I bought this thing in early March of this year and have made progress on virtually every front, but I still am not comfortable just getting in and driving it more than a couple miles at a time. It just seems lacking power in every respect.
I think I may have finally stumbled upon what’s going on with her.
I know this is a low horsepower engine (advertised at 135, but actually more like 120 hp), and the truck is heavy at 4000 lbs, but it has always felt particularly sluggish. That became super obvious when I drove my son's again last week. His truck is lighter and has 10 more horsepower, but the difference was night and day. My truck will hardly pull the small hill up to my nearby shop. It also backfires occasionally when I try to accelerate quickly pulling into traffic.
I decided to mess around with the timing and carb to see if I could get it sorted out. When I set the timing at the bubble (7 btdc), it would idle and sort of accelerate with no load on it, but put a load on it and it wouldn’t hardly pull itself. To get it to run decent at all, I need the initial timing set at 16-18 degrees. I made sure the advance mechanisms are working and was able to set the points out on my bench to make sure they are dead nuts on. It's driveable, but just doesn't feel free. Also, I can’t detect vacuum at the advance pot.
I broke out my vacuum gauge (and had to fix it, because it has been sitting so long) but at idle, the engine only pulled 2” hg (-1 psi). I have verified that I do NOT have any vacuum leaks, I’ve made sure of that. I have tried two different carburetors and the problem persists. I pulled the intake/exhaust off, and made sure they are flat and co-planar.
Having eliminated everything else, I'm left to conclude the only thing it can be is that the cam is retarded. Turns out that these early f135 engines (at least up to '65) came from the factory with a “silent” fiber cam gear. While I don't know for sure about the '66, I believe mine has been replaced and whoever did it didn’t align the cam and crank correctly. That would go a long way to explaining why I found ALL the front cover bolts loose when I went to change the water pump back in May.
I guess it's time to yank the radiator, pull the balancer and front cover and see what I have.
Cheap fix, but gonna take a few hours.
Any other ideas, gents?
I think I may have finally stumbled upon what’s going on with her.
I know this is a low horsepower engine (advertised at 135, but actually more like 120 hp), and the truck is heavy at 4000 lbs, but it has always felt particularly sluggish. That became super obvious when I drove my son's again last week. His truck is lighter and has 10 more horsepower, but the difference was night and day. My truck will hardly pull the small hill up to my nearby shop. It also backfires occasionally when I try to accelerate quickly pulling into traffic.
I decided to mess around with the timing and carb to see if I could get it sorted out. When I set the timing at the bubble (7 btdc), it would idle and sort of accelerate with no load on it, but put a load on it and it wouldn’t hardly pull itself. To get it to run decent at all, I need the initial timing set at 16-18 degrees. I made sure the advance mechanisms are working and was able to set the points out on my bench to make sure they are dead nuts on. It's driveable, but just doesn't feel free. Also, I can’t detect vacuum at the advance pot.
I broke out my vacuum gauge (and had to fix it, because it has been sitting so long) but at idle, the engine only pulled 2” hg (-1 psi). I have verified that I do NOT have any vacuum leaks, I’ve made sure of that. I have tried two different carburetors and the problem persists. I pulled the intake/exhaust off, and made sure they are flat and co-planar.
Having eliminated everything else, I'm left to conclude the only thing it can be is that the cam is retarded. Turns out that these early f135 engines (at least up to '65) came from the factory with a “silent” fiber cam gear. While I don't know for sure about the '66, I believe mine has been replaced and whoever did it didn’t align the cam and crank correctly. That would go a long way to explaining why I found ALL the front cover bolts loose when I went to change the water pump back in May.
I guess it's time to yank the radiator, pull the balancer and front cover and see what I have.
Cheap fix, but gonna take a few hours.
Any other ideas, gents?
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