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So I work for an LS based performance shop in my area and over the last year we have seen at least 2 LS7 lifter failures on engines a short time after installing a Texas speed Cam package.
In both cases the lifter failed and the body of the lifter broke lodging the lifter in the bore and both times they were a pain to extract and did damage to the lifter bores as well. I decided to do as much research as I could to determine if this had happened to others and try to find a possible cause and solution to the issue. After researching for a while I have come up with a possible cause that might explain the failures that I have experienced as well as others i have read about online. The Texas Speed kit that we typically install includes a Dual valve spring kit which of course increases the open spring pressure over the stock springs. When looking into the specs it appears that the dual springs have an open pressure of somewhere around 415 lb. This is almost 100 lb more than the pressure exerted by the OEM style spring used with LS7 lifters.
Does anyone else think that the spring pressures on these dual valve springs is too high for OEM LS7 lifters? Could that be the reason we have seen failures? From the research I have done everything suggests that you should not use OEM style lifters with spring pressures over 360 lb but even Texas speed recommends using the LS7 lifters. I'm curious if anyone else has more info on this or experienced any of these failures using dual valve springs.
So, dual valve spring kits have been sold with LS7 lifters for over a dozen years. And going back to the Patriot Gold springs, all of them have 380lbs+ of open spring pressure. The BTR kit is 400lbs and is one of the most popular. BTR also recommends the LS7 lifter as it has been spintron tested. If you want to move to a Johnson or Morel, I recommend it, especially over 7K RPM with heavier than LS7 valves (which is pretty much everything).
I'm not sure what's causing the issues you see, but it's likely they are not original Delphi lifters and ACDelco is outsourcing to a lower quality producer.
But many many shops sell and use the LS7 lifters. To a much larger degree than anything else--so having a few failures is not unexpected given the sheer number of installs.
As for what you have seen, what was the preload setting on the lifters? They have about .200" of travel, but if they were run at very low preload or very high, that could cause them to fail with an aggressive lobe and heavier valve & spring setup.
Also, if you look at this sticky I did some years ago, it talks about harmonics, pushrod stiffness, valve weight, rocker weight, etc necessary to build a proper valvetrain: https://ls1tech.com/forums/generatio...alvetrain.html
Thanks for posting that spec sheet.
LS7 lifters are really not suitable for even a mild build.
All aftermarket hydraulic roller camshafts require springs rated to at least 400lb open pressure.
I would certainly never use them.
Chevrolet Performance LS7 lifters are $219 at BTR... That is what I run in my builds unless I'm building something super special. They worked for 3 years in my 1200rwhp LS9 block setup with cast LS crank/Compstar rods/Wiseco pistons/MAST LS3 heads and revving it to 7500-7800rpm with an 88mm Precision turbo. https://www.briantooleyracing.com/ch...-12499225.html
The $99 Delphi LS7 lifters are the ones of inferior quality.... and if you think about it $99 divided by 16 lifters makes each one a little over $6 per unit... which includes shipping! If BTR is making money on them which they are.... it means they are probably closer to the $4 or $4.50 price per unit. Then Delphi is making money on them.... which means they are closer to the $3 price range. There is no way in hell I'm putting that POS in my motor and anyone that does in a performance setup should have their head checked.
Delphi are not OEM gm lifters.. there's part of your problem.
Been running BTR platinum spring kit with stock 02 ls1 lifters for years turning over 7k rpm yet to have a lifter failure.
In the past i ran stock 99 ls1 lifters with even heavier springs (bigger diameter comp duals which came with absolute speed stg2.5 cnc 5.3 heads).. did over 30,000 miles street/track with those heads on the car 7200 rpm shifts, lifters never failed. I returned the engine/car back to stock and sold it, in top condition!
Thanks for posting that spec sheet.
LS7 lifters are really not suitable for even a mild build.
All aftermarket hydraulic roller camshafts require springs rated to at least 400lb open pressure.
I would certainly never use them.
Thats false. Lots of NSR (No Springs Required) aftermarket camshafts out there.
The valvetrain is a system of parts. The LS7 lifters are a low end mass produced lifter. It works well if the lifter isn’t punished with aggressive lobes and flimsy pushrods/rockers. Keep the valvetrain under control and the LS7 lifters will last.
Thats false. Lots of NSR (No Springs Required) aftermarket camshafts out there.
The valvetrain is a system of parts. The LS7 lifters are a low end mass produced lifter. It works well if the lifter isn’t punished with aggressive lobes and flimsy pushrods/rockers. Keep the valvetrain under control and the LS7 lifters will last.
Not false at all.
The majority of performance orientated camshafts require stronger springs than stock.
I know there are some that don't but most people don't go this route.
If you are using a cam that doesn't require a spring change I would imagine that the performance wouldn't be much better than stock and for such a setup an LS7 lifter would survive if set up correctly.
The specs of the LS7 lifter show what they are designed to deal with.
If you want to go over that's your choice.
Not false at all.
The majority of performance orientated camshafts require stronger springs than stock.
I know there are some that don't but most people don't go this route.
If you are using a cam that doesn't require a spring change I would imagine that the performance wouldn't be much better than stock and for such a setup an LS7 lifter would survive if set up correctly.
The specs of the LS7 lifter show what they are designed to deal with.
If you want to go over that's your choice.
What you said was 100% false, thats why you went from saying all aftermarket camshafts to the majority of aftermarket camshafts .
Those crazy people at GM! What were they thinking making V8 engines that rev to 7k that are meant to survive hundreds of thousands of miles on those "garbage LS7 lifters".
Delphi are not OEM gm lifters.. there's part of your problem.
Been running BTR platinum spring kit with stock 02 ls1 lifters for years turning over 7k rpm yet to have a lifter failure.
In the past i ran stock 99 ls1 lifters with even heavier springs (bigger diameter comp duals which came with absolute speed stg2.5 cnc 5.3 heads).. did over 30,000 miles street/track with those heads on the car 7200 rpm shifts, lifters never failed. I returned the engine/car back to stock and sold it, in top condition!
Same here except in an 04 ls1, stock lifters. spinning 7000-7100. same spring kit.
Those crazy people at GM! What were they thinking making V8 engines that rev to 7k that are meant to survive hundreds of thousands of miles on those "garbage LS7 lifters".
I've said this a lot and even in this thread... LS7 uses much lighter valves. Those Ti valves are like 71g. It's much eaiser to control them with lighter springs. Plus, the LS7 lobe intensity is milder than most aftermarket cams. Therefore, the LS7 lifter in the LS7 engine (with it's 3/8" pushrods to boot) is not a comp to an LS7 lifter in your typical Dual Spring, fast ramp lobed, flimsy 5/16th pushrod controlled, actuating a 110g aftermarket stainless valve in a ported head that most people slap together combo. Or you know, 20 pounds of boost on top of all of that.
I've said this a lot and even in this thread... LS7 uses much lighter valves. Those Ti valves are like 71g. It's much eaiser to control them with lighter springs. Plus, the LS7 lobe intensity is milder than most aftermarket cams. Therefore, the LS7 lifter in the LS7 engine (with it's 3/8" pushrods to boot) is not a comp to an LS7 lifter in your typical Dual Spring, fast ramp lobed, flimsy 5/16th pushrod controlled, actuating a 110g aftermarket stainless valve in a ported head that most people slap together combo. Or you know, 20 pounds of boost on top of all of that.
The LS6 also used "ls7" lifters and rev'd to 7k, while the LS2 would also rev to 7k with a tune.
What does an LSA/LS9 use (honestly asking as I haven't investigated them)?
Agree that there are limitations with massive cams,etc. but far too many people crap on them for the basic Joe build. There are significantly more LS7 lifter failures than everything else because of the sheer volume of them being used compared to everything else. Unless you're running a monster cam or crazy spring pressure, you have a very high probability of success with LS7 lifters.
LS6 was hollow-stem intake and sodium filled exhaust as well. I think the LS6 was around 75g. It wasn't much heavier.
LS2 used the solid-stem valve which was around 100g. And it lopped like 500 RPM off the range.
LS3 was 91g with the 2.165" hollow-stem. LSA was a heavier valve... don't recall the weight but the RPM was not the same as the LS3. LS9 was titanium.
Point is--to get more RPM out of the valvetrain setups, GM lowered the mass of the valves pretty significantly. Aftermarket LS3 valves are 120g for the same size. Still not a heavy valve... but heavier than stock. And that needs to be controlled. Which means more spring pressure... which means more robust components to handle it.
LS6 was hollow-stem intake and sodium filled exhaust as well. I think the LS6 was around 75g. It wasn't much heavier.
LS2 used the solid-stem valve which was around 100g. And it lopped like 500 RPM off the range.
LS3 was 91g with the 2.165" hollow-stem. LSA was a heavier valve... don't recall the weight but the RPM was not the same as the LS3. LS9 was titanium.
Point is--to get more RPM out of the valvetrain setups, GM lowered the mass of the valves pretty significantly. Aftermarket LS3 valves are 120g for the same size. Still not a heavy valve... but heavier than stock. And that needs to be controlled. Which means more spring pressure... which means more robust components to handle it.
No disagreement that you need to plan your setup properly. We've seen instances where people spend $$$$ on lifters and pushrods and still can't make power or control the valvetrain. Plan accordingly, and for many, that means LS7 lifters will work, just not for all.
I've said this a lot and even in this thread... LS7 uses much lighter valves. Those Ti valves are like 71g. It's much eaiser to control them with lighter springs. Plus, the LS7 lobe intensity is milder than most aftermarket cams. Therefore, the LS7 lifter in the LS7 engine (with it's 3/8" pushrods to boot) is not a comp to an LS7 lifter in your typical Dual Spring, fast ramp lobed, flimsy 5/16th pushrod controlled, actuating a 110g aftermarket stainless valve in a ported head that most people slap together combo. Or you know, 20 pounds of boost on top of all of that.
I also forgot to add this point too.
LS7 lifters are the ones for tight asses.
Sure you can get them to work but for the question is for how long.
It's wiser to get a lifter within spec for your spring pressures and rpm range.
Then again.....some people don't feel the need to waste over $1000 on lifters and pushrods to find out their junk still doesn't make power. Just different strokes for different folks I guess.
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Researching LS7 Lifter Failures!! Interesting Find 
