I have i 383 in a 63 nova that tore teeth off the distributor. i took the dist out of the motor to only ralize that it has about .20 play all the way around it when it sits in the manifold. i ordered a new dist from sumit and i measured it with a mic and still .20 gap. im baffeled its a eldelbrak victor jr intake. and all the ports lined up when it was instaled. any thoughts???
The distributor has a precision fit to the block only. The intake hole is loose, otherwise there'd be no tolerance for misalignment and you'd have to install the distributor before torquing the intake.
Been through this problem a few times before. First, we need to answer a couple of questions. How many miles/how long did it take for this to happen ? Have you rebuilt/changed anything recently ? Is it a stock or aftermarket cam? Roller or flat tappet? What brand of distributor is it ? Let us know, and we can proceed ! Dave
the motor has about 5,000 miles on it and it is an msd dist,the cam is a roller. the guy i got it from said that he had to keep adj the timing every 1500 miles. this seems rly odd to me. thank you for the help i would love to kn why this happened.
That sounds like a ton of slop to me, which is enough to let the distributor wobble around and gobble up the gear. Also great to have those nice shards floating about in the oil pan. Was there something missing from the manifold like a bushing? It would be easy enough to make up from oilite bronze and lightly press it into the manifold. Bob
OK, next question.. Are you running the nova front sump pan and pump combo ? IF so then maybe somebody installed the std length op driveshaft and it is holding the drive gear up off the cam.. Take a look at the worn gear.. Is the wear centered or down toward the bottom ? Dave
the oil pan looks like a rear sump. the reason i say that is because the front is extremly shallow and the rear is so big it wraps around some linkage.
i was thinking about a bushing but i dont have an easy means to a mill or lathe. it doesnt seem right that i would have to do that but i do love machineing (sp)
seen that with msd's, use cam break-in lube on the gears when you put the new gear on the distributor. i THINK the lack of zinc (in the newer oil) is killing 'em.... not sure if you mean the distributor fits loose in thehole or just doesn't go it all the way... if it's not going in all the way,has the block been decked or have the heads been milled? you MAY have to run more than on gasket on the distributor.... seems to me msd has some spacers for that...but i could be wrong
I think he means the distributor is too long, and it's bottoming out at the gear before the housing meets up with the manifolds, so there's a .2" vertical gap between the manifold and the clamp area of the distributor. I wonder if the oil pump drive shaft is hunky dory?
IF the problem is the distributor sitting too high above the manifold this can happen if the oil pump is a big block version. The shaft on a BB pump sticks into the block farther than a SBC pump. There is a shorter intermediate shaft made to use a BB pump in a small block. I once made one by cutting the slot longer in the intermediate shaft. I think the difference is 180 thou. which is pretty close to the measured .2 inch. I seem to remember that the SBC pump has a 4 bolt cover and the BB pump has a 5 bolt cover.
it may have been a bad gear, how long do they last on the street ? we had them wear out on stock cars.
is there a good cam button to keep the cam from eating the gear, only supposed to be .005 to .008 end play on the roller cam
I believe the distributor housing has two places that are machined to barely fit into precise holes down in the block. I think those parts of the housing have much more to do with locating the distributor than the hole in the manifold.
Why not use a mellonized dist gear (or a nylon?) instead of the bronze gear? Arent the bronze gears designed to be a "sacrifice" part that are subject to wearing out quickly? As far as the slop in the manifold, I dont think it is an issue. Seen it on lots of engines. I have used the mellonized gears without issue, ever...
has thier been any resolve to this before I post a similar thread. Loose distributor in hole on aftermarket offy intake... o-ring, bushing? Thanks
I think I'd take a look at the diameter of a stock iron or alum. intake , if it's different ,you can make up a bushing or replace the intake. Jack
....has about .20 play all the way around it when it sits in the manifold. Do you really mean that the hole in the manifold is almost a half inch bigger than the distributor?? .20 is two tenths on an inch. On each side?? If that is true, the manifold has been machined improperly. Or, the distributor is undersize. I could see .020 (20 thousanths), but not 2 tenths.
Normal fit is the distributor gasket only contacts the intake around the outer half of the gasket. DISTRIBUTOR FIT IS ESTABLISHED BY THE BLOCK. The hold down clamp is just that, it holds the distributor down so it can't come up out of the precision-fit block hole. If the gasket don't fall in the intake's hole, you're good! Start "fitting" the distributor to the intake and now you're forcing the distributor at both ends without precision, it's not designed for that and will f*ck up bushings, shafts, & gears due to the resulting misalignment If distributors were precision fit at both ends, intake manifolds would require alignment dowels.
Shifty, What you say is exactly right. But, if the slop is .2 on each side, would not the hold down clamp be pushing the distributor down onto the gear too hard if the manifold hole is bigger than the distributor dia??
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