Do You Own Big Block MP Valve Covers?? Please Read This ... and Share

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Jarlaxle said:
OK, I make no claims to be a metallurgist or a machinist. Therefore, all I ask is: please do not laugh at this probably-stupid question. Could (gently) shot-peening them help by removing what I figure are stress riders from a crappy casting job? Also, to reduce stress on the mounting ears, am I right in thinking that you want the LEAST-compressible gaskets?

Note to self: make sure to stick with stamped-steel valve covers on all Mopars.

Edit...here's a scary thought: what would the new MP valve covers look like if someone were to Magnaflux one, I wonder?
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Once that they are cast with hairline cracks in them, you can't fix them by shot peening. In mateirals class they teach you that an interstitial defect (imperfection) will eventually propogate (get worse). Like that crack in your windshield that keeps growing over time. Peening it will just compress the metal around the cracks, not fix the cracks. Once the cracks are in the metal, you can't get rid of them without remelting the metal.
 
But are they CRACKS, or do they start as stress risers that crack from handling/installation/sandblasting/the phases of the moon?
 
What I posted pictures of are most definitely hairline cracks. I can completely assure you that none of the stuff I worked on was damaged here, and most especially not by media blasting it. It's not "the" reason I take my Before Pictures by any means, but I have to admit that they sure are coming in handy in light of this.
 
CudaChick1968 said:
I can completely assure you that none of the stuff I worked on was damaged here, and most especially not by media blasting it. It's not "the" reason I take my Before Pictures by any means, but I have to admit that they sure are coming in handy in light of this.
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leanna: what would it cost to do a set of big block valve covers that way, if I send a 1'" round paint chip to match the dark blue on my 68 form. s , with them? P M if you want ---bob
 
bob, it's the same now as it always was, by the hour for however long it takes to get your metal as close to perfect as I can first and crank out a multi-color job we can both be proud of. They've ranged from a couple hundred bucks on up and most of my labor billed on MPs is devoted to bodywork / cleaning up the crappy castings. Some are nice -- the 6-color MPs for MarPar on FBBO were $321 shipped because he got lucky with his castings -- and others, well, if you're reading this thread then you already have an idea of what I come up against sometimes and the bill most certainly reflects the extra work involved.

Shoot me a few good pictures of yours with close ups of dings / dents / damaged fins / etc., and I'll get back to you with an estimate. As of July 15, the hourly rate is $30 per hour; as it's always been, FABO members get a 5% labor discount and Gold members enjoy a 10% labor discount. I look forward to working with you!
 
Jarlaxle said:
But are they CRACKS, or do they start as stress risers that crack from handling/installation/sandblasting/the phases of the moon?
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No, it's most likely caused by lack of maintaining the dies. If you do not keep the dies clean and the gates start to get restricted, then they do not fill completely. If you do not fill completely, you get a "short shot" which doesn't allow the material to "pack" properly before cooling and you get hairline cracks and/or porosity in your metal.


Tooling maintenance is something that companies often take shortcuts on to save costs.
 
Well...so much for that idea, then.

Seriously: anyone willing to Magnaflux one? That would probably be scary.
 
Dang, and I was all set to buy the fabbed alum SB covers and I'm guessing they probably aren't any better. I have a set of cast ones that came with my block, I'll have to blast 'em at work and see if they're junk too.
 
I guess when a customer returns substandard valve covers (or any part) it gets reboxed and restocked! lol. Problem fixed for Vendor. Maybe the next lunkhead wont notice.
 
I haven't seen as many outright defects in the small block versions but the casting flaws can be severe.

And just as an update to illustrate the points made throughout this thread, more than 300 people have contacted me in response to this advisement with their own 'suspected over-tightening' stories in the meantime. Most were purchased new within the last five years and were installed by competent individuals.
 
I just noticed this thread has THREE STARS. Who resents this, and why??? I always thought honesty and open communication were good things. :-(
 
Jarlaxle said:
Well...so much for that idea, then.

Seriously: anyone willing to Magnaflux one? That would probably be scary.
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You can't magnaflux aluminum. That's only for magnetic materials. Fluorescent penetrant inspection would be the choice for these valve covers. Many machine shops have the FPI equipment. But nothing short of x-ray inspection can see cracks or voids inside the metal.
 
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