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Offical 1FZ head gasket debate

Discussion in '80-Series Tech' started by cruiserdan, Jul 16, 2005.

  1. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    By request we have opened the floor to discuss the suitability of the 1FZ head gasket.......Bring it on.

    This is my perspective.

    First let me state that the 1FZ engine is one of the most advanced in-line 6 cylinder gasoline engines ever offered to the public, in addition to being one of the largest displacement.
    The overall design and build quality of this engine is at the very top end as far as I am concerned. Limiting factors include, but are not limited to, "acceptable" gasket materials.
    We are dealing with an engine that is composed of an iron block and an aluminum cylinder head. The result is dis-similar metals that react to temperature changes at different rates.
    The challenge for the designers was to come up with gaskets that can deal effectively with the expansion rates of dis-similar metals.
    Before asberstos fell from grace it was a prominent feature in head gaskets for all auto manufacturers and it was very effecive.
    When asbestos fell from grace there was a scramble to find a suitable replacement and early "fixes" did not perform well in the long run. Toyota has, along with everyone else, changed head gasket part numbers for virtually all engines multiple times in the last several years (1FZ included) while they have searched for the best replacement.
    My personal read is that the great long aluminum head on the great long iron block moves around a bit with every heat cycle and that may be part of the cause. The latest version of the head gasket is visibly different than the originals and is significantly reinforced. I further believe that if asbestos was not "offed" as a bad guy we would not be having this discussion.
     
  2. IdahoDoug

    IdahoDoug

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    My position on this is that the head gasket of any vehicle is vulnerable to damage from leaving old coolant in it (acids attack the gasket material, protective coolant additives break down). Other vehicles in the market are off the road at lower miles due to other problems that have made the vehicle too expensive to keep running, where 80s are still on the road well into the 150,000 mile range even if not maintained well. However, the 80s head gasket is damaged at the same rate as any other vehicle, and so the head gasket becomes the first major component to fail.

    I don't have any emperical data to back this up. However, it is worth noting that Toyota engineers designed the LandCruiser and all its components specifically to endure a life of hardship. With no data to support my position or the opposite position that the head/gasket/block interface was improperly designed, one has to make a choice as to which position fits the logic test. For me, it is far more probable that past owner issues are the issue, versus that Toyota did a poor job on this design.

    DougM
     
  3. mooker82

    mooker82

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    I will let you know how i feel about the head gasket after I test my fan clutch. I hope its not a head gasket.
     
  4. MLX450

    MLX450

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    Nice info. What is this new gasket made of? interesting. Do you have a pic of the new gasket?
     
  5. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    Toyota does not publish what goes into it's gaskets, or anything else for that matter. Nor does any other manufacturer that I can think of.

    Photos of the newest gasket have no value without a sample of an old one to compare to.
     
  6. beno

    beno 23424-23216 Moderator GOLD Star

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    So let me understand this correctly:

    Since the 'good' asbestos ones were taken off the market, my reading of Dan's post is that the head gasket itself is constantly being updated (or, is that just that part number for it?).

    Is the head gasket on a 97 when it came off the assembly line in 97 the same head gasket we'd get today if we ordered from you Dan?

    Related: Would anyone recommend a head gasket job as a PM maneuver to possibly take care of any future problems with the gasket? If so, why? And to extend this, what type of :banana: job is this? I assume many, many :banana: 's on this one...way beyond me, is what I am saying. :eek:

    I have one sitting in my garage just in case, though I don't think the rig has any of the problems as posted in many archived threads about HG failure/symptoms.

    Thanks for the enlightenment.

    Best.
    -onur
    Akron, OH
     
  7. medtro

    medtro

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    Any comments on running it with just water, no red or green coolant?
     
  8. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    Rust baby, big time.
     
  9. Rich

    Rich

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    If one searches out publications catering to the engine repair and rebuilding trades it will not take long to find out that 1) asbestos gaskets did indeed perform better than what is used now, 2) Aluminum heads on cast iron blocks are just asking for trouble due to the significant differences in their coefficients of expansion, 3) Due to the unacceptable headgasket failure rates the industry has innovated a number of different approaches to headgasket design, 4) more care and different techniques are required to help ensure successful headgasket replacement, and 5) the industry is not finished trying to improve the reliablity of headgaskets used on aluminum head / cast iron block engines.
     
  10. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    Man, I love it when somebody backs me up like that.....:D
     
  11. Rich

    Rich

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    I read too much. Just sharing what others in the somewhat obscure (to the regular joe) industry press have to say.
     
  12. RavenTai

    RavenTai

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    Toyota did publish a little info about the head gasket in the 96LX NCF I don’t know if stainless/graphite (in the form of carbon fiber?) was used in other years also.

    [​IMG]


    one thing to note IIRC carbon and aluminum do not get along. especially in the presence of water.

    Beno, I have heard in the that the HG you buy now is updated and different than the one on your truck , Dan will know for sure. So far I have not heard of anyone with the new gasket having any problems.

    I have debated back and forth about replacing mine as PM, finding something to drive wile the cruiser is down has been a stumbling point hard to get around when it is running just fine. Also if I do the HG I might as well pull the engine and do the rear main, if I am going to do that I might as well do rings and bearings and some head work also. Making a larger job.

    One reason to consider doing it as PM as some have found pitting/erosion on the head or block when the HG is allowed to fail. So it may be more expensive once it fails than if done as PM. Another is you get to choose the time and place.

    On the other hand yours may make it without even needing one so it may be wasted effort. Opening the engine should only be done by a trusted honest mechanic some hack trying to beat the clock may do more harm than good. If you have the ability to so it your self it would be best for many reasons. But keep in mind I have a deep distrust of auto mechanics.
     
    Last edited: Jul 17, 2005
  13. gbell210

    gbell210

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    Sounds like I may have 2 toyotas (both I6's) with potential HG problems. Currently neither do though. But I know many on the supraforums board say to change to a metal headgasket if you are going to be adding more boost. Also if a HG job is need to upgrade to a metal headgasket as it will hold up better in the long run. So far, I've pretty much stayed stock on boost for my 89 supra (3.0L I6 w/turbo) and just make sure the cooling systems has no air in it and all its components are up to par. Also, its not just the turbo engines either.. HG problems are with the N/A versions of the 86-92 supra (MKIII). Infact you'll see appearal sold with "BHG" on it, so it seems common but not enough to cause a recall, like it there was on the V6's in 2nd gen 4Runners (3VZ).

    From what I have understood, the HG's were redesigned at least once sometime in the late 90's for the MKIII Supra also. Besides upgrading to a MHG, most also recommend ARP headbolts/studs, as it was found the stock bolts stretched to much and they should have been torqued down more from the factory (stock ~55ft/lbs recommended for new bolts: 78ft/lbs.) Still some have problems, but they are also running large amounts of boost (25+psi compared to stock ~8psi)

    I know I mentioned alot about the supra engine (7MGE/GTE - NA/ turbo), but it seems to me from reading posts here and on the supra board.. that an inline 6 engine has a much greater potential for HG failure, probably due to the surface area and expansion as opposed to 2 smaller gaskets for a V6. (Both Supra and LC have iron block w/ aluminum head)

    I guess this leads me to wonder.. those that have done a headgasket job on their LC's, are the factory specs on headbolt/studs enough or has anyone upgraded to better grade bolts/studs with more torque? Also, how are other I6 engines doing on headgaskets? SOHC and DOHC versions.

    -Gary
     
  14. parabola

    parabola

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    I call BS on everyone. :D Toyota knows how to make good HGs in iron block/AL head motors. Look no further than the amazing 2JZGTE. These cars not only have no HG issues, but they take INCREDIBLE power outputs, and, by my own experience, INCREDIBLE punishment without failures. How about nearly 800HP on a motor that was built to handle 320HP? How about that as a DD in TX heat and humidity? How about me running 1.5 bar of boost (~23psi) DAILY on this motor? How about the dozen cars that do almost 1500HP on stock HGs?

    Toyota figured out how to do it. They didn't put this technology into the 1FZ. That sucks, but I'm OK with it. These trucks run nearly forever anyway, just think of the HG as an (expensive) maintenance item. Just wish I could get the nice metal HG from my 2JZ on my 1FZ.
     
  15. landtank

    landtank SILVER Star

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    I'll start my post by stating that I'm nothing more than a simple technician by trade. I've been repairing various equipment for over 22 years and have NO formal schooling past 12th grade.

    I tend to focus on 3 basic things when determining a plan of action on handling any particular problem whether immediate of not.

    1. failure rate or likely hood of a particular problem occurring.

    2. a redesign of a part that is associated with the problem.

    3. personal comfirmation that the redesigned part attempts to address the problem.


    With the HG I have hit the trifector. I changed out my HG as a PM item and did so without #3. It was on a strong hunch and the fact that I rely so much on the truck for work that I did it. Once the gasket was out I saw first hand what was happening to the gasket at the #6 position and how Toyota redesigned the HG at the #6 position to help address this.

    I'm not sorry one bit that I replaced the HG. Some like the comfort feeling of thinking they have done something worth while and will reap the rewards from it. I on the other hand know I'll be reaping the rewards from my effort.
     
  16. Cruiserdrew

    Cruiserdrew On the way there SILVER Star

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    Rick-this is my plan as well. I'm at 95K currently, and will do this service by 120k. I'll do the radiator at the same time.

    What bugs me is that Toyota makes the head in cast iron for the mil-spec vehicles. I suspect that an iron head would have solved the problem and added only 40 pounds or so. I have 2 other I-6's with original headgaskets. One is almost 30 years old and the other is 21 years old. Both have iron heads, so I think the long aluminum head was a bad idea, and likely the underlying problem in the 1FZ motors. If there was an advantage to the aluminum head, please share it. If Cruiserdan can source on of the cast heads, I may go that route just for grins.
     
  17. concretejungle

    concretejungle SILVER Star

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    A little question regarding the headgasket material and asbestos. I'm curious why asbestos could not be used still in head gaskets? I worked for a company where we would perform asbestos surveys in homes. The main reason asbestos was considered harmful was for it's cancer related effects on the lungs of humans. This however was only a problem once the asbestos was disturbed and had become "friable", meaning broken up into many small particles that could be inhaled. Many of the contractors that would come in behind our survey to dispose of asbestos containing materials would simply spray everything down with a water hose while ripping and pulling the suspect material out and throwing it into a dumpster. I would not think that an asbestos gasket bolted between a cyclinder block and head would become a health hazard?

    I would think that the main desirable attribute of asbestos as use of a gasket material would be it's heat/fire resistant qualities. Surely there are other materials out now that have these similar qualities? No? Maybe?

    EDIT: Did you know that the snow in the poppy field scene in the wizard of oz was asbestos.?
     
    Last edited: Jul 17, 2005
  18. concretejungle

    concretejungle SILVER Star

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    Is it possible to get an iron head for the fzfe? If so would it be a desirable swap?
     
  19. bjowett

    bjowett Supporting Vendor

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    The TIS also states a graphite gasket was used in 93, under new model features - engine.

    My take, the original gaskets were inadequate to deal with a hot spot back by #6. The new gasket should remedy it. For a composite gasket, it appears to be top of the line.... metal gaskets are the best, they require ULTRA smooth sealing surfaces on the head and block, though... that is something that can't be done in the driveway, or by some machine shops.

    Bolts are also a biggy... they work, but nothing compares to a stud and nut. Torque To Yield is pretty much the norm on head bolts today.
     
  20. turbocruiser

    turbocruiser SILVER Star

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    Sorry this is so long but hopefully it is as helpful as it is long...

    My position on problems with headgaskets mirrors almost all the thoughts that Dan (dissimilar metals with dissimilar expansion and contraction rates), Doug (chemical reaction attack from crappy coolant, hydrolysis, crappy water or altered pH), and others (asbestos was able to handle these things better than most alternative materials).

    However, I have a few more thoughts (I emphasize thoughts because I'm not an engineer or a chemist or a mechanic by career but just someone who tends to think too much!!!). These thoughts combine my experience with Toyotas (several cruisers, a 4Runner - the one with the truly terrible HG, RAV's, Corollas, etc) with my experience with classic Mercedes Benz engines (all BTW with iron block and aluminum head). Again I emphasize minimal expertise and too much thought.

    I have now had to have two headgasket replacements done. One on my 4Runner which was a Toyota factory recall program, and on an old 1967 Mercedes Benz 280 SE Coupe. I'm not sure what the material of the 4Runner gasket was but since it was an 88 model I'm thinking it was asbestos, the material on my old MB gasket I'm sure was asbestos and it still failed. Not only that, but being an active member of the MBCA and having one of my closest friends own an extremely reputable MB, Porsche, VW, Audi, BMW repair shop, I have seen so many HG's fail on iron block with aluminum head vehicles.

    Due to these experiences I reduce it mostly to dissimilar metals BUT ALSO TO the exactness of the marrying surfaces between block and head. The reason I say this is all related to the MB repairs in which, in all cases the block AND head was perfectly and precisely resurfaced to be smoother than stock and in all cases, AFAIK, the HG material was not changed from the vintage of the car til the time of the repair. IOW, if you replace a failed HG with the same exact HG and the replacement lasts much much much longer (as all the replacements thus far have) than you have to look at something other than strictly the material of the HG and in ALL these cases the only other difference was the care taken to tighten up the tolerances between block and head.

    I'm going to cut and paste some stuff here to elaborate:

    Head resurfacing is just one of the jobs that’s sometimes required when rebuilding an engine or reconditioning a cylinder head. It’s an extremely important job because the surface finish that’s put on the head (and block) affects not only the head gasket’s ability to cold seal fluids and combustion gases, but also its long term durability.

    For years, most aftermarket gasket manufacturers have said surface finishes with a roughness average (RA) of anywhere from 55 to 110 microinches (60 to 125 RMS) are acceptable. The preferred range they have recommended is from 80 to 100 RA. Even so, as long as the surface finish on the head and block end up somewhere between the minimum smoothness and maximum roughness numbers, there shouldn’t be any cold sealing or long term durability problems with the head gasket (assuming everything is assembled correctly and the head bolts are torqued in the proper sequence and to the specified torque, too).

    But like everything else, these numbers have been changing. These recommendations were primarily for older cast iron heads on cast iron blocks. As castings have become lighter and less rigid, the need for smoother, flatter surfaces has become more important. Consequently, some aftermarket gasket manufacturers now recommend a surface finish of 30 to 110 RA for cast iron head and block combinations, with a preferred range of 60 to 100 RA for best results.

    ALUMINUM HEADS

    For aluminum heads, the numbers are even lower. The typical recommendation today for an aluminum head on an OHC bimetal engine is a surface finish of 30 to 60 RA, with the preferred range being from 50 to 60 RA.

    Smoothness has become a major issue with bimetal engines because the difference in thermal expansion rates between an aluminum head and cast iron block creates a tremendous amount of sideways shearing force and scrubbing action on the head gasket. If the surface finish is too rough (more than about 60 RA), the metal will bite into the gasket and pull it sideways as the head expands and contracts. The cumulative effect over time can cause a delaminating effect in the gasket, literally tearing it apart causing it to leak and fail.


    Even lower numbers may be required for certain engine applications. General Motor’s, for example, specifies a surface finish of 27 to 47 RA for its 2.3L Quad Four engine when the OEM replacement gasket is used. Some aftermarket gaskets can handle a rougher finish on these engines, but it all depends on the design of the gasket. Even so, smoother is definitely better on these engines.

    Ford specifies an unusually smooth surface finish for its 4.6L V8 engine. This engine, like a growing number of late model Japanese engines, uses a multilayer steel (MLS) head gasket. This type of laminated steel gasket is extremely durable because the multiple layers of metal (each of which is coated with a thin layer of rubber) prevents the gasket from losing torque over time. The design also reduces the amount of torque that’s required on the head bolts to seal the gasket, which in turn reduces cylinder bore distortion for better combustion sealing and reduced blowby. The recommended surface finish for the OEM gasket on the 4.6L V8 is 8 to 15 RA!

    AN ALMOST POLISHED SURFACE

    To appreciate just how smooth this is, compare the surface finish requirements for the head and block on the Ford 4.6L V8 to those for a typical cylinder bore. Honing with #220 grit stones typically leaves a finish in the 38 to 45 RA range. Honing with #280 grit stones will generally produce a finish of 18 to 25 RA. Honing with #400 grit stones, a finish of 10 to 15 RA can be achieved, and honing with #600 grit stones can push the numbers down to 5 to 10 RA. A pane of window glass, by comparison, measures about 3 to 4 RA.

    Honing cylinder bores is obviously an entirely different process than resurfacing cylinder heads or blocks. For one thing, the walls of a cylinder bore must have a certain amount of crosshatch to retain oil so the bores can’t be too smooth. But neither can they be too rough because a rough finish can wear the rings excessively as they seat in.

    The ideal finish for a cylinder bore is a "plateau" surface where the sharp peaks have been knocked off but the valleys remain. This provides plenty of bearing area to support the rings but also leaves the crosshatch for proper ring lubrication. More importantly, it virtually eliminates ring wear during the initial break-in process because the surface already has the profile of a broken-in cylinder. This kind of surface is produced by going in with a final honing step that uses a fine grit stone (#600) or a flexible abrasive.

    Although an unusually smooth finish may be required for the Ford 4.6L V8 and certain late model Japanese engines that have MLS head gaskets, smoother is generally better for all engines because it improves cold sealability.

    One thing you don’t want on the surface of the head or block is scratches or any warpage any at all. Every scratch is a potential leak path along which fluids and pressure can migrate. If a scratch is deep enough, coolant may find its way into the crankcase or cylinders before the engine is fired up. Or, combustion gases may force their way past the gasket into the cooling jacket or an adjacent cylinder eventually causing the gasket to burn out and fail. Either way, it’s bad news. So the best way to avoid cold sealing and durability problems is to take the proper steps when refinishing the head and block to ensure the surface finish is within the recommended limits of the gasket manufacturer and/or original equipment manufacturer.

    TOO SMOOTH?

    Can a head or block surface be too smooth? After all, the smoother the surface the better the initial cold seal of the gasket and the less likely you are to have problems with coolant and combustion leaks.

    Though most gasket manufacturers do not specify a minimum smoothness spec for aluminum heads that have MLS head gaskets, they do recommend a minimum of 30 RA for engines with aluminum or cast iron heads and a nonasbestos or graphite head gasket. The reason for doing so is because soft-faced head gaskets require a certain amount of lateral support from the head and block.

    When the head is bolted to the block, the metal on both sides bites into the gasket to help hold it in place. You don’t want too much bite when the head is aluminum and the block is cast iron because of the sideways shearing forces that result from the expansion and contraction of the aluminum head. Yet a certain amount of support is necessary to keep the combustion gases in the cylinders from distorting the gasket and blowing past it. This is especially critical in the areas with narrow lands and between the head bolts where there is nothing to keep the gasket in place but the gasket itself. In high output or heavy-duty applications where combustion pressures exerts even greater force against the head gasket, a surface finish that’s below the minimum smoothness spec might lead to premature gasket failure.

    HOW SMOOTH IS IT?

    Most engine rebuilders have no idea how smooth a surface finish they’re actually putting on the heads and blocks they resurface. As long as the head gasket seals initially and doesn’t fail during the warranty period, they assume they’re doing everything right—and maybe they are. Then again, maybe they aren’t. They may not be seeing the long term consequences of their actions because the head gasket doesn’t fail until the engine is out of warranty.

    In many instances, a premature head gasket failure because of leakage or burn through can be traced back to the surface finish that was put on the head and block. Of course, there may be other factors involved, too, like engine overheating, detonation, etc., or mistakes that were made during engine assembly such as not torquing the head bolts properly. But if a head gasket fails, there’s always a reason why. Paying closer attention to the details of resurfacing, therefore, can help eliminate this as a potential source of trouble.

    Most people can’t look at a finish and tell if it’s 20 RA or 60 RA. So the only way to know if a resurfaced head or block is within the proper range is to measure it. Judging surface finishes by appearance alone, or even feel, is not a very accurate means of controlling quality. Most people can’t tell the difference between an acceptable finish and one that isn’t unless it is really bad. Even then, their judgment may be shaded by outdated notions of what’s "good enough" and what isn’t. If they’re resurfacing aluminum heads the same way they’ve always done cast iron heads, chances are the surface is too rough.

    One way to judge surface finishes is with an inexpensive comparator gauge. Available from at least one aftermarket gasket manufacturer as well as various tool suppliers, a comparator gauge has sample patches etched on a metal plate that indicate the different surface finish ranges. By placing the comparator gauge next to a resurfaced head and visually comparing and feeling the sample patches on the gauge to the head you can get an approximation of whether or not you’re in the correct range. But it’s not very exact, and it’s often hard to tell just how close you actually are to a given range of numbers.

    A far better method of judging the quality of your work is to actually measure the surface finish with an electronic profilometer. The least expensive profilometers start at around $1500, and go up from there depending on the features they offer.

    A profilometer measures surface finish by dragging a diamond-tipped stylus across the metal. This reveals the roughness of the surface as well as some other important parameters that can tell you even more about what the surface is really like.

    RA, or the roughness average, is an arithmetical average of the absolute values within the area sampled by the stylus. It gives you an approximation of how rough the surface is, but doesn’t tell you much about the actual profile of the surface. The accompanying illustration shows three very different surfaces that all have the same RA value.

    The top surface in Figure 1 shows a fairly flat surface with some deep scratches (much like a plateaued cylinder bore with crosshatch). This type of surface would probably be okay on a cast iron or aluminum cylinder head provided the scratches are not too deep and don’t create leak paths. The middle surface has sharp peaks and deep valleys. A surface like this on an aluminum head would provide too much bite, and may not cold seal because of the deep valleys between the peaks. The bottom surface is more irregular overall, and may or may not be acceptable depending on the depth of the deepest scratches and the waviness of the overall surface.

    The point here is that you really need to know more than just the RA numbers to judge the quality and acceptability of the overall surface finish. An electronic profilometer can measure the maximum peak-to-valley height (called "RY") as well as the arithmetic mean of the peak-to-valley heights ("RZ") and other parameters that may be needed to get a more accurate picture of how the surface actually looks.


    Soo, after all that, my theory is that not only the dissimilar metals, and not only the material and construction of the HG, and not only cooling system care, but also the surface perfection or imperfections between the head and block are ALL VERY IMPORTANT CONTRIBUTING FACTORS that added together make ANY engine with iron block, aluminum head, and less than exact tolerances (either via surface prep at the factory or warpage due to cooling system care) will all add up to increased risk of HG failure. Whew, glad I'm done with that, whaddya all think???