T.O'Brien

So,

A little introduction:

The HG's blew mach in March, after a complaint to the BAR for the warranty on my re-built 3.0 it has boiled down to me replacing the HG's. No too easy, not too duficult a task as I originally though, and as I'm ready to put it back together, things seem to not be too difficult again. However, after getting the heads back from the machine shop a few things were explained to me. One, they were in such bad condition Terry (the guy running the shop, I thought I knew quite a bit about my engine...nope, Terry is the Toyota Engine Bible himself lol) was surprised my truck was even running let alone I hadn't snapped the timing belt. He had to take 9 thousandths off the heads out of a maximum of 10 thousandths My intake valves.

So long story short...I'll cut off my ranting there, but I have two different HG's to put back on the truck as I assemble it. Their both MLS gaskets, and this is where I need your guy's help.

First one Terry gave me when I picked up the heads, it is kinda like a hybrid MLS & Carbon gasket. There's a metal surface for the head to ride on as it expands and contracts, and the underside is the carbon/paper/composite part that goes against the block. Gasket number two is a full blown MLS gasket that has 4 layers of metal riveted together.

Now, Terry pointed out that the HG's on the 3.0's blew not because of bad heads, but because of a badly machined block from Toyota. If after going through the FSM and finding my block to be within tolerances my big question is:

Which HG Should I use? Should I take the chance that the riveted MLS gasket might blow in a couple miles, or use the composite gasket?

Mind you, the gasket that blew was the composite gasket, but it was installed upside down by the rebuild shop and lasted ~3.5 yrs. If installed correctly it should last just as long if not longer correct?

I'm just so fed up with how long this process it taking, I really don't want to have to do it again any time soon. I'm leaning towards using the composite gasket, but this is where I'd like to have some opinions/experience before make my final decision.

Thank you guys in advanced!

Tom

MudHippy

The story on the OEM/composite gaskets is kind of long. In short:

a. It's called a Slipperplate™, or expanded bore grommet. Only the 3VZ-Es made after the head gasket recall ever had them. The original OEM design was only different in that it lacked that particular design feature. The head gaskets with them are technically NOT "a hybrid MLS & Carbon gasket". And it's a graphite composition, technically, NOT carbon(and the original OEM design contained asbestos in the composition, or so I've heard). So, technically speaking, they're a "graphite composition over perforated steel core w/expanded bore grommet" type head gasket

b. The ones that were installed "upside down" really weren't. You can't install any of them upside down. They were the 3rd generation type/design, where the Slipperplate™ faces the block. The current OEM head gaskets made by Ishino are manufactured in this fashion. See here.

c. The original redesigned head gaskets, or second generation type/design as I call them, are made with the Slipperplate™ facing the head. I'm not sure that these were ever made by an OEM manufacturer. Though, the design concept is identical to the 3rd generation OEM types. Aside from them being made "upside down". But since their design pre-dates the 3rd generation design, I tend to call them "right side up". Since the original engineering concept of the Slipperplate™ head gasket design calls for it to be facing the head(NOT the block). Toyota basically stole the idea from an aftermarket company, inverted it, and had another/OEM company make them that way for them. For what good reason? Nobody knows(afraid to infringe on a copyrighted/trademarked design perhaps?). Anyhow, I happen to think they were wrong in doing so. As such, I put my faith in the second generation design(which is still widely available). Though, the 1st generation design(w/o Slipperplate™/expanded bore grommet) was more than adequate for ~218k miles on my 3VZ-E(but is no longer available). So it's hard for me to say that succeeding generations/designs have ever gotten any better(though we have no choice but to use them or MLS). I've got A LONG ways to go on the 2nd gen. Slipperplate™ type installed on mine currently to ultimately prove their durability in comparison.

O.k., enough on Slipperplate™ theory.

Should you use the MLS gaskets instead? Not unless you're aware of what's required for those to have a good chance of working properly. And you've taken those necessary preparatory measures, or intend to. Meaning you better have the head and block mating surfaces finished super flat and super smooth(20 microinches RA or less). http://www.aa1car.com/library/2005/ic010532.htm(pay no heed to the information regarding 3.0L head gaskets, which is inaccurate, all 2nd/3rd generation Slipperplate™ designs have had a "slippery coating" on them, the addition of the Slipperplate™ itself was actually the significant change in the design)

I'd never heard about the .010" limit on resurfacing the heads. That sounds like it might possibly be right to me though. So I guess I'll buy that...for now. And I suppose he could be right about Toyota badly machining the blocks, but that I HIGHLY doubt is a very common cause for the head gaskets to fail. Meaning, they may have machined a bad block or two, but not very likely too many of them. Sounds to me like Terry/"Mr. Know-it-all Toyota guru" thinks he knows about things a little better than he really does on that one(i.e. he's most likely making that up, and/or or has little evidence to back it up...smells like BS to me). I've never heard of such a thing being the case on any 3VZ-E. Let alone it being something that's known to be a common occurance, and/or a given with them.

T.O'Brien

Ok, good info, fair enough on "Terry".

I figured mine failed because the HG etched it's metal core into the head. The core looks like a cheese grater (looks identical to the one pictured in you link) and this etching into the head made it fail.

If I understand you correctly, if my Slipperplate HG has the plate facing the head (2nd generation), like yours is, I should be fine? I appreciate your help with this. My heads have been surfaced to accept the MLS gasket, but after a $800 bill I'm out of cash to do the block to use the MLS. So...I shall be using the SlipperPlate instead.

Again, thank you.

MudHippy

That's an inevitability when you use a perforated steel core type of head gasket w/o a Slipperplate™/expanded bore grommet facing the head. It happens to both the heads and the block surfaces when you use the 1st generation design HGs. Though depending whichever of the later types you choose to use, you get to save either the heads(2nd gen) or block(3rd gen) surfaces from being damaged in that manner. Meaning, EVERY 3VZ-E having non-MLS HGs installed has similar damage to either their head surfaces, their block surfaces, or both.

Anywho, it doesn't stand to reason that such damage is causing any 3VZ-E head gaskets to fail(yours or any other). Since, not only is Toyota still selling/installing head gaskets on this engine that cause damage of the sort, there are also literally thousands of 3VZ-Es running around with said damage(on their block, heads, or both) without having blown HGs. For instance, my 88 3VZ-E went 218k miles on the original HGs from the factory, despite having such damage on both the heads and the block(caused by the use of 1st generation design HGs). I've also got over 10k miles on my 2nd generation type HGs, and I didn't have the block resurfaced(though the heads I did, in effort to provided a better seal against the Slippperplate™/expanded bore grommet). So I highly doubt that it makes much difference, if any, as far as what causes most 3VZ-E HGs fail. Keeping in mind also that...ALL HEAD GASKETS WILL FAIL EVENTUALLY REGARDLESS OF THEIR DESIGN! SINCE THERE'S NO SUCH THING AS AN INVINCIBLE HEAD GASKET!

And yes, if I were you I'd use the 2nd generation design. Barring being able to afford having the block resurfaced. Because being able to use the MLS head gaskets would be optimal...in theory. Though many of our 3VZ-Es are doing just fine without them.

T.O'Brien

Thank you, you've been very helpful.