Blown Head Gasket

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Ok after letting the truck warm up its running pretty good. A little bit of a slow idle, but I think I can get that dialed in.

After warming up, however there is smoke coming from the exhaust manifold behind the little coiled up spring thingy. Totally lost on what to do with that.
 
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70 FJ40 said:
Ok after letting the truck warm up its running pretty good. A little bit of a slow idle, but I think I can get that dialed in.

After warming up, however there is smoke coming from the exhaust manifold behind the little coiled up spring thingy. Totally lost on what to do with that.
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Congrats on being up and running. Regarding the carb - I would at least use the lean drop method to get it dialed in on the new setup. I’m assuming you have the FSM since you’ve gotten this far - the lean drop steps are in there. Not too difficult. You’ll be adjusting the idle mix and idle speed screws to find the carb’s happy place. Think of it as baselining the carb. This would be a good time to bust out your vacuum gauge to see where you’re at and where you end up after the lean drop.

A pic of the manifold issue would be helpful. Are you sure it’s not anti-seize or some other reassembly chemical burning off? When I got mine running after a head swap it was like Three Mile Island for a while with all the Never-seize burning off.
 
I think you're right @DFXR. It burned off pretty quick. No more smoking. Took it for a couple drives yesterday after I re-torqued the head bolts and the manifold bolts and adjusted the valves after it warmed up. Carburetor is still off a little. I just had it dialed in using the lean drop method before I tore it all down for the blown head gasket. I figured it would still be dialed, but it makes sense that I'd have to tune it again, I suppose. I'll get to that tonight after work, hopefully.
 
70 FJ40 said:
Ok after letting the truck warm up its running pretty good. A little bit of a slow idle, but I think I can get that dialed in.

After warming up, however there is smoke coming from the exhaust manifold behind the little coiled up spring thingy. Totally lost on what to do with that.
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As mentioned it could be some goop burning off. That spring thing is what controls the heat riser flap, and it's connected to a shaft that goes inside the exhaust manifold. When the truck is cold started it diverts hot exhaust gasses towards the bottom of the intake manifold to warm up the incoming charge so the fuel atomizes better while it's warming up. Once the engine is hot, the spring flips the heat riser flap closed so the exhaust gasses are going straight out the downtube and not next to the intake manifold. It's hard to catch it, but if you watch for the moment the springs starts closing the flap, it's pretty cool. The spring is "bi-metallic", made out of of two laminated, dissimilar metals that absorb heat differently, so when it warms up they kind of pull on each other and wind the spring up. There's a simple bushing there and it's prone to an exhaust leak. We all live with it.
 
I'm still having trouble getting the carb tuned. I can't get it to idle at less than about 900 RPM without the it dying. I've checked for vacuum leaks with a fog machine and I don't see anywhere that is leaking in the system. I'm admittedly a novice mechanic so it could be something simple or elementary but any suggestions would be appreciated. :D
 
70 FJ40 said:
I'm still having trouble getting the carb tuned. I can't get it to idle at less than about 900 RPM without the it dying. I've checked for vacuum leaks with a fog machine and I don't see anywhere that is leaking in the system. I'm admittedly a novice mechanic so it could be something simple or elementary but any suggestions would be appreciated. :D
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This does sound like a vac leak, but smoke machines or spraying starter fluid have never been a silver bullet solution for finding leaks for me. Are the nuts that hold the carb down tightened well enough? How about the two nuts on the PVC/EGR inlet flange on the side of the intake manifold that faces the driver's side? I assume you checked EVERY vacuum hose including the larger PCV and brake booster ones?

Did you follow the carb tuning procedure in the manual? That involves some back and forth between the fuel mixture screw (towards the valve cover) and the idle adjustment screw (towards the firewall) If somehow the balance is off and you've turned the idle adjustment screw too far in to compensate for the mixture screw being too far out you might not be able to get the idle down. Or vice versa. The idle screw introduces a small air leak and puts the throttle blade past into the transition slot (meaning more fuel & air than you would need for idle). If you think this might have to do with it, reset the screws - fuel mixture screw all the way in until it LIGHTLY bottoms out, then about two turns outwards, idle speed screw so that's it's just barely NOT contacting the metal piece the end of the screw hits - and follow the manual for the "lean drop" carb tuning method.

For what it's worth, there are two of these in your engine bay and if they haven't been replaced with the blue/black 80 Series pieces, they are guaranteed leaking vacuum. Photo from City Racer's website.

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Beyond that ... it could be any number of the vacuum widgets in the engine bay. Worst case scenario your intake manifold is cracked directly below where the carb sits, on the "floor" of the manifold.
 
70 FJ40 said:
I'm still having trouble getting the carb tuned. I can't get it to idle at less than about 900 RPM without the it dying.
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Where is your ignition timing? Sometimes I might advance mine a bit (which should increase your idle speed) so that I can turn down the idle speed screw on the carb
 
Thanks guys for the input.

It is possible there is a vacuum leak that I cannot find. The intake and exhaust manifold were resurfaced prior to me installing them. It was years ago and all the parts I got are from an abandoned project, but I assumed that the manifold was checked for cracks when it was resurfaced. All those valves like the one in your picture have been removed from my Cruiser by the PO when he did the smog delete. I am pretty familiar with the lean drop method of tuning the carb. That's how I was able to get it running nicely before the head gasket blew. I have used the OTRAMM video on YouTube as a guide. The nuts on the base of the carb are tightened down quite well.

@Pighead I was wondering about timing and dwell. I don't understand what dwell is or what how to adjust it. Timing should be in the same place it was before I tore it all down because I did not take the distributor out. Do I need to start over with the timing anyway? Again, I'm sorry if these are dumb questions. I'm definitely not a natural mechanic. Nor do I have much experience or prior knowledge on a lot of this stuff.
 
Have you put a vacuum gauge on it to see what/how it's reading?

And you're sure the ICS is functioning properly?

A few pictures might help, here.

If you have the stock electronic Dissy, Dwell is not adjustable. (it's normally the degree of rotation, or amount of angle, the points are open). With the electronic, it's a signal, through the pickup coil in the dissy, that triggers the igniter to tell the coil when to fire. (very crudely described, here).
 
70 FJ40 said:
Do I need to start over with the timing anyway?
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No, don't start over, just check and adjust and tune. Your engine is different now, you're going to need to adjust a few things and do it a few times to find what your engine likes best. This will make you a better mechanic and your rig a better ride. I always involve my dizzy in my tuning procedure. I try to get the best manifold vacuum at a good idle. Some people think that a 2F likes a bit more advance than the FSM calls for, I tend to agree.
A vacuum gauge to measure manifold vacuum is very handy, so much so that I've put one in my dash. You can time your engine with just a vacuum gauge and maybe a tach.
Forget about dwell, does not apply. More pics always help
 
Thanks guys. I'll do some more checking on things and post a few pictures of my engine compartment.
What is the ICS?
I do have a vacuum gauge but I need to find a better way to hook it up while tuning. Its been pretty crude and ive not been able to know for sure if vacuum is leaking through how I have it hooked. How/where do you guys hook up vacuum gauge?
 
Have you sucked on the vacuum lines going to distributor and see if they hold? The diaphragms can leak. You can that that out of the equation by capping it off at the carb or manifold.

If properly desmogged, you should really only need the line going to brake booster, pcv and vacuum advance on distributor. (Maybe vacuum to ac idle up if you have that).
 
Here are a few pictures of my engine.

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I was able to get a barbed fitting to thread into the manifold so o could get a better reading on the vacuum. This is what it reads at about 950 RPM. It does fluctuate a quite a bit. And it seams to stumble and drop to below 40 every few seconds. I took a video with a tach hooked up. If I can figure out how to post it, I will.

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Here is a video. This is after the rig got completely warmed up and no choke pulled.

 
70 FJ40 said:
And it seams to stumble and drop to below 40 every few seconds.
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You need to look at the inner scale, where it's hovering around 16. Them's not great numbers. You want 20 or so, what's your altitude?
 
You may want to get the engine to operating temp and do the valve adjust again.

Jim C posted a really good procedure for it, years ago. I'll see if I can find it.
 
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