2f engine, pistons and head.

[tltaylor22]

I'm having a new issue with fuel. The engine has brand new fuel pump with the spacer as it's an 87 2f. I've always run a glass filter up near the carb. Right now I've got a disposable clear filter prior to the pump and the glass filter. The stainless headers on this engine produce a ton of heat. I'm running the 76 fan and fan clutch as the 87 one hits my power steering pump. Brand new radiator and I've run a coolant flush through the system. I'm running a Chinese knock off Aisin carb with no fuel return line. I have not replaced the thermostat. I also noticed that 30+ yrs ago the plastic part of the fan was modified to fit the fan shroud. Each fin was shortened. The symptom is that at 50mph or higher or running at high rpm's,, fuel doesn't seem to get the the carb. The engine will sputter and die. If i get off the throttle soon enough and let it idles, the fuel bowl seems to fill back up. The fuel in the glass filter almost looks like it's boiling, maybe causing vapor lock? I made an aluminum heat shield Friday that covers the front three exhaust pipes. The issue was still there if i went over 50-55 on an hour drive that night. The odd thing is that this didn't happen in the first couple weeks after the motor install, even on hot days. Any thoughts?

 

[Pighead]

The fuel in the glass filter almost looks like it's boiling,

View attachment 3688278

View attachment 3688279

View attachment 3688282

...Or sucking air. I might go back to the fuel tank, rod out the outlet tube with a coathanger or something and make sure fuel flows out freely. then make sure every hose clamp is tight at every junction. Also, do you still get the fuel starvation symptoms if you run with the fuel cap off? Did the old carb have a fuel return line?

 

[Grayscale]

It is easy to look at the spark plugs for a vacuum leak.

I thought that the formula was a Remflex? gasket and glue on the manifold plus Mark's / Downey header?

 

[Pighead]

I thought that the formula was a Remflex? gasket and glue on the manifold plus Mark's / Downey header?

Sometimes, the answer is as easy as re-torquing the manifold nuts/bolts and snugging down the carb.
Any header is going to need a lot of work matching it to the intake manifold to prevent leaks.

 

[Grayscale]

Sometimes, the answer is as easy as re-torquing the manifold nuts/bolts and snugging down the carb.
Any header is going to need a lot of work matching it to the intake manifold to prevent leaks.

My aussie-bay header needed no work. I took it off, checked ports and valve stems, and reassembled, no sweat. It is really close to the manifolds, with a micrometer. The problems with it was the horizontal part of the flange had issues with the 2F heat-riser and heat shield, that and it has poor clearance, routing the exhaust below the skid plate. The header sports a grinder-fix on the head-flange, and an exhaust dent from some wheeling on a utility-road in the forest. I used a SOR gasket. Yes, check the torque, after running it for awhile, post-assembly.

 

[tltaylor22]

On a brighter note, my brother in law and I taught 4 of our kids how to drive a manual transmission, including starting on small hills. They can all say the first standard transmission vehicle they ever drove was a 1976 FJ40 with a 70 yr old transmission. Awesome!

...Or sucking air. I might go back to the fuel tank, rod out the outlet tube with a coathanger or something and make sure fuel flows out freely. then make sure every hose clamp is tight at every junction. Also, do you still get the fuel starvation symptoms if you run with the fuel cap off? Did the old carb have a fuel return line?

The old carb was a stock Aisin with a return line that Jim C rebuilt 25 yrs ago. I didn't clean it out when I removed it and it was encrusted too heavily to get running very quickly. It's on my list of things to do.

 

[tltaylor22]

It is easy to look at the spark plugs for a vacuum leak.

I thought that the formula was a Remflex? gasket and glue on the manifold plus Mark's / Downey header?

I pulled the plugs and they were all pretty white. I should have taken pictures. It means it is running a little hot and lean, right?

 

[Grayscale]

I pulled the plugs and they were all pretty white. I should have taken pictures. It means it is running a little hot and lean, right?

Probably. It makes sense at the rpm / speed that you describe. I have a vacuum gauge that I attached somewhere on the manifold, it will tell you about a baseline factory spec at idle, not much help above that.

With more throttle, the less gasoline will be delivered thru the 'circuits' of the carb, if there is a leak somewhere. You can also have low-vacuum by the valves being carbon-caked, or the valve-lash being set so that the rocker arms are not pushing the intake valves down far enough.

Some people check for a vacuum leak at the intake manifold with carburetor cleaner, if the idle goes up, you have an intake leak. However, if you happen to have an exhaust leak, you are likely playing with fire.

 

[tltaylor22]

Probably. It makes sense at the rpm / speed that you describe. I have a vacuum gauge that I attached somewhere on the manifold, it will tell you about a baseline factory spec at idle, not much help above that.

With more throttle, the less gasoline will be delivered thru the 'circuits' of the carb, if there is a leak somewhere. You can also have low-vacuum by the valves being carbon-caked, or the valve-lash being set so that the rocker arms are not pushing the intake valves down far enough.

Some people check for a vacuum leak at the intake manifold with carburetor cleaner, if the idle goes up, you have an intake leak. However, if you happen to have an exhaust leak, you are likely playing with fire.

Sounds like I've got some playing around to do this week. I'll get my vacuum gage hooked up. It's plugged on the manifold right now.

 

[Grayscale]

Valve lash that is set with too much gap will often make a light 'clacking' sound at idle.

I could literally see the intake leak on a 2F manifold gasket when I acquired it. When disassembled, every one of the exhaust ports was sealed and clean. The intake ports had engine crud on the gasket. Mouse pee, or water may have entered there, as the intake ports were heavily corroded. The flanges on Toyota F ('71) and 2F for '75 were spot-on 10 mm or .393-inch; the downey/mark's header was 13/32 plate at .406-inch, iirc. In theory, a bead of gasket sealant that is about as thick as 10-lbs monofilament fishing line should be all that is needed to seal things up properly, if you have an intake leak. If the intake manifold ever was assembled with just nuts, or split-lock washers, or galling took place, it might need more attention to get it to seal properly.

Nice photos of your truck in the mountains.

 

[tltaylor22]

My 76 2f had a port on the intake right above the brake booster hose to hook my vac gauge to. This 87 motor uses that port to go to the pcv valve on the pass side of the motor. Is that right? Where else would you attach the vac Guage.? I put a tee on the vac advance port of the carb but I was only pulling 5 in.hg at idle and 15 or so rev'd up.

 

[Grayscale]

Attach to the intake manifold, for manifold vacuum. The carb is throttle-dependent, so that can't be right; 5-or-so-inches of vac is too low. My '75 has a three barbs on an pipe-fitting inlet in front of the carb. That is an emissions-control spot. The '76 should have two barbs there. My Bosch vac gauge came with a tapered plug, iirc so it could fit into a pipe-thread hole on the manifold, or use small diameter hose directly on a barb. Disconnecting the brake booster at the manifold inlet is probably a good diagnosis option.

My Harbor Freight multimeter can do dwell, and tachometer readings. I had about 13 or 14-inch of Hg (at about 600-ish rpm); that is below spec. I did it at 6,800' above sea level, so it should be better than that. Compression was just above factory spec. Highway throttle was accecptable, shortly after initial engine install. Back then. the valves were visually-congested with carbon; now who knows?

 

[tltaylor22]

My previous 2f had a single barb to the right of the carb. This motor had been converted to throttle body but I removed it until this winter when I'll play with that. I have another intake that has the 3 port but I can't seem to get air to blow by it. Clogged or something. Does the PCV valve normally go to the intake?

 

[Pighead]

My PCV dumps into the carb base insulator

 

[tltaylor22]

My PCV dumps into the carb base insulator

View attachment 3692543

View attachment 3692546

I can probably reroute it that way.

 

[Grayscale]

I think that by appearance, Pighead's intake manifold and carburetor is for F engines; oil filter mounts is on driver's side, and a clamp-on the circumference of airhorn-type air cleaner assembly.

tltaylor22's emissions equipment hose looks to be from a later year, as they were probably metal in '76 and two-barb. The '75 Federal carbs had an auxiliary accelerator pump that would add fuel when manifold vacuum got low, and the emissions barb is metal.

On my 2f manifold, the spot where tltaylor22's brass fitting and nail is the vac source for the PCV valve, under it on the vertical surface of the manifold is the brake booster hose barb.

I'd hook up the vac gauge to the front of the carb, where the clogged-up emissions hose connects.

However, you might have a PVC barb on the carburetor insulator? I thought that 2F insulators also included the aluminum plate that covers most the area over the intake manifold from exhaust heat, which your photos don't show.

 

[tltaylor22]

I've cleaned my 3 barb vacuum fitting and installed it where my pcv hose was plumbed. I pulled the cap off the metal tube coming off the carb spacer. Unfortunately the tube was loose so I removed it and rtv"d it back in. I'll hook up the pvc hose tomorrow and see what's next.

 

[tltaylor22]

Barb and spacer

 

[fjc-man]

I've cleaned my 3 barb vacuum fitting and installed it where my pcv hose was plumbed. I pulled the cap off the metal tube coming off the carb spacer. Unfortunately the tube was loose so I removed it and rtv"d it back in. I'll hook up the pvc hose tomorrow and see what's next.

The linkage alignment is off. That short link shouldn’t be on a diagonal and your relocated vacuum fitting is in the way of the second return spring.

 

[tltaylor22]

Good catch. The short kink is actually disconnected and shifted out of the way to screw in the 3 port fitting. I'll fix that. The main linkage is angled for some reason. I'll look at that. Thanks for the keen eye.