Do I need custom length pushrods?
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Race Director
Joined: Oct 2000
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Do I need custom length pushrods?
This is really stupid...both what happened and the excuse. What happened is my mom lost my adjustable pushrod, the excuse is that all I can remember about when she lost it is that I said, "I'm never going to find it there." I can't remember where there is.
So, now that I'm ready to measure, I'm at a loss for a measuring device. I can't figure out why this would possibly matter though. Can I use the stock length?
My motor is composed of a medium cam, and 1.6 roller tip rockers. Stock heads, 1.94/1.50, new springs/increased spring rate.
What is to be lost if I use the stock pushrods instead of a custom length.
And lastly, is 5/16" big enough for a motor that will never rev over 4,900 rpms, or should I go bigger? If so, how much bigger? Thanks.
So, now that I'm ready to measure, I'm at a loss for a measuring device. I can't figure out why this would possibly matter though. Can I use the stock length?
My motor is composed of a medium cam, and 1.6 roller tip rockers. Stock heads, 1.94/1.50, new springs/increased spring rate.
What is to be lost if I use the stock pushrods instead of a custom length.
And lastly, is 5/16" big enough for a motor that will never rev over 4,900 rpms, or should I go bigger? If so, how much bigger? Thanks.
Thread Starter
Race Director
Joined: Oct 2000
Posts: 16,477
Likes: 1
From: Enter Post Count Here
Re: Do I need custom length pushrods? (NoWorries)
Alright, I think I've answered one question, it sounds like Cheby SBC's that come with hyd-roller cams require 5/16 inch ends, and it sounds like mucho bucks and even a waste of $$$ to get a thicker shank and still have to have 5/16 inch *****.
Burning Brakes
Joined: Dec 2000
Posts: 849
Likes: 0
From: Lafayette LA
Re: Do I need custom length pushrods? (NoWorries)
Don't you just hate when that happens? The dog ate my homework once, so I know how you feel.
You can install a pushrod and paint the tip of the valve (where the rocker contacts it) with some metal dye. Turn the motor over by hand a few times and see where the dye rubs off. If it is centered, the length is OK.
You can install a pushrod and paint the tip of the valve (where the rocker contacts it) with some metal dye. Turn the motor over by hand a few times and see where the dye rubs off. If it is centered, the length is OK.
Safety Car
Joined: Apr 1999
Posts: 4,623
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From: Ohio
Re: Do I need custom length pushrods? (NoWorries)
If you didn't shave the heads, deck the block or change the lifters, I would not alter the factory length. The recommendation above is a good one, if you want to check. BUT, you can't do it with the springs on the valve you're checking. You must temporarily install a checking spring which is just strong enough to keep the valve from falling into the CC. If you used a 110# seat pressure spring and turned the motor over by hand, the lifter would colapse and not give you an accurate indication. BTW, you would measure the pushrod height at half lift and want a "wear" pattern of .070" in the center of the valvestem. I learned about this the hard way...don't ask. I can't take credit for the outlined procedure, I got it from the cam guys, with Brian Crower being most helpful.
