Through a little bit of driver error at the dragstrip last Sunday I suffered a bent pushrod. Luckily I did no further damage. I contacted Wegner Motorsports, my engine builder, hoping to get a replacement for the bent one. They said to try these from Comp. They are almost too pretty to seal up inside the engine.
__________________ Jeff
99 Miata LS6
67 Camaro Street Fighter 599 HP L92-SOLD
Through a little bit of driver error at the dragstrip last Sunday I suffered a bent pushrod. Luckily I did no further damage. I contacted Wegner Motorsports, my engine builder, hoping to get a replacement for the bent one. They said to try these from Comp. They are almost too pretty to seal up inside the engine.
You know Greg I don't remember a backfire, but I had a lot going on at the time. I wanted to get a couple of runs in before the long Wisconsin winter so I took it out because it was a nice day.
After getting off the line with some wheelhop and starving for fuel for a split second in 2nd and 3rd gear I was amazed at how hard it was pulling. So much so that I sort of missed 4th and coasted it through for a 12.59 at 95 mph. I was going 94 at the 1/8 mile. I think there might be a low 11 or maybe a hair better in this thing if I can get it off the line and shift all the gears.
Todd, I hooked the air compressor up to that cylinder with 100 lb in the tank. I left it hooked up for a minute or so and went to the tailpipe and intake to listen for air rushing out and heard nothing. When I unhooked the fitting on the air hose there was a pretty good volume of air that rushed out of the cylinder and the tank on the compressor still read 98 PSI.
I am going to compression test a couple of cylinders tomorrow to double check when I install the new pushrods.
__________________ Jeff
99 Miata LS6
67 Camaro Street Fighter 599 HP L92-SOLD
Many years ago I had a similar problem that I solved, to this day.
"No bent valve, minor valve float, rocker arm binding" ?
My case found that when the rocker arm exceeded its normal travel (valve float),
the pushrod seat edge contacted the side of the push rod.
This contact forced the pushrod out of alignment with the rocker arm.
Smith Brothers, a NASCAR push rod manufacturer, has the ability to install a "high angle" rocker ball.
The lifter side ball is the normal straight design.
These cost the same as the standard design, just ask.
This last week I received my latest order, ordered on 4:59PM Thursday, on Tuesday
Their ability to create a pushrod with custom length and ship in the same day states a well operated business.
Your case could also benefit with a "rocker arm pivot height check". I know that Mike, Dan, "the guys" are
very aware of the importance of Rocker Arm Geometry.
I always recheck this because it is so simple to "just mark" the valve tip with a felt marker
before I install the pushrod/rocker arm.
Then turn the engine over with the starter, reinspect the contact area of the valve stem.
Thanks for your input Lance. There were no marks on that particular rocker arm that showed wear that was inconsistent with the others. What I did not mention is that 2nd gear was engaged briefly when shifting to 4th. I assume that is what did the damage. Under "normal" use and eliminating driver error, I don't anticipate any problems especially with the Comp pushrods that Dan sent me.
On another note, I am sneaking up on the tuning. I do want to bounce a couple of things off you. I will try calling you on Monday.
__________________ Jeff
99 Miata LS6
67 Camaro Street Fighter 599 HP L92-SOLD
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
Pushrods
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