom of the long shaft floats axially in oil pump via that drive hex , I think . Been a long time . Melling made good ones in the day .. On Jul 22, 2026, at 9:33 PM, 'Neal Thomas' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx> wrote: -- For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang --- You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group. To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/DED439CE-F902-4A7E-97C6-A14BA6CD8792%40gradyresearch.com. |
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