I purchased a 1980 Toyota 4x4 a few weeks ago. It wasn't running too well as I mentioned in an earlier post. An area mechanic put new plug wires and plugs on and that helped a great deal. He also ordered a new rotor and rotor cap but it wouldn't fit so he figured they had sent him the wrong one. The parts store sent another. It was the one listed for the 1980 20R but it was too big. I took the existing rotor cap and rotor off today and carried it to a couple of parts places. They both pulled the one for the 1980 20R and it was too big. The 2nd one decided to try one for the 1979 20R and it was a match. He said that even thought the truck is a 1980 "model" it could have been manufactured in 1979 calendar year. I checked the ID plate on the driver door post but it says the following (as best I could read):
INC. VEH. MFD.: JUL/80
GVWR(LBS/KGS): 4550/2063
GAWR(LBS/KGS): FRT. 2630/1192 WITH H78-15 B__

TIRES,15X5 1/2-JJ RIMS, AT 32PSI 220KPA COLD.
RR. 3000/1360 WITH H78-15 8__

TIRES, 15X5 1/2-JJ RIMS, AT 32PSI____
VIN: RN37-039904

So, what do I have here?

BTW, when I put the new rotor and rotor cap on, the tachometer (which had previously been very intermittent) seemed to work fine. It cold idled at 3,000. I drove it around the block and the idle was at about 1,800. I will have to wait until next weekend to check it out further. The truck definitely seemed to run smoother but still had that hesitation or dead spot in the acceleration unless I had the rpms up around 3,000 when taking off from a stop or when shifting gears.

Is this normal or do I still need to keep looking? I'm considering checking all vacuum lines, wiring harnesses and such and maybe replacing them. This is a 1980 and hasn't had all that loving of care.

you have a 79. on the ID tag, the first six or seven months means the truck was manufactured in the previous year. Most parts you order for the truck will be 79. You should check the timing it could have allot to do with the performance of the motor. also replace the fuel filter. <img src="/forums/images/graemlins/cheers.gif" alt="" />

i know the distributor on a '79 is slightly different(only 1 vacuum modulator instead of 2 like newer trucks) but i figure the caps would interchange <img src="/forums/images/graemlins/confused.gif" alt="" />

20R engines didn't have the greatest of carbs like the 22R did. my recommendation would be to get a weber or buy an adapter that'll let you run a 22R carburetor on your truck

Turns out the cap on the 79 20R is smaller in size than the one on the 80.

I'll check out the fuel pump and the timing. Carb will have to wait for the winter most likely.

I appreciate the input on the year model and parts ordering. I hope to have a little time over the next couple of months to do some small experimentation. More major things will have to wait until deer season is over in early January, 2005. I did find a Haynes manual Sunday afternoon with a list of tools one should gather for light duty maintenance and a separate listing for more major work. I'll try gathering up the minor list first, including a timer light and another ohm meter (seems I may have misplaced mine). Again, thanks for your help.

A bit of a belated welcome to the board!

Also, if you do a little shining just aft of the alternator; or behind it, there's a flat spot there which should have the block and serial number stamped in it, if you want to confirm what you have. A mirror might be handy, but that's where the real deal on the mill is at. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Also, the 20R carb opening is round; the 22R is an oblique rectangle, short of mods, of course.

if money is tight, you can rent a timing light from some auto parts stores. that saves from buying an expensive tool that you only use once in a great wile. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Thanks a lot guys. I'm in Atlanta during the week and only in SE GA for short weekends. The toy is located in SE GA for the time being. So, my progress will be SLOW. I appreciate everyone's patience.

If the Jul/80 date on the tag is correct, you should have a LATE model 1980.

The way Toyota's model years run, anything from Aug 79 to Aug 80 should be an 80.
Tho if Aug is on the tag, it could be either. I think the I heard the 3rd week of Aug is when they officially change over, so an Aug tag could actually be one of two different model years.

Yours SHOULD be an 80, tho. <img src="/forums/images/graemlins/kewl.gif" alt="" />

A PO may have swapped or modded the motor, or used parts from a different year motor.

a good indicator of a '79-80 truck is to check the transmission. a '79 or '80 will have a side loading, side shifting tranny while an '81 or newer will have a top shifted transmission