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slick56
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Group: Forum Members
Last Active: 2 Months Ago
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I have done about 40 miles on my new engine, and today, while taking off from the lights, the engine started running rough.On looking in the rear view mirror, the r.h. pipe was blowing heaps of smoke, and at idle the revs were up about 200.Upon getting it home i hooked up a vacuum guage and restarted it. No smoke for a couple of minutes (then plenty) but still running rough.Pulled the pass. side valve cover and no pushrod for no.4 intake. Pushrod cup broken into 3 pieces, luckily still in the rocker area.I have installed new camshaft and all new top end; valves, springs, collets, retainers; rocker shafts, 1.54 rockers and longer pushrods. i put in longerpushrods because i kept the '56 oil trays.I have no idea why the pushrod broke, there does not appear to be anything wrong, other than lash was a bit loose, i was going to re-adjust valves when i got home today.As i do not have another long pushrod, will it be ok to run one of the slightly shorter ones that came from the engine, until i can source a new one from the USA, or should i replace them all with the shorter ones (which were a bit of a mismatch of two different styles) ??Thanks, Al.
South Australia
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PF Arcand
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Similar problems were reported here a year or so a go. Apparently in one case, the pushrod socket was not a proper match for the ball on the adjuster. Hopefully someone will come on here with further information for you . Good luck..
Paul
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slick56
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Group: Forum Members
Last Active: 2 Months Ago
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 Have just pulled out the pushrods from two engines (the rebuilt 292 and the old 312) and, including the long pushrods i got from John Mummert, there are four different types ! Effective lengths are approximate, but close.Still can't upload pics, so have added as attachment..bottom is the long one, length of 8.112", .312 dia.next up has no ball but machined insert, length of 7.982, .311 dia.next up has large ball, length of 7.975, shaft dia. of .270top one has small ball, length of 7.915, shaft dia. .3125Not a bloody set amongst them...
South Australia
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charliemccraney
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Group: Moderators
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The pushrod cup is probably too small for the adjuster screw ball. You should use pushrods of the same length. The longest possible will yield the highest ratio at the rockers. Usually, if you do vary the length, the intake will use one and exhaust will use another. If you have enough pushrods, you can experiment with that but you probably won't notice much, if anything.
Lawrenceville, GA
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jonnireb
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Group: Forum Members
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Check to make sure that valve isn't stuck.
55f100West Monroe,La.
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slick56
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Group: Forum Members
Last Active: 2 Months Ago
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"The pushrod cup is probably too small for the adjuster screw ball." charliemccraney
These were a new set of pushrods, but i guess one out of a few hundred could be faulty..
jonnireb (6/15/2014)
Check to make sure that valve isn't stuck.
The first thing i did; put a brass drift on the valve and gave a whack with a hammer, valve moves ok.
South Australia
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charliemccraney
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New does not necessarily mean manufactured correctly - I know because I've been there. I also would not call what you have a set. That's just a bunch of mismatched pushrods. Check them all on the ball of the rocker arm before you reinstall them.
Lawrenceville, GA
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2721955meteor
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when you pre lubed wher you getting oil to all rockers.when i bought my ranchero it had a broken push rod,Reason poor oil flow to rocker arm.Re your push rod delema ,why not remove the trays,which in efect lengthens the push rods.you may want to think about eliminating drain tubes,or at least pinch them off some.if eng. rebuilt i would guess you ar using comp head gaskets,that makes push rods shorter.push rodes are in most cases the result not the problem, good luck
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slick56
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Group: Forum Members
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charliemccraney (6/15/2014)
New does not necessarily mean manufactured correctly - I know because I've been there. I also would not call what you have a set. That's just a bunch of mismatched pushrods.
I put in a full new set of long ones from J Mummert, it was one of those that broke the cup.
Plenty of oil to the top end, everything new including outside grooved cam bearings. Two of the reasons i put in the long ones, to make up for the thickness of the composition head gaskets, and i want to keep the trays.
South Australia
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Ted
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Was the fuel fresh when the new engine was fired? Old fuel will varnish the intake valve stems/guides and cause them the stick. This in turn typically bends the original style 1/4" intake pushrods but if tubular pushrods are being used, then I can see the cups taking the blunt of the force. Beyond that, the lifters are the next failure point and having pushrods fail would definitely be preferable to that.
  Lorena, Texas (South of Waco)
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