Question> 7.400 pushrod is 7.417 ??
Question> 7.400 pushrod is 7.417 ?? In verifying existing pushrod length, I was reacquainted with LS1 pushrods being .017 longer than their advertised length. This .017 is never referred to.in any of the YT "measure for pushrod length" videos, though prominent reputable businesses such as, Thompson, Brian Tooley, Summit, etc, create the videos. Is this 17 a built in extra to compensate for hot engine expansion? This presents a problem... When I use my adjustable pushrod length checker, and come up with, say, 7.400 (verified with dig caliper), this length would include the tip to tip size of the checker, Yet, if I order a 7.400, I get 7.417. If it's not to account for expansion, does the .017 count toward lifter preload? for example, (.017) > If for preload and not expansion... having measured for zero lash, I come up with 7.325. Then add .075 for preload, minus .the 017 extra from the pushrod tip(s). ...or, is the 17 "invisible" to valve function? Thanks
In verifying existing pushrod length, I was reacquainted with LS1 pushrods being .017 longer than their advertised length. This .017 is never referred to.in any of the YT "measure for pushrod length" videos, though prominent reputable businesses such as, Thompson, Brian Tooley, Summit, etc, create the videos. Is this 17 a built in extra to compensate for hot engine expansion? This presents a problem... When I use my adjustable pushrod length checker, and come up with, say, 7.400 (verified with dig caliper), this length would include the tip to tip size of the checker, Yet, if I order a 7.400, I get 7.417. If it's not to account for expansion, does the .017 count toward lifter preload? for example, (.017) > If for preload and not expansion... having measured for zero lash, I come up with 7.325. Then add .075 for preload, minus .the 017 extra from the pushrod tip(s). ...or, is the 17 "invisible" to valve function? Thanks
Thank you, Scott. 10 years go by, and suddenly, I'm "grandpa". From a different angle, considering the added .017, and added .075 preload, I would be headed toward what might be the high end of preload for these lifters/Comp 850s. I've saved the original, existing measurements, and will review everything. i'm using a couple of different-sized, but closely-sized pushrods, because the engine had some water in it upon arrival, and certain valves had to be replaced. There is some valve train noise on certain cylinders after full warmup, which disappears with throttle. This is accented by a rear-facing hood scoop, which amplifies the noise,
Thank you, Scott. 10 years go by, and suddenly, I'm "grandpa". From a different angle, considering the added .017, and added .075 preload, I would be headed toward what might be the high end of preload for these lifters/Comp 850s. I've saved the original, existing measurements, and will review everything. i'm using a couple of different-sized, but closely-sized pushrods, because the engine had some water in it upon arrival, and certain valves had to be replaced. There is some valve train noise on certain cylinders after full warmup, which disappears with throttle. This is accented by a rear-facing hood scoop, which amplifies the noise,
What is the total travel on the lifters. Generally half the total lifter travel is your target. Also the larger your total travel, the more leeway you have on the preload number.
The 850 lifters go .200 travel. Preload target is .075.
Here is the issue.. there are several pushrods that, because pushrods generally are offered in only .025 increments, fall short of the .075 target. Add a hot engine, and there is ticking/sewing/etc, introduced at low RPM.
I'm ok with being over the target, and not ok with being under by these (cold) amounts... generally, several, .019 short of .075 + hot engine. The next step up is 7.450, which is too long.
I happened upon an old thread (mine) that addressed this. The replies suggested Manton Pushrods, so, a call to Manton put me in touch with their machinist/tech, who said that when I order a, For Example, 7.400, that his finished product, end to end, is 7.400. I told him that the caliper measurement of a TR 7.400 actually is 7.417, which is true of any common LS pushrod. He replied that Manton doesn't consider the extra .017, so that when they manufacture a 7.400, that end-to-end is 7.400. This would leave me right back where I presently am.
At this, he balked, and rather than say, "Ok, we'll add .017 to each of your stated lengths, and this will put us in agreement", I suggested it, which would have solved our disagreement.
Again, he balked at this, and I decided to let it go.
There is a good machine shop, nearby, and the person over there instantly knew what I was referring to, so I'll have him manufacture exactly what I need.
For the record, the existing lengths/combo, makes 418 whp, which is good for a modest TR 224 cam.
Thanks, everyone, for your experiences.
Here is the issue.. there are several pushrods that, because pushrods generally are offered in only .025 increments, fall short of the .075 target. Add a hot engine, and there is ticking/sewing/etc, introduced at low RPM.
I'm ok with being over the target, and not ok with being under by these (cold) amounts... generally, several, .019 short of .075 + hot engine. The next step up is 7.450, which is too long.
I happened upon an old thread (mine) that addressed this. The replies suggested Manton Pushrods, so, a call to Manton put me in touch with their machinist/tech, who said that when I order a, For Example, 7.400, that his finished product, end to end, is 7.400. I told him that the caliper measurement of a TR 7.400 actually is 7.417, which is true of any common LS pushrod. He replied that Manton doesn't consider the extra .017, so that when they manufacture a 7.400, that end-to-end is 7.400. This would leave me right back where I presently am.
At this, he balked, and rather than say, "Ok, we'll add .017 to each of your stated lengths, and this will put us in agreement", I suggested it, which would have solved our disagreement.
Again, he balked at this, and I decided to let it go.
There is a good machine shop, nearby, and the person over there instantly knew what I was referring to, so I'll have him manufacture exactly what I need.
For the record, the existing lengths/combo, makes 418 whp, which is good for a modest TR 224 cam.
Thanks, everyone, for your experiences.
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The 850 lifters go .200 travel. Preload target is .075.
Here is the issue.. there are several pushrods that, because pushrods generally are offered in only .025 increments, fall short of the .075 target. Add a hot engine, and there is ticking/sewing/etc, introduced at low RPM.
I'm ok with being over the target, and not ok with being under by these (cold) amounts... generally, several, .019 short of .075 + hot engine. The next step up is 7.450, which is too long.
I happened upon an old thread (mine) that addressed this. The replies suggested Manton Pushrods, so, a call to Manton put me in touch with their machinist/tech, who said that when I order a, For Example, 7.400, that his finished product, end to end, is 7.400. I told him that the caliper measurement of a TR 7.400 actually is 7.417, which is true of any common LS pushrod. He replied that Manton doesn't consider the extra .017, so that when they manufacture a 7.400, that end-to-end is 7.400. This would leave me right back where I presently am.
At this, he balked, and rather than say, "Ok, we'll add .017 to each of your stated lengths, and this will put us in agreement", I suggested it, which would have solved our disagreement.
Again, he balked at this, and I decided to let it go.
There is a good machine shop, nearby, and the person over there instantly knew what I was referring to, so I'll have him manufacture exactly what I need.
For the record, the existing lengths/combo, makes 418 whp, which is good for a modest TR 224 cam.
Thanks, everyone, for your experiences.
Here is the issue.. there are several pushrods that, because pushrods generally are offered in only .025 increments, fall short of the .075 target. Add a hot engine, and there is ticking/sewing/etc, introduced at low RPM.
I'm ok with being over the target, and not ok with being under by these (cold) amounts... generally, several, .019 short of .075 + hot engine. The next step up is 7.450, which is too long.
I happened upon an old thread (mine) that addressed this. The replies suggested Manton Pushrods, so, a call to Manton put me in touch with their machinist/tech, who said that when I order a, For Example, 7.400, that his finished product, end to end, is 7.400. I told him that the caliper measurement of a TR 7.400 actually is 7.417, which is true of any common LS pushrod. He replied that Manton doesn't consider the extra .017, so that when they manufacture a 7.400, that end-to-end is 7.400. This would leave me right back where I presently am.
At this, he balked, and rather than say, "Ok, we'll add .017 to each of your stated lengths, and this will put us in agreement", I suggested it, which would have solved our disagreement.
Again, he balked at this, and I decided to let it go.
There is a good machine shop, nearby, and the person over there instantly knew what I was referring to, so I'll have him manufacture exactly what I need.
For the record, the existing lengths/combo, makes 418 whp, which is good for a modest TR 224 cam.
Thanks, everyone, for your experiences.
