head gasket 109K 1997 LX450

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I have come to the conclusion that there is no way to prevent the gasket from failing (at some point). I think it is partly the result of the dis-similar metals doing what they do and the fact that the head gasket fire rings on original gaskets are just rings. The more heating cycles the engine has gone through the more apt the fire ring is to move around (my opinion). If the engine were held at a constant operating temperature I don't think the gasket would fail but cycle it a few thousand times and BINGO, you have a leaker. The new version of the gasket has a lot more support for the fire rings and it looks as though they are not able to move around like they can in the early gaskets.


D-
 
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CDan- I think someone asked this before but I cannot find the answer. Did *any* of the '93-97 LCs or LXs come from the factory with this new, upgraded HG?
 
Has anyone checked the torque of the head bolts prior to disassembly? I'm wondering if there sholud have been a "check head bolt torque" PM at the same time as running the valve clearances.

When I worked for the John Deere dealership, we did head bolt retorques every time we had the rocker arm cover off and IIRC it was part of a 10K hour service.

Just a stupid thought...


:cheers:
Dave
 
alaskacruiser said:
CDan- I think someone asked this before but I cannot find the answer. Did *any* of the '93-97 LCs or LXs come from the factory with this new, upgraded HG?
Click to expand...



No.
 
MoGas said:
Has anyone checked the torque of the head bolts prior to disassembly? I'm wondering if there sholud have been a "check head bolt torque" PM at the same time as running the valve clearances.

When I worked for the John Deere dealership, we did head bolt retorques every time we had the rocker arm cover off and IIRC it was part of a 10K hour service.

Just a stupid thought...


:cheers:
Dave
Click to expand...

The 1FZ cylinder head is attached with "plastic region" bolts that are torqued to a particular specification and are then rotated an additional 180 degrees, in two passes, to obtain the proper clamping force. This is a one-time deal and is not required to be re-done. In addition one would have to remove both camshafts to reach the head bolts in order to re-torque them. Hardly a simple task.
 
MoGas said:
Just a stupid thought...
Click to expand...

Not a stupid thought at all. :D

In fact, I asked this same question of the 80sCool list about 4 or 5 years ago. I was told at that time that nobody had tried retorquing the head. The main reason (as C-Dan pointed out) is that getting to the head bolts is 90% of the work in removing the head and if you're going that deep then you may as well replace the HG.

They didn't mention the point Dan makes about the special head bolts which is even more of a reason why a retorque would be of little value. The head bolts are not losing their torque, the HG fire rings are losing their shape.

-B-
 
you can switch the bolts out for studs. Bjowett has decided to do it for his performance rebuild. I imagine the studs could be retorqued and it could be done without removing the intake plenum or either manifold or possibly any of the coolant hoses other than the ones going to the t-body. although you do still have to pull the cams once the valve cover is off, that is still significantly less work than a full tear down.

so, you could maybe try pulling the head bolts and replacing with studs and retorquing without pulling the head as a PM move. maybe 6 or 7 hours of labour. the real issue is whether this would make a difference to the weak spots in the gasket. given dan's theory about expansion movement, I suppose it is possible but I think it is also possible that retorquing against a h/g that is breaking down could lead to uneven pressure and crack the head.
 
Even thought there is not reccommendation you may always take it upon your self to retorque. While this may help, It may not help. If you look at some of the failures at the back of the head (where the gasket and fire ring are deformed), retorqueing would not help(imo), it may actually create more movement or deformation. The best thing is to do the HG as a PM and get it over. IMO

Redline water wetter is silicates(mainly) to absorb heat, water wetter works better with less coolant and more water. I also did not know if Redlines package with mess with the organic salts in the toyota red. I look into this stuff years ago for a application and used it in warmer non winter climates. With regular coolant. Maybe they have updated it to work with organic salts, I do not know. If the stock system is all up to snuff, all will work fine. But there is a problem with the gasket at the back of #6 and the new gasket corrects this.

I hope to be around on the IH8MUD over the next few months when possiable. But I signed a contract to Drive the FJ Cruiser for the next 8+ months around the USA (mostly central region) So I may get to see a bunch of you guys when I travel around. I will get to put faces to the names. So I will not be able to do any Head gaskets(or other work) for any one until after November of this year.
Hopefully you can find some one in your area that has done this job before, or if you are mechanically inclined and patient you may be able to do this job your self with Doug's DVD (I have not seen it nor do I make anything off it). The FSM is a great aide and patientance is the key. later robbie
 
Another thought...from what I've learned about big HD diesel engines(I work in the industry). The head bolts are not to be re-used because they "stretch"

MoGas said:
Has anyone checked the torque of the head bolts prior to disassembly? I'm wondering if there sholud have been a "check head bolt torque" PM at the same time as running the valve clearances.

When I worked for the John Deere dealership, we did head bolt retorques every time we had the rocker arm cover off and IIRC it was part of a 10K hour service.

Just a stupid thought...


:cheers:
Dave
Click to expand...
 
There is a measurement that can be taken with the bolts out. Also the visual inspections. That said I have never replaced one yet. The bolts even with 200k miles still pass all the inpections. later robbie
 
powderpig said:
I hope to be around on the IH8MUD over the next few months when possiable. But I signed a contract to Drive the FJ Cruiser for the next 8+ months around the USA (mostly central region) So I may get to see a bunch of you guys when I travel around. I will get to put faces to the names. So I will not be able to do any Head gaskets(or other work) for any one until after November of this year.
Click to expand...

Geeze, nice work. Tell Toyota to give you a laptop with wireless access and a camera. Better for them anyway....
 
I used to own several Supras and these were notorious for HG failures. These were mainly caused by Toyota not specifying enough torque on the headbolts. You could go in, re-torque the head and be good to go. That being said, they were a lot easier to do than a 1FZ and I'm sure it has nothing to do with the FZ's HG failures. It was also recommended to replace the head bolts if you performed a HG job on those 7M-GT(E)'s you replace the head bolts. But if Robbie reuses them then that is what I will do when I do my HG PM. I think it is to the point where it is just good PM to do this. Catch it on your terms.
 
Robbie, you oughta start a thread where you post where you're gonna go so folks can make plans to see ya! :)
 
Wow, another one.

I agree with the comments that retorquing won't help, and someone (Semlin?) also said it could cause damage. I agree. The head is designed to be torqued down onto a uniformely flat gasket. Let certain parts of that gasket deteriorate a bit over time, then retorque the head down onto this uneven surface and you may cause stress in the head's structure, or move the camshaft journals out of alignment.

Informationally, I had faith in reusing my bolts through talking with Robbie. On the 97, I had to subsequently remove the head to fix a crack, and I even reused them AGAIN. I actually paid a machine shop to precisely measure them for me even though I have a caliper, because they do this all day, every day. All bolts were well within spec for the 3rd use (including the original factory install) - not even close. I had a full set on hand in case they did not measure up.

DougM
 
Damnit Robbie!!!:grinpimp: You go off on a trip right when we need you. ha. Anyone know about a 3fe h/g replacement? CDan? Upgraded gaskets?
 
What Jason did you mess up a 3fe HG. These too can show signs of leakage. Look under the intake/exhaust manifold where the head meets the block. Some times you can see little bubble of gass popping. If you pull the head, replace the injectors or send them out. You can mill the head in the range of .030-.040, with no real problems. It will also boost Hp and fuel ecomany. Mark Whatley had said that these head can take up to .100 milling. I know daring sole that has let mill to .060 , with a full rebuild and over boreing the block. It runs good, real good. What else do you want to know about the 3fe. later robbie
 
E9999 the marketing firm that is handling the gig, will be hosting a web site to show where we are and what we are doing. I got a e-mail from the guy that is scheduling some stuff. He, in the e-mail,said the schedule with be month to month on the web site. The web site should go up on the 27 of march. I will post some links and more info later, more than likely in the FJ section.
 
Hope you make it to Texas!
 
Robbie, be sure to tell them to spend a lot of time in California! For us to see you really, but tell them it's cuz all the college chicks will want sto buy lotsa FJs here (in white). Eh, you might even meet (and impress) some yourself! :D

and you get to go play in the dunes in Pismo!

(dang, where do I sign for a job like that? or maybe you have to wheel Moab in a 6" lift monster first? :) )
 
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