Broke a lifter twice,
Thread Starter
7th Gear
Joined: Nov 2016
Posts: 7
Likes: 0
Broke a lifter twice,
What would cause this a broken lifter,
will give some background on the motor and the build,
motor is a GMPP block 5.7 the newer style with the shorter head studs,
motor was all stock, but had a Schneider Race cam and broke one lifter on #5 cylinder, and had comp single springs, the lifter was missing all the rollers and was flat at the bottom,
we rebuilt the motor to a 383, uses a cam I had in my 383 for over a year, and is the same Lunati cam we use in our motors for the last 5 years, and on the dyno it broke a Ls-7 lifter on cylinder #6
can this be a issue with this block, the LS-7 lifter was purchased from the dealer not an ebay no name so called lifter,
lifter came from a major size GM Dealership, have purchased the same lifters for years, all the pushrod length was checked chromoly
pushrods and lunati Dual Springs
same as the last 15 or so motors we have done,
but this motor came to us with a broke lifter and then broke another on a different cylinder, new durabond cam bearings and new oil pump,
will give some background on the motor and the build,
motor is a GMPP block 5.7 the newer style with the shorter head studs,
motor was all stock, but had a Schneider Race cam and broke one lifter on #5 cylinder, and had comp single springs, the lifter was missing all the rollers and was flat at the bottom,
we rebuilt the motor to a 383, uses a cam I had in my 383 for over a year, and is the same Lunati cam we use in our motors for the last 5 years, and on the dyno it broke a Ls-7 lifter on cylinder #6
can this be a issue with this block, the LS-7 lifter was purchased from the dealer not an ebay no name so called lifter,
lifter came from a major size GM Dealership, have purchased the same lifters for years, all the pushrod length was checked chromoly
pushrods and lunati Dual Springs
same as the last 15 or so motors we have done,
but this motor came to us with a broke lifter and then broke another on a different cylinder, new durabond cam bearings and new oil pump,
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
While there can be any number of issues that would result in the lifter damage, the fact that two were broke and and the second one so quickly would rule out some of the things that might cause this. Do you have a photo of the broken lifter? Any evidence it turned in the lifter bore? Have you looked closely at the cam to make sure the lobes meet roller requirements?
Safety Car
Joined: Mar 2016
Posts: 3,534
Likes: 432
From: Atlantic Beach FL.
Are the springs bottoming out? By chance are you using 1.8:1 rockers?
The push rods could be too long. Otherwise maybe something is getting stuck in the valve-train.
The push rods could be too long. Otherwise maybe something is getting stuck in the valve-train.
Last edited by Rob 02; Jan 2, 2017 at 08:58 AM.
Drifting
Joined: Feb 2010
Posts: 1,720
Likes: 38
From: Colorado
+1 to the incorrect pushrod length. thats the first thing I thought of and about the only thing I can think of that'd do it twice. i didnt think about 1.8 ratio rockers, but technically its the same problem - valvetrain is extruding the pushrods too hard/far into the lifter.
Thread Starter
7th Gear
Joined: Nov 2016
Posts: 7
Likes: 0
I checked the pushrod length, .060 plunge used my 8'' digital mic, it beat the bearings out of the rollers, cam was a cam out of my LS1 used for a year with no issues, lift was a .589, use the same springs 8 other time in past motors some still running with .665 lift,
can it be something in the block?
or can it be the Tuner he is using with bad timing causing predestination
can it be something in the block?
or can it be the Tuner he is using with bad timing causing predestination
Drifting
Joined: Jul 2005
Posts: 1,484
Likes: 27
From: Torrance Calif
I have noticed that some of the "high lift" cams achieve this by decreasing the cam lobe diameter which allows the lifter to drop farther.
This can allow the lifter skirt to fulcrum against the side of the lifter hole and it may bind.
I suggest you check the lifter skirt and the hole for wear or traces of binding.
This can allow the lifter skirt to fulcrum against the side of the lifter hole and it may bind.
I suggest you check the lifter skirt and the hole for wear or traces of binding.
Drifting
Joined: Feb 2010
Posts: 1,720
Likes: 38
From: Colorado
I have noticed that some of the "high lift" cams achieve this by decreasing the cam lobe diameter which allows the lifter to drop farther.
This can allow the lifter skirt to fulcrum against the side of the lifter hole and it may bind.
I suggest you check the lifter skirt and the hole for wear or traces of binding.
This can allow the lifter skirt to fulcrum against the side of the lifter hole and it may bind.
I suggest you check the lifter skirt and the hole for wear or traces of binding.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
7th Gear
Joined: Nov 2016
Posts: 7
Likes: 0
Well Damn just stupid of me,
I washed up all the lifter trays, and one tray was wiped out on the flats, I can spin the lifter by hand in the tray, Totally stupid of me to try to make a dead line and rushed to get it out, and not wait for the new trays to come in,
thanks everyone for all the advise and quick response,
I washed up all the lifter trays, and one tray was wiped out on the flats, I can spin the lifter by hand in the tray, Totally stupid of me to try to make a dead line and rushed to get it out, and not wait for the new trays to come in,
thanks everyone for all the advise and quick response,
Drifting
Joined: Feb 2010
Posts: 1,720
Likes: 38
From: Colorado
Well Damn just stupid of me,
I washed up all the lifter trays, and one tray was wiped out on the flats, I can spin the lifter by hand in the tray, Totally stupid of me to try to make a dead line and rushed to get it out, and not wait for the new trays to come in,
thanks everyone for all the advise and quick response,
I washed up all the lifter trays, and one tray was wiped out on the flats, I can spin the lifter by hand in the tray, Totally stupid of me to try to make a dead line and rushed to get it out, and not wait for the new trays to come in,
thanks everyone for all the advise and quick response,
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
ALWAYS ALWAYS replace the trays as they are only a few dollars.
ON ANOTHER NOTE,,,,,, Something else that I have found that can cause valve train issues:
Ive learned to check for abnormal wear on the two Aluminum Rocker Perches that the rockers sit on.
The small area that each rocker sits on can and does wear and that causes the rocker to sit crooked on the valve stem surface and can cause the pushrod to contact the pushrod hole in the head.
Bill