PTV clearence issues
03-21-2015, 04:18 PM
#1
On The Tree
Thread Starter
iTrader: (1)
Join Date: Nov 2014
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
PTV clearence issues Hey guys. I was installing cam today. Checked ptv with clay and intake valve is hitting piston. Before I call who spec cam I was wonder if maybe I'm doing something wrong. So motor is a 06 lq4. Stock bottom end. It has the factory valve reliefs for the exhaust already on Pistons. I'm running ls3 821 heads that milled .007 to clean them up. 7.4 pushrods, which are good. I checked valve stem tip as I was doing ptv checking. So I lined up the dots on timing gears used checking springs , used feeler gauges to makeup for .051 gasket thin knead. Torqued rockers arms down to 22lbs when piston at tdc.
cam specs are
.632/.627 lift
227/243 .050 dur
110+4 lsa
106 ICL
cam specs are
.632/.627 lift
227/243 .050 dur
110+4 lsa
106 ICL
Last edited by jerr6; 03-21-2015 at 04:32 PM.
03-21-2015, 05:19 PM
#2
10 Second Club
The LS3/L92 heads have huge valves....this combined with the dur on the exh side is the reason we need to fly~cut 
This can be done on the motor, in the car, with the proper tools and precautions.
This can be done on the motor, in the car, with the proper tools and precautions.
03-22-2015, 08:24 AM
#4
May be able to create some clearance by retarding the cam w/ an adjustable timing set, but, it probably won't be enough. So, looks like you're gonna need to flycut the intake side.
03-22-2015, 01:32 PM
#5
On The Tree
Thread Starter
iTrader: (1)
Join Date: Nov 2014
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
When I tighten rocker arms to check ptv should the dots on timing gears be lined up like the pic or should crank be 12 o'clock and cam be 12 oclock? Maybe that's what I did wrong?
Trending Topics
03-23-2015, 07:00 AM
#8
On The Tree
Thread Starter
iTrader: (1)
Join Date: Nov 2014
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
No I did not use solid lifter. I did use light checking springs. I wouldn't think its enough pressure to compress lifter.
The heads were milled .007. I did buy the heads used and that's what I was told they were milled. I did check pushrod length while I was at it and the 7.4 pushrods are the right length so wouldn't that confirm heads haven't been milled even more?
The heads were milled .007. I did buy the heads used and that's what I was told they were milled. I did check pushrod length while I was at it and the 7.4 pushrods are the right length so wouldn't that confirm heads haven't been milled even more?
03-23-2015, 02:45 PM
#10
TECH Enthusiast
Weird. A 236/246 615/615 110 will fit, it's bizarre that yours doesn't. Checking with hyd lifter is tricky as you don't know it is pumped up or bled down. 7thou off is nothing, just a clean up of the face. Wonder if worthwhile actually using a head gasket instead of feeler guage?
But yeah, retarding the cam will help see where you are at. Fly-cutting easy to do though
But yeah, retarding the cam will help see where you are at. Fly-cutting easy to do though
03-23-2015, 04:37 PM
#11
On The Tree
Thread Starter
iTrader: (1)
Join Date: Nov 2014
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
So I'm gonna try and come up with extra lifter or take one of mine apart to make it solid. If I use solid lifter do I have to use a pushrod length checker as the pushrod and adjust til zero lash?
03-24-2015, 10:42 PM
#12
03-25-2015, 09:33 AM
#14
Hey guys. I was installing cam today. Checked ptv with clay and intake valve is hitting piston. Before I call who spec cam I was wonder if maybe I'm doing something wrong. So motor is a 06 lq4. Stock bottom end. It has the factory valve reliefs for the exhaust already on Pistons. I'm running ls3 821 heads that milled .007 to clean them up. 7.4 pushrods, which are good. I checked valve stem tip as I was doing ptv checking. So I lined up the dots on timing gears used checking springs , used feeler gauges to makeup for .051 gasket thin knead. Torqued rockers arms down to 22lbs when piston at tdc.
cam specs are
.632/.627 lift
227/243 .050 dur
110+4 lsa
106 ICL
cam specs are
.632/.627 lift
227/243 .050 dur
110+4 lsa
106 ICL
I would do 2 things: Check it again with a solid lifter set at "0" lash and measure the valve drop on the intake side.
03-25-2015, 06:08 PM
#15
On The Tree
Thread Starter
iTrader: (1)
Join Date: Nov 2014
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
It is a comp cam. Not sure what lobe profile. Just got the pushrod length checker today. Still have to make up solid lifter. I will look into valve drop. Hope to recheck clearence this weekend.
Last edited by jerr6; 03-25-2015 at 08:50 PM.
