1HZ head bolts (1 Viewer)

[Mickldo]

I have just replaced the cylinder head on my HZJ80. Just finished torquing the new head bolts down and started looking for the manifold studs. As I was searching through the bucket with all the nuts and bolts in it I discovered a couple of the old head bolts with washers on them. I didn't remove the head and because I had brand new head bolts I didn't even look at the bolt bucket till after the head was already on. So I don't have any washers under the heads of the head bolts. Did I mention



When I torqued the bolts down and used the angle gauge to tension them properly I am positive they didn't bottom out in the bottom of the holes. I lubed the threads and under the bolt heads before installing.

Is it absolutely vital to have the washers there? If it is will I need to replace the gasket and/or the bolts again?

The motor hasn't been finished off yet so it hasn't been started or gone through any hot/cold cycles.

If I just remove the bolts to put washers under the heads and don't move the cylinder head hopefully the head gasket will be OK............

Anybody know??????

 

[matt 105]

Thats a tough one Mick....
If the washers are not neccissary to stop the bolts bottoming out, and seeing as they are angle torqued, and no bigger than the head of the bolt, then friction is not so much of an issue, I think you have 2 options.
On the one hand, you could change the bolts out 1 at a time, fully torquing them down, preferably in the pattern you installed them in, seeing as the gasket is already crushed down - but my worry is the stretch in the bolts.- However I have reused those bolts on a number of engines.
But on the other hand, if you are confident they didnt bottom out - and I think you are right there,... if it was mine, I would just leave it be and in 6 months time, tell people that the washers are not neccisary.
Tough call, bolts I have reused but shouldnt VS washers that may not be neccisary.
Have a few Rum cans then think about it again
Hope this has helped

Matt

 

[Mickldo]

Thanks Matt

I plan on selling the 80 once the head is back on so its not as if I will be able to check up on it easily in a few months.

I like your idea of doing them one at a time. The only thing I was worried about was the head bolts stretching. So do you reckon they might be OK?

 

[Ron R]

Head bolts stretch is no issue. They may be re-used when within limits.

The Toyota Engine maintenance/repair manual states:
"Check diameter of bolts at the position they are constricted (Don't know or this is the right expression but a certain part of the bolt can/will be 'thinner' than the overall thicknes -compare to a persons waist)
Standart diameter is 10.800 - 11.000 mm
Minimum diameter required 10.55 mm. If smaller- replace."

I think I would leave them in there. Getting them out one by one is an option, and like Matt suggests, I would do it in the order they have to be fitted. Though they should be taken out in the opposite order when dismanteling.
I think there is some risk of damaging the head doing it one by one, but if you want to take them all out in one go, you'll have to replace the gasket.

 

[Mickldo]

Thanks Ron

I might measure one of my old bolts to see how much it stretched over 370,000kms. If it is still within specs I should be OK with the new ones.

 

[matt 105]

I think there is some risk of damaging the head doing it one by one, .

Explain this please.

 

[matt 105]

, you'll have to replace the gasket.

Havnt you ever re-used a head gasket before?

 

[Ron R]

Explain this please.

Because all the bolts are fully tightened loosing just one bolt could put unacceptable stresses on the head. It *is* alu.

Because the procedure of (un-)tightening is described to minute detail in the repairmanual I assume there is some risk if you do it NOT according the manual.
I've never tried it and I never will, because I'd rather buy a new set of bolts (not always necessary. It depends on the condition - see my previous posting) and a new gasket instead of risking to damage the head.

 

[Ron R]

Havnt you ever re-used a head gasket before?

Nope and I never will once it was fully tightened. Getting the head of again if untight in my opinion is not worth the savings.
And don't forget, when you tighten the bolts for the second time (re-using the gasket) would put quite a differend strain on the head because the structure of the gasket changed as a result of the first application.

Of course all this under 'normal' conditions. If you're out it the field, having no spares at hand and it's a matter of getting out - it's a different story.

 

[Big Blue 84BJ60]

if youve got a toyota quality head gasket i caint see it getting crushed warped or hardening (no supper hot to quenching/cooling) and at least the 3b head gasket are all metal steel to be exact all u might have to doo replace is a rubber o ring and clean up the head gasket

 

[Ron R]

Well, if you're confident, who am I to say you are not allowed?

Maybe it's fine for the 3b engine, but the OP was talking about a different kind of engine, I think

I wouldn't do it, having experience with similar kind of gaskets, however not Toyota ones.

 

[lynchmob]

Because all the bolts are fully tightened loosing just one bolt could put unacceptable stresses on the head. It *is* alu.

If by this you mean aluminum.... that is some heavy aluminum.

 

[Ron R]

If by this you mean aluminum.... that is some heavy aluminum.

No I mean aluminIum....

And no, by specific weight it is not heavy..

But you're right, it is a heavy part.

However, dispite being it a heavy part, it still can be damaged.

I myself would not risk damaging the head to save some money on a gasket (I know headgaskets are expensive).
That is simply the way I do my wrenching. In some cases this will be overkill but it makes me feel good when I'm on the safe side.

All I want to express in these postings is that if one thinks he can do it differently from what the repair manual says, be my guest.
Who am I to say you have to do it my way?
I just want to advise to my best knowledge and the way I think about how to act.
I tend to do it accordingly as I want to minimize the risk of a brakedown while I'm in a remote area (and I've been in some) as much as I can. Untill now this has paid off I like to think, never having encountered serious problems during these trips.

 

[lynchmob]

No I mean aluminIum....

And no, by specific weight it is not heavy..

But you're right, it is a heavy part.

However, dispite being it a heavy part, it still can be damaged.

Ron my point was that the head on the 1HZ is CAST IRON and not aluminum....

If you have one that is aluminum post up some pics as I think others would like to see it.

 

[Ron R]

Ron my point was that the head on the 1HZ is CAST IRON and not aluminum....

If you have one that is aluminum post up some pics as I think others would like to see it.

You'll have to wait a bit to get pics of an alu head

Dunno how I could make that mistake.

Never had the head of my own engine, but I doubt the other one was of alu either.;p
And I should have known better doing all the maintenance myself including adjusting valves.