0821 heads shaved .010 / pushrod length
Thread Starter
Teching In
Joined: Dec 2018
Posts: 33
Likes: 8
The reason I'm asking is because I just rebuilt a 2013 LS3 that dropped a valve (sheered the hollow intake valve) so I had to shave the head a bit. Everything is stock except for the forged -2cc pistons, camshaft, headers and a bit of polishing the runners. The quinch is .048 and the piston/valve clearance is .070. After starting the engine, it ran perfect for about 10 miles (no warning lights came on at all in the gauges)
then it started skipping and the dash lit up with check engine light, stable track, traction control, tire pressure... I think it's either the pushrods, blown head gasket or the camshaft sensor, maybe even the cam sensor pigtail. Haven't had time yet to do any diagnostic. I understand these LS engines have to relearn once a cam, crank sensor is changed, or a different cam is installed. I just went out and fire it up and only 3 cylinders came up to temp 325 degrees (at the exhaust port) the others were between 97 and 225 degrees plus I hear a slight ticking sound. I'm now 90% sure it's the pushrods. Any thoughts...
*I did change the valve spring from stock to single beehive .0625 capable and the valve spring install height is 1.80
then it started skipping and the dash lit up with check engine light, stable track, traction control, tire pressure... I think it's either the pushrods, blown head gasket or the camshaft sensor, maybe even the cam sensor pigtail. Haven't had time yet to do any diagnostic. I understand these LS engines have to relearn once a cam, crank sensor is changed, or a different cam is installed. I just went out and fire it up and only 3 cylinders came up to temp 325 degrees (at the exhaust port) the others were between 97 and 225 degrees plus I hear a slight ticking sound. I'm now 90% sure it's the pushrods. Any thoughts...
*I did change the valve spring from stock to single beehive .0625 capable and the valve spring install height is 1.80
Last edited by SRB; Dec 12, 2023 at 10:09 AM.
The reason I'm asking is because I just rebuilt a 2013 LS3 that dropped a valve (sheered the hollow intake valve) so I had to shave the head a bit. Everything is stock except for the forged -2cc pistons, camshaft, headers and a bit of polishing the runners. The quinch is .048 and the piston/valve clearance is .070. After starting the engine, it ran perfect for about 10 miles (no warning lights came on at all in the gauges)
then it started skipping and the dash lit up with check engine light, stable track, traction control, tire pressure... I think it's either the pushrods, blown head gasket or the camshaft sensor, maybe even the cam sensor pigtail. Haven't had time yet to do any diagnostic. I understand these LS engines have to relearn once a cam, crank sensor is changed, or a different cam is installed. I just went out and fire it up and only 3 cylinders came up to temp 325 degrees (at the exhaust port) the others were between 97 and 225 degrees plus I hear a slight ticking sound. I'm now 90% sure it's the pushrods. Any thoughts...
*I did change the valve spring from stock to single beehive .0625 capable and the valve spring install height is 1.80
then it started skipping and the dash lit up with check engine light, stable track, traction control, tire pressure... I think it's either the pushrods, blown head gasket or the camshaft sensor, maybe even the cam sensor pigtail. Haven't had time yet to do any diagnostic. I understand these LS engines have to relearn once a cam, crank sensor is changed, or a different cam is installed. I just went out and fire it up and only 3 cylinders came up to temp 325 degrees (at the exhaust port) the others were between 97 and 225 degrees plus I hear a slight ticking sound. I'm now 90% sure it's the pushrods. Any thoughts...
*I did change the valve spring from stock to single beehive .0625 capable and the valve spring install height is 1.80
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Yes. I shouldve commented on that, too. .070" is way too close. It should run great, for awhile. I've always gone with a minimum .100". Wonder what LSA he's running? Tighter LSA reduces clearance......
Thread Starter
Teching In
Joined: Dec 2018
Posts: 33
Likes: 8
LSA is 113. I found the problem; I rebuilt the factory rocker arms to get rid of the crappy factory needle bearings. The kit had new sealed bearing with new trunnion that travel 360 degrees instead of the factory 60 degrees, they also came with new rocker arm bolts that were in a package at the bottom of the box under some soft Styrofoam. I did not see them until today and evidentially you have to use the supplied bolts because when I removed the valve cover, I noticed that many of the rockers were walking side to side halfway off the valve stem head but no lash. After looking closely, I noticed that the trunnions were about .060 off the rocker tray. I am assuming that once the hydraulic lifters pumped up (5 miles) the .060 showed itself and it started skipping. Puzzled as to why they didn't seat I went to my work bench to take a break and think about it and picked up the trunnion box and it felt oddly heavy so... low and behold I found 16 new ricker bolts. I compared the two and the seat is .060 longer on the new ones... You would think they wouldn't hide the damn bolts like that. What a pain in the ***.
* I did check the pushrod length and it came out to factory 7.4.
* I did check the pushrod length and it came out to factory 7.4.