Notices
C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Cam guru's, come on in

 
Old 07-06-2019, 07:25 PM
  #1  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default Cam guru's, come on in




Took old crispy for a spin today and didnt make it far before I heard the dreaded cam/lifter chirp at a stop light.

Tore it down and found cylinder 1 dogbone was above the spider and both lifters had spun in the bore.

Now my question: what came first? The chicken or the egg?

I over-revved the car substantially a few weeks ago - hard enough to spit a lash cap. After re-assembly the car seemed fine. I've been running it hard since then.

The dogbone is torn up pretty bad like this had been going on for a while - but the motor was quiet...

So, what happened? Just coincidence? Wheel locked and got ground down to the point where the lifter picked up the dogbone? Dogbone caught a burr and the lifter tossed it up past the spider?

Edit:
Original lifters from my dads 1987 vert.
Old comp/tpis 288/288 .570/.570 cam
Regularly shifting at 6400rpm

Last edited by TravisSchoech; 07-06-2019 at 07:30 PM.
TravisSchoech is offline  
Old 07-06-2019, 09:25 PM
  #2  
Kevova
CF Senior Member
 
Kevova's Avatar
 
Member Since: Sep 2013
Location: near the thumb in the mitten
Posts: 4,104
Received 386 Likes on 370 Posts
Default

Over revving would be my guess. Although constantly turning 6500 rpm, will test the valve train.

Last edited by Kevova; 07-06-2019 at 09:26 PM.
Kevova is offline  
Old 07-06-2019, 09:49 PM
  #3  
cardo0
CF Senior Member
 
cardo0's Avatar
 
Member Since: Oct 2002
Location: Las Vegas - Boycott Hypocrisy!
Posts: 6,309
Received 229 Likes on 219 Posts
Default

It reads like you just adjusted the valves/lifters just days before this happened. Well you didn't do it correctly as the lifters hammered themselves into the cam lobes. Now the cam will be trash also and metal partilces will circulate in the oil unless the oil filter catches all of it.

I maybe a bit unsympathetic here but that's an a typical example of overconfidence. I'm out as I think you need some training before trying this again.
cardo0 is offline  
Old 07-06-2019, 11:14 PM
  #4  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default

Originally Posted by cardo0 View Post
It reads like you just adjusted the valves/lifters just days before this happened. Well you didn't do it correctly as the lifters hammered themselves into the cam lobes. Now the cam will be trash also and metal partilces will circulate in the oil unless the oil filter catches all of it.

I maybe a bit unsympathetic here but that's an a typical example of overconfidence. I'm out as I think you need some training before trying this again.
Thanks for the diagnosis there, doc.

Fyi, a hydraulic roller adjusted too tight will just hang valves open.
TravisSchoech is offline  
Old 07-06-2019, 11:22 PM
  #5  
Tom400CFI
CF Senior Member
 
Tom400CFI's Avatar
 
Member Since: Aug 2004
Location: Park City Utah
Posts: 14,603
Received 719 Likes on 624 Posts
Default

Originally Posted by TravisSchoech View Post
Thanks for the diagnosis there, doc.

Fyi, a hydraulic roller adjusted too tight will just hang valves open.


I'd completely ignore post number 3.
Tom400CFI is offline  
Old 07-06-2019, 11:30 PM
  #6  
Pwnage1337
Tech Contributor
 
Pwnage1337's Avatar
 
Member Since: Oct 2008
Location: Custer, WI
Posts: 3,396
Received 66 Likes on 59 Posts
Default

Hard to say what happened, I was always amazed at how thin the spider was.

Are the lifter bores scored or nice and smooth?

Last edited by Pwnage1337; 07-06-2019 at 11:31 PM.
Pwnage1337 is online now  
Old 07-06-2019, 11:36 PM
  #7  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default

Originally Posted by Pwnage1337 View Post
Hard to say what happened, I was always amazed at how thin the spider was.

Are the lifter bores scored or nice and smooth?
Lifter bores will clean up with a dingle hone. I'm going to toss in a new cam and some LS7 lifters that have been on my workbench for a while.

New cam is a 236/248 @.050" HR on 113LSA. It should help the motor breath a bit better.
TravisSchoech is offline  
Old 07-07-2019, 10:54 AM
  #8  
rklessdriver
CF Senior Member
 
rklessdriver's Avatar
 
Member Since: Apr 2005
Location: Dale City VA
Posts: 3,388
Received 192 Likes on 159 Posts
Default

I've seen the stock type lifters kick a dog bone out and bend the spider before just like yours.... same scenario. Overreved and ran fine for a while then ate itself. LS engines will do the same thing except they bust the plastic lifter guides.

Hopefully the oil filter caught most of that metal but I highly doubt it.

Good luck with the repair.
Will
rklessdriver is offline  
Old 07-07-2019, 11:00 AM
  #9  
Kevova
CF Senior Member
 
Kevova's Avatar
 
Member Since: Sep 2013
Location: near the thumb in the mitten
Posts: 4,104
Received 386 Likes on 370 Posts
Default

Because you like to spin it up so high regularly, you might consider " linked" lifters and do away with spider.
Kevova is offline  
The following users liked this post:
64Scout (07-08-2019)
Old 07-07-2019, 11:39 AM
  #10  
cardo0
CF Senior Member
 
cardo0's Avatar
 
Member Since: Oct 2002
Location: Las Vegas - Boycott Hypocrisy!
Posts: 6,309
Received 229 Likes on 219 Posts
Default

Originally Posted by TravisSchoech View Post
Thanks for the diagnosis there, doc.

Fyi, a hydraulic roller adjusted too tight will just hang valves open.
I imagine that the preload was to little and the lifter was allowed to bounce. But blaming over reving the motor and bad parts is not helping you Travis. You are having one valve train problem right after the other. Denial happens with all of us and I can say I've wiped at least one cam and didn't/couldn't admit it until I pulled the lifter to see it.

Okay enough.
cardo0 is offline  
Old 07-07-2019, 05:12 PM
  #11  
Pwnage1337
Tech Contributor
 
Pwnage1337's Avatar
 
Member Since: Oct 2008
Location: Custer, WI
Posts: 3,396
Received 66 Likes on 59 Posts
Default

Someone has to make an aftermarket spider that isn't the thickness of a ****** tin can. If I was you and frequented high rpms (sounds like your new cam is gonna like rpm) I'd invest some dollars in more bulletproof ****

Then set the rev limiter for 7200 and let er ****** eat I wanna see more YouTube videos of Mexico!

Last edited by Pwnage1337; 07-07-2019 at 05:13 PM.
Pwnage1337 is online now  
Old 07-07-2019, 07:20 PM
  #12  
rklessdriver
CF Senior Member
 
rklessdriver's Avatar
 
Member Since: Apr 2005
Location: Dale City VA
Posts: 3,388
Received 192 Likes on 159 Posts
Default

Originally Posted by Pwnage1337 View Post
Someone has to make an aftermarket spider that isn't the thickness of a ****** tin can. If I was you and frequented high rpms (sounds like your new cam is gonna like rpm) I'd invest some dollars in more bulletproof ****

Then set the rev limiter for 7200 and let er ****** eat I wanna see more YouTube videos of Mexico!
It's really pretty easy to solve this with stock parts and just throw away the spider.

Just drill a hole in the middle of each of the dog bones and then use the dog bones with a pair of lifters as a guide to drill and tap the block on top between each pair of lifter bores.... bolt the dog bone to the block with a stud and nut.

This is how we do our Stock Eliminator LTXs, L98s and LB9s.
Will
rklessdriver is offline  
Old 07-07-2019, 07:25 PM
  #13  
tequilaboy
CF Senior Member
 
tequilaboy's Avatar
 
Member Since: Aug 2003
Location: Lakeville MI
Posts: 2,365
Received 29 Likes on 27 Posts
Default

I'm thinking that one of the lifters launched off the cam lobe resulting in excessive lift that the valve spring couldn't control. The dogbone and other lifter came along for the ride. Remember those "launcher" cams they used to sell to get around static lift limits of 0.400" in some racing classes. Same idea, but doesn't work so well with roller lifters if they can become mis-aligned.

Might be interesting to know the lift at coil bind compared to the expected valve lift to get an idea of how far the valve could have really been lifted. Enough to cause the damage, I guess.
tequilaboy is offline  
Old 07-07-2019, 08:01 PM
  #14  
Kevova
CF Senior Member
 
Kevova's Avatar
 
Member Since: Sep 2013
Location: near the thumb in the mitten
Posts: 4,104
Received 386 Likes on 370 Posts
Default

Originally Posted by rklessdriver View Post
It's really pretty easy to solve this with stock parts and just throw away the spider.

Just drill a hole in the middle of each of the dog bones and then use the dog bones with a pair of lifters as a guide to drill and tap the block on top between each pair of lifter bores.... bolt the dog bone to the block with a stud and nut.

This is how we do our Stock Eliminator LTXs, L98s and LB9s.
Will
Do you have a photo of this mod? What kind of cam lift did you have?
Kevova is offline  
Old 07-07-2019, 10:58 PM
  #15  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default

Originally Posted by rklessdriver View Post
It's really pretty easy to solve this with stock parts and just throw away the spider.

Just drill a hole in the middle of each of the dog bones and then use the dog bones with a pair of lifters as a guide to drill and tap the block on top between each pair of lifter bores.... bolt the dog bone to the block with a stud and nut.

This is how we do our Stock Eliminator LTXs, L98s and LB9s.
Will
Now THAT is genius...
TravisSchoech is offline  
Old 07-07-2019, 11:04 PM
  #16  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default

I swapped the cam out today and everything looked pristine aside from the cylinder 1 mishap.

New cam seems fat and happy. About 20 more exhaust duration and 10 more intake duration at .050" 113LSA advanced 2

All of the other lifters rolled smooth and looked perfect, so I'll chalk this up to a failing lifter that didnt like years of abuse and one huge over-rev.




TravisSchoech is offline  
Old 07-07-2019, 11:08 PM
  #17  
TravisSchoech
CF Senior Member
Thread Starter
 
Member Since: Aug 2016
Location: North TX
Posts: 152
Likes: 0
Received 11 Likes on 11 Posts
Default

Originally Posted by cardo0 View Post
I imagine that the preload was to little and the lifter was allowed to bounce. But blaming over reving the motor and bad parts is not helping you Travis. You are having one valve train problem right after the other. Denial happens with all of us and I can say I've wiped at least one cam and didn't/couldn't admit it until I pulled the lifter to see it.

Okay enough.
Not denying the abuse I have put this car through, but the preload was untouched on all cylinders except cylinder 2 which spit a lash cap on the over-rev. Unless I boned the adjustment a year and a half ago, your theory of too little preload is no good here.

I appreciate your input, but tone it down a bit. No need to come out guns blazing about how I can't set preload on a hydraulic roller lifter. That's a task even hellen keller could have accomplished with great success.
TravisSchoech is offline  
Old 07-08-2019, 11:19 AM
  #18  
rklessdriver
CF Senior Member
 
rklessdriver's Avatar
 
Member Since: Apr 2005
Location: Dale City VA
Posts: 3,388
Received 192 Likes on 159 Posts
Default

Originally Posted by Kevova View Post
Do you have a photo of this mod? What kind of cam lift did you have?
No. I won't ever take pics inside of a Class Racing engine. We spend way too much time developing these things.

Stock Eliminator engines are limited to the same camshaft lobe lift as factory. The duration and valve events can be moved but lift remains same stock.

If you just want a visual representation of what we do, google "Jesel Dog Bone Lifters". That's identical to what we do by modifying and reusing the stock lifter guides instead of using billet.
Will
rklessdriver is offline  
Old 07-08-2019, 11:47 AM
  #19  
Krusty84
CF Senior Member
 
Krusty84's Avatar
 
Member Since: Mar 2018
Location: DFW TX
Posts: 247
Received 41 Likes on 36 Posts
Default

Travis,

A new video will be required or come out on a Thursday or Friday night for the rolls over in Dallas. Your car will eat up a lot of rides out there for sure.
Krusty84 is offline  
Old 07-08-2019, 02:34 PM
  #20  
Pwnage1337
Tech Contributor
 
Pwnage1337's Avatar
 
Member Since: Oct 2008
Location: Custer, WI
Posts: 3,396
Received 66 Likes on 59 Posts
Default

Originally Posted by Krusty84 View Post
Travis,

A new video will be required or come out on a Thursday or Friday night for the rolls over in Dallas. Your car will eat up a lot of rides out there for sure.
If your car is shifting before 7000 rpm your cam is too small!
Pwnage1337 is online now  

Thread Tools
Search this Thread
Quick Reply: Cam guru's, come on in


Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: