Spongy lifters?
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Spongy lifters?
Hey guys, I just replaced my HS modified stock rockers with some Yella Terra's, and they were kinda noisy. I pulled everything apart, and adjusted the wipe so its perfect. I had to shim it so naturally I assume I need to adjust my pushrod length. I have a comp PR length checker, and while I was playing with it I noticed a few of my lifters felt really spongy. The car has sat for about a week, so I'm sure they have bled down some, but I ran it for about a minute or two about an hour ago, wouldn't they have pumped up almost immediately? I've gotta say, with them being spongy it is really hard to check my PR length. I'm feeling kinda sick to my stomach right now so any input is appreciated. Thanks!
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Banned Scam/Spammer
Joined: May 2007
Posts: 15,685
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From: Machineguns, because I don’t compromise
wow, kinda odd with such low mileage..
If they are impeding you being able to check that would give concern.. If they are just (not perfect) then do the best job you can... Button it all up, see if it's quieter, and check 'em again some other day after you've run the engine a bit more.
If they are impeding you being able to check that would give concern.. If they are just (not perfect) then do the best job you can... Button it all up, see if it's quieter, and check 'em again some other day after you've run the engine a bit more.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
wow, kinda odd with such low mileage..
If they are impeding you being able to check that would give concern.. If they are just (not perfect) then do the best job you can... Button it all up, see if it's quieter, and check 'em again some other day after you've run the engine a bit more.
If they are impeding you being able to check that would give concern.. If they are just (not perfect) then do the best job you can... Button it all up, see if it's quieter, and check 'em again some other day after you've run the engine a bit more.
LS7 lifters, I bought them brand new from Gene about 2 years ago when I put this motor together.
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Melting Slicks
Joined: May 2005
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From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
I just got an LT1 back togethor "same lifters" and they were really easy to push down also. I was also thinking it was strange. In my case the lifters just bleed down really quick when the pushrod is removed but after running for about 10 min they all got quiet again like they were before. Sometimes they take a bit to pump back up and get quiet. As for the rockers damaging the lifters I really don't think so.
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
Sounds like they just aren't pumped up completely. I'd do the best job you can for now.. if it gets loud again then I'd do a little warm up right before tearing it down to help make sure they're pumped up.
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Having the engine down for a a while and with different valves on or off base circle or peak lift point on the lobe will affect how much oil will bleed past the high pressure area of the lifter. Some will be low some high. This is common and will sometimes take a good while for the lifter to pump back up again.
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
If you removed the pushrods from lifters that were in a running preloaded position, the internals will push the cup to the top. They will feel spongy. Just measure carefully. Problem with running it more is they could be up against the clip if your pushrods are too short and the GM clip is kind of wimpy. Also, if you used the YT provided shims your pushrod length just changed by roughly 0.100".
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
If you removed the pushrods from lifters that were in a running preloaded position, the internals will push the cup to the top. They will feel spongy. Just measure carefully. Problem with running it more is they could be up against the clip if your pushrods are too short and the GM clip is kind of wimpy. Also, if you used the YT provided shims your pushrod length just changed by roughly 0.100".
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
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From: In the pit, trying to love someone.
Team Owner
Joined: May 2001
Posts: 87,315
Likes: 1,585
From: Western NY
You need to run it longer. Oil flow is from the lifter upward through the pushrod. I doubt any pieces-parts would have found their way to the lifters.
Having the engine down for a a while and with different valves on or off base circle or peak lift point on the lobe will affect how much oil will bleed past the high pressure area of the lifter. Some will be low some high. This is common and will sometimes take a good while for the lifter to pump back up again.
Having the engine down for a a while and with different valves on or off base circle or peak lift point on the lobe will affect how much oil will bleed past the high pressure area of the lifter. Some will be low some high. This is common and will sometimes take a good while for the lifter to pump back up again.
That's part of the equation, however I think you also need to figure in the rate of expansion between "hot" and "cold" engines and their components.
I put a set of Comp 875R "anti-pump up" lifters in my LT1 powered Camaro. I didn't know before I bought them, that they are a PITA to adjust. Nonetheless, a lot of the "hop-up" work done on my cars is done in the winter, when they're off the road. It was during the winter that I put these new lifters in, and of course "adjusted" them.
Long story short, they were noisy when I put the car back on the road the following spring. The only way I was able to get them reasonably quiet was A) when the ambient air temp was around 80 degrees, and B) the engine was FULLY warmed up, before I set them.
Safety Car
Joined: Nov 2002
Posts: 4,394
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From: Melbourne FL
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Maybe I'm not the most informed on this topic, but I thought that was the whole point of installing the shim. To increase the the distance between the rocker and the lifter so you have the correct amount of preload on the lifter without purchasing different length pushrods Assuming you maintain a good wipe pattern of course with the shim.
Team Owner
Joined: May 2001
Posts: 87,315
Likes: 1,585
From: Western NY
No, unfortunately that is what LS1howto states but the reason for the shim is to adjust the geometry to obtain a correct wipe pattern. I found I needed a shim bigger then the one supplied by YT. Once the geometry is correct then you measure for pushrod length. The shim is not used for preload correction as some would have you think.
The more I hear about rockers self destructing, the less comfortable I am with my stock rockers. Are there any replacements that can be installed easily in place of the OEs??
