Last week I finally adjusted my valves, which was long overdue. As it turned out, all but the #2 and #4 intake valve rockers (which were several thousandths loose) were spot on after about 15 years of use. I didn't take into account needing a new valve cover gasket and bolt grommets (durrrr) until I had it off so I had to order a set from the local Toyota dealer.
Since I was stuck waiting for the new gasket and grommets, I pulled the throttle body and ICS to give them a good cleaning. The idle screw and other hardware I ran through my ultrasonic cleaner, installed a new O ring on the idle screw and a dab of thread locker on the threads to further prevent movement once the idle was set. Before removing it I turned it all the way in to see how far out I was starting with. It was just a hair over two full turns out. The idle passageways and screw also had never been cleaned in the life of the truck and were pretty caked up so I went to town on them and got everything absolutely pristine. I calibrated the TPS when I put it back together and got that dialed in properly. From looking at the markings the screw heads left on it when I removed it compared to how it sat after calibration, it looks like it was a good amount out of whack before removal. The ICS and its passageways in the intake manifold were also pretty coated with carbon so they got a good thorough cleaning as well. There's no calibration on that aside from checking the condition of the solenoid, which mine is still good. New gaskets and both were reinstalled and the dash pot adjusted (which I still need to finish dialing in. The FSM procedure actually resulted in my engine racing slightly when I would push the clutch in to upshift).
Protip: To easily remove remnants of fiber/paper gaskets, saturate them with contact cleaner. It breaks down the adhesive compounds in them beautifully and makes them a piece of cake to remove. It also evaporates quickly if it gets somewhere it shouldn't be, plus is plastic safe.
I also went ahead and gave the valve cover a good cleaning, soaking and scrubbing it with hot water and what amounted to a couple gallons of Castrol Super Clean when I was finished. I filled with fresh hot water and cleaner four times (just high enough to submerge the cover so it wouldn't dilute the degreaser too much) and each time the solution poured out just black from all the oil and sludge that got cleaned away. This cover had never gotten cleaned in the entire life of the truck, so even the first hundred thousand miles of dyno oil sludge and buildup that had gotten caked on was still there. After a hot water rinse and drying in my oven at low temperature to get the internal baffles good and dry (don't judge me) I sprayed a ton of carb cleaner through all the holes and openings in the baffles to get them as clean as I possibly could. Still was a little hard baked on varnish in the cover, but came impressively clean.
So here's where it gets interesting. I got it all back together. New gaskets and all in place; oil was changed while it was apart. Idle screw on the TB installed to exactly two turns out. Fired it up, and it idled at just under 2K RPM! I dialed the screw in until I got it down to 900 RPM (moved it in just over a full turn, so now it sits just under a full turn out). Once warm it idled down to about 700 RPM. Right where I want it. Idle is not much more stable (wasn't having any issues before that led me to think anything was out of whack beyond just the "it's just an old engine" train of thought), and performance is FAR improved. I get up to speed much faster when merging onto the freeway, and I can now make it up long grades much farther before having to shift back into 4th gear. I'm honestly blown away because aside from the ICS and the idle screw and passageways, nothing really seemed that dirty, and I wouldn't have expected the two loose intake valve rockers to be robbing me of that much power. I guess I was wrong. Sure wish I had dyno numbers for before and after, because it REALLY woke up, obviously so.
What else is interesting is that last spring after a 300 mile drive across the state, my PCV catch can was FULL (I had emptied it before the drive so that was over 3 ounces of oil that was getting pulled into the PCV system during that drive). I changed the PCV valve and grommet before driving back home, and on the drive home got about half that amount in the PCV can. It stayed pretty consistent with oil amount versus miles driven since then for a handful of 400-mile trips. Fast forward to my valve adjustment, cleaning of the valve cover, new gaskets, and cleaning/calibration of the throttle body and ICS, and this last weekend, a just over 400-mile trip gave me what looks to be not even a quarter teaspoon of oil in my catch can. I had been suspecting excessive blowby when it was filling faster but haven't gotten around to a leakdown test yet, but now this is even less PCV oil than I would expect out of a fresh new engine!
Yes that's a modified Husky moisture trap. Something else very interesting, is once I gas up to come home it's about 190 miles back home on these trips. Typically my fuel gauge reads a bit under a quarter tank by the time I'm home. This time it's reading just under a half tank. I haven't filled up again yet to see what exact economy I got, but that's sure got me curious. I'll post it once I fill up the tank.
Since I was stuck waiting for the new gasket and grommets, I pulled the throttle body and ICS to give them a good cleaning. The idle screw and other hardware I ran through my ultrasonic cleaner, installed a new O ring on the idle screw and a dab of thread locker on the threads to further prevent movement once the idle was set. Before removing it I turned it all the way in to see how far out I was starting with. It was just a hair over two full turns out. The idle passageways and screw also had never been cleaned in the life of the truck and were pretty caked up so I went to town on them and got everything absolutely pristine. I calibrated the TPS when I put it back together and got that dialed in properly. From looking at the markings the screw heads left on it when I removed it compared to how it sat after calibration, it looks like it was a good amount out of whack before removal. The ICS and its passageways in the intake manifold were also pretty coated with carbon so they got a good thorough cleaning as well. There's no calibration on that aside from checking the condition of the solenoid, which mine is still good. New gaskets and both were reinstalled and the dash pot adjusted (which I still need to finish dialing in. The FSM procedure actually resulted in my engine racing slightly when I would push the clutch in to upshift).
Protip: To easily remove remnants of fiber/paper gaskets, saturate them with contact cleaner. It breaks down the adhesive compounds in them beautifully and makes them a piece of cake to remove. It also evaporates quickly if it gets somewhere it shouldn't be, plus is plastic safe.
I also went ahead and gave the valve cover a good cleaning, soaking and scrubbing it with hot water and what amounted to a couple gallons of Castrol Super Clean when I was finished. I filled with fresh hot water and cleaner four times (just high enough to submerge the cover so it wouldn't dilute the degreaser too much) and each time the solution poured out just black from all the oil and sludge that got cleaned away. This cover had never gotten cleaned in the entire life of the truck, so even the first hundred thousand miles of dyno oil sludge and buildup that had gotten caked on was still there. After a hot water rinse and drying in my oven at low temperature to get the internal baffles good and dry (don't judge me) I sprayed a ton of carb cleaner through all the holes and openings in the baffles to get them as clean as I possibly could. Still was a little hard baked on varnish in the cover, but came impressively clean.
So here's where it gets interesting. I got it all back together. New gaskets and all in place; oil was changed while it was apart. Idle screw on the TB installed to exactly two turns out. Fired it up, and it idled at just under 2K RPM! I dialed the screw in until I got it down to 900 RPM (moved it in just over a full turn, so now it sits just under a full turn out). Once warm it idled down to about 700 RPM. Right where I want it. Idle is not much more stable (wasn't having any issues before that led me to think anything was out of whack beyond just the "it's just an old engine" train of thought), and performance is FAR improved. I get up to speed much faster when merging onto the freeway, and I can now make it up long grades much farther before having to shift back into 4th gear. I'm honestly blown away because aside from the ICS and the idle screw and passageways, nothing really seemed that dirty, and I wouldn't have expected the two loose intake valve rockers to be robbing me of that much power. I guess I was wrong. Sure wish I had dyno numbers for before and after, because it REALLY woke up, obviously so.
What else is interesting is that last spring after a 300 mile drive across the state, my PCV catch can was FULL (I had emptied it before the drive so that was over 3 ounces of oil that was getting pulled into the PCV system during that drive). I changed the PCV valve and grommet before driving back home, and on the drive home got about half that amount in the PCV can. It stayed pretty consistent with oil amount versus miles driven since then for a handful of 400-mile trips. Fast forward to my valve adjustment, cleaning of the valve cover, new gaskets, and cleaning/calibration of the throttle body and ICS, and this last weekend, a just over 400-mile trip gave me what looks to be not even a quarter teaspoon of oil in my catch can. I had been suspecting excessive blowby when it was filling faster but haven't gotten around to a leakdown test yet, but now this is even less PCV oil than I would expect out of a fresh new engine!
Yes that's a modified Husky moisture trap. Something else very interesting, is once I gas up to come home it's about 190 miles back home on these trips. Typically my fuel gauge reads a bit under a quarter tank by the time I'm home. This time it's reading just under a half tank. I haven't filled up again yet to see what exact economy I got, but that's sure got me curious. I'll post it once I fill up the tank.
