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Discussion Starter · #1 ·
I'll make this post pretty simple if I can. Bought my car a few months back, changed my annoyingly loud exhaust out and heard a ticking noise. found collapsed lifters. Fats forward a few months of life etc. and I've finally have all my parts and measuring my pushrods. I purchased the Comp cam lifter tool and watched a few guides on using it before hand. This is where I need some help.

I purchased Johnson 2110R lifters, as both a local shop and even Texas speed told me with the cam that is in my car they would only recommend those lifters ( previously had run of the mill ls7 Lifters in the car. TSP Camshaft 235/248 .649"/.615" 111 LSA is the specs of the cam FYI.

Here is what I have found and my measurements have been consistent after triple checking everything. This is only the measuring tool, no preload being added to this.

Here is what I need help with Johnson lifter state .035 pre load and +- .010. I feel like I have had 2 people give me bad advice. I need to add the .035 to the below numbers and then I can add .010 or subtract .010 for variance? I've been told you don't want to go the -.010 better to add. However the lengths wouldn't add up to what I can find to buy. If i'm doing this right it seem like i'll be running 3 different pushrods sizes. Thanks

Cylinders Cylinders
#2 #1
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#4 #3
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#6 #5
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#8 #7
Exhaust- 7.3625 Intake -7.3875
Intake -7.3875 Exhaust- 7.375
 

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Seems like the only real variance is between intake and exhaust lifters. Running two sizes is fine. Some engines are actually designed that way from the factory, with different intake and exhaust pushrod lengths.

I would recheck that odd lifter that read 7.3625". Maybe you got the the measuring tool riding on the edge of the lifter plunger cup or something.
 

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Discussion Starter · #3 ·
Seems like the only real variance is between intake and exhaust lifters. Running two sizes is fine. Some engines are actually designed that way from the factory, with different intake and exhaust pushrod lengths.

I would recheck that odd lifter that read 7.3625". Maybe you got the the measuring tool riding on the edge of the lifter plunger cup or something.
I checked that one 4 times yesterday and 2 times the day before. I might hit it 1 more time at lunch today and to see.
 

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Yes my name is Holden
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Greetings KSG & all; Consider Smith Brother's push rods out of Washington state. They have most every length on the shelf. And they make a wonderful product. Also they supply many for the retailers with retailer's name on the rods. Ole' Bob.
 

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Discussion Starter · #5 ·
Greetings KSG & all; Consider Smith Brother's push rods out of Washington state. They have most every length on the shelf. And they make a wonderful product. Also they supply many for the retailers with retailer's name on the rods. Ole' Bob.
Thanks Bob, I'm actually trying to understand pre load. With the measurements I have listed above, If Johnson states pre load is .035 I need to add the .035 to what I cam up with with comp pushrod tool correct? And then if it shows +- .010 i can adjust that to get the final length?
 

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Monaro, Ute, Commodore wagon
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I'm not sure what the comp cams lifter tool is, but assuming you've measured it correctly to zero lash and with no preload, then you want to add 0.035" to that length, which is your desired preload.

The + / - 0.010" is just a range within which you still have an acceptable amount of preload, so they're basically saying 0.025" to 0.045" of preload is the acceptable range.

Why you'd shoot for anything other than 0.035" I don't know, perhaps maximising preload to make the short travel lifters even shorter travel I suppose.

Unless you're going mental on the details in pursuit of every last fraction of a horsepower, I'd suggest you want the best chance of preload remaining within the preload range Johnson advise. If you added 0.035" and +0.010", you're basically shooting for 0.045" preload, so if the pushrod or your measurements are 0.001" out, you'd arguably have too much preload...

Add the 0.035" and get them made up.

Having different lengths isn't a problem, make sure you keep the rockers and lifters 'together' with their respective cylinder and intake / exhaust etc. now that you've measured them.

Manton (and I'm sure others) will make up pushrods to whatever length you want, I ended up with a decent variety of measurements (also was shimming my rockers to get ideal valve tip sweep pattern as I'm using YellaTerras)

Tire Automotive tire Motor vehicle Tread Wheel


Given inevitable tolerances in manufacturing (and my measuring) I ended up ordering this:

7.610 x 2
7.620 x 4
7.625 x 1
7.635 x 5
7.640 x 2
7.645 x 2
 

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Discussion Starter · #7 ·
I'm not sure what the comp cams lifter tool is, but assuming you've measured it correctly to zero lash and with no preload, then you want to add 0.035" to that length, which is your desired preload.

The + / - 0.010" is just a range within which you still have an acceptable amount of preload, so they're basically saying 0.025" to 0.045" of preload is the acceptable range.

Why you'd shoot for anything other than 0.035" I don't know. You want the best chance of it remaining within the preload range Johnson advise. If you added 0.035" and +0.010", you're basically shooting for 0.045" preload, so if the pushrod or your measurements are 0.001" out, you'd arguably have too much preload...

Add the 0.035" and get them made up.

Having different lengths isn't a problem, make sure you keep the rockers and lifters 'together' with their respective cylinder and intake / exhaust etc. now that you've measured them.

Manton (and I'm sure others) will make up pushrods to whatever length you want, I ended up with a decent variety of measurements (also was shimming my rockers to get ideal valve tip sweep pattern as I'm using YellaTerras)

View attachment 511777

Given inevitable tolerances in manufacturing (and my measuring) I ended up ordering this:

7.610 x 2
7.620 x 4
7.625 x 1
7.635 x 5
7.640 x 2
7.645 x 2

Thank you for the response, basically the comp cam tool is a adjustable pushrod. each turn ins .050. So i got on base circle and started at 7.35 and adjusted 1/4 turn and checked for zero lash. then went back through and check it all again as this is my first rodeo and wanted to make sure what I was doing didn't vary each time I tried.

Like you, I have a note pad I wrote everything down onto clearly see and that is what I posted above.

Now here is where 1 some confusion is coming into and 2 people telling me I am over thinking what I am doing and just throw "X" pushrod and be done.

I have
7.375 x7
7.3875 x8
7.3625 x1

So following that

7.375 +.035 is 7.41. + goes to 7.42 or - goes to 7.4
7.3875 + .035 is 7.4225 + goes to 7.4325 and - goes to 7.4125
7.3625 + .035 is 7.3975 + goes to 7.4075 and - goes to 7.3875

If I go with stand size Pushrods and no custom made.

I could do 7.375 to 7.4 but that's on the bottom side of the the .010
Then the 7.3875 standard 7.425 would fit right in that threshold fine.
the one 7.3625 a standard 7.4 would also fit right in there.

So my concern is do i even mess with the +- .010 or get 100% right on the .035 range? Thanks
 

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7.375 +.035 is 7.41. + goes to 7.42 or - goes to 7.4
7.3875 + .035 is 7.4225 + goes to 7.4325 and - goes to 7.4125
7.3625 + .035 is 7.3975 + goes to 7.4075 and - goes to 7.3875


So my concern is do i even mess with the +- .010 or get 100% right on the .035 range? Thanks
As the Johnson lifters need to be preloaded quite accuractely (at least from what Tony Mamo told me) you might want to use a digital caliper to measure the tool as opposed to just using the markings on the tool. If this is already what you did, then apologies and ignore the next paragraph! :)

You could knock something up to hold the pushrod / caliper in place for speed / repeatability, or just do it on the edge of a bench but be thorough with ensuring the pushrod is straight etc. So for example I put some tape over the caliper, drew a mark across it, then cut the tape, so I had a mark on each jaw to align the pushrod to...

Wood Hardwood Gas Engineering Wood stain


I started with the above, but the polystyrene wasn't holding the pushrod consistently enough (I didn't want to buy a router to make it out of wood!) so just did it on the edge of a bench and took my time.

Are you using the standard rocker arms? When you go to torque these down, you can get an idea of the preload (although can't change it!) by the amount of rotation from zero lash to when you start torqueing the bolt.

Basically when you hit zero lash, reset the socket wrench at 12 o' clock. With your sensitive fingers on, continue to tighten the bolt, you should feel mildly more resistance than you felt on the way up to zero lash, as you're now depressing the lifter cup. At some point you'll feel the amount of resistance suddenly jump up, because you're no longer depressing the lifter cup, you're now torqueing the bolt. The angle you've now ended at gives you an indication of your preload.

From my rough recollection of the standard rocker bolt thread pitch and such, I think you'd basically be wanting the wrench to end up at about 6 o'clock (so having done just half a turn) when going from zero lash to the extra resistance of torqueing the bolt, which is when the rocker has seated and you're not going to get any more preload.

Hopefully that makes some sense, there's quite a few guides out there, the rotation is just to give you a rough indicator / sanity check though, you're doing it the right way by using an adjustable pushrod.

If the adjustable pushrod isn't the locking type (i.e. with the extra nuts on to stop it rotating when you put it in / pull it out) then be really careful putting it in and out that it doesn't rotate and change its length!

When all is said and done, with the effort you're putting in, personally I'd just get a custom length set made up so you know it's good, although yeah it's frustrating 9 of them would sit perfectly with off the shelf sizes... No reason someone like Manton couldn't supply you the 9 in off the shelf sizes and you just get 7 made up in the 7.410" if that's what your motor wants.
 

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All that work and it'll be meaningless when you take into consideration the expansion rate of an aluminum block and the cylinder heads. You were better off getting the closest common length and then moving the rockers around to verify they aren't the real issue with the tolerance stack up...
 

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All that work and it'll be meaningless when you take into consideration the expansion rate of an aluminum block and the cylinder heads. You were better off getting the closest common length and then moving the rockers around to verify they aren't the real issue with the tolerance stack up...
Can you elaborate on that a bit?

So in the OP's case, get a set of 7.400" pushrods say, put those in, and then swap rockers around and what's he looking for?

Presuambly you'd need the engine hot for this so it's expanded a representative amount? Or is he perhaps better off shooting for a little too much preload, so that when the ally block and heads expand more than the steel pushrod, the preload slackens off a touch?

I'm a n00b at all this stuff so I'm genuinely interested, not trying to be awkard.
 

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That odd one is the issue to verify first... Might be a crap rocker.

Then the length crisis is a non-issue...

Reminds me of the guys who spend hours getting valve spring installed heights perfect but never actually check the spring pressures first. There are more important battles to fight.

Bottom line... This is not an all out race engine or a Drag Week build so a tolerance of +/- .015" of lifter preload is going to amount to fly crap in a power delta.
 

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My initial response would've been buy a set of 7.400" pushrods and send it, and it sounds like EDC is sort-of saying the same thing. If they were off by .10" or so, I can see that would be a problem. But a variance of +/-.0125" might not be worth trying to correct, IMHO.
 

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I'll make this post pretty simple if I can. Bought my car a few months back, changed my annoyingly loud exhaust out and heard a ticking noise. found collapsed lifters. Fats forward a few months of life etc. and I've finally have all my parts and measuring my pushrods. I purchased the Comp cam lifter tool and watched a few guides on using it before hand. This is where I need some help.

I purchased Johnson 2110R lifters, as both a local shop and even Texas speed told me with the cam that is in my car they would only recommend those lifters ( previously had run of the mill ls7 Lifters in the car. TSP Camshaft 235/248 .649"/.615" 111 LSA is the specs of the cam FYI.

Here is what I have found and my measurements have been consistent after triple checking everything. This is only the measuring tool, no preload being added to this.

Here is what I need help with Johnson lifter state .035 pre load and +- .010. I feel like I have had 2 people give me bad advice. I need to add the .035 to the below numbers and then I can add .010 or subtract .010 for variance? I've been told you don't want to go the -.010 better to add. However the lengths wouldn't add up to what I can find to buy. If i'm doing this right it seem like i'll be running 3 different pushrods sizes. Thanks

Cylinders Cylinders
#2 #1
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#4 #3
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#6 #5
Exhaust- 7.375 Intake -7.3875
Intake -7.3875 Exhaust- 7.375

#8 #7
Exhaust- 7.3625 Intake -7.3875
Intake -7.3875 Exhaust- 7.375
Hey champ
Check this out this might be helpful
I think he added preload
 
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