Better Engine Building: How to Determine Correct Pushrod Length

It's a bad idea to ever simply drop a set of pushrods into your fresh engine build. Improper pushrod length can cause excessive wear to the valve stems and early valvetrain failure. Thankfully, the process to checking to determine the proper pushrod length is both simple and quick. Big thanks to Erson Cams for their support.

Here are some of the tools I used in the video:
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[tinkmarshino]

I haven't built and engine in about 20 some years now.. But I have been getting the itch again.. Built a lot of them back in the day.. I think I would like to build just one more before it become impossible for me to do.. thanks my brother.. I appreciate even the dream of doing it again..

[janeberg]

Did I miss something? Guide plate under rocker stud will raise the height and change the push rod, liked your video was fun

[vikinghauler]

If you are doing a hydraulic set up would add any length for preload ?

[francfurian]

Excellent explanation, simple, clear & informative.

Cheers😊

[BKMDano]

Thank you. I'm building a 460 and I have a lot of this stuff sorted out but that's always been one of the things I didn't know. Want to help?

[TheSlimgt]

To each their own, but I always adjust until I get the shortest possible sweep no matter where it falls. As long as it isn't rolling off the edge, the rocker always pushes straight down. Wide sweep patterns lead to guide wear.

[ercost]

Doing this in 2022 on a Corvair motor. These old heads have had lots of valve jobs, and valves & guides replaced over 50+ years, so every single valve gets a custom pushrod. Seems like you and all the books say to have rocker contact centered across the valve tip but I disagree. Valve spring force starts at 100# and increases to over 250# at full lift. Valve/guide load & wear vary proportionally to the lift. So I prefer to cheat the contact area closer to the valve, "higher" as you call it here. Of course this is upside down compared to a Corvair. Anyway my goal is to have the contact point centered at max lift & spring pressure. Maybe just barely past center (lower in your terminology). My 2 cents.

[johngolding]

As an old hot rodder, Did mine in the 70’s, and a shade tree mech this was an informative vid. Can’t ever have to much stable horsepower. Thanks!

[peterbuilttough]

So..my intake side is perfect..centered and correct geometry. Now the exhaust side seems like the rocker arm studs are way to close valve stem, I've used adjustable pushrod, Not possible to get centered, like I need a shorter rocker arms, Only thing I can think of is I have to tall of exhaust valves I have no idea, This is why you should never buy Chinese made heads people,

[macfranks]

You were checking your valve stem pattern at 0 lash which is not how you run. Why didn't you put in your valve lash?

[danielwilson]

HP Monster....The pushrod checking procedure isn’t extremely difficult but your smooth flowing technique and confident demeanor simplifies the process even more.

My 351 Cleveland build is at the point where I need to check pushrod length. I will be ordering a set of custom length Smith Brothers pushrods so I can’t afford to make any mistakes. I’m going to measure three times and order once 😉.

I like the measuring rods that don’t have lock nuts to interfere with the guide plates. They have something like a micrometer with the indicator marks etched into threaded sections for reading the results but I don’t feel like the accuracy is reliable. I have a couple of digital calipers but they aren’t long enough for the length of the checker.

So I need to order a 12” digital caliper to take measurements that are usually around 8.300” for my valve train using a solid roller cam and lifters with Harland-Sharp 1.73 roller rockers. Your tool list in the foot notes didn’t mention the digital caliper you used. Do you have any particular preferences for the caliper or additional tech information you could share with the group about digital measurements ?

Thanks for sharing and keep the good stuff coming !

[brianmaynard]

Thank you!! Very informative! I needed to know this for my engine rebuild!!

[ronaldlewis]

Thanks for sharing. I’ll be checking my push rod length soon as my cam comes in!! I’m using a hydraulic roller I don’t know if solid roller lifter are the same height until I check that out also to get correct length! Great explanation!!

[scottduke]

Im always learning from this channel! Thanks!

[youthised]

There is a "ticking" at start-up coming from my 1989 B-150 Dodge Van's engine.
The "ticking" lasts anywhere from 5 - 10 minutes then stops. Do you think it's coming from a lifter or it needs a valve adjustment (if it can be adjusted)? The engine has just over 500, 000 miles on it. Its never been rebuilt. I'm the original owner. The engine runs strong and still wants to rip the wheels off when I hit the gas. I've used Marvel Mystery Oil in the crank and in every gas fill-up. The "ticking" has been going on for over 15 years.
Great videos! I'm sure there are a bunch of viewers like me out there who appreciate you taking the time to produce them.

[nategarlic]

Very informative video, Ive watched a few of these and saw in some of the videos that you would have to add .05" to adjust for preload in a hydraulic cam. Is that true?

[kevinwest]

Its amazing to me that all the auto manufacturers have to measure all push rods and corresponding parts on every lobe with every rocker...? I'm surprised they don't have boxes of push rods, these are for a 5.0 these are for 6.0

[VGHCX]

Is rocker arm ratio the same as mechanical advantage? If no, how are they different?

[SuperDave]

Love this channel and your builds. I noticed the retainer to rocker arm clearance looked to be very small in this video, did you observe this? Keep up the awesome videos !

[ordinaryguygarage]

I like your videos... short and to the point!