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GearheadMon Jan-25-10 01:34 PM
Member since Mar 18th 2009
9 posts
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"Broken push rods - T140V"


  

          

I have a 73 T140V with all 4 push rods damaged on the lower (tappet) ends. Not wear damage but broken and chipped. The engine has true NOS TT cams with high perf valve springs and push rods. I know that some cams require these high perf items. Are they nessasary with TT cams? I haven't check for coil bind on the springs yet but will today. Don't think I'll find this to be the cause for the broken push rods because this engine worked fine for several hundred miles with many high RPM runs. Although I won't rule coil bind out until I check. No valve striking marks on the pistons and the push rods aren't bent. Head and cylinder are not plained/decked but will be before temp reinstall to check coil bind. Do I have an inferior set of push rods? Can I use stock springs and push rods? Any opinions are welcome.
Steve

  

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GearheadThu Jan-28-10 04:33 PM
Member since Mar 18th 2009
9 posts
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#1. "RE: Broken push rods - T140V"
In response to Reply # 0


  

          

Semi update.

Further inspection has revieled a few things.

First, the high perf valve springs. 120 lbs to open the valve. Wow!
Going back with stock springs.

Second,the high perf push rods. I compaired and measured the cup size of the HP ones and a used stock push rod. No doubt the aftermarket high perf ones have smaller cups therfore not allowing the them to set deep enough onto the tappet. New push rods on order.

Third, the tappets. After measuring the ball end of the tappets I found something I've never seen before. The tappet ball ends measured slightly larger than the HP push rod cups opening. This would explain why they broke the way they did. However, the tappet balls measure very slightly smaller than the used stock push rod cups they still do not seat fully. Deeper than the HP's but not all the way to the bottom of the push rod cup.

When I get the new push rods, I'll use lapping compound to see how deep they seat into the tappets. May need tappets.

  

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