Am I Looking at buying a distributor? (1 Viewer)

[aktundra]

I have been chasing down a runability issue with a stock, fully IM compliant 1980 2F.

Up at higher RPM, when the engine is accelerating under load, about 30-40 MPH, say about the shift point 3rd to 4th. the engine starts bucking & hesitating. took the rig to a shop that focuses exclusively on 60's-70's carb'ed engines. spends most his time on hot rods & Detroit restorations. The technician cleaned up vacuum lines, and it helped a little. The technician stated that with a vacuum pump, could only get the distributor to advance 7* but would like to see about 15*.

I doubt he has a Toyota FSM. Probably shooting for 15* as a rule-of-thumb

A couple of questions for the forum:

Do these runability symptoms sound like a distributor advance issue?

Does it sound like this distributor needs to be replaced?

If the answers to the above are yes yes. If I go with HEI replacement, will this violate the IM laws of most states? Do I need to go with a straight OEM or exact aftermarket replacement?

 

[1911]

A couple of questions for the forum:

Do these runability symptoms sound like a distributor advance issue?

Yes.

Does it sound like this distributor needs to be replaced?

Maybe; the problem is that advance mechanism parts for 40 distributors are NLA or otherwise getting hard to find.

If the answers to the above are yes yes. If I go with HEI replacement, will this violate the IM laws of most states? Do I need to go with a straight OEM or exact aftermarket replacement?

Can't help you with that (don't know the answers) but another possible solution is to buy a big-cap distributor from a 60-series Cruiser and have distributor/carb guru Jim C. rebuild it for you. It should be a plug 'n play installation in your 1980, with the exception that you'll have to replace your pushrod gallery cover with the dished one from a 60-series, to fit the bigger dizzy.

 

[honk]

I'd be thinking about carb accelerator pump things, and not worry much about the distributor.

 

[62Cruiser]

In the same boat with the distributor advance..I'm pretty sure you can just put vacuum on the dizzy and see if it holds, mine does not on one side. If you find a good replacement or parts availability, please post it, as it appears the advance/distributor is NLA.

 

[Curt]

I would also check the accelerator pump thing.

7* advanced for a stock unit is right on the money, I am unaware of a vacuum pump on a 2f. My dizzy is set to 10-11*, 15* would be to far advanced for these engines. Get a hold of Trollhole and check out his replacement dizzy it is electric with vacuum advanced.

 

[Output Shaft]

My guess is the engine is getting starved of fuel.

The distributor doesn't care if the engine is under load or not. It's only RPM dependent.

The main problem is not the accelerator pump in the carb. It's mainly used for starting and quickly squirting in extra fuel when pushing down the pedal quickly. A worn pump piston will cause hard starting and initial hesitation when the gas pedal is pushed down, but it won't cause bucking.

Bucking is classic fuel starvation. (Too lean).

 

[1911]

7* advanced for a stock unit is right on the money, I am unaware of a vacuum pump on a 2f. My dizzy is set to 10-11*, 15* would be to far advanced for these engines.

But that is just the base timing, before the advance kicks in.

The late-model advance distributors like we are talking about with the O.P.'s 1980 have two advance ports:

The maximum additional vacuum advance from the inner port is 18-20 degrees.

The maximum additional vacuum advance from the outer port is another 6-7 degrees.

So the 7* BTDC is only the base timing, and the total advance at high rpm/high vacuum/high load is much more. If your vacuum advance(s) are not working properly, you will not have enough advance at higher rpm and/or under load.

 

[65swb45]

My guess is the engine is getting starved of fuel.

The distributor doesn't care if the engine is under load or not. It's only RPM dependent.

The main problem is not the accelerator pump in the carb. It's mainly used for starting and quickly squirting in extra fuel when pushing down the pedal quickly. A worn pump piston will cause hard starting and initial hesitation when the gas pedal is pushed down, but it won't cause bucking.

Bucking is classic fuel starvation. (Too lean).

/this\

Try running a hose from a gas can to the fuel pump and driving to see if it's an issue with your 36 year old tank.

Best

Mark

 

[aktundra]

Googled a little before I posted this thread. Seemed like there was some HEI distributors that needed a gear swap to work in a 2F. Anybody have a PN or a reliable source to get something that will just drop in ?

 

[65swb45]

Another 1980 dizzy would be a straight drop-in. I have a couple for sale. BUT I WOULD MUCH RATHER you try the gas can test first. I'm with @Output Shaft on thinking this is a fuel delivery issue, not an electrical one. Mark

 

[Random Dan]

If you peel back your rear carpet and remove the fuel sending unit (easy job), you can shine a flashlight in to see if the filter on the fuel pickup is clogged, causing fuel starvation. There's also the inline fuel filter and another little filter in the carb at the fuel inlet, if you remove the inlet fitting you can see it. Don't start replacing stuff until you know what's wrong.

 

[Random Dan]

For what it's worth I ran my truck for a week or so with stuck vac advance and broken weights so it had no advance at all past the 7* baseline. It was really low on power at the top end and fuel economy was terrible but it never had any bucking or hesitating.
However, when the needle valve filter was clogged it would buck and backfire under high load because it couldn't fill the float bowl fast enough and leaned out.

 

[aktundra]

Thanks ill see what I can find on the fuel system.

 

[aktundra]

Thanks to those that steered me towards a fuel issue. One frustration with chasing this down, is that sometimes there is no problem, other times it's just not drivable over 30 mph

Saturday decided to take the 40 on a long drive to try and get to the bottom of the problem. Drove an hour north of town 50-65mph, left with 1/2 tank of gas, no issues. Stopped to visit a friend. Continued, my trip, had to really jump on it to get onto a 2-lane highway with heavy traffic. Now bucking & hesitating in only 2nd gear!! Limped into a gas station, topped off the tank. Ran around town, then an hour back home on the highway, No issues !!!

Seems to me might be crap in the bottom of the tank, plugging/disrupting fuel lines/filters.

We'll see if it comes back again at the bottom 1/4.

 

[Pin_Head]

X3 on the fuel delivery issues.

Since it is intermittent, chances are it is rust in your tank.

 

[Weber Sarge]

Might want to check those fuel line connections at the tank - they could be backwards . The bottom outlet feeds the fuel pump , the other higher one is the return - I had to find this out on mine thanks to the PO...
Sarge

 

[Cleg]

No firm opinion on whether this sounds more like a fuel delivery or ignition issue.
I have seen what you describe from a clogged fuel filter.
The engine would run OK at low speed but falter if pushed faster.
Maybe you could test the ignition theory by advancing the distributor about 7 degrees at idle & lock it back down to see if you could get it to run crummy at low speed and OK higher.

My vacuum advance was not working because the diaphragm was perforated.
At the time I could find just the actuator component for $70 or an aftermarket A1Cardone complete rebuilt distributor assembly for $75 w/ exchange.
Mine was a rusted mess so I made the swap.
The replacement looked like a new unit, plugged in and has been fine so far for 3K miles.

These are no longer available off the shelf but you can send one in and have it rebuilt for about $140, Rockauto.
Caution; I think different years used different amounts of advance.
I've seen some bad press about the durability of the drive gear on non-Toyota distributors.