i like how tsp told me it wasnt anything to worry about when i ordered the lifters and pushrods.. they said the 7.4 was fine

 

Yea alot of people told me that.. idk where there getting info from because 7.4 is WAY to long for the ls7 lifters, it wouldn't even turn until we went to a 7.35 which was perfect and right in the middle. I'm awaiting my pushrods now so this can be done already!

 

What do you mean it wouldn't even turn? I have only put about 15 miles on my heads and lifters since the install. If the 7.4" pushrods are indeed too long I'm going to change them out. Don't want to beat the new lifters up.

 

You would know if they are to long.. We measured with a adjustable pushrod, do you have a cam? heads? and ls7 lifters? that all could affect it, I just think that the ls7 lifters were the ones that affected it the most since my heads aren't milled. And when I say it wouldn't turn, I mean we couldn't manually crank it, the pushrods were to long it wouldn't even move. When we tried 7.35 it was perfect!


This is my motor as it sits now, im awaiting my new pushrods.

 

I am goin to be using 7.350 with the LS7 lifters in a few weeks for head install.

 

Yep, told me the same thing. Only they told me a 7.45 and the heads I ordered had a 59cc chamber.

 

If i were to do it agian, i would be asking predator z everything instead of takng the salesman advice

 

Yea just measure to be on the safe side!

 

yes, the only way to know is to measure, once install pushrods once.

 

I was also told the LS7 were the same as LS1's. When I did my heads, we welded an old LS1 lifter to make it solid to check ptv clearance because I milled my heads to 62cc and I came up with 7.300, then figured in .075 preload for a total of 7.375. The math seemed to verify my measurements since I was running 7.425's cam only w/ stock heads, so I didn't re-measure. I got about 500 miles on it w/ the LS7's & 7.375's and so far so good, but after seeing this, its got me worried & now I guess I need to go measure again w/ the LS7's in there.

 

this has been driving me nuts for months.

i installed a new cam (228, 232, .590, .590 @ 113lsa) and it blew one of my already failing LS1 lifters out. replaced the lifters with LS7s and then valvetrain noise took over my life. when the oil got hot, it would CLACK CLACK CLACK like crazy, something you could hear from a block away... literally.
so, i had another NEW set of LS7 lifters installed yesterday and im hearing some of the same noises, just not as pronounced.
im ordering a PR length checker today, my question is this: if i have ~300 miles on the new LS7 lifters and the preload is too much (runnin the TSP 7.40 PRs now) will changing the pushrods out do anything? will it correct the problem (assuming PR length is it) or do the lifters 'set' themselves to the pushrod in some way?

thanks!

 

Below is an email that I sent to Patrick G. and his response below that.



ME:
Patrick, I have decided to change my lifters to LS7 lifters when I do the cam swap. You recommended 7.425" pushrods with stock lifters. Should I go with a shorter pushrod now that I am going to be putting LS7 lifters in? Thanks for your help.


Patrick G:
The LS7 lifters use the same preload as LS1 lifters. The 7.425" pushrods will work well in this case.

Patrick Guerra - The Guerra Group - 114 Spokane Avenue - Victoria, Tx. 77904 -

 

what are your cam specs?

 

Yes they use same preload range, however we have determined by measurement that the internals of the LS7 lifter (with pic) sit higher.
So if the 7.425 get you let us say .100 preload or more on LS1 lifters, that would be like .125+ in LS7 and that would make it too close to plunger bottoming out.
So bottom line, measure instead of shooting a dice roll.

 

226/234 .598”/.602” 111LSA +3 advance

 

this must explain why i had set of ls7 lifters fail on me. i was using 7.4 pr. i switched over to comp oem lifters and it has been much quieter.