[Schurkey]

Originally Posted by KEN CROCIE

what does the rocker sweep pattern lock like on the other valves?

YES! There's fifteen other spring/retainer/keeper/valves that need to be examined...or scrapped.

[Qball]

Originally Posted by KEN CROCIE

what does the rocker sweep pattern lock like on the other valves?

Here’s a pic of the rocker sweep for 5 & 7. Also, I just saw #1 exhaust was not far behind. See how sunk the valve stem is? I included a pic of where that stem height was initially.

[Qball]

Here’s the other head. Looks like every retainer has witness marks on it. The rockers are Comp 1.52 ratio roller tip.

[steve25]

I now think I see what the cause of this failure is and if you did not assemble the heads then the builder / machine shop is to blame by maybe a full 100%.

Here is a photo of a stock Pontiac keeper with its lock bead about .140” down from the top.

From what I see in the photo of your failed keepers I think they were offset keepers which brought the retainer up too high.

Offset keepers are used to make a fine adjustment to the valve spring installed height and in turn the spring pressure.

If a more of a factory thickness retainer might have been used then you might have gotten away with out a problem, but I think that once these parts heated up and expanded that your where on the road to having issues .

This may have been ok if a stock stamped steel rocker was used, but not for a roller rocker set up with a small diameter roller that brings the body of the rocker down too close to the retainer.

Another factor in this all might be valve stem tip length, the stock height as shown in my other photo is about .220”.

What I mean by 100% is that if the builder knew you where going to run these ball type roller tip rockers then he should have checked out that the clearance needed was present, on the other hand if you put these rockers on and did not check everything out then I would say the the builder is 80% at fault and the rest is on your shoulders.

Please post up a photo of one of your other unharmed keepers and the end of a valve stem.

PS.

On a side note the dish on the top of your rocker studs is a bad thing if you ever switch over to Polylocks.

A Polylock needs a flat top stud to lock down onto properly .

[Formulas]

Now that there is more inclusive photos you can see two different sets of locks associated between intake and exhaust and they are offset locks, You might have .050 and .070 offsets, Both of which move the keeper up and you can get them to go in the other direction as well for reduced height...

Also with new pics you can see you have numerous rubbing marks on the keepers themselves from the rocker arms you may of been OK in the long run with .050 - .100 longer pushrods to raise the pushrod side of the rocker..

When you assemble a engine with a mix of non OE parts its highly important to examine every aspect of those parts to ensure compatibility mainly is there space for them to operate in when they are in action because dimensions change.........

The problem you had should of been found when the first rocker / pushrod was dropped on to establish pushrod length, That's when you first have a reasonable opportunity to analyze things in that space, rocker sweep, rocker clearances, rocker travel at fulcrum in respect to lift, valve cover clearance, pushrod to head clearance, best alignment with valve

Even the best engine builder can miss something which happens less as they gain experience you just got experience,

[Qball]

Originally Posted by steve25

I now think I see what the cause of this failure is and if you did not assemble the heads then the builder / machine shop is to blame by maybe a full 100%.

Here is a photo of a stock Pontiac keeper with its lock bead about .140” down from the top.

From what I see in the photo of your failed keepers I think they were offset keepers which brought the retainer up too high.

Offset keepers are used to make a fine adjustment to the valve spring installed height and in turn the spring pressure.

If a more of a factory thickness retainer might have been used then you might have gotten away with out a problem, but I think that once these parts heated up and expanded that your where on the road to having issues .

This may have been ok if a stock stamped steel rocker was used, but not for a roller rocker set up with a small diameter roller that brings the body of the rocker down too close to the retainer.

Another factor in this all might be valve stem tip length, the stock height as shown in my other photo is about .220”.

What I mean by 100% is that if the builder knew you where going to run these ball type roller tip rockers then he should have checked out that the clearance needed was present, on the other hand if you put these rockers on and did not check everything out then I would say the the builder is 80% at fault and the rest is on your shoulders.

Please post up a photo of one of your other unharmed keepers and the end of a valve stem.

PS.

On a side note the dish on the top of your rocker studs is a bad thing if you ever switch over to Polylocks.

A Polylock needs a flat top stud to lock down onto properly .

Originally Posted by Formulas

Now that there is more inclusive photos you can see two different sets of locks associated between intake and exhaust and they are offset locks, You might have .050 and .070 offsets, Both of which move the keeper up and you can get them to go in the other direction as well for reduced height...

Also with new pics you can see you have numerous rubbing marks on the keepers themselves from the rocker arms you may of been OK in the long run with .050 - .100 longer pushrods to raise the pushrod side of the rocker..

When you assemble a engine with a mix of non OE parts its highly important to examine every aspect of those parts to ensure compatibility mainly is there space for them to operate in when they are in action because dimensions change.........

The problem you had should of been found when the first rocker / pushrod was dropped on to establish pushrod length, That's when you first have a reasonable opportunity to analyze things in that space, rocker sweep, rocker clearances, rocker travel at fulcrum in respect to lift, valve cover clearance, pushrod to head clearance, best alignment with valve

Even the best engine builder can miss something which happens less as they gain experience you just got experience,

This makes so much sense. I have to shoulder some of this blame. It never dawned on me that the rocker arm could make contact with the retainer. When we measured for pushrods, we just looked at the sweep pattern to determine length. Never even considered rocker arm to retainer clearance. I appreciate all of the responses and helping me make this a teachable moment. This is going to be one pricey lesson. I just hope the block can be saved. There's significant cracks in the cylinder.

On my next visit to the shop, (I work remotely but visit the shop once a month), I'll get the block magnafluxed to see if I can get away with a sleeve.

Thanks again, everyone!

[KEN CROCIE]

are the retainers aluminum?

[jhein]

This is the exact type of failure that killed my motor when I was a kid. The #8 exhaust valve came loose and got sucked into the cylinder. I'm guessing I was at a higher RPM when it happened compared to you based on the damage I had. It obviously destroyed the piston, broke the rod, blew the cylinder wall wide open and also cracked the crank. The only major engine component that was salvageable was the driver side head. It was nasty.

[Dragncar]

Originally Posted by Qball

No. A friend of mine built the heads. He sourced everything. He's an excellent machinist/engine builder. I think this was just bad luck.

I don't know my man. All it takes is one look at those valves,keepers/retainers and how they are situated to know there is a problem and a big one.
Sucks to loose a engine like that.

[Qball]

Originally Posted by KEN CROCIE

are the retainers aluminum?

Hi Ken. No, they’re not aluminum.

[Qball]

Originally Posted by jhein

This is the exact type of failure that killed my motor when I was a kid. The #8 exhaust valve came loose and got sucked into the cylinder. I'm guessing I was at a higher RPM when it happened compared to you based on the damage I had. It obviously destroyed the piston, broke the rod, blew the cylinder wall wide open and also cracked the crank. The only major engine component that was salvageable was the driver side head. It was nasty.

I was in the garage when it happened. Engine was still cold. I was at 12-1500 rpm. My choke sucks sometimes so I try to help keep things going. Had about 30 seconds of run time on that start when the shinola hit the fan.

[jhein]

Originally Posted by Qball

I was in the garage when it happened. Engine was still cold. I was at 12-1500 rpm. My choke sucks sometimes so I try to help keep things going. Had about 30 seconds of run time on that start when the shinola hit the fan.

I was probably at somewhere between 3-4K rpm when it came apart. Like I said, it was ugly.

[steve25]

I hope the block just needs a sleeve.

Did the crank make it?

[Qball]

Originally Posted by steve25

I hope the block just needs a sleeve.

Did the crank make it?

It seems to have. Once I got the blown up piston out, the crank spun freely. The journals all look great. I'm taking the block, crank, and rods to our machine shop next week to have everything evaluated. I'm hoping that a sleeve will fix the block. I'm hoping for the best, while preparing for the worst. You know how it is with this stuff.

[HWYSTR455]

Original block to that car?


.

[Qball]

Originally Posted by HWYSTR455

Original block to that car?


.

No. It's a '68 YS block.

[steve25]

Get that crank magafluxed without fail after that failure no matter how good that rod journal might look!

[unruhjonny]

dare I ask;
How bad was the carnage to the cylinder head?

[Qball]

Originally Posted by steve25

Get that crank magafluxed without fail after that failure no matter how good that rod journal might look!

Definitely!

[Qball]

Originally Posted by unruhjonny

dare I ask;
How bad was the carnage to the cylinder head?

The head took a bit of a beating.