What have you done to your Land Cruiser this week? (39 Viewers)

[Grayscale]

Typically the protocol is to machine the heads mating surface when a there is a head gasket failure. At a minimum check it for flatness. I hope your repair works out for you. At this point I would cross my fingers and run it.

I agree. However, I'd have tons more confidence in the new head gasket. Look at the aftermarket one vs the new green one. There is a single piece of metal on the cylinder-crowns for the new one? The old aftermarket looks like six different rings assembled on the asbestos-looking material?

Torque in incremental steps, and sequence, for tightening or loosening. Check head bolt torque after the specified amount of use (whatever that is). Use clean head bolts, and lubricate the threads prior to installation (whatever that means).

 

[Pighead]

Found a like-new can of mint tennis balls at my favorite second-hand store. Had been looking for some period-correct tennis balls so I could re-install my 102" stainless steel whip CB antenna (which I did buy at Radio Shack a while back). Nothing says 1974 like a big CB antenna...

 

[Roastchestnuts]

Tested for exhaust gases and failed... I had been noticing the coolant reservoir would overflow occasionally starting back early September. Temp would do occasional weird things but always came down and stabilized. checked the compression back when I first started and everthing seemed pretty good/normal in the compression (I think it was 145 on #6 and #1 and #2-5 were all exactally 130psi just within spec with variance if I recall) I finally decided what the heck and ordered a 20 dollar head gasket tester off the jungle website. Part of me didn't want to admit possible head/headgasket but the signs were there.

At least the fj40 will get some much needed attention and I get to play auto-mechanic! Going to pull the head and go from there soon!

 

[Roastchestnuts]

@pb4ugo was absolutely right, nailed it! I blew the head gasket! Not sure why I thought it was the valves, maybe because I know they aren't Toyota, but they are still fine. Great info too about when you have no compression on 2 consecutive cylinders it is likely the gasket, I had not thought of that. And the way this one failed, there was no water in the oil and visa versa, it was directly between cylinders 2 and 3.

View attachment 3784117
The only problem I saw when I took this apart is likely the reason that the gasket blew. The Intake Valve Stem Seal on cylinder 2 was riding on the valve stem, up and down, no longer stuck to the head at all. This was likely letting a lot of oil into cylinder 2... so I think that would have increased the pressure and blown the gasket? Well, the valve stem seals were non-Toyota, so off they go and 12 new (expensive) Toyota valve stem seals replace them.

View attachment 3784118

CityRacer has the OEM head gasket for half the price of Toyota right now!
View attachment 3784119

And here is the shiny new goodness in place
View attachment 3784120

I quit around dark yesterday and still need to bolt back on the manifolds and accessories, but the new gasket is in and the head is on and torqued, as well as the pushrods and rocker assembly. It's not easy lifting that head straight out over the block and lowering it back into place nice and easy! But the rest will wait till next weekend, had to come back to work for a break, and so I could post on MUD Ya'll have a great day!

Going to be in the same boat as you! bought a head gasket from city racer too! crossing my fingers its as simple as an obvious head gasket failure!

 

[archie73]

You can park it over here for a few years…

I’m shopping for a financier for the next build as well…

 

[Chuckha62]

For you guys with head gasket issues... Do yourself a favor and have the head surfaced by a competent machine shop. Putting a head back on with an unknown flatness is asking for trouble. I just had to replace my 135 head (cracked) and the replacement was out by nearly .014" with a slight twist front to back.

 

[clrussell]

For you guys with head gasket issues... Do yourself a favor and have the head surfaced by a competent machine shop. Putting a head back on with an unknown flatness is asking for trouble. I just had to replace my 135 head (cracked) and the replacement was out by nearly .014" with a slight twist front to back.

This

I won’t put a head back on unless it’s been machined.

 

[charliemeyer007]

Checking with a good straight edge and a feeler's gauge set isn't all that hard. If the warpage is within spec I see no need to spend money to try and get a tractor motor to 0.0001 of flat. Any gasket I put on that has fiber I put on wet - as in soaked in warm water for half an hour. I try really hard to fire up the unit that day. Torqued in pattern by 1/3. After it has done like several heat/cool cycles I retorque at 100% in pattern. I cut a notch in the air filter bracket to allow the socket to fit better. I made custom stepped washer to compensate for flange thickness differences between header and intake manifold. Longer "studs" to accommodate the step washers and running 2 man-a-fre header gaskets. Stainless steel nuts with high temp anti seize compound. Torqued in 1/3's. After a few heat cycles retorqued at 100%.

 

[Roastchestnuts]

Checking with a good straight edge and a feeler's gauge set isn't all that hard. If the warpage is within spec I see no need to spend money to try and get a tractor motor to 0.0001 of flat. Any gasket I put on that has fiber I put on wet - as in soaked in warm water for half an hour. I try really hard to fire up the unit that day. Torqued in pattern by 1/3. After it has done like several heat/cool cycles I retorque at 100% in pattern. I cut a notch in the air filter bracket to allow the socket to fit better. I made custom stepped washer to compensate for flange thickness differences between header and intake manifold. Longer "studs" to accommodate the step washers and running 2 man-a-fre header gaskets. Stainless steel nuts with high temp anti seize compound. Torqued in 1/3's. After a few heat cycles retorqued at 100%.

I did this above. Did the strait edge test per factory manual for the 2f and it was with in spec . however I should have had a machine shop check for cracks and I 100% SHOULD HAVE gotten a OEM TOYOTA head gasket. I bought a kit for I think 150$ that had all the gaskets included I think it was ITM brand. and so far all but the timing cover gasket had to be replaced again.

Luckily I found a machined head and I bought a OEM head gasket. I am going to double check everything again and then hopefully have it running after Christmas.

Part of the fun of owning a 60 year old vehicle right?

 

[charliemeyer007]

I think the dye penetrate tests are easy/cheap enough. I have used the big magnaflux units before, though the new little hand units look way more affordable.

 

[Chuckha62]

Yeah, that's the other thing... a machine shop can look for cracks, over cut valve seats, loose guides, etc. For me, doing the head was just enough of a task that I didn't want to do it again for something that could easily have been caught by a competent machinest.

 

[mrboatman]

I’ve had a couple of cracked heads. It helps to have a bypass on the heater valve to keep flow to the back of the head.

 

[Thechief86]

If you have access to a clean piece of glass or a glass table that's thick enough to support the head, it is a nice true way to check flatness with feeler gages. If it's within 0.050 at the high spots, I have always had decent luck with the squish of the head gasket and the torque of the bolts closing the gap just fine and lasting long term.
On higher horsepower builds with high compression or something that will see forced induction, I'm a little more picky about true flatness, and try to use multi-layer stainless steel head gaskets where applicable.
But on a lazy, low compression tractor motor like a 2F or similar, it's just not been that crucial in my experience. But I ALWAYS check.
Except on mild builds of air cooled VW engines, lol. It's not like those are gonna leak coolant
Edit: 0.050 is more than a full millimeter, which is about 0.040. It seems like a lot when measured on the glass, but a nice thick gasket will take up most of it.

 

[Pighead]

I 100% SHOULD HAVE gotten a OEM TOYOTA head gasket. I bought a kit for I think 150$ that had all the gaskets included I think it was ITM brand. and so far all but the timing cover gasket had to be replaced again.

The superiority of the official Toyota head gasket is obvious when compared to another brand

 

[Grayscale]

 

[Grayscale]

I don't know from experience, but, I'd say that the exhaust valve seat is going to be the first thing to distort from thermal exposure, at least as far as the original engine head casting.

 

[flee]

I don't know from experience, but, I'd say that the exhaust valve seat is going to be the first thing to distort from thermal exposure, at least as far as the original engine head casting.

I have experienced an overheat warped FJ40 cylinder head in my distant past while in my 20's. (I even managed to lift it off without any help.)
I remember that the machine shop guy said the iron in that casting was particularly dense and tough! It went back on and was as good as new.

 

[hanzo111]

Definitely need to machine the surface at the very least. Excellent advise. I had my 250 head fully rebuilt by my local (reputable) race shop, cost me $1,100 but it’s a piece of art. Def worth the price considering the work involved in removal of the head.

 

[RevISK]

Definitely need to machine the surface at the very least. Excellent advise. I had my 250 head fully rebuilt by my local (reputable) race shop, cost me $1,100 but it’s a piece of art. Def worth the price considering the work involved in removal of the head. View attachment 3786356View attachment 3786357

Was rebuilding the head a choice? Seems young to have to.

 

[Grayscale]

But, what shop is going to just deck a head? Do they stand by their work if there are further issues? The head also needs to be cleaned, as the milling process can introduce metal chips into the water jacket. It needs magnifluxing, if the cast iron has yielded anywhere to pressure and thermal exposure. If the head is no longer flat, maybe the block is also no longer flat. Maybe the block and head conformed to each other, that is why they are warped, and bringing the head back to a plane will actually create a mismatch that wasn't there before it was decked? If the head needs resurfacing, maybe the valve seats are no longer round, due to warping. If the valves leak, how can a compression test be used to check the fresh seal on the headgasket? How will the piston rings be properly lubricated, when the cylinder hone is all gone in places; I see obvious deficits in the cylinder walls of that 250 straight-6? The engine builder fixes leaks, both obvious and sub-clincal. I watch the Dave's Auto Center on YouTube, and he always says that customers just want him to replace a piston, or whatever, but every time it is a full rebuild.

@hanzo111 I would love to see more of that 250. I'm intrigued by the tech, and I once had a 250 in a '79 Nova.