Put about 50 miles on the new engine and made maybe 3-5 pulls to around 6000-6500 rpms. After a few things needing to be addressed I pulled the engine out. While I had it out i figured I would check some things out and found a few problems. Had 5 lifters that failed. Lifters are Comp Cam lifters (dont know the part number - 875-16 I believe) Not happy with them at all. Failure came very early. Motor is a 355 lt1 cc306 cam. ported and polished heads with 2.02/1.60 valves with gm dual plane intake a holley 750 double pumper with mech. sec. After having bad luck with a "good name brand" lifter I have decided to use a set of LS7 lifters. I want to run a rev kit for extra insurance. Not trying to get into a debate on if a rev kit is needed or not. The problem I hae is most companies dont give much info on Rev kits and I cant seem to find out if they will work with a OEM style lifter.

I am not interested in buying anything from Comp Cams anymore. Not based on the premature failure of the lifters but more due to the shitty customer service I received when calling to inquire on a more durable lifter option. All I received from Comp Cams was how my setup must be wrong (cam and springs) even though the springs I have is their recommended beehive spring for that cam. Then he said my "lifters must be garbage, who makes them?" Changed his tune when he found out they were Comp lifters. And then proceeded to tell me I should not spin the motor above 6000 because the cam and lifters are no good above 6000 but still had no recommendation as to a way to address the issue at hand. I have gotten better engine building advice from my local advance auto clerks than what this guy could give me.

ANYWAY... My main interest in the rev kits anyone have experience with and also anyone using LS7 lifters in stressful situations. The car is a 2600lb 944 road race car and a lot of time is spent at high rpms.

Thanks in advance for all the help.

Chris

 

Do a search for LS7 lifter failures before you buy them, very common for some reason. People have better luck reusing 100,000 mile stock ones.

 

Did you diagnose the CAUSE of the failure?
Were the springs all wrong? No guarantee the cam and springs were what was ordered. Friend ordered a custom Comp cam with lobes spec'd by his builder and the guy at Comp just chose something "close" and the valvetrain went wildly out of control.
Were the plungers bottomed by incompetent adjustment?
That cam needs over 6000.

There is a cause and buying some halfassed bandaid meant for aggressive setups to use on a fairly mild one isn't going to fix the base issue. If you smashed the plunger and don't identify that problem you will just do it again.

Morel has an entry level lifter that is $200ish.
I would do that, pick a nice spring and have someone help you set the preload.

I know that isn't the answer you want, you wanted to come here and ask a question and dictate the answer. Well if you don't want EXPERIENCED guidance, don't ask for it.

I have experience with more aggressive cams in this application and never seen a lifter failure first hand.

 

Springs are correct. Valve adjustment was correct. Don't need assistance. Plunger did not bottom out. Lifter just failed. Suspect is rpm range. Morel seems to be a popular lifter, might look into a set of those. I wouldn't call a rev kit a "half assed bandaid" because it's function is not a bandaid. It has a legitimate function in the right application. Like I said "extra insurance". With the current failure it made me look into a rev kit for the just in case moments.

 

I am not buying that in 50miles you broke 5 lifters and all the parts were right and assembled right. If Comp's supplier(doubt they build them) had a run of lifters that bad they would know about it and so would we and they would have very likely made it right.

The budget Morels are around $200 not much more than LS7s.

I just searched the PN you gave for the lifters and those are "short travel" for high rpm and a recommended preload of .005" which would be amazingly easy to set preload too tight on. With a 3/8" stud that is under 1/8th turn from contact, less than 1/10th if you have the 7/16" stud. Could probably get that preload by finger.

Did you "spin the pushrod" to find zero lash?

What was the lifter failure?


What spring did you use, Comp usually hoses up their LT1 specs, now you do have a dual plane intake which would reduce rpm to help get their spring spec back in line BUT you also have unnecessarily larger valves which are probably heavier which could contribute to needing a little more spring. Not enough that I would expect this damage but the valvetrain is a system and one that is too often modified without much understanding of how it all meshes together. For road race I would pick a vendor you trust and have them pick a spring not pick the one Comp recommends. Sustained high rpm and potentially heavier valves needs to be addressed

I know I am not giving you the answers you want, but I have put tens of thousands of miles on cammed LT1s, never a valvetrain failure. I have worn springs out and needed fresh ones to solve valve float but springs are like sparkplugs once you get to modified engines, they are a wear item. I might know more about this than someone who fragged a valvetrain in 50miles.


The 2.02 valves, the Comp lifters, the considering LS7 lifters, it all speaks to poor research skills or trusting the wrong person for advise. "too much rpm" is the automatic go too answer for the Comp tech line and is definitely not the cause here. I wouldn't buy those lifters but they should be fine at 7000rpm if the valvetrain system matches.

 

what did you lash the 875's at, zero or 1/8th turn??

 

I had this damage to comp lifters once - with a mild cam and dual springs - all comp parts - low mileage on the parts and synthetic oil. Comp was the usual idiots on the phone when I emailed them the photos and asked about the problem. Damage was only to the ones shown, the rest were fine. The engine was not revved very high - it probably never saw over 6100 - this was with the stock engine and a S trim blower. When the engine was redone later with a more aggressive Comp cam, Comp Beehives, CRANE lifters, I did install a rev kit.. My reasoning was just to let the kit control the lifter bodies on the cam and let the springs work the valves, rockers, and push rods. It works fine, but it is just a different approach than most builders use.

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I understand the automatic go to is always "you did it wrong" but that is not the case. I specifically ordered the 875's bc of my plan for higher rpm. The way I have always found zero lash is by checking for play up and down. Once all play is removed by hand I tighten these lifter to 1/8th turn. On a standard travel lifter I normally add 1/2 turn. I understand 96caprice has had amazing luck with all his builds but after searching info on the comp lifter I am not the only one having failures. Many many many post about premature lifter failure and its normally only a few out of the group. Now on a quick search my initial research from older post were people having good luck with the LS7 lifter and the CTSVR lifter. After the recommendation from bufmatmusclepants I researched "LS7 lifter failure" and there also seems to be an issue there as well. Thank you KevinBlown95TA for actually giving an answer to the question. I have not looked into Crane lifters yet. Which specific lifters did you go with and which rev kit as well. How did you like the overall fit of said rev kit and is there anything you would have done different.

 

Surprised no one has asked what your spring pressures at at open.

I run the mid level crower link bar lifters, because after a LS7 lifter debacle I said **** it and spent the money. Why in the world would you cheap out on lifters, and yes, LS7 stuff is IMO cheap level. I learned the lesson on that the hard way.

What exactly failed on the lifters? The wheels?

 

The plunger failed. I noticed a couple rockers were loose as I was just checking random stuff while i haf the engine out and decided to readjust all the valves. When I got to valve #3 I went to set the preload and it felt different. No resistance. I then checked all the lifters by simply pushing down on the pushrod by hand and found 5 that shared similar characteristics. My initial concept of going with the LS7 lifter was because my initial purchase was a good quality lifter and I had problems. After a short search I found that the LS lifter would worth fine with the setup and many people had no troubles with them. But then it was recommended to search specifically for "ls7 lifter failure" and found people are experiencing problems but I also see many recommendations coming from reputable companies incuraging people to use them. It's all about personal preference. Many run them and have no problems and some have a problem with a lifter and consider the whole brand junk. Given my setup with the rpm range I want to operate within and the low lift design of the lt1, I feel the ls7 lifter will work fine but I am going to use the Morel 5315 lifters instead. Fit and finish of the lifter body is better with the Morels. After everything I have read you can find failures with every lifter company. I d ok nt not think comp is a bad product or company I just do not like their customer service skills and therefor will not buy anything else from them. There are plenty of options out there to settle. Also I'd still like some insight running a rev kit with the Morel 5315 lifter. Anyone have / had this setup?

 

Keep in mind the OPs usage is not the traditional usage we are used to here so don't automatically assume it was installation error. While I agree lifter failures are rare, most of us here thing about mods and repairs in the case of street driving or a few seconds of WOT at the drag strip.

Road racing is a whole other animal, and way more stressful on valvetrain parts then street duty or drag racing.

Different uses wear down parts differently. In drag racing we worry about rear ends and clutches, in street driving we worry about transmission temps and cooling capacity, and in road racing it is about as hard as it gets on valvetrain parts.

I have personally had a comp lifter fail in under 200 miles on a fresh build that was installed correctly, but it was only one single lifter. The clip broke and jammed the plunger, knocking the rocker off the valve stem and ruining that rocker and lifter. Bits of lifter and roller rocker were in my valley under the intake, and after dropping the pan and screening the oil I was the luckiest SOB alive and not a single piece made it into the oil or through the motor. Mine was an isolated occurrence, and I changed the single lifter and all the rockers and the rest of them are still fine 20,000 miles later.

 

50 miles should be less than needed to wear the springs down even in this application.

Like I said though I have concerns about the usual Comp rpm range inaccuracy and him exaggerating that problem with the bigger valves when I will guarantee the popular 2.00 valve heads make more power. The 2.02 valves are pretty much proof of things being done ignorantly. Sure there comes a time when bigger valves are necessary but popular 2.00 valve ported stock castings have done over 500rwhp enough times that 2.02 is at best ignorant for a build that I doubt made but 380rwhp.

Again please describe how you found zero lash. LOTS of bad info on that and LOTS of guys have screwed it up the first few times, myself included.

First time I adjusted valves a mechanic friend told me to "spin the pushrod" till I felt resistance, then half a turn. Set them so tight the engine wouldn't idle.

 

Still curious to know what springs you are running, I have ~400lb open and every tech I talked to laughed when I said I wanna run HR lifters. Getting cheap lifters when you know you killed a decent set, seems pretty lousy of an idea.

If you are stuck on the morels, check out Lunati or elgin, both are made by Morel and are cheaper.

As far as rev kits, fairly certain AFR is the only option for you. But, not sure it would have really saved you here.

 

Yea spinning the PR usually ends up way too tight. I wiggle the PR up and down until it stops moving vertically, then tighten for lash.

If he is running the cam card springs for the 306 then he has the 918s. Open pressure will only be around 350 tops.

 

Thanks for all the responses. In post #8 I described how I find zero lash. But it is done like you describe. Up and down check then tighten. 918's are what I am using. Beehive design. Last night I ordered the Morel 5315 from Colorado Speed. Does anyone know the recommended preload for them?

 

OP

if the 918's don't test to the open and seat pressure you need, might want to consider the Lunati spring kit. I got my kit from Lloyd Elliott.

http://www.lunatipower.com/News.aspx?id=79

 

I would have went for the morel or lunati link bar lifters. They are around $500-600 and worth it. Ls7's would have failed in your setup as well.

 

I bet with the Comp lot preload you can overtighten them by finger, still not convinced you didn't wreck them.
Yes folks have killed hem but 50miles is awful fast.....

 

Weren't too tight. End of story. If you have nothing else to add, go troll somewhere else.

If I remember correctly open pressure is near 320. Max lift is rated at .600 and with the 1.6r, I believe in I'm in the .544 / .576 range.

 

I had a similar issue: https://ls1tech.com/forums/lt1-lt4-m...ttle-help.html

I think these were also the COMP Lifters, that the previous owner had installed.

I also think that I could have had catastrophic failure if this thing didn't have a rev kit. It had the AFR hydra rev kit on it the whole time it had the heads/cam.

But on the plus side, they had 60k on them....