How to Detect Valve Train Instability

Reply Subscribe

Thread Tools

03-15-2017 | 06:40 AM

#31

BenPerfected

Platinum Member

Joined: Dec 2002

Posts: 2,195

Likes: 2

From: Dallas, TX

Quote:

Originally Posted by offshorexcursion

You can have your combo SpinTron tested to find problems before installing. The cost is not horrible but can add up if you need to make multiple changes and retest.

What has been changed, upgraded, rebuilt since your last build?

Spintron testing is a good value compared to a broken valve train. When you are running at + 4000 RPM you can't hear much and and the odds are you will do signicant damage if something in the valve train fails. If you use solid lifters, a good indicator is you have to adjust the valves. When the valve train is stable, nothing moves.

03-20-2017 | 03:00 PM

#32

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by Panther

Any time.

Here's an example of what you DON'T want to see.
[ATTACH=CONFIG]565414[/ATTACH]

Were you able to determine what was wrong with the engine valve train configuration that caused this damage?

03-20-2017 | 03:15 PM

#33

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by underpsi68

Were these Raylar setups? I'm asking because I get the itch from time to time to do the Raylar kits on mine.

Raylar parts in the engine are the intake and stroker kit only. In my mind a fully engineered Raylar engine upgrade package would be one of the safest routes since it is just that...fully engineered and proven and you know what power you will get. Knowing what I know now if I had to do it over again that is the route I would take as a do it yourselfer. It would have saved me a lot of $$$ as well.

03-20-2017 | 03:19 PM

#34

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by dereknkathy

they have those cheapy valve spring testers which hook on the valve and are kinda like a flex beam torque wrench. quickie method of checking for failing spring.

I have one of those and have used it over the years as you suggest. Thanks.

03-20-2017 | 05:23 PM

#35

underpsi68

Registered

Joined: Oct 2012

Posts: 2,239

Likes: 541

Quote:

Originally Posted by Rage

Thank You

03-21-2017 | 08:23 PM

#36

KAAMA

Registered

Joined: Oct 2000

Posts: 4,541

Likes: 107

From: Western Michigan

How to detect valve train instability?----well, one way is when you start seeing little white surrender flags start popping out of your engine compartment.

04-29-2017 | 09:09 AM

#37

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by Panther

The push rod guide plates not being properly aligned, the rocker arm not being perfectly perpendicular to the valve or on aftermarket heads, the pushrods hitting the inside of the head.

So the push rods should never touch the push rod guide plates?

04-29-2017 | 09:14 AM

#38

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by Panther

Take the rocker arms off and look at the top of the valve to look for cross marks which is an indication of valve float and/or instability in the spring setup. Also check rocker arm wheels for flat spots or erosion which is usually an indication of side load. These are just a few simple things to check while it's together.

Well I checked the valve stem tips after about 5 hours running. Most of it lower rpm. The witness mark on the valve stem tip is narrow and in the center. However there are lots of them not just one and all at different angular positions to each other. Like an asterisk "*". Only looked at even bank so far and each and every valve stem tip is marked like that. Five valves had previous use but I cleaned up their tips, maybe not well enough but three were brand new. Only been up to WOT 5800 rpm briefly twice with the rest 5000 rpm or mostly below that trying to tune the Holley EFI. From just a glance at the cam lobes from lifter galley they look nice with smooth even roller lifter witness mark track.

I am afraid to ask for comments.

04-29-2017 | 06:50 PM

#39

dereknkathy

Registered

Joined: Feb 2012

Posts: 4,031

Likes: 10

From: westville, NJ

sounds like the valves are rotating. don't know if a bad thing or not. they used to design them to rotate. heck, they still do, but not at real spring pressures and lifts.

04-30-2017 | 06:34 AM

#40

Rage

Thread Starter

Gold Member

Joined: Sep 2005

Posts: 1,987

Likes: 0

From: Missouri

Quote:

Originally Posted by dereknkathy

sounds like the valves are rotating. don't know if a bad thing or not. they used to design them to rotate. heck, they still do, but not at real spring pressures and lifts.

No rotators under valve springs. Valve springs are PAC1255X Beehive springs with PAC retainers and keepers which seem to lock onto the valve stem and make assembly rigid. Previous setup was Comp Cam 929 springs with Comp Cam retainers and keepers which seemed to be a more free fitting assembly with valve stem. The Comp Cam spring and retainers produced a single rocker arm roller witness mark on the valve stem tip. Previous cam was less lift/aggressive.

Not concerned about rotation by itself assuming it is not the signature of something more insidious (damaging) going on. I guess a different question would be is valve rotation normal with the PAC beehive spring and retainer system?