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So with the new canted valve heads bolted on and new johnson 2116lsr lifters these are the measurements im getting. So just to clarify i need to add .035 give or take to the lengths?
Im thinking intake length of. 8.050
exhaust pushrod length of. 8.000
im not sure how much thermal growth ill get, the car hardly gets over 160 degrees.
An aluminum block will grow .010-.011 at 170. Closer to .015” at 210. Heads grow a bit also. A steel pushrod will grow .006” to help chase the difference.
Your oil temps will be much higher than water, so the block is going to grow consistently, irregardless of water temps. Add .045 preload. It will help quiet the lifters at temp.
Hell just shoot for middle ground @ 0.040 preload, it's not going to hurt a damn thing. What diameter PR's are you planning to use?
I was just planning on running a Manley 3/8 .080 wall since they have 8.00 and 8.050 in stock at summit. But now with the discussion of thermo growth my preload of .030 and .037 with only end up with .020 and .027 preload. Im also worried about ordering too long of a pushrod and hanging the valves open.
An aluminum block will grow .010-.011 at 170. Closer to .015” at 210. Heads grow a bit also. A steel pushrod will grow .006” to help chase the difference.
Your oil temps will be much higher than water, so the block is going to grow consistently, irregardless of water temps. Add .045 preload. It will help quiet the lifters at temp.
dont some of these pushrods come a little longer than what's printed on them?
dont some of these pushrods come a little longer than what's printed on them?
I have all my custom stuff built by Manton, for short/limited travel lifters such as you’re using. In fact, I’m ordering a set this week for a build with the 2116 Johnson’s. To answer your question, yes. Some are long and some are short as well by a thou or two That’s to be expected. A thou or two up or down wont affect anything here. But not allowing for thermals with a limited travel lifter will net you short by as much as .010-.015. Trust me, I build a lot of engines. Add .045. Order custom rods from Manton or Smith, etc. Measure all 16 individually. You’ll find you’ve got 14 different lengths. Happens every time. Group them down into groups of 3-4 by rounding up with the closest ones. Example…
7.685
7.686 ————————-Order 5 at 7.686”
7.687…need 3
7.678
7.679
7.680 ————————Order 4 at 7.680”
7.682
7.690
7.692…need 3 ————-Order 7 at 7.692”
7.691
7.693…need 2
just an example again, but this is very common. I do this a lot. Take notes. Have Manton or smith or whoever etch the lengths on the rods to make install easier. You’ll find your self measuring these and them being off a couple thou…and you’ll swear they messed the order up. Forget that! Pay the extra for the etching, trust the etching, clean the rods good, and install them. You’re not going to be able to make this work correctly by ordering a set of BTR 7.680’s…not with 2116 Johnson’s. Will it run? Sure, but it’s not gonna be right and you’re giving up the advantages of a limited travel lifter on several cylinders. Spend the money, take the time, and do it right. You’ll be glad you did.
Used a different method to measure the pushrods and remeasured 3 times after that. Came up with these.
Looks about right. It’s bizarre how manufacturing tolerances play such a diverse range, but it is what it is. Order them! Manton turns them around FAST. Don’t forget etching!!!
It is not uncommon on LS motor for the pushrod on intake being different than exhaust. On the LS7 I think the lash cap on the titanium intakes can cause the delta. I have the medium travel lifters which have a preload of .025 to .045. My pushrods on my BR7 head motor are 7.940, 7.950. and 7.960. The intakes taking the longer pushrod. I have a single test pushrod of 7.900 which gets me close to zero lash (torque rocker arm bolt to 22 foot pounds) and use a feeler gauge to fine tune from there and then add the .040 preload. I stick with Manton for consistency. Che70velle has the right idea he builds a lot of these. What I have found is that last 1/8 turn or so final 22 ft. pound tweak does nothing for the preload.
I haven't messed with the canted valve heads yet but on The Cathedral style heads I shim under the Die Cast stands to get them closer.
the BTR heads have built in stands as part of the casting.
I spoke with Johnson lifters today and they said preload will be fine anywhere from .025 to .045 and to get with Manton. I then spoke with Matt at Manton and he suggested just using my measured length plus .035. New pushrods will be here Wednesday.
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Pushrod length help 
