Elongating push rod holes...

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Oct 10, 2003 | 04:49 PM

HDIronman

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From: somewhere south of normal

Elongating push rod holes...

Tried to install 1.6 rockers but the push rods are binding on the heads. I can only get about 340 degrees of rotation before they start to rub. Tech at W/P said they probably needed to be opened up a bit.

How did you guys, and or gals, elongate your push rod openings? What tool did you use, and how much to remove?

I'd sure like to drive this vette one time before winter. This should be the last thing I need to get the motor back in the car.

Your help now could mean the difference between total insanity and total bliss :cool:

Oct 10, 2003 | 05:01 PM

Smokehouse69

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From: Semper ubi, sub ubi

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Re: Elongating push rod holes... (HDIronman)

1/2" drill bit at the same angle as the holes. Of course the heads have to be off the car to do that. Learned that trick from Chevy Highperformance Magazine. Here's a link to the article;
http://www.chevyhiperformance.com/te...148_0208_vort/

Oct 10, 2003 | 05:17 PM

clem zahrobsky

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Re: Elongating push rod holes... (HDIronman)

there is a drill jig called a "louis tool" that the cam companies sell to make the slot longer. you can not just drill the holes bigger unless you are going to use bolt on push rod guides. if you remove the intake and place newspaper in the tappet chamber and you are carefull you can do it on the engine. "been there done that" :chevy

[Modified by clem zahrobsky, 5:18 PM 10/10/2003]

Oct 10, 2003 | 08:02 PM

joe73vette

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Re: Elongating push rod holes... (clem zahrobsky)

I used a round file on my old 400, but I did have guide plates installed. Joe

Oct 10, 2003 | 09:55 PM

cardo0

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Re: Elongating push rod holes... (clem zahrobsky)

:iagree: Yes. I did see a cheap “louis tool” copy made by Proform. And if you cover that lifter valley well enough with rags, then vacuum, you should be able to leave heads on. The company that sold me WP Torquer heads just drilled out my guide slots enough with a big drill since I ran guide plates. Don’t recommend this without guide plates. :yesnod:

Oct 11, 2003 | 10:20 AM

HDIronman

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Re: Elongating push rod holes... (joe73vette)

Thanks for all the replies.

The engine is not in the car, it's on a stand in the garage right now. I took the heads back off, and with a rat tail file, made the openings longer. I am using hardened guide plates. I put one head back on the block to check the clearence, and no more binding. So I'll do the other head and I should be good to go.

While I'm at it, I think I will unshroud the valves.
:cheers:

Oct 11, 2003 | 10:29 AM

clem zahrobsky

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Re: Elongating push rod holes... (HDIronman)

if you are using guide plates make sure you have clearance all around the push rod or you will have a binding problem. the holes must be wider and longer that they were before. i would drill the holes to at least 7/16" dia. :chevy