Ignition? (1 Viewer)

[Tigger72]

Ok here's a question for those of you who know the internal workings of the vacuum retard dizzy... is there a chance the vacuum retard plate could be moving around when running? Maybe diaphram went bad? Maybe tossed something loose in an adjustment or in the washboard. Just a thought.

 

[CruiserInProgress]

Ok here's a question for those of you who know the internal workings of the vacuum retard dizzy... is there a chance the vacuum retard plate could be moving around when running? Maybe diaphram went bad? Maybe tossed something loose in an adjustment or in the washboard. Just a thought.

I'm not familiar with the earlier Toyota vacuum retard distributors, but there is a common problem that can develop with age on the centrifugal advance mechanism, that I noticed on my 79 OEM small cap distributor and the big cap OEM that I upgraded to. This tip came from another member post here (JimC?).

If you locate the arrow in my 79 distributor, it points to the centrifugal advance stop pin. That pin affects the range of centrifugal advance, both min and max.

From the Toyota factory, that pin comes with a plastic bushing on it, limiting the range. Over time, that plastic bushing becomes brittle and eventually falls into pieces at the bottom of the distributor.

The fix for mine involved finding a suitable aluminum bushing (spacer) at home depot (for #8 or M4 pin, 1/4" OD).

You might have look under your breaker plate to see if this problem may apply to your distributor. Just a thought.

 

[charliemeyer007]

As engine rpm's go up so must the advance, vacuum declines so either your vacuum advance/retard must do the right thing or your rig doesn't run correctly. No plastic guts in my real Delco or the china unit.

 

[Tigger72]

Ok... been a while... back at it. I took the dizzy out and bench cleaned it. Re-installed and timing changed, but adjusted for that, and it ran pretty well! But. Parked over night, restarted in the morning, and it went back to rough!. Talking to th PO... my father, I pushed the armature to see if I could move the points. I can. It takes pressure, but can move them open with strong thumb pressure in the direction of the lobe pad. Is this a sign of bad dizzy bearing? Replace dizzy?

 

[Tigger72]

Ok... been a while... back at it. I took the dizzy out and bench cleaned it. Re-installed and timing changed, but adjusted for that, and it ran pretty well! But. Parked over night, restarted in the morning, and it went back to rough!. Talking to th PO... my father, I pushed the armature to see if I could move the points. I can. It takes pressure, but can move them open with strong thumb pressure in the direction of the lobe pad. Is this a sign of bad dizzy bearing? Replace dizzy?

Questuon is... should I be able to move the points against pressure with my thumb on the shaft. My brain says no, because the dizzy sits in pretty tight tillerance holes, except for the bearing In between. When running, could that flex, as my thumb made it do, make run rough? Thoughts?

 

[charliemeyer007]

I don't think there are bearings, they are bushings and yes they wear out. Sometimes it eats the shaft also. There needs to be some play as in you can just feel it - lots of play is erratic timing that makes the engine run rough.

I just looked at $OR and a rebuilt fuel pump was like $600. looks like a dizzy is $600 too.

 

[DeskJock]

Ok... been a while... back at it. I took the dizzy out and bench cleaned it. Re-installed and timing changed, but adjusted for that, and it ran pretty well! But. Parked over night, restarted in the morning, and it went back to rough!. Talking to th PO... my father, I pushed the armature to see if I could move the points. I can. It takes pressure, but can move them open with strong thumb pressure in the direction of the lobe pad. Is this a sign of bad dizzy bearing? Replace dizzy?

Installing a pertronix would eliminate a failure point.

Because the points are in place with two screws to mount the points - there are two axis to have to control when setting the points.

I found impossible to get a perfect dwell angle.

The cam stem for the distributor will have some play. Not allot.

I’m running a $325 Racer City Distributor- running 18 month lab with pertronix - runs perfect.

 

[Tigger72]

Ok... distributer and points are off the list. Put in a new OEM distributer with pertrinix elec points today (thank you cruiser outfitters!). No change.

An anomaly sticks out as i go back to thinking.... drove it. Ran good, cooled, ran bad. Took dizzy out, put it back in ran fine, cooled, ran bad.

Just another thought to explore, what could be effected by expansion and contraction and cause a rough running issue? Vaper lock of sorts? Dirt clogging something?

Today after putting in the new dizzy, getting it started, and played with timing/idle mixture adjustment and having it run the same level of rough... after maybe 30 minutes, idle got more varied in speed and started to idle worse! Then the only way to smooth it out a little was advance the timing till it wouldn't turn any more because of clearance of the snap and the side cover... but it was a ridiculous amount of advance... 40deg from my light! Evan before this it liked about 17deg advanced.

Running out of options here! Ha

Thanks for more thought you might have based on this.

 

[Tigger72]

What would be happening where the motor would want or be able to be that far advanced...

Sorry also. Now that I have the vacuum advance carb. I connected the dizzy to the base of the carb and plugged the evap control switch bix and the nipple in the intake. Is that correct?

 

[charliemeyer007]

Maybe the cam gear has wear, or the oil/dizzy drive gear. You have fresh gas and filter - put a yellow bottle of gas dryer in anyway. Maybe the fuel pump is weak or has a hairline crack that sometime lets it suck air. Wire inline a $10 electric diode fuel pump with a switch. You did the WD-40 vacuum leak check for the intake and carb gaskets. Put a hemostat on the brake booster hose.

 

[Tigger72]

Fuel pump strikes some intrest... hadn't gone there yet exept for sea foam the fill previous. The root trip for these problems was a very washboard road. The tank and pump could be effected by that too. I know the pump is working because its been running as i have been trying to adjust. But maybe not well because its not well sealed in the tank and when cold seals, and hot loosens up? I didnt think it was a presurized tank though?

When it was Running well the other day (for some strange reason after reinstalling the old dizzy) I did fill it up with fuel because I though id be able to go for a drive the next day! So in that way, the fuel system was a touch point too. When the dizzy was out. It was in my garage where it could actually cool down then it sat outside in 100 deg temps since.

What would I look forward if I closed off the brake booster hose? Show a leak in the brake booster itself?

 

[charliemeyer007]

Yes a leaking booster is a giant vac leak, can be intermittent like on a rough road - vac leaks affect idle. A bad leaking booster will cause #5 cylinder to run lean and will burn it up in short order. You will need more leg pressure for the brakes to work while it the hose is clamped off.

 

[Tigger72]

Yes a leaking booster is a giant vac leak, can be intermittent like on a rough road - vac leaks affect idle. A bad leaking booster will cause #5 cylinder to run lean and will burn it up in short order. You will need more leg pressure for the brakes to work while it the hose is clamped off.

Here's a question for yah.... right now, the brakes feel good. BUT I have had a problem of the fluid being pushed from the fire wall side reservoir (rear brakes?) The front reservoir and the front over flowing. I replaced the innards of the master cylinder with no change. Is there a way that could indicate a booster leak?

 

[charliemeyer007]

It more indicates that the master still has issues internally. Brake fluid can leaking into the booster which could cause it to leak/fail.

Have you hooked up a good vacuum gauge yet? Compare readings at idle with and without the booster clamped off - then do it again at 3/4 throttle. See what the gauge does if you hold the brakes on for like 2 min at idle and 3/4.

Vac leaks are way more effective at idle than at higher rpms.

 

[pb4ugo]

After you honed the cylinder, were there low spots in the cylinder walls?