Classic Engine Tech 1967 - 1981 Engine Related

Valve train geometry question

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Old Jun 1, 2003 | 04:24 AM
  #1  
SLO SS K2's Avatar
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From: Lake Zurich, IL, USA
Valve train geometry question

The roller part of the rocker touches the outside edge of every valve. I have been told I need a shorter push rods because I will prolly damave the guides. Is this info corrrect, 383, Dart Fead, and crane 1.52 Roller rockers. How much shorter dhould I go. (Had to ask that, sorry.)
Thanks,
Steve
Old Jun 1, 2003 | 09:25 AM
  #2  
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You really need to get an adjustable length pushrod or a pushrod length checker; both are very inexpensive. I use the adjustable length pushrod. I use a felt tip marker to "paint" the top of the valve black and then put the pushrod in and adjust the valve. Rotate the engine over a couple of revolutions and remove the rocker arm. The wear pattern should be in the center of the stem. If it's to the outside of the engine like yours then the pushrod is too long. Shorten up the adjustable pushrod and re-do until you get the pattern centered. Then measure the pushrod (consider taking to a machine shop if you don't have an accurate way to measure the length; a tape measure isn't going to cut it!).

It is fairly critical to get the length right, especially if you're near the edge of the valve. Going over the edge would be a problem!

Jody
Old Jun 1, 2003 | 01:41 PM
  #3  
SLO SS K2's Avatar
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Well, I started it up anyway. One of the Studs broke. I'm guessing that I should have tried something else. That's life.
Does anyone know the length of a stock pushrod?
Thanks
Old Jun 1, 2003 | 06:21 PM
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Dirt Reynolds's Avatar
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I'm guessing that I should have tried something else.
Jody gave you the proper advice. Why ask a question and then not bother to follow sound advice?

I'm not trying to be an ***, but clearly you have a geometry issue and an adjustable pushrod is the only way to find the exact proper length you'll need.

None of us can help you out with what length pushrod you'll need; you *must* check this yourself.

Most pushrod manufacturers these days are pretty good about taking your order, and shipping your custom-length push rods fairly quickly.

Frequently when going to aftermarket heads/valvetrain, the pushrod length will need to be changed as well; this is usually a custom ordered part.

Jody explained in pretty good detail how to go about doing this. If you can't or won't be bothered to follow his advice, its pretty much guaranteed your broken stud is only the beginning of your problems.

Your alternative is to take your car into a reputable shop local to you, and have them finish the job properly, as well as repair the broken stud.

Good luck.
Old Jun 1, 2003 | 06:39 PM
  #5  
SLO SS K2's Avatar
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Dirt. First and foremost. I appreciate you direct approach. No offense taken. I do listen to advice here. But, I wanted to get the car running. The post was several hours after the original question. The correct length of the new pushrod is 7.3" While I was at it I added a few other items. I'm hoping I didn't bnd a valve. If I did. I will deal with that too. I can guarantee I will learn from my mistakes.
SPK
Old Jun 1, 2003 | 07:05 PM
  #6  
Dirt Reynolds's Avatar
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From: Surrey, BC
Sounds good. Let us know how it all goes for you.

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