My Camaro went home to Oshawa to die......

[mikeSS]

Originally Posted by Camarowguy

Also, one of the guys there said keep the factory oil pump on it. Im scared to do that with all the failures I've heard about. I won't sleep at night keeping the stock pump....

honestly there are more failures of after market parts fail, or install wrong, or not upgrading certain things. than there are oil pump problems. sure i have seen a few here. but when you talk to a shop there are more important parts to upgrade first. like a 3 bolt cam, right rods, springs etc... this thread is pure human error. nothing to do with oil pump failing.

[htron50]

Sorry to hear about your mod fail. I'll leave mine stock. Don't have $$ to burn on mods, and prefer to avoid stress of fixing.

[2SSRS@Gen5diy]

Have all the parts needed for power upgrade's other then the new heads needed, but now that the pin was checked and is fine, need to take apart the oil pump and have the head porter make shore the valves is fine, Hope the new heads are out soon.

[Huggerorange73]

Just a quick rundown of the parts that were used :

Comp Cams ( XR281HR13 XFI Series ) : .571/.590 228/240 LSA 113
Trick Flow Chromemoly Pushrods ( TFS-21407400 ) : 5/16 in. Diameter, 7.400 in. Length
Patriot Gold LSx spring kit ( PAT-8401 ) : This kit will work with both stock and aftermarket rocker arms. No cutting or machining of the stock spring pocket is needed. Fits LS1, LS2, LS3, LS6 cylinder heads & one spring kit does a pair of cylinder heads.
Technical Specs:
• Installed Height: 1.800
• Max. Valve Spring Lift: 0.650
• Spring Pressure Closed: 135 lbs. @ 1.800
• Spring Pressure Open: 375 lbs. @ 1.150
• Coil Bind: 1.090
• Retainer Material: Titanium


I re-used the OEM timing chain, tensioner, oil pump & timing set.

[Russell James]

Originally Posted by Huggerorange73

But if the pin isn't load bearing, and is only a locator.....why does pin breakage lead to epic failure?!?!

The pin is load bearing. Just not intended to be the main load bearing factor. It's just like a crank pin/key for a balancer. It locates the balancer in it's exact spot and supplies some locking mechanism to prevent it from moving out of position - but the balancer bolt is the main clamping force securing it.

The cam pin locates the cam and provides a lock to prevent it from turning, but the bolt is the main player in the clamping force torquing the gear flatly to the cam.

Think of the pin as like a lock. You've got bolt torque and a lock. You can't rely on just the lock, it will fatigue over time if the bolt torque isn't solidly clamping the gear to the cam.

[Huggerorange73]

Originally Posted by Russell James

The pin is load bearing. Just not intended to be the main load bearing factor. It's just like a crank pin/key for a balancer. It locates the balancer in it's exact spot and supplies some locking mechanism to prevent it from moving out of position - but the balancer bolt is the main clamping force securing it.

The cam pin locates the cam and provides a lock to prevent it from turning, but the bolt is the main player in the clamping force torquing the gear flatly to the cam.

Think of the pin as like a lock. You've got bolt torque and a lock. You can't rely on just the lock, it will fatigue over time if the bolt torque isn't solidly clamping the gear to the cam.

Okay that makes sense....so let me ask this. It would seems as though this failure has been caused by improper torque to the camshaft bolt. Is it possible over time as the bolt got looser that the cam timing changed ever so slightly?

I only ask this because the more I look at the pistons, I'm questioning if the valve marks on the pistons were caused over time or are the result of the failure at a high RPM.

[2SSRS@Gen5diy]

You my get some timing movement, but not much, till that pin fatigue then the cam will shift and then.... well the rest is history.

The only differences in the outcome is how fast the motor is revving.

[Huggerorange73]

Originally Posted by 2SSRS

You my get some timing movement, but not much, till that pin fatigue then the cam will shift and then.... well the rest is history.

The only differences in the outcome is how fast the motor is revving.

I have to assume the pin went south at 6000 RPM + would that account for the defined valve marks on the pistons?

[garcmol]

Originally Posted by Huggerorange73

Okay that makes sense....so let me ask this. It would seems as though this failure has been caused by improper torque to the camshaft bolt. Is it possible over time as the bolt got looser that the cam timing changed ever so slightly?

I only ask this because the more I look at the pistons, I'm questioning if the valve marks on the pistons were caused over time or are the result of the failure at a high RPM.

That's what I'm thinking, since it was actually torqued down to the protruding pin and not the camshaft gear. I think that would have been a vibrating mess and caused your timing to slowly change. Then the massive rev when the drivetrain failed sent it over the top.

I say this because the pictures clearly show that bolt dug into the pin on the cam.

[Russell James]

Originally Posted by Huggerorange73

Okay that makes sense....so let me ask this. It would seems as though this failure has been caused by improper torque to the camshaft bolt. Is it possible over time as the bolt got looser that the cam timing changed ever so slightly?

I only ask this because the more I look at the pistons, I'm questioning if the valve marks on the pistons were caused over time or are the result of the failure at a high RPM.

I doubt it occured over time. I think more likely when the pin sheared, all that chaos happened in a split second.

It was probably torqued plenty tight, but also bottomed out on the pin - messing up the 360 deg clamping force the bolt shoulders should be flatly clamping the gear to the cam. Not being fastened as designed, then harmonics can beat up that connection and fatigue the pin.

If you watch a Spintron test at high RPM with slomo video - the timing chain can really see some violent harmonics. Anything wrong under the timing cover is not going to last long.

[SSOOCH]

Should have used "red" loctite!

[Huggerorange73]

Originally Posted by Russell James

I doubt it occured over time. I think more likely when the pin sheared, all that chaos happened in a split second.

It was probably torqued plenty tight, but also bottomed out on the pin - messing up the 360 deg clamping force the bolt shoulders should be flatly clamping the gear to the cam. Not being fastened as designed, then harmonics can beat up that connection and fatigue the pin.

If you watch a Spintron test at high RPM with slomo video - the timing chain can really see some violent harmonics. Anything wrong under the timing cover is not going to last long.

So it's safe to say because the shoulder of the bolt was touching the pin, the clamping force wasn't fully squared against the timing gear. Over a period of time the harmonics/vibration finally caused the the pin the sheer off.

Originally Posted by SSOOCH

Should have used "red" loctite!

Unless I'm mistaken, the new cam bolt already has GM supplied Loc-Tite on it.

[SSOOCH]

Originally Posted by Huggerorange73

Unless I'm mistaken, the new cam bolt already has GM supplied Loc-Tite on it.

I'm joking...you know I have no idea what the hell I'm taking about!! LOL

[Huggerorange73]

Originally Posted by SSOOCH

I'm joking...you know I have no idea what the hell I'm taking about!! LOL

I knew that