weird noise after cam swap?
01-14-2012, 05:53 PM
#11
TECH Fanatic
Thread Starter
Join Date: Feb 2009
Location: Saudi Arabia
Posts: 1,020
Likes: 0
Received 0 Likes
on
0 Posts
will this .075" hurt the lifter? really? its just 2mm...how much is the preload on the ls7 lifters?
some info
single
stock none dod 5.3 lifter 17122490
single ls7 lifter 12576400
some info
single
stock none dod 5.3 lifter 17122490
single ls7 lifter 12576400
01-15-2012, 09:19 AM
#14
That is something that needs to be taken up with pushrod length adjustment. That's why pushrods are available in such small (.025") increments. That is more than likely the source of your noise. Either the rods are too long and the preload is way off(too tight), and you may have bent one or several pushrods...or they are too short and you are hearing them slap around in the guides.
Get a pushrod length checker and get the right length rods in there.
Get a pushrod length checker and get the right length rods in there.
01-19-2012, 12:45 AM
#15
Teching In
iTrader: (1)
Join Date: May 2011
Location: Central CA
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
I had a similar issue.
Stock 4.8 put the TR224 cam and had 7.4's.
I slowly tightened the rockers until the push rod did not spin easily in my fingers. from there it only took 1/4 turn to get to 22ft/lbs. This means I did not have enough pre-load. I bought 7.425 and did the same thing except I then had 7/8 to 1 turn to 22 ft/lbs. I then had enough pre-load. It is an easy way to check with out buying a tool and waiting.
Stock 4.8 put the TR224 cam and had 7.4's.
I slowly tightened the rockers until the push rod did not spin easily in my fingers. from there it only took 1/4 turn to get to 22ft/lbs. This means I did not have enough pre-load. I bought 7.425 and did the same thing except I then had 7/8 to 1 turn to 22 ft/lbs. I then had enough pre-load. It is an easy way to check with out buying a tool and waiting.
01-19-2012, 09:33 PM
#18
Negative. 17122490 is what your truck came with, 12576400 is the part number gm came out with shortly after the DOD engines started puking lifters. Nobody will tell me why but they cost half as much so I am left to assume its a cost savings move. If you look up lifters for a Z06 it shows a 12576400 now but if you open up a GMPP LS7 lifter kit it contains 16 17122490s. A year ago they all showed to use they 17122490. They are interchangable. Does all this make sense?
Thread
Thread Starter
Forum
Replies
Last Post
GrooveCityZ71
GM Engine & Exhaust Performance
7
08-31-2015 12:05 PM
V-seriesTech
GM Engine & Exhaust Performance
7
07-28-2015 12:31 PM
