Excessive Lifter Preload Question
Thread Starter
Staging Lane
Joined: Jun 2016
Posts: 71
Likes: 4
From: Cloquet, MN
Excessive Lifter Preload Question I ordered a set of BTR pushrods at 7.375 and I guess they use gauge length for the measurements because they measure 7.395 with the dial caliper. I'm a little concerned because some lifters will have .095 preload using these and the lifters recommend no more then .080 preload. Do you guys think I'm ok to run these with the extra .015 preload or will I have valves hanging open?
Thanks in advance.
Thanks in advance.
I've measured for overall length before and called a certain company to give them my measurement and ended up getting longer than needed pushrods. The lifters I was running would have not lasted long had I ran them. Smith Brothers actually asked me the question if its overall length or not to clear up any confusion. Like Smith Brothers pushrods and that's all I run in my engines now.
This depends on how you measured for pushrod length. Did you use an adjustable pushrod and measure that for overall length with a caliper, then add the preload amount? If so, you want pushrods that have overall length of whatever you calculated (7.375?).
Thread Starter
Staging Lane
Joined: Jun 2016
Posts: 71
Likes: 4
From: Cloquet, MN
Yes, I used a pushrod length checker and measured for 0 lash then added the desired preload. My 0 lash measurements with the dial caliper ranged from 7.300 - 7.307 on the intake and exhaust valves of #1, #2, #7, #8 cylinders. With the pushrods having an actual length of 7.395 I'll have a maximum of .095 preload on some lifters. I read a few other forum posts on the matter and it sounds like others have run these same lifters(comp cams 850-16) at as much as .100 preload without issues so I've decided to just run them. It sounds like the lifters have a total travel of .160 so I think I'll be fine, I'd like to hear other opinions on the matter though if anyone strongly disagrees.
I was using Trickflow pushrods from another vendor on here, were listed as overall length 7.425, when I finally got a long enough caliper I found out that was actually gauge length. So as you found, only way to know is to measure them.
Since you know the lifter travel, sounds like your preload will work fine. I also have new lifters from BTR, delphi "gen V", I don't know the total travel, BTR also says preload of .080 for those. Maybe you got the same ones? Or maybe they say .080 for all their lifters lol? I decided to go a little shorter, with about .060 preload. Haven't got the engine back in the car yet so can't comment on how well that works.
Since you know the lifter travel, sounds like your preload will work fine. I also have new lifters from BTR, delphi "gen V", I don't know the total travel, BTR also says preload of .080 for those. Maybe you got the same ones? Or maybe they say .080 for all their lifters lol? I decided to go a little shorter, with about .060 preload. Haven't got the engine back in the car yet so can't comment on how well that works.
Thread Starter
Staging Lane
Joined: Jun 2016
Posts: 71
Likes: 4
From: Cloquet, MN
I was using Trickflow pushrods from another vendor on here, were listed as overall length 7.425, when I finally got a long enough caliper I found out that was actually gauge length. So as you found, only way to know is to measure them.
Since you know the lifter travel, sounds like your preload will work fine. I also have new lifters from BTR, delphi "gen V", I don't know the total travel, BTR also says preload of .080 for those. Maybe you got the same ones? Or maybe they say .080 for all their lifters lol? I decided to go a little shorter, with about .060 preload. Haven't got the engine back in the car yet so can't comment on how well that works.
Since you know the lifter travel, sounds like your preload will work fine. I also have new lifters from BTR, delphi "gen V", I don't know the total travel, BTR also says preload of .080 for those. Maybe you got the same ones? Or maybe they say .080 for all their lifters lol? I decided to go a little shorter, with about .060 preload. Haven't got the engine back in the car yet so can't comment on how well that works.
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