Build Sanity Check - Measuring for Pushrods
Thread Starter
Joined: Mar 2007
Posts: 1,145
Likes: 49
From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
Build Sanity Check - Measuring for Pushrods Seems like this is the flavour of the day - confirming measured pushrod lengths.
Specs:
SBE 2002 LS1;
TSP LS6 Stage 1 heads (ordered specifically without milling) and loaded w/BTR dual springs;
Straub trunnion upgrade;
Stock 5.7/5.3 HO GM MLS gaskets;
BTR SLR lifters; and
Cam Motion .627"/.613" 228/234 112+3
Out came the adjustable pushrod and 8" caliper.
The figures are (intake / exhaust):
#1 7.301 / 7.302
#2 7.294 / 7.296
#3 7.299 / 7.307
#4 7.285 / 7.284
#5 7.291 / 7.296
#6 7.299 / 7.300
#7 7.307 / 7.302
#8 7.286 / 7.295
These numbers indicate the possibility of milled cylinder heads, a larger base circle, and/or a taller lifter cup height - the block temperature is about 6-10*C - because who doesn't love stacking tolerances, right?
I have to reach out to BTR to get some more info on the lifters (which are recommended to have a preload of .025"-.075") before ordering suitable pushrods.
Obviously the sidebar concern here are the PTV clearances going out the window.
Any thoughts or reassurances in the interim would be greatly appreciated.
Specs:
SBE 2002 LS1;
TSP LS6 Stage 1 heads (ordered specifically without milling) and loaded w/BTR dual springs;
Straub trunnion upgrade;
Stock 5.7/5.3 HO GM MLS gaskets;
BTR SLR lifters; and
Cam Motion .627"/.613" 228/234 112+3
Out came the adjustable pushrod and 8" caliper.
The figures are (intake / exhaust):
#1 7.301 / 7.302
#2 7.294 / 7.296
#3 7.299 / 7.307
#4 7.285 / 7.284
#5 7.291 / 7.296
#6 7.299 / 7.300
#7 7.307 / 7.302
#8 7.286 / 7.295
These numbers indicate the possibility of milled cylinder heads, a larger base circle, and/or a taller lifter cup height - the block temperature is about 6-10*C - because who doesn't love stacking tolerances, right?
I have to reach out to BTR to get some more info on the lifters (which are recommended to have a preload of .025"-.075") before ordering suitable pushrods.
Obviously the sidebar concern here are the PTV clearances going out the window.
Any thoughts or reassurances in the interim would be greatly appreciated.
Even if the heads are milled that cam should not give you and PTV. If that helps.
Might ask BTR if the lifter cups are higher than stock LS1 lifters. Stocknpushrods are 7.385 iirc, sonif you ran a 040 head gasket. A stock 058, you're basically in the right ballpark.
Might ask BTR if the lifter cups are higher than stock LS1 lifters. Stocknpushrods are 7.385 iirc, sonif you ran a 040 head gasket. A stock 058, you're basically in the right ballpark.
Thread Starter
Joined: Mar 2007
Posts: 1,145
Likes: 49
From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
Called both BTR and Cam Motion today, both were very helpful. Unfortunately things are still a little inconclusive.
Per BTR: Lifter cup height is the same as the LS7 at 2.648" +/-.010", preload is good at a target of .050", and pushrod tip size is 5/16".
Per Cam Motion: The base circle should be cam bearing diameter (2.165") - lobe lift (.369") - lobe lift (.369") = 1.427"; 1.427" - 0.015" to keep the lobe from nicking the cam bearing turns out 1.412" (round down to 1.400"). Factory should in the 1.450-1.550" (http://www.silveradoss.com/forums/to...m/#entry798443). The final statement was: ...it seems you lost .100".
Measured a stock pushrod and it came out to 7.390".
Anywho, I am going to run with what I have and get some 11/32" pushrods from either Trend or Manton.
If that's what you have, then that's what you have. Conjecture is awesome but measured results are better.
I'm assuming those measurements are at zero lash? If so, then some 7.350 would be about right.
I'm assuming those measurements are at zero lash? If so, then some 7.350 would be about right.
Thread Starter
Joined: Mar 2007
Posts: 1,145
Likes: 49
From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
