Valve seal/spring failure

pcdrj · Nov 22, 2010

My latest engine failure was caused by a broken valve going through the motor. When we tore it apart this is what the seals look like. You can see the deep grooves in the seals. We're running Comp cams and springs. The springs do have some runout but Comp states its's expected with beehive (conical) type springs. The seals were stock with about 4 hours of run time.

Anyone see anything like this? Any known issues with Comp springs?

Anthony05GT · Nov 22, 2010

Yeah, and you spend good money to avoid this kind of shit. What's new? Sorry to hear that happened...I've been lucky so I'll sign off now.

saleen07gt · Nov 23, 2010

Are they valves stock or have the heads been reworked with aftermarket valves ? Where you running the Comp Cam retainers also. I've got 20K miles on my Comp valve train without a problem.

SteveP · Nov 24, 2010

need more information on your head work to help ya out buddy.

pcdrj · Nov 24, 2010

Steve@DezRacing said:
need more information on your head work to help ya out buddy.

Ferrea valves, Comp cams with custom grind (Comp did the grind), Comp beehive valve springs, I'm not sure what brand the seals are but they are softer than the OEM ones.

What other info should I be looking for?

saleen07gt · Nov 24, 2010

With your custom grind cam was it specified that you run cam phaser limiters or lockouts to eliminate any valve to piston contact ? I'll bet this is what caused your failure not a seal problem. Also, we don't know anything about your cam specs.

SteveP · Nov 24, 2010

next question, who did the install?

US-1 · Nov 25, 2010

pcdrj said:
Ferrea valves, Comp cams with custom grind (Comp did the grind), Comp beehive valve springs, I'm not sure what brand the seals are but they are softer than the OEM ones.

I see all sorts of places where shit could go wrong with this deal.

Steve@DezRacing said:
next question, who did the install?

Ditto.

pcdrj · Nov 26, 2010

US-1 said:
I see all sorts of places where shit could go wrong with this deal.

Ditto.

This is not my area of expertise and I may not be asking the right questions so bear with me.

Upon inspection we found the after market seals are much softer that OEM's. It's hard to get an actual reading based on the flange thickness but my guess is a difference of at least 20 RC points based on the stylus penetration. We compared the springs to OEM and a competitor's brand for hardness, concentricity, and the perpendicularity of the faces.

OEM's have the best geometry but are slightly softer. Our Comp springs were definitely better the brand X.

The cam profile is very similar to Comp's standard stuff in the initial lift an seating dynamics. Again, Comp did the grind. Cam timing is being limited to 20º. Lockouts are not being used.

This exact setup has been done numerous times with no issue so we're still looking for the smoking gun here.

Can you throw me some examples of what "all sorts of places" may be?

Thanks in advance.

PS: As far as the builder, let me just say he's well known and respected here. Some of the fastest cars on this site are running his engines. With the internet being what it is, putting a name out while trying to solve a problem can quickly deflect the conversation away from tech.

Gray Ghost GT · Nov 26, 2010

Did these heads have 2mm oversize intake and exhaust valves? I'm wondering if an error in CNC machining (valve job) contributed to the problem [thinned valve guides] - causing a broken valve to go through the motor. Did you say there was piston to valve contact? Were you using cam phaser limiters or lockouts with the custom cams. I'm learning too.

pcdrj · Nov 26, 2010

Gray Ghost GT said:
Did these heads have 2mm oversize intake and exhaust valves? I'm wondering if an error in CNC machining (valve job) contributed to the problem [thinned valve guides] - causing a broken valve to go through the motor. Did you say there was piston to valve contact? Were you using cam phaser limiters or lockouts with the custom cams. I'm learning too.

Valves were stock size. No limiters or lockouts in use. We did have a valve to piston meeting but we believe that was a seperate issue.

Let me back up a bit. We're running a Saleen S/C. The heat exchanger sits in the blower case and just rests on a ledge. There is a stamped aluminum bracket welded to the outside of the H/E which creates a flange that sits on the ledge. The two coolant ports are the only thing that actually secure the H/E in the case.

Apparently the H/E was bouncing inside the case and the backside of the welded bracket broke off and went into the motor. We removed the visible debris and ran a leak down test which showed loss of pressure in one particular piston. Dyno test showed same power curve and subsequent leak down showed improvement. Our assumption was some aluminum debris was working it's way out of the cylinder. All else looked normal so we went back to the track (road coarse). Within 40 minutes we had a broken valve. The stem of the valve has aluminum galled on it so we figured the H/E particles may have caused the valve to stick.

Once we tore it down we found the guides with these worn grooves. The H/E has been repaired and at this point we're trying to understand how the seals got that way. We are working under the assumption there was another cause.

US-1 · Nov 26, 2010

What guides are in the heads and what valve-guide clearance was used? Also, do you know what lash clearance was used?

05stroker · Nov 26, 2010

Subscribing

SteveP · Nov 27, 2010

Was the motor lean popping before it did this? IE you would hear a popping noise when u hit the gas pedal from under the hood.

MexGT · Nov 27, 2010

I've had that issue of a broken valve making an entire new engine fail, though the ones I was using were Manley

Anthony05GT · Nov 27, 2010

That's about the third person in 2 years that I've seen have a Manley valve break. WTF?

Gray Ghost GT · Nov 27, 2010

I've never been impressed with Manley Performance products. For example, the Manley valve springs in the GM LSx engines are known for breaking compared to similar Comp Cams and PAC springs. I believe Manley Performance parts are often used because their relatively "cheap" - but you get what you pay for. I think they're made in India or China. IMHO, Ferrera valves are a better product.

kevinatfms · Nov 28, 2010

i wonder if you had an oiling issue.

Anthony05GT · Nov 29, 2010

Gray Ghost GT said:
I've never been impressed with Manley Performance products. For example, the Manley valve springs in the GM LSx engines are known for breaking compared to similar Comp Cams and PAC springs. I believe Manley Performance parts are often used because their relatively "cheap" - but you get what you pay for. I think they're made in India or China. IMHO, Ferrera valves are a better product.

That makes me feel real good about my Manley springs. I see more junk out there these days than ever before. When I was a kid, it was junk if it came from Japan. Now everything is Chinese and even their cardboard falls apart on the trip over.

Gray Ghost GT · Nov 29, 2010

Anthony05GT said:
That makes me feel real good about my Manley springs. I see more junk out there these days than ever before. When I was a kid, it was junk if it came from Japan. Now everything is Chinese and even their cardboard falls apart on the trip over.

If the valve spring didn't fail in his engine, a worn valve guide can contribute to valve breakage since a worn guide will allow the valve to wobble slightly as it opens, which cause it to drift off-center with respect to the seat. This can cause the head of the valve to flex slightly each time it closes. After so many cycles, the metal fatigues and the head of the valve breaks off from the stem.

Valve seal/spring failure

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