Choose your New GM 4.2L LL8 Head Gasket WISELY...

[mrrsm]

The VOP (Video Original Poster) here goes off on an unfortunate RANT while impugning the undeserving FelPro Company about his own mistaken actions of ending up installing the Wrong MLS Stainless Steel-Composite Head Gasket on top of some GM 4.2L Engine. The useful information he imparted for us though, is that this is a situation that CAN happen to any of us.

This is a Cautionary Tale for us to understand as much as possible about our own unique LL8 Motors beforehand and arrive at the Parts Counter with our Old Head Gasket 'In Hand' to compare very carefully with a Graduated Eye-Ball against the one we want to buy.

All MLS (Multi-Layered Stainless Steel) Gaskets are held together with Brass Rivets that are not Zero Elevation Items. If you wind up purchasing a Head Gasket that looks a lot like the Original OEM Head Gasket, but presents with any subtle differences in the positioning of these Brass Rivets at the WRONG LOCATIONS, then the Engine Head will not seal during the thread-in and torque up of the unique LL8 (17) Various types of Head Bolt Fasteners in the Set.

Be Thoughtful and Suspicious... Double Checking will Avoid Doing Double Duty, Having Double The "Head" Ache and Suffering Double The Expense:

 

[Mooseman]

The VOP (Video Original Poster) here goes off on an unfortunate RANT while impugning the undeserving FelPro Company about his own mistaken actions of ending up installing the Wrong MLS Stainless Steel-Composite Head Gasket on top of some GM 4.2L Engine.

Fel Pro DID deserve it because it's a design flaw, not a wrong part selected by the technician. Sure he could have double checked but it was such a subtle design flaw from the manufacturer, it could have been easily missed by the best technician.

This is an instance where an OEM part is the better choice.

 

[cornchip]

The aftermarket should be solving OEM issues, not creating them.

 

[mrrsm]

The thing is, we know that ALL GM Atlas 4.2L LL8 Engines are NOT Identical in every respect of their overall Dimensions. For example… the larger Exhaust Ports and Larger Valving in the Post 2003 LL8 “Lost Foam” Castings versus those of the 2002-2003 years.

It cannot be overemphasized that whenever getting this deep into any Engine, to seek out the resources necessary for research and confirmation such as present in this Fel-Pro Gasket Catalog inclusive of the Years 1991 to 2016 in PDF Format:

https://images.carid.com/fel-pro/items/pdf/catalog.pdf

Chapter 49 on Page 547 of the 1,309 Page Fel-Pro Complete Gasket Set Catalog shows Two Distinct Head Gaskets are available (with Different Part Numbers) along with Different Engine Assembly Gasket Set Kits to accommodate the Year Differences present with the GM 4.2L LL8 Motors:



So if obtaining a New Gasket Set at a GM Dealership is out of the question, having the Old Head Gasket available at the NAPA Parts Counter (or by Checking with RockAuto FIRST) to compare against The New Felpro One(s) seems like a Good Idea...

 

[Mooseman]

Chapter 49 on Page 547 of the 1,309 Page Fel-Pro Complete Gasket Set Catalog shows Two Distinct Head Gaskets are available (with Different Part Numbers) along with Different Engine Assembly Gasket Set Kits to accommodate the Year Differences present with the GM 4.2L LL8 Motors:

Uh, no. One number, for 02-03, shows as superseded and to use the new new part number, which says are for 02-09, once stock of the old number are depleted. If that new number is not for 02-03, then that is Fel-Pro's mistake. They also have numbers for head sets for 02-03, 02-04, 05 and 06-09. Those seem more credible than the 02-09 number for the head gasket alone. To me, they listed the years incorrectly.

It's not the first time that aftermarket part manufacturers list wrong part numbers. We all remember the debacle with belts for the SWB and LWB where they asked which amp alternator it had (they all had 160A). It was the power steering pump pulley that was different. And they still list the wrong belt for the LWB, being too long.

The Tech was right, Fel_Pro was wrong.

 

[mrrsm]

"To me, they listed the years incorrectly."

It's Quite Possible...

Aside from the suggested use of ONLY a GM Replacement Part in such cases... These are RockAuto’s Listing for the Available Replacement Head Gaskets:

2002 Chevrolet Trailblazer 4.2L Engine

https://www.rockauto.com/en/catalog...l+l6,1398719,engine,cylinder+head+gasket,5412

2008 Chevrolet Trailblazer 4.2L Engine

https://www.rockauto.com/en/catalog...l+l6,1441133,engine,cylinder+head+gasket,5412

I'm almost tempted to get One of the FelPro versions AND the One from Victor Rienz... just to perform that "Graduated Eye-Ball" Check in between them to see if there are any real discrepancies present AND also compare them Both against Screen Prints of the ill-placed Brass Rivets the VOP showed vs. his Engine Head Exemplar.

 

[mrrsm]

I promise to Follow Up with whatever I discover about these two different Gaskets after they arrive from the two different RockAuto Warehouses:

 

[Mooseman]

You know you really didn't have to do this. I was going with that page of the Fel-Pro catalog you posted. However, in RA's catalog, they only list one part number from all manufacturers, including Mahle, which has been historically GM's supplier. Fel-Pro's catalog is all over the place.

Hope you still have an original gasket from your tear downs to compare them with.

 

[mrrsm]

I know... But I Never do ANYTHING By Halves... and since I raised this issue as a Very Serious Concern in the first place, I owe it to the Membership (and The Lurkers) coming to GMT Nation for the most accurate information about Engine Building possible where my Posts are involved and to see all of these issues through to their logical conclusion.

I DO still have TWO Old Head Gaskets from prior Jobs. But if you recall, I covered them both during all of the work I did with my LL8 Motors with Duct Tape to prevent dropping "dirt-N-junk" down inside the engine blocks (Yuk!) ...So after stripping off that stuff, I'll have them both to compare against whatever comes in as Brand New MLS Head Gaskets from RockAuto.

FWIW... I value and respect your input and that of many other Members here at GMT Nation. So when either You or @cornchip try to keep me on "The Straight and Narrow" in all of my Threads, I pay very close attention to what is at stake, I will always heed sound advice and acknowledge being wrong whenever such events happen and adjust and correct things accordingly.

But presently, I just want to ensure that we don't "Throw The Baby Out With The Bath Water" regarding FelPro as a company I have always valued as a Quality Automotive Gasket Vendor in such general terms that they might get painted with a wide brush of criticism in the absence of checking all of the facts.

This is my only way of trying to find out what is actually going on with these Stainless Steel MLS Head Gaskets. If I'm wrong in this... Eventually... Everyone will know it.

 

[mrrsm]

Before continuing… Here is a little something about “Victor Reinz” as an Automotive Gasket Supplier…

The Brand Name “Victor Reinz” is a combination of two of the Last Names of Two of the Five Founding Fathers of international Automotive Supplier Giant “The Dana Corporation” Joseph Victor and Hugo Reinz.

The V-R Branch’s focus is on Automotive Gaskets and Fasteners and as such, is a direct competitor with FelPro and other After-Market Suppliers. The 118 Year Old Dana Corporation is valued at over 8 Billion Dollars in annual profits and employs over 36,000 personnel, worldwide.

Source:
https://en.wikipedia.org/wiki/Dana_Incorporated

The Victor Reinz On-Line Catalog:
https://victorreinz.us/online-catalog

It was not possible for me to acquire one of each Engine Head covering the possible variations of the 2002-2005 vs. 2006-2009 Heads when laid out upon the work-bench. But because the Rivet Placement Differences and Distinct Ear Marks between the FelPro vs,the Victor Reinz Gaskets and these Two Exemplar Engine Heads became quite obvious, all Mechanics can understand the Need for Caution from what I’ve discovered and memorialized with the images below:

The Gasket Candidates:

FelPro MLS Head Gasket Part #26214-PT



Victor Reinz MLS Head Gasket Part # 61-10390-00



Here is a comparison of the “Bad Rivet” Contact areas of concern on the Engine Head shown on in the Video above ...with a sort of ‘side by side’ view with an image of a 2004 Re-Manufactured Engine Head for comparison against the “Ear Mark” differences in the Rivet Placements between the FelPro Gasket and the Victor Reinz Gasket, THESE two Engine Heads appear to have “Physical Agreement” here:




Know that based upon these Real MLS Gasket Rivet Distinctions (Highlighted in Red Circles), it confirms that there MAY be significant variations among some of the GM Atlas Vortec LL8 4.2L OEM Engine Heads.

However, in the absence of having One Of Each Species of these Various Engine Heads by YOM to lay out both of these Gaskets upon and make any fair comparisons, it was impossible for me to either prove or disprove whether or not the FelPro Gaskets are appropriate for installation on ALL of them:




Nonetheless, we do have proof now that any notion of having a “One Gasket Fits All” solution will NOT apply in the repair of ALL Engine Head Gasket Replacements. The other thing that HAS been proven is that for whatever Engine Head the VOP has displayed in his Video AND for the 2004 Re-Manufactured Engine Head images I provided from one of my Builds… ONLY the Victor Reinz After-Market Gasket Part # 61-10390-00 will work BUT... Note the Presence of the FelPro Part# 26214PT on THEIR Label:



The MOST Important Thing to Remember… is to Bring the Original GM Atlas Vortec LL8 4.2L OEM Head Gasket with you and lay it out on the NAPA Sales Counter. Insist upon having the Counter Person bring BOTH of these ‘Clear Wrapped’ Head Gasket Options out for your “Cross-Examination” so you can Un-Box BOTH and thus... Make Certain to Purchase The Right One. :>)

In closing, I think that I've carried out this otherwise inconclusive investigation about as far as it was reasonable and possible for me to do in order to improve our understanding of this matter. I hope it proves useful in the future.

 

[Mooseman]

So can we agree that the Fel-Pro has an incorrect rivet placement for the applications it indicates? AFAIK, the heads are interchangeable between all years and therefore there shouldn't have been a change in head casting.

And with the popularity of online parts ordering, it's not always possible to compare with the old part before buying. In this case, I would feel more confident about buying the Victor-Reinz gasket.

Putting this thread in the FAQ.

 

[mrrsm]

Absolutely... The Video Original Poster stands in vindication for his not having caught these oh-so-subtle, but very critical physical distinctions and It follows on ***QED that You and @cornchip have been RIGHT from the Very Start.




*** QED = "Quod Erat Demonstrandum"

 

[mrrsm]

Following up on the Question of “Are there Any Real Physical Differences in the GM 4.2L LL8 "Lost Foam” Cast Aluminum Engine Heads between the 2002- 2005 vs, the 2006 to 2009 versions?” , at 3:00 Minutes into THIS Video from The GM 4.2L Turbo-Charging Guru…”NIVLAC57” (Calvin... Spelled Backwards) observe the REAL changes to the Head Castings showing up in these Red Circle or Blue vs. Red Highlighted Line Screen Prints:

Even so… without being able to lay the Two Test Head Gaskets along the Later Model Engine Head and make a closer examination, I am still unable to say whether or not the FelPro Gasket Brass Rivets would either be in alignment or in misalignment. :>(

 

[Mooseman]

The heads on the gasket side look the same to me so the rivet on the Fel Pro gasket would not work on any engine.

 

[mrrsm]

No Argument There... And for anyone looking to perform a Head Gasket R&R on the 2006-2009 LL8 Engine Heads, Amazon sports THIS Upper Gasket and Head Bolt Fastener Combo that should be looked over very carefully with what is listed above:



“EngineTech” Assembles Kits like this one for many different Engine Rebuild Projects, boasting that their contents are “NOT Cheap Chinese Knock-Offs”... However... Keep in Mind that the (14 of 17) Main Fasteners H-10 Hex Cap Screws (M11 X 2.00) display the "TTY Spread Line" of the Early Bolt Design, whereas the Later Model Bolts have that S-T-R-E-T-C-H Line moved further up the length of their shanks:



The Two "FelPro Flavors" (Choose Wisely...)



https://www.amazon.com/dp/B08Y636M5B/?tag=gmtnation-20

...and for a Complete Re-Manufactured Engine Head for the 2002-2005 LL8 Engines that requires a Core in Return, they offer THIS Kit:

Amazon.com: Remanufactured Trailblazer GM Envoy 4.2 DOHC Cylinder Head 02-05 + Gasket Set & Head Bolts (CORE RETURN REQUIRED) : Automotive

Buy Remanufactured Trailblazer GM Envoy 4.2 DOHC Cylinder Head 02-05 + Gasket Set & Head Bolts (CORE RETURN REQUIRED): Head Gasket Sets - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

...another 'decent view' of the smooth underside of that head. :>)

 

[Mooseman]

In any case, knowing what I know, I wouldn't do a head job on this engine. I'd swap the whole engine but even then, I think I'm out of that game now too.

 

[mrrsm]

Hmmm... A Sad Testimonial that such a Marvelous Motor should present us with So Many Difficulties. Well... If nothing else... Let's hope that those who might wander into doing these Complex Repairs will appreciate coming to (and Joining) GMT Nation for access to this and all other kinds of Help and Information.

 

[JayArr]

Well I'm a little late to this thread but a big Thank You to all.

I just went out and looked at the FelPro gasket I bought to do my engine and sure enough the rivets are in the wrong place. I never would have caught this without this forum!

The guy on the video said he was just going to remove the rivets. Since they are only there to hold the steels together does anyone think this is a bad solution?

 

[mrrsm]

Because the "MLS" (Multi-Layer-Steel) Gasket is meant to 'move ever so slightly' as the Extra LONG "Lost Foam" Engine Head Heats Up at 3 Times the rate of **** Cast Iron...and thus Contracts in a likewise Dimension as it Cools Down... Those Rivet Placements are meant to prevent "The Sandwich" from deviating off-kilter a Bit TOO Much.

Whether you decide to 'Burn Off" those offending Rivets - or Not ... should depend upon whether you are expecting another 100-150,000 Miles out of your LL8 Engine. Given the endemic problems that come right along with this "Gasket Creep" from the potentially troublesome (17) 14 Main Hex Head Bolts +3 Minor Fasteners TTY M11 X 2.00 X 155mm Head Bolts... It might be best to wait and get "The RIGHT" Gasket and remove any doubt.

Fun Fact:

**** Cast Iron Expands (or Contracts) at the rate of 1/64 Millionths of an Inch per Degree Fahrenheit Increase-Decrease.

 

[JayArr]

I bought this a year ago and put it on the shelf, I'm like that, I slowly collect parts and tools for a project and I don't start until I've got everything so sometimes new parts sit around a while. I'm not going to get a refund on this so I'll have to chuck it in the garbage and buy the Victor one.

I not fond of losing $100 this way!

 

[JayArr]

WAIT ONE MINUTE!!!

I just went and opened my gasket and pulled the head off my engine (it was just sitting there - no bolts.)

Too much attention is being spent on the head and not enough on the block!

This gasket will work with my block!

The head doesn't have any wells or clearance for the rivets in the modified positions but the block does and as long as there isn't aluminum on both sides they won't hold the head from sealing.

My guess is Felpro knew this all along.

Look at these two pics...

The first shows a well in the block where that D3 is, this is where the rivet head will sit, there is no surface on the block side pushing the rivet toward the head.

The second shows the other side, there is also no surface area over there, my finger lides right under the gasket and you can see my finger through the rivet.

 

[JayArr]

Here are two more pics with the gasket off.

The first shows a well where the D3 is cast and that's where the rivet will sit - no interference

The second shows that the block doesn't come all the way out like the head does, my finger is where the head of the rivet will sit on that side, again - no interference.

 

[JayArr]

So I guess the question is which blocks have these areas with no interference.

That is the original block out of my 2005 Envoy.

Maybe the early blocks that weren't made with the foam are the problem?

I went and re-watched the video but didn't see the top of his block to compare, he does claim near the end that there is no pocket on his block at those locations.

 

[mrrsm]

Good Follow Up!

AFAIK.... ALL of the GM Atlas Cast Aluminum 4, 5 & 6 Cylinder Engine Blocks were manufactured using Hardened Styro-Foam Pre-Fab Sections that get stacked inside of cylinders filled with vibrated and compacted fine sand.

Then during subsequent exposure to Boiling Hot Pours of A-380 Aluminum with some wear - resistant Silica added into the mix... The heat from the Liquid Metal vaporizes the Styro-Foam as the Alloy deposits within, hence the process has come to be called, The "Lost Foam" Technique.

GM also switched from using Regular Coarse Sand in their Casting Molds over to re-usable, Fine Grain Powder that presently, is largely recycled very efficiently.

This change eliminated creating Mountains of Old Casting Sand discarded by the Tons as useless, contaminated Sand Waste all around, as had been done back in the days of Sand Casting Pig Iron into Engine Blocks, Engine Heads, Camshafts and Crankshafts.

FWIW... The Artifacts proving the use of "The Lost Foam Technique" are VERY Easy to observe in the full line of The Atlas Aluminum Engine Blocks and Heads. This is because this process leaves a sort of "Styro-Foam Coffee Cup" Texture and Motif all over various places within the Lost Foam Castings.

These imprints are easily observed and occurred because the Styro-Foam Plastic Foam Planks defining internal and external Engine Shapes and Structures get made from using some similar, Highly Compacted and Compressed "Styro-Foam Beads".

These Hardened, Precise Shapes get instantly vaporized into a Noxious Gas as the Hot Liquid Aluminum makes contact with the Foam Planks buried within in their Fine Sand Molds. This happens fast enough to completely replace those Planks with the Aluminum-Silicate Alloy filling up all of the voids to near perfection.

So if you find any of those "Funky Coffee Cup Dots" present anywhere on (or inside of) your Engine Block or Head, their presence will likely confirm that these Aluminum Components were manufactured in this identical fashion.

And to that end... while you are looking things over for this evidence, it will be very helpful if you Find and List the GM Atlas LL8 Engine Head Part Numbers and those on the Atlas "Lost Foam" Engine Block as well.

This data can probably be gleaned from the White Bar Code Number Label that should still be glued somewhere on the flanks of that Aluminum Engine Block. You'll also notice just how little Post - Process Line boring and Complex Machining is required for finishing these Amazing Motors.

There should also be some "Micro-Punched Alpha-Numeric Identification Numbers" stamped upon both components during their manufacture that could prove very helpful for cross-reference checks by others concerned with this issue in the future.

These are probably located along the margins or sides or at the ends of the Head and on the upright portions of the Engine Block.