I seem to have a lack of power? (1 Viewer)

[70 FJ40]

Here are a few better pictures of my accelerator linkage. Still not great but better. I would really like to get this figured out so
i can try to adjust it for the secondary and move on to the next thing that could be the culprit in this problem.

I am going to try to get an appointment set up next week to get a compassion check and a vacuum test.

 

[Pin_Head]

There is nothing obviously wrong by looking at pictures, but that does't tell you what you need to know. You have to test it yourself. Put a brick on the accelerator pedal and look inside the carb to see if the primary is all the say open and fiddle with the linkage to confirm that it can't open any more. If it is not open all the say, you are going to need to fiddle with the linkage by either bending the arms or brackets or shimming them to make it move more.

 

[Downey]

Ok, here's what I believe, Pin Head can correct me if I'm wrong. Landcruiser 6 cylinder engines require about 40 degrees advance spark during a hard acceleration. Unlike most non-Toyota distributors that can only give about 26 degrees mechanical, your Toyota distributor can give about 32 degrees mechanical. So if the distributor can give 32 degrees mechanical, you then can set your static timing at 8 degrees, there's your 40 degrees that will be demanded (with or without the vacuum "on demand" system coming into play). When your toyota distributor has vacuum retard only, you have no way of ever reaching the 40 degrees that will be demanded because your distributor can and will only subtract from the 40 degrees, thus a sluggish engine on accelerations????? Because of this problem, many set their static timing way up at 14 degrees or more, trying to kick the vacuum retard's ass??? But then that means when you want to idle down (first gear, low range, rocky creek bed) you are still at 14 degrees advanced, static timing doesn't go away.

 

[Pin_Head]

Jim-
That sounds about right. Most mid 70's Toyota distributors are mechanical advance with an electro-mechanical retard for special situations like what Toyota calls "lean burn" cruise which was adopted mainly to meet CAFE standards. They don't have to worry much about preignition under load because they are relatively low compression engines.

PS I was a pretty regular and happy customer of yours over the past 20 years. Think globally, buy locally.

 

[70 FJ40]

Thanks Pin_Head. I did have my wife step on the pedal and it definitely doesn't get close to opening the secondary. I was hoping to find out there was some way Toyota made to take up slack in the linkage. I will look down the carb to see if the primary is open all the way with the pedal on the floor.

 

[MoCoNative]

Not to get too far off topic, but Jim, which Toyota dizzy will advance that much??????

I'm playing with this right now, a lack of power when accelerating and on hills. It seems to be a combo maybe of carbureation and timing advance.

I have tried two of Trollholes distributors, the early style and his most recent 2F non-usa distributor. The earlier distributor is speced to make about 16 degrees of max mechanical advance, his other makes about 10 degrees. Best performing mechanical advance distributor I could find is the FJ-60 at about 24 degrees. Both of these "non-usa" performance distributors are not making any power for me.

I slapped my mechanical advance Mallory back in, I get some of my power back. It provides 24degrees of advance. I have run at 11 degrees static for years, and that is where I set it.

I agree with you, I'm trying to keep my static down and get the total advance up. Neither of the Toyota style distirbutors are making anywhere near the spark advance I need at 6500 feet of elevation. The Mallory will make a good solid 35 at 3000 RPM, which seems to get me down the road better and did for many years. To get anywhere over 30 degrees from the other two distributors I have the static so far advanced that it will not crawl in 1st at all, it is like a racehorse in the gate, jittery.

Vacuum advance has very little to add when accelerating or climbing a big hill, so you have to only look at mechanical numbers. I'm at a loss to make enough advance with a Toyota ignition. When the vacuum pots actuate, sure I get the 30-40 I need, but they do not help under WOT.

 

[Coolerman]

Since we are off topic...

I found this note from (I believe) Jim C concerning advance on Toyota electronic distributors:

"FWIW, the typical Toyota electronic distributor will read 12 degrees mechanical advance @ 1900 distributor RPM and 11 degrees of vac advance. This gives a total 23 degrees of distributor advance or 46 degrees crankshaft advance. This is why an FJ60 w/ a healthy engine and no smog equipment will rattle like crazy under load. We want a max total ignition timing of 34-38 degrees on the 81-87 engines, a few more degrees on the earlier low-compression engines. The way to achieve this is curve the distributor for 7 degrees vacuum, 21 degrees centrifugal and 9 degrees base. Max crankshaft advance is then 37 degrees."

 

[MoCoNative]

Now I'm even more confused. Fooling around last night, with 12degrees initial on the flywheel, at 3000ish or less RPM I get about 28degrees at the flywheel with an early non-usa vac advance distributor. Throw in the vacuum I get about 40total. That all makes sense if you take the specs on the distributor from the FSM, however it lists distributor RPM, and the corresponding rates of advance. If they were doubled at the flywheel I should have more advance. Am I missing something. We need Jim to set us straight. I assume the flywheel marks are crankshaft advance, but is the FSM giving us distributor advance numbers or crankshaft advance numbers?

 

[Downey]

I can't answer to the various numbers y'all are throwing out there, I can only address my first hand knowledge. Back in the day Downey was offering the non-USA 19100-60061 vacuum advance distributor while MAF was offering the Delco mechanical advance distributor. We had both dnyo tested, I was then told the Delco could only give 24 or 26 degrees mechanical (with no additional vacuum available, then required static timing to be set up at about 14 degrees), it had no advance until 1200 RPM, and peaked at 2400 RPM (small window of available advance). The Toyota 19100-60061 could give 32 degrees mechanical, and any amount of vacuum advance demanded, began to advance just off idle, and could continue to advance beyond 5,000 RPM. This made the 19100-60061 a screaming hot rod distributor.

 

[Coolerman]

Now I'm even more confused. Fooling around last night, with 12degrees initial on the flywheel, at 3000ish or less RPM I get about 28degrees at the flywheel with an early non-usa vac advance distributor. Throw in the vacuum I get about 40total. That all makes sense if you take the specs on the distributor from the FSM, however it lists distributor RPM, and the corresponding rates of advance. If they were doubled at the flywheel I should have more advance. Am I missing something. We need Jim to set us straight. I assume the flywheel marks are crankshaft advance, but is the FSM giving us distributor advance numbers or crankshaft advance numbers?

Found another note on the early dizzy:
E-'68: Xtra small distributor, vacuum advance (correctly called "non-smog", also sold as "non-USA").
Toyota still sells the non-USA distributor under the p/n 19100-61080.

E-1968 world spec dissy
mechanical:
900rpm advance begins
1800rpm 18*
3200rpm 30* All in

Vac:
4" adv begins
12" 16* all in

 

[MoCoNative]

Damn Jim, that is the distributor I need. It seems Trollholes copy is not of that distributor. Your Delco stats seem pretty close to the mech advance Mallory I was running.

 

[Downey]

I know.

 

[MoCoNative]

For the original poster, is there any adjustment in the last link at the carb??? or is that a solid piece, I can't remember or see it in your picture. Otherwise your linkage is not that bad looking, but any wear or wobble in the ball joints of the linkage or the holes the rods ride in will give you slop. One thing to try is just bend the gas pedal up off the floor a little and see if that gives you more motion, that is if you hit the floor before the secondary is tapped. A block of wood or something may be needed to pry against.

Jim, I found a used one, along with a couple other vac advance distirbutors, package deal, I'm going to see what they do. I wish you were closer to me, I've told you this before, I ran a Holley for years and never got it 100%. I did some pretty advanced stuff to it trying to get the best all around performance. I wish we could sit and compare.

 

[subzali]

To the OP, before bending your gas pedal, disconnect the linkage and operate the throttle arm on the carb by hand and see if you can get it to go far enough to ALLOW the secondary to open.

*JUST TO BE CLEAR* - moving the linkage will NOT open the secondary - it will just move a lever out of the way so that the secondary MAY open. The secondary on your carb is vacuum actuated, as you already know. But before the vacuum can open it the lever has to be out of the way. Moving the lever is what you are looking to achieve with the throttle actuation.

On earlier carbs the secondary is mechanically actuated, and moving the throttle enough WILL open the secondary, so just to be clear in what you need to be looking for.

You also don't necessarily need a helper as the actuation can be performed from under the hood.

 

[70 FJ40]

Sorry I haven't posted up in a while. thanks for all the help and suggestions. I did operate the throttle linkage by hand and it goes far enough to kick open the secondary. I was able to take my Cruiser in to a shop I've used before to get a compression check and a vacuum test. We ran out of time for the vacuum test but the guy was very helpful.
The results of the compassion check were:
#1 - 145 psi
#2 - 135 psi
#3 - 135 psi
#4 - 140 psi
#5 - 128 psi
#6 - 135 psi

That seemed pretty good to me. He thought so as well. I know #5 cylinder is a little low but not bad enough to need rebuilt right? He gave me some fuel additive to help clean out some carbon and maybe get them all a little more even. He checked my points gap while we were under the hood and it was 10 mm instead of 18mm or was that 100ths of an inch? Anyway he fixed that and it helped a lot. we were able to adjust the idle back down to where it should be and it did seem to help some with power. I'm assuming it will help quite a bit with milage as well? He also recommended bending the pedal. I had never thought of it but it makes sense that after nearly 40 years of getting stood on it might get a little out of wack. We bent it to the left and now it has nearly full throw on the linkage. I think I will try to bend it up a little as well.

I also ordered a vacuum diaphragm from SOR. So this weekend I will see if I can get it to move the paperclip.

Feel free to let me know if I'm missing something or you have more suggestions that would be great too.

 

[1phrogguy]

Those are good compression numbers, I wouldn't worry about the #5.

I can't add anything useful about your lack of power, but it sure looks like your brake fluid levels could use a top off. Nice cruiser btw.

 

[cuencanolenny]

I bought the MAF vacuum advance distributor they offered with a 6-1 header a couple of years ago. Had the header sent to Seattle for ceramic coating. I have not installed it, however, after no sale offers down here in Cuenca I am picking it and my ceramic coated intake manifold up tomorrow. Plan is to obtain a good Mark's Off Road rebuilt Aisan 2bbl and do a valve job which will probably include a .020-.030 head shave. When I received my timing light and dwell meter from the USA in mid-January I was able to get "serious" about tuning and jetting. One thing I checked into was the issue of ported vacuum vs manifold vacuum. And I can certainly attest to the improved drivability of the manifold vacuum. The only "adaptor" I could find for the intake manifold plug hole was a PCV, that presents no problem. I checked my stock/existing distributor and the vacuum advance was not working. I installed the new MAF distributor, I have no idea who makes it, and it works fine. I set the timing just a little more advance than the bullet mark (I have a slash at TDC and a bullet at 7 degrees). My timing light does not show total advance. Like the original poster here, I complain about the lack of low end power, hence the plan noted above. It doesn't burn oil, however, when I took the valve and side covers off for cleaning/painting and checking valve lash I found on an ice cold motor I couldn't get .003 through either of #1 valves. This indicates to me that when hot I have valves hanging in space and probably burned edges which could dramatically reduce compression. It aggravates me that riding around in a Nissan 2WD 4dr taxi truck with a 2.4L diesel he can negotiate these hills around here in 4th gear where I require 1st most of the time to keep rpm's up as it has no bottom end power. This surprises me, although I have no other LC experience to relate, because of the high torque figures listed for the engine.