Pushrod Length
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
Pushrod Length Hey guys, hoping someone can guide me in the right direction. First time build. 6.0 ls2 forged bottom end with stock 243 heads. Gonna be running a 4l80 turbo. Goal is 800-900 wheel. Got a custom btr stage 2 turbo cam and Johnson 2116LSR’s (tiebar).
Basically where I am at is I installed ls9 head gaskets, installed ARP head studs and torque everything down to spec. Then I put each cam lobe on base circle and measured with an adjustable pushrod to zero lash. Measured with a set of Mitutoyo calipers and wrote down measurements. Everything varies… measurements below. Should I go spend a ton with Manton and get all custom varying lengths to match each lifter bore? Or…. get an average, add in preload and order through a cheaper source?
Measurements:
I1: 7.499”
E1:7.510”
I2:7.497”
E2:7.510
I3:7.505”
E3:7.510”
I4:7.500”
E4:7.512”
I5:7.503”
E5:7.512”
I6:7.503”
E6:7.515”
I7:7.503”
E7:7.515”
I8:7.506”
E8:7.518”
Basically where I am at is I installed ls9 head gaskets, installed ARP head studs and torque everything down to spec. Then I put each cam lobe on base circle and measured with an adjustable pushrod to zero lash. Measured with a set of Mitutoyo calipers and wrote down measurements. Everything varies… measurements below. Should I go spend a ton with Manton and get all custom varying lengths to match each lifter bore? Or…. get an average, add in preload and order through a cheaper source?
Measurements:
I1: 7.499”
E1:7.510”
I2:7.497”
E2:7.510
I3:7.505”
E3:7.510”
I4:7.500”
E4:7.512”
I5:7.503”
E5:7.512”
I6:7.503”
E6:7.515”
I7:7.503”
E7:7.515”
I8:7.506”
E8:7.518”
If you measured correctly, you have a maximum of .021" between your shortest and longest measurement. This would be nearly irrelevant with stock lifters, but since you have short travel lifters that is not good. Johnson shows .035" preload + or- .005", and part of that tolerance includes the fact that whatever pushrods you order may be rounded to the nearest whatever length and also have a manufacturing tolerance in their lengths as well. Are you certain about those measurements? They seem unusually long.
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
If you measured correctly, you have a maximum of .021" between your shortest and longest measurement. This would be nearly irrelevant with stock lifters, but since you have short travel lifters that is not good. Johnson shows .035" preload + or- .005", and part of that tolerance includes the fact that whatever pushrods you order may be rounded to the nearest whatever length and also have a manufacturing tolerance in their lengths as well. Are you certain about those measurements? They seem unusually long.
I measured everything twice, which took forever and am confident in my measurements. If you actually look at it by just the intakes and exhausts only, my intake swing is 7.497” to 7.506 so for intakes only .009”.
And then the swing for exhausts only is 7.510” to 7.518” so for exhausts only .008”.
I feel then I should either get all intakes and exhausts identical to each other? Or make sure they are all precisely to the measurement taken in each bore?
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
If you measured correctly, you have a maximum of .021" between your shortest and longest measurement. This would be nearly irrelevant with stock lifters, but since you have short travel lifters that is not good. Johnson shows .035" preload + or- .005", and part of that tolerance includes the fact that whatever pushrods you order may be rounded to the nearest whatever length and also have a manufacturing tolerance in their lengths as well. Are you certain about those measurements? They seem unusually long.
Also if 7.4 is stock then 7.5 and above with shorter lifters would make sense no?
TECH Addict
Joined: Dec 2017
Posts: 2,180
Likes: 969
shorter lifters
I feel then I should either get all intakes and exhausts identical to each other?
If your planning on going with manton, I have a spare pushrod ill send you for the cost of postage. This way, you could cut it in half and add some threads to make a custom tool.
reason being, when I used a pushrod measuring tool, all the pushrods I ordered didnt provide the same preload. The numbers end to end were the same, but the result with checking springs at the rocker tip were off .040 or so. The ball end radius is where the cup actually touches, so if they are different, the numbers from a std checker and calipers wont work.
with an actual manton pushrod, you’ll have the exact same tips they use, and not end up spending more on a reorder like I did.
my numbers with 2116’s, milled tfs235’s, btr shaft rockers, and a cammotion cam were from 7.580 to 7.614 oal for reference.
reason being, when I used a pushrod measuring tool, all the pushrods I ordered didnt provide the same preload. The numbers end to end were the same, but the result with checking springs at the rocker tip were off .040 or so. The ball end radius is where the cup actually touches, so if they are different, the numbers from a std checker and calipers wont work.
with an actual manton pushrod, you’ll have the exact same tips they use, and not end up spending more on a reorder like I did.
my numbers with 2116’s, milled tfs235’s, btr shaft rockers, and a cammotion cam were from 7.580 to 7.614 oal for reference.
Last edited by bthomas; Apr 12, 2025 at 09:31 AM.
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
You don't have "shorter lifters". You have SHORT TRAVEL lifters. All that means is, that the piece with the push rod seat in it, has less room to get pushed downwards than stock ones.
Given your measurements, that seems reasonable. If for example you got 7.535" intakes and 7.550" exhausts, you'd be right where you need to be. Although I gotta agree; 7.5" does seem kinda long, but if that's what they measure, then that's how long they are. That's why we measure anyway, to see what they really are, instead of guessing or just buying the stock length or whatever.
Given your measurements, that seems reasonable. If for example you got 7.535" intakes and 7.550" exhausts, you'd be right where you need to be. Although I gotta agree; 7.5" does seem kinda long, but if that's what they measure, then that's how long they are. That's why we measure anyway, to see what they really are, instead of guessing or just buying the stock length or whatever.
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Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
If your planning on going with manton, I have a spare pushrod ill send you for the cost of postage. This way, you could cut it in half and add some threads to make a custom tool.
reason being, when I used a pushrod measuring tool, all the pushrods I ordered didnt provide the same preload. The numbers end to end were the same, but the result with checking springs at the rocker tip were off .040 or so. The ball end radius is where the cup actually touches, so if they are different, the numbers from a std checker and calipers wont work.
with an actual manton pushrod, you’ll have the exact same tips they use, and not end up spending more on a reorder like I did.
my numbers with 2116’s, milled tfs235’s, btr shaft rockers, and a cammotion cam were from 7.580 to 7.614 oal for reference.
reason being, when I used a pushrod measuring tool, all the pushrods I ordered didnt provide the same preload. The numbers end to end were the same, but the result with checking springs at the rocker tip were off .040 or so. The ball end radius is where the cup actually touches, so if they are different, the numbers from a std checker and calipers wont work.
with an actual manton pushrod, you’ll have the exact same tips they use, and not end up spending more on a reorder like I did.
my numbers with 2116’s, milled tfs235’s, btr shaft rockers, and a cammotion cam were from 7.580 to 7.614 oal for reference.
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Verdad Gallardo TECH Addict
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All of this about "ball end" and so forth, is why you shouldn't use calipers on PRs in the first place. The aftermarket mfrs spec PRs as if the end was a complete perfect sphere, butt it's NOT; there's an oil hole there, and the PR is shorter by some amount, because of that. The adj PR gauges don't have that confusion and confounding factor. The difference isn't the ball radius, since that's always the same (half of the stock PR thickness) which it HAS TO be, to fit into the cup in a lifter, and which the adj PR takes into account; what throws the caliper reading off, is the diameter of the oil hole, and how much it's chamfered.
The adj PR is the RIGHT number. ALWAYS. The caliper number is the one with the error in it.
With somebody like Manton though, if you tell them how you got your numbers (that is, via a proper gauge, or by calipers, and if by calipers, what object you were measuring with them) they'll be able to take that into account when making their product. I'd suggest calling them and asking what measurement method they want, and providing them what they ask for.
GM, by the way, specs theirs by the caliper method or something close to it. Nobody else does.
The adj PR is the RIGHT number. ALWAYS. The caliper number is the one with the error in it.
With somebody like Manton though, if you tell them how you got your numbers (that is, via a proper gauge, or by calipers, and if by calipers, what object you were measuring with them) they'll be able to take that into account when making their product. I'd suggest calling them and asking what measurement method they want, and providing them what they ask for.
GM, by the way, specs theirs by the caliper method or something close to it. Nobody else does.
On The Tree
Joined: Oct 2011
Posts: 126
Likes: 44
From: Colorado
Sounds to me like that BTR cam has a smaller base circle on the exhaust lobes which could account for the difference in push rod length for zero lash; you might ask them about that On my build with LSA heads, I used LS3 intake and LY6 exhaust valves. When I measured for PR length, I got two different lengths. Measured again and the same story. Wondering where I went wrong, I laid a straight edge across the top of my valve tips and lo and behold, the intake valves were taller than the exhausts! So I ordered two different length PRs from Manton. My build uses a completely different valve train so my PR lengths won't mean much here, but for reference, the intakes were 7.478" and exhausts were 7.515". I read somewhere that GM used a smaller base circle, higher lift intake lobe on LS6 and later Gen 4 performance LS engines and used a taller intake valve to compensate so they could use the same length push rods.
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
All of this about "ball end" and so forth, is why you shouldn't use calipers on PRs in the first place. The aftermarket mfrs spec PRs as if the end was a complete perfect sphere, butt it's NOT; there's an oil hole there, and the PR is shorter by some amount, because of that. The adj PR gauges don't have that confusion and confounding factor. The difference isn't the ball radius, since that's always the same (half of the stock PR thickness) which it HAS TO be, to fit into the cup in a lifter, and which the adj PR takes into account; what throws the caliper reading off, is the diameter of the oil hole, and how much it's chamfered.
The adj PR is the RIGHT number. ALWAYS. The caliper number is the one with the error in it.
With somebody like Manton though, if you tell them how you got your numbers (that is, via a proper gauge, or by calipers, and if by calipers, what object you were measuring with them) they'll be able to take that into account when making their product. I'd suggest calling them and asking what measurement method they want, and providing them what they ask for.
GM, by the way, specs theirs by the caliper method or something close to it. Nobody else does.
The adj PR is the RIGHT number. ALWAYS. The caliper number is the one with the error in it.
With somebody like Manton though, if you tell them how you got your numbers (that is, via a proper gauge, or by calipers, and if by calipers, what object you were measuring with them) they'll be able to take that into account when making their product. I'd suggest calling them and asking what measurement method they want, and providing them what they ask for.
GM, by the way, specs theirs by the caliper method or something close to it. Nobody else does.
I use the thicker end of the caliper if that makes sense so it actually covered nearly the whole pushrod. We’re probably talking a difference of no more than .001-.002” if I measured the hole of the comp cams adjustable pushrod right?. I mean if the preload is .038” to .045” that’s a decent range
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
Sounds to me like that BTR cam has a smaller base circle on the exhaust lobes which could account for the difference in push rod length for zero lash; you might ask them about that On my build with LSA heads, I used LS3 intake and LY6 exhaust valves. When I measured for PR length, I got two different lengths. Measured again and the same story. Wondering where I went wrong, I laid a straight edge across the top of my valve tips and lo and behold, the intake valves were taller than the exhausts! So I ordered two different length PRs from Manton. My build uses a completely different valve train so my PR lengths won't mean much here, but for reference, the intakes were 7.478" and exhausts were 7.515". I read somewhere that GM used a smaller base circle, higher lift intake lobe on LS6 and later Gen 4 performance LS engines and used a taller intake valve to compensate so they could use the same length push rods.
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
Sounds to me like that BTR cam has a smaller base circle on the exhaust lobes which could account for the difference in push rod length for zero lash; you might ask them about that On my build with LSA heads, I used LS3 intake and LY6 exhaust valves. When I measured for PR length, I got two different lengths. Measured again and the same story. Wondering where I went wrong, I laid a straight edge across the top of my valve tips and lo and behold, the intake valves were taller than the exhausts! So I ordered two different length PRs from Manton. My build uses a completely different valve train so my PR lengths won't mean much here, but for reference, the intakes were 7.478" and exhausts were 7.515". I read somewhere that GM used a smaller base circle, higher lift intake lobe on LS6 and later Gen 4 performance LS engines and used a taller intake valve to compensate so they could use the same length push rods.
my BTR stage 2 turbo cam has same lift on intake and exhaust .618”
Hey guys, hoping someone can guide me in the right direction. First time build. 6.0 ls2 forged bottom end with stock 243 heads. Gonna be running a 4l80 turbo. Goal is 800-900 wheel. Got a custom btr stage 2 turbo cam and Johnson 2116LSR’s (tiebar).
Basically where I am at is I installed ls9 head gaskets, installed ARP head studs and torque everything down to spec. Then I put each cam lobe on base circle and measured with an adjustable pushrod to zero lash. Measured with a set of Mitutoyo calipers and wrote down measurements. Everything varies… measurements below. Should I go spend a ton with Manton and get all custom varying lengths to match each lifter bore? Or…. get an average, add in preload and order through a cheaper source?
Measurements:
I1: 7.499”
E1:7.510”
I2:7.497”
E2:7.510
I3:7.505”
E3:7.510”
I4:7.500”
E4:7.512”
I5:7.503”
E5:7.512”
I6:7.503”
E6:7.515”
I7:7.503”
E7:7.515”
I8:7.506”
E8:7.518”
Basically where I am at is I installed ls9 head gaskets, installed ARP head studs and torque everything down to spec. Then I put each cam lobe on base circle and measured with an adjustable pushrod to zero lash. Measured with a set of Mitutoyo calipers and wrote down measurements. Everything varies… measurements below. Should I go spend a ton with Manton and get all custom varying lengths to match each lifter bore? Or…. get an average, add in preload and order through a cheaper source?
Measurements:
I1: 7.499”
E1:7.510”
I2:7.497”
E2:7.510
I3:7.505”
E3:7.510”
I4:7.500”
E4:7.512”
I5:7.503”
E5:7.512”
I6:7.503”
E6:7.515”
I7:7.503”
E7:7.515”
I8:7.506”
E8:7.518”
Manton will etch your length numbers in them for $35 I believe it is….makes install so much quicker. Make sure you clean the new PR’s well. Never trust a new part for cleanliness.
You can break this down into 3-4 groups (rounding numbers up or down 2-3 thou) and use 3-4 different lengths to get closer to .045, but with the +/- .010 window built in for production tolerances, you won’t notice any difference imo.
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
Looks right to me. Good on you for measuring all 16. You can do a bit of rounding up or down here. For instance, You can round all your intakes to 7.5, because .006 won’t affect anything. Then I’d round all exhausts to 7.512, which is .006 from longest. 2116 preload window is .045 +/- .010 so I’d add a preload number of .042 to all your lengths and call Manton. Tell them it’s all caliper measurements and pick your diameter and wall. They are my go-to PR guys, and will get them out quick.
Manton will etch your length numbers in them for $35 I believe it is….makes install so much quicker. Make sure you clean the new PR’s well. Never trust a new part for cleanliness.
You can break this down into 3-4 groups (rounding numbers up or down 2-3 thou) and use 3-4 different lengths to get closer to .045, but with the +/- .010 window built in for production tolerances, you won’t notice any difference imo.
Manton will etch your length numbers in them for $35 I believe it is….makes install so much quicker. Make sure you clean the new PR’s well. Never trust a new part for cleanliness.
You can break this down into 3-4 groups (rounding numbers up or down 2-3 thou) and use 3-4 different lengths to get closer to .045, but with the +/- .010 window built in for production tolerances, you won’t notice any difference imo.
Bro you are the one that talked me into measuring all 16 a few months back! And I’m glad I did. And I measured everything twice I’m super **** lol! Yeah I actually just learned…. That Manton prefers overall length vs “gauge length” when you speak to them which makes a HUGE difference when speaking to different companies. I guess Manton pushrods the rumor is they actually will ship a little bit longer like .012” if you tell them 7.500 they will come in around 7.512. So should I compensate for this and tell them 7.488? But also I read for an aluminum engine heat affects preload as well so many things to consider here……
Thread Starter
Staging Lane
Joined: Oct 2024
Posts: 51
Likes: 1
Looks right to me. Good on you for measuring all 16. You can do a bit of rounding up or down here. For instance, You can round all your intakes to 7.5, because .006 won’t affect anything. Then I’d round all exhausts to 7.512, which is .006 from longest. 2116 preload window is .045 +/- .010 so I’d add a preload number of .042 to all your lengths and call Manton. Tell them it’s all caliper measurements and pick your diameter and wall. They are my go-to PR guys, and will get them out quick.
Manton will etch your length numbers in them for $35 I believe it is….makes install so much quicker. Make sure you clean the new PR’s well. Never trust a new part for cleanliness.
You can break this down into 3-4 groups (rounding numbers up or down 2-3 thou) and use 3-4 different lengths to get closer to .045, but with the +/- .010 window built in for production tolerances, you won’t notice any difference imo.
Manton will etch your length numbers in them for $35 I believe it is….makes install so much quicker. Make sure you clean the new PR’s well. Never trust a new part for cleanliness.
You can break this down into 3-4 groups (rounding numbers up or down 2-3 thou) and use 3-4 different lengths to get closer to .045, but with the +/- .010 window built in for production tolerances, you won’t notice any difference imo.
btw what does Manton charge for all 16 pushrods?
Well that is interesting. Johnson does not show their recommended preload specs on their website. Most of the distributors show .035" + or - .005". Katech says mfr recommended .025-.035, but they recommend .035-.045. One oddball distributor showed .030 + or - .005. Long story short, I guess they have a wider range of acceptable preload tolerance than I thought.
Bro you are the one that talked me into measuring all 16 a few months back! And I’m glad I did. And I measured everything twice I’m super **** lol! Yeah I actually just learned…. That Manton prefers overall length vs “gauge length” when you speak to them which makes a HUGE difference when speaking to different companies. I guess Manton pushrods the rumor is they actually will ship a little bit longer like .012” if you tell them 7.500 they will come in around 7.512. So should I compensate for this and tell them 7.488? But also I read for an aluminum engine heat affects preload as well so many things to consider here……
