Just a daily, never been on the track. I’ve street raced some people but only a handful. Mainly just cruises highway speeds and did random pulls in it

 

Bingo on all this.

I ran 9 different length pushrods on my Johnson short travel lifters to get around .035" preload. I wouldn't recommend them for folks who just bolt and go.

But that wouldn't be a geometry issue. The rest of what Darth states is what actually causes geometry issues.

 

Well thank y’all for the info and I will be looking into all of it to fix any further issues! Very much appreciated

 

Darth,
that was a great writeup. I think it should be a sticky

 

Thank you. Very much appreciate the compliment.

 

The spec for lifter preload (that you quoted earlier) is the paperwork. Every engine is a little bit different, so it's up to you to measure your own engine and determine the correct pushrod length for each lifter to achieve that lifter preload. If you had measured every lifter hole in your engine then you would have seen it was impossible to meet the preload spec with one size pushrod.

The Johnson short-travel lifter preload specs are so tight that you really need to get measurements down to the gnats ***. The "turns to length" method of the checker tool isn't good enough. You'll need a proper 12" or 16" caliper to measure actual length. And you'll have to partner with a company like Manton that has experience with those lifters and will make custom length pushrods to suit your engine.

After you make repairs to your engine and change out damaged lifters, measure for pushrod length using technique described in this thread and keep track of which measurement belongs to which hole, https://ls1tech.com/forums/generatio...od-length.html

But the measured length is NOT the length you'll order. Call up Manton and share your measurements and the brand and part number of length checker tool you used. They'll add more length to account for differences of shape of the ends of the pushrods vs. the checker tool, and things like growth of the block after engine warm up. Then they'll group your results according to the length increments they are able to manufacture. You'll likely end up with 4 or more different pushrod lengths when they're done, and you'll need to keep track of which one goes in which hole.

Now the pushrods themselves have a tolerance as well, so you'll want to measure every pushrod that you receive. I ended up switching a couple around based on actual measurements in the groups that I received. Don't be surprised if they're not exactly what you ordered because they will shrink or grow depending on room temp. Manton verifies measurements in the factory at 70°F.

The whole process sounds really **** because it is. In reality the Johnson lifters aren't quite that sensitive to preload, but in practice we aim small so we miss small.

 

For what it's worth, I cross-checked technical advice from Mamo, Johnson, and Manton when I did the H/C/I swap on my LS7. Here are my own notes from each phone call.

Mamo: Shoot for 0.038" preload when ordering pushrods. Real concern is preload when assembled. Acceptable range is between 1/3 to 3/4 turns of wrench.

Johnson: 5W-30 oil is ideal to pump up the lifter. Preload spec is 0.030" +/- 0.005.

Manton: Pushrods have a 0.003- 0.008" tolerance as manufactured and will grow or shrink by 0.015" with a 25F temp swing. Manton sells and has a lot of experience with Johnson lifters and is the primary supplier of pushrods because they are so accurate with lengths. 0.045" preload is what Manton uses which accounts for 0.015" growth of aluminum head and block. Main goal is to not overload the lifter. A 0.025" preload when hot is perfect (corresponds to 0.040 cold). A window of 0.038 - 0.045" preload during assembly is a good range. The more the plunger is pushed in (preloaded) the less vacuum the engine will produce. Johnson is being really conservative about the preload tolerance because they don't want to overload the lifters, they used to advertise wider specs with the same product.

 

Alright, I really appreciate the good info guys! It really is a massive help to me because it is hard and tedious to do all of the research by yourself and compare what a lot of manufacturers and builders prefer. I will take all of this into account when I get it put back together

 

Really a short travel lifter is a tricky valvetrain to set up for your first one without really good coaching.

 

Yeah, I was a first timer and it scared me to death. Immediately wondered why I didn't order the mid-travel lifters instead.

I ended up doing the measurements many times over and probably drove Tony FREAKIN' CRAZY with my e-mails. I know I'm one of those "high maintenance" customers that over thinks to the point of confusion. I learn better by watching, not so much reading, and there was nobody to watch in my garage. But it's all pretty straight forward in hind-sight.

 

Here is solution to your pushrod problem https://www.compcams.com/xd-a-7-320-...-shim-kit.html
Comp Cams XD-A™ Adjustable Pushrods, you can adjust all individual pushrods exactly the lenght/preload you need. And they are extra stiff too😉

 

I wanna day thank you to Darth for all of the info! It’s great I will be using it all for years to come.

QwikTrip I completely understand. I’m very **** myself and if they had said to measure every hole I would have. If they had said I needed shims or roller tipped rockers I would have. But I guess you love and learn. It’s sad cause I thought I was building a bullet proof motor basically and gonna have something great and fun and people are building junkyard motors and daily them with more power and more reliability

 

That is pretty crazy. The price is crazy too. But it gives you all the control you need. This would be good in a LLSR application as well. Much cheaper than adjustable rockers but provides about as much adjustment.

 

So, setup on those is a bit of an investment. For a solid roller lash adjustment you need to go to the next size higher shim, and lap the thickness down by the .001" on a wetstone or something.