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Engine Parts: Pushrods - The Long And Short Of It

The Perfect Pushrod Length

By Mike Petralia, Photography by Courtesy Of ETC, Inc.

When it comes to assembling a host of go-fast engine parts, pushrods are rarely thought of as being anything more than a simple link between the cam and the valves-that is, until one of them breaks or you're putting a new combination together and you find that your stock pushrods won't work anymore. Why wouldn't they work, you might ask then?

There are many factors that determine whether or not a pushrod will fit and operate correctly. Unfortunately, there's little information out there showing you how to determine if yours are correct. We wanted to know what was involved in properly measuring for new pushrods and then see if those measurements would translate correctly into a real, working engine. To find out how to measure pushrods we called Lunati Cams, and they supplied their Pushrod Length Checker, which is a practically foolproof way to determine the proper length. Then, to see how accurate our measurements were we used a Rocker Arm Geometry Checker from Ferry's Aluminum Cylinder Head Repair to see if the proper length pushrods put the rocker arms in contact with the right spot on the valves.

Vital Measurements
Stock engines are easy to order new pushrods for. Just tell the cam company what type of cam you're running (i.e. hydraulic roller, flat-tappet, etc.) and what diameter you'll need to fit your guideplates (i.e. 5/16, 3/8, or the big 7/16). But what about engine blocks that have been decked or heads that have been milled? Machine operations like those can require custom-length pushrods, and there's really no way to know exactly how long they'll need to be without a trial assembly first.

That's where Lunati's kit comes in. The parts included with the tool are: an adjustable length pushrod (two different lengths for big-blocks), a modified roller rocker that's missing the trunion bearing assembly but has a regular roller tip, and a long poly-lock nut without the locking set-screw. Instructions included with the kit tell you to first put the cam lobe of the valve you're checking on its base circle as if you were going to set the valve lash. Insert the adjustable pushrod with its end turned most of the way down to clear the rocker arm. Then, screw the modified rocker arm on by hand until all clearance between the valve and roller tip is taken up. It might help to use some light lube on the rocker nut and adjustable pushrod tip to free things up.

Then, simply turn the pushrod until the tip contacts the rocker arm cup and creates a tight assembly. You'll know just by the feel of things when you've got all the slack removed. Then, secure the pushrod's adjustable lock nut finger tight before removing it. It might be necessary to remove the pushrod guideplates when you perform this check. If you do, make sure to keep the rocker arm tip centered on the valve. It's then a simple matter to measure the adjustable pushrod with a large dial caliper or machinist's rule to determine your new length.

Checking Things
How will you know if the new pushrod length you just came up with is ideal? Even though the Lunati tool is utterly foolproof, there's always room for human error. That's where the guys at Ferry's Aluminum Cylinder Head Repair can help out. They make a tool to check roller tip placement with any length pushrod. The tool works by measuring the roller tip placement relative to the valve stem tip, and a little math tells you if you've got it right. Centering the roller tip on the valve when the cam is at mid-lift is the best way to ensure longevity and increase horsepower, as well.

The increase in longevity comes from a decrease in side-loading of the valves that happens when the roller tips are too far off center. The horsepower increase comes from the reduced frictional losses from having the tip off center also. Ferry's testing has shown that it can take several foot-pounds more torque to turn the engine over by hand when the rocker tips are off center. Consider measuring for new pushrods an integral part of building a performance engine. After all, you wouldn't assemble an engine without checking bearing clearances or degreeing the cam, would you? This is just one more step towards perfection, and it's an easy step at that.

Official Sweepstakes Rules

1. McMullen Argus Publishing, Inc. is offering the Toys for Your Tools Sweepstakes ("Sweepstakes").
NO PURCHASE NECESSARY. A PURCHASE DOES NOT IMPROVE YOUR CHANCES OF WINNING.<

2. Sweepstakes begins at 12:00:01 a.m. E.T. on Tuesday, November 6, 2001 and ends at 11:59:59 p.m. E.T. on Monday, August 12, 2002. Sweepstakes is only open to residents within the fifty (50) United States who possess a valid driver's license and are 18 years or older as of August 12, 2002. Sweepstakes void where prohibited by law. Employees of McMullen Argus Publishing, Inc. ("Sponsor"), their respective parents, subsidiaries, affiliates, advertising and promotion agencies and their family/household members are not eligible to enter. All federal, state, local, municipal and provincial laws and regulations apply.

3. Enter by filling out (1) one official entry form available in the following participating magazines, or by providing your name, address and phone number on a 3 1/2" x 5" card containing the magazine's address and the name of the sweepstakes. You may also enter the sweepstakes by visiting the web site addresses indicated:

Auto Sound & Security, PO Box 56953, Boulder, CO 80322-6953 (www.autosoundmag.com); Car Audio and Electronics, PO Box 58265, Boulder, CO 80322-8265 (www.caraudiomag.com); Classic Trucks, PO Box 56643, Boulder, CO 80322-6643 (www.classictrucksweb.com); Custom Rodder, PO Box 56899, Boulder, CO 80322-6899 (www.customrodder.com); Drag Racing USA, PO Box 56492, Boulder, CO 80322-6492 (www.dragracingusaweb.com); 4 Wheel Drive & SUV, PO Box 56311, Boulder, CO 80322-6311 (www.4wdandsportutility.com); GM High-Tech Performance, PO Box 56133, Boulder, CO 80322-6133 (www.gmhightechperformance.com); High Performance Mopar, PO Box 56412, Boulder, CO 80322-6412 (www.highperformancemopar.com); High Performance Pontiac, PO Box 56351, Boulder, CO 80322-6351 (www.highperformancepontiac.com); Import Tuner, PO Box 56467, Boulder, CO 80322-6467 (www.importtuner.com); Kit Car Illustrated, PO Box 56521, Boulder, CO 80322-6521, (www.kitcarillustrated.com); Lowrider, PO Box 56857, Boulder, CO 80322-6857 (www.lowridermagazine.com); Lowrider Euro, PO Box 56455, Boulder, CO 80322-6455 (www.lowridereuromagazine.com); Mini Truckin', PO Box 56677, Boulder, CO 80322-6677 (www.minitruckinweb.com); Muscle Mustangs & Fast Fords, PO Box 56388, Boulder, CO 80322-6388 (www.musclemustangfastfords.com); Mustang Illustrated, PO Box 56563, Boulder, CO 80322-6563 (www.mustangillustrated.com); Off Road, PO Box 56761, Boulder, CO 80322-6761 (www.off-roadweb.com); Popular Hot Rodding, PO Box 56157, Boulder, CO 80322-6157 (www.popularhotrodding.com); Street Rodder, PO Box 56282, Boulder, CO 80322-6282 (www.streetrodderweb.com); Super Chevy, PO Box 56026, Boulder, CO 80322-6026 (www.superchevy-web.com); Truckin's SUV, PO Box 56464, Boulder, CO 80322-6464 (www.truckinssuv.com); Turbo & High Tech Performance, PO Box 56461, Boulder, CO 80322-6461 (www.turbomagazine.com); Vette, PO Box 56824, Boulder, CO 80322-6824 (www.vetteweb.com); VW Trends, PO Box 56001, Boulder, CO 80322-6001 (www.vwtrendsweb.com).

Individuals may enter this sweepstakes by filling out the online form only once. Entries may be handwritten or typed. Multiple entries are not permitted. One entrant per entry. No more than one entry per envelope. One entry per person per e-mail address. More than one entry from any person or e-mail address will void all entries from that person or e-mail address. All entries must be received by 11:59:59 p.m. E.T. on August 12, 2002. Sponsor is not responsible for late, lost, illegible, incomplete, stolen, or misdirected entries. Entries that are printed by machine, mechanically reproduced, tampered with, illegible or incomplete are not eligible.

4. The prizewinner will be selected in a random drawing conducted on or around September 12, 2002, from among all eligible entries received as of August 12, 2002. The total number of eligible entries received will determine odds of winning. Entries become the property of Sponsor and will not be returned. Sponsor will have the right to photograph the winner. Entry constitutes permission to use winner's name, picture, likeness and city and state of residence for purposes of trade, publicity or promotion for no additional compensation.

5. One (1) grand prize winner receives: a Craftsman 1,197 piece tool set, 52-inch chest and mobile tool cart, and a Craftsman 2-stage 25 gallon compressor. Ten (10) runners-up will receive a 159 piece Craftsman tool set. Sponsor makes no warranties with regard to the prize. Prize is not transferable. No substitutions of prize allowed by winner, but Sponsor reserves the right to substitute a prize of equal or greater value. Prizes are not redeemable by winner for cash value. Estimated combined retail value of prizes is $8270.00.

6. The winner (or the parent/guardian if winner is a minor) will be required to execute an affidavit of eligibility showing compliance with Sweepstakes rules and a publicity/liability release. All taxes on prizes are solely the responsibility of the winners.

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8. Failure to execute and return any requested document within twenty-one (21) days of postmark, or return of notification or prize as undeliverable may result in forfeiture of prize and an alternate winner may be selected at the sole discretion of Sponsor. All reasonable effort will be made to contact the winner.

9. Void where prohibited by law. All federal, state and local laws and regulations apply.

10. In the event of a dispute, entries made by Internet will be deemed made by the authorized account holder of the e-mail address submitted at the time of entry. The "authorized account holder" is deemed the natural person who is assigned to an e-mail address by an Internet access provider, service provider or other online organization that is responsible for assigning e-mail addresses for the domain associated with the submitted e-mail address.

A potential winner may be requested to provide Sponsor with proof that the potential winner is the authorized account holder of the e-mail address associated with the winning entry. If for any reason the Sweepstakes is not capable of running as planned, including due to infection by computer virus, bugs, tampering, unauthorized intervention, fraud, technical failure, human error or any other causes beyond the control of Sponsor that corrupt or affect the administration, security, fairness, integrity, or proper conduct of the Sweepstakes, Sponsor reserves the right in its sole discretion, to disqualify any individual who tampers with the entry process, and to cancel, terminate, modify or suspend the Sweepstakes.

Sponsor assumes no responsibility for any error, omission, interruption, deletion, defect, delay in operation or transmission, communications line failure, theft or destruction or unauthorized access to, or alteration of, entries. Sponsor is not responsible for any problems or technical malfunction of any telephone network or lines, computer online systems, servers, or providers, computer equipment, software, failure of any e-mail or entry to be received by Sponsor on account of technical problems or traffic congestion on the Internet or at any web site, any combination thereof, or otherwise, including any injury or damage to entrant's or any other person's computer related to or resulting from participation or downloading any materials in the Sweepstakes.

CAUTION: ANY ATTEMPT BY AN ENTRANT TO DELIBERATELY DAMAGE ANY WEB SITE OR UNDERMINE THE LEGITIMATE OPERATION OF THE SWEEPSTAKES MAY BE A VIOLATION OF CRIMINAL AND CIVIL LAWS AND SHOULD SUCH AN ATTEMPT BE MADE SPONSOR RESERVES THE RIGHT TO SEEK DAMAGES FROM ANY SUCH PERSON TO THE FULLEST EXTENT PERMITTED BY LAW.

11. A complete list of prize winners will be available on the web sites listed in Section 3 on Friday, November 9, 2002 or by sending a stamped self-addressed envelope after January 15, 2002 to McMullen Argus Publishing, Inc., Attn: CIRCULATION Dept., Toys for Your Tools Sweepstakes Winner's List, 2400 E. Katella Ave., 11th Floor, Anaheim, CA 92806.

12. The sponsor of this sweepstakes is McMullen Argus Publishing, Inc., 2400 East Katella Ave., 11th Floor, Anaheim, CA 92806.

SOURCES
Ferry's Aluminum Cylinder Head Repair
710 Quietwood St.
Dallas
TX  75253
Powerhouse Products
3402 Democrat Rd.
Memphis
TN  38118
800-872-7223
901-795-7600
www.powerhouseproducts.com
Lunati Cams
Olive Branch
MS
6-62/-892-1500
lunatipower.com
Reher-Morrison Racing Engines
1120 Enterprise Place
Arlington
TX  76017
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By Mike Petralia
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