Difficulty setting timing on 20r
 

Truck: 1980 hilux 4x4 20r, 4spd.

Background:
Tore apart to do headgasket, had head gone over, surfaced, etc. New timing chain, radiator, thermostat, header, water pump, oil pump, radiator, cap, rotor, wires, ignition coil and module. Ignition coil/module are GM, did the swap.
Posted last week having difficulty trying to get the engine running; adjusted valve lash again and the engine runs.

The problem is now that the timing is extremely off. When I set the engine at TDC on compression and adjust the distributor until the rotor is sparking #1 plug, the engine runs but barely. When any throttle is applied, it either immediately dies or it begins backfiring (loudly) out of the carb and slowing down. When the engine is cut off, it will occasionally backfire as it slows to a stop.

With a timing light, the timing appears to be set about 15 degrees before after TDC. In case I'm wrong, when shining the timing light at the harmonic balancer with it running, the mark is 15 degrees or so clockwise of the 0 BTDC mark on the oil pump (too far to the right). edit-This is with vacuum advance lines pulled and plugged. With them attached, the engine runs better and the timing is at 3 degrees or so after TDC. I'm attempting to get the timing set at 0 BTDC with the lines disconnected.

My first thought was that the distributor was "off a tooth". Reinstalling the distributor with it moved one tooth in either direction causes a no-start. While the engine is running, turning the distributor clockwise causes it to slow down and die, turning it counter-clockwise increases idle speed until rotation is stopped by the retaining bolt (which I discovered seals a hole in the cylinder head by the way. For other newbies, running the engine without that bolt in will spray oil everywhere). Counter-clockwise rotation retards(?) the timing, moving the mark counter-clockwise towards 0 but no where near enough.

I examined the distributor, and checked that the springs are not binding in the advance mechanism.

Thoughts stewing in my ignorant brainmush:

When I installed the timing chain, perhaps I misaligned the bright links, leaving the timing between the crankshaft and cam slightly off.

My ignition setup is janky cause I'm a numbnuts.


Clueless here, any help would be awesome. What steps should I follow to isolate the problem and figure out what I did wrong?

When installing the distributor, the rotor should be just counterclockwise of the number one spark plug lead with the crankshaft and cam set at TDC. Timing should be set at eight drgrees.

I meant after TDC on the harmonic balancer, the timing mark is 15 degrees or so past 0.

I'm going to take a look at the truck tomorrow and see if frustration caused a stupid error, wouldn't be the first time.

To clarify, this is precisely what I am attempting to do; when I do this, the timing with the vacuum leads pulled and plugged is 15 degrees after TDC, with the lines attached it is about 3 degrees after TDC. With the lines attached it runs better, but still obviously very rough as it's firing on the beginning of the down stroke. This is what is driving me nuts- changing the tooth the distributor is on in either direction, which should advance or retard the timing from my understanding, causes the engine not to start. I've replaced a distributor before on a 22r with no issues, but I was just doing that one part.

Im also having problems setting the timing right. This is what the rotor and timing mark looks like.
https://cimg6.ibsrv.net/gimg/www.yot...763416012c.jpg
Pointing at the position of cylinder #1.
https://cimg7.ibsrv.net/gimg/www.yot...93db816b91.jpg
When driving the truck I don't really have speed in 5th gear. I have more power in 4th and when switching to 5th the truck losses power and it does not climb really good in that gear. Also top speed is 65mph, even if I floor the peddle.

First off, this thread is over 4 years old.
Secondly, your pictures mean nothing if we don't know that the #1 cylinder is actually on the compression stroke and exactly where the #1 plug wire would be in relation to the rotor. And that is just to get you in the ballpark to set you up for using a timing light to dial it in.
Thirdly, 65 mph was topped out on the last truck I had with a 20R, downhill with a tailwind it might have hit 70.

This thread is like my truck, old but still running. I can't express the gratitude I have for the fact that you replied. Sometimes it helps to talk things out, with some one that knows these trucks. No mechanic around me wants to touch it, or can give some sort of sound judgment. Like they have never seen a 4 cylinder engine before. When I first purchase the truck this thing was zippy. 78-85mph on the freeway, first gear did not have much in it but 4th and 5th could climb hills with out a problem. It was running rich and high rpms. Then the igniter went out and I upgraded to an MSD box, new distributer cap and rotor cause the old one was old and moldy. Took it to a shop that claimed they knew what they were doing. Truck never ran the same again, no power, can't climb hills with out ˟˟˟˟ting it self, 4th and 5th gear are worthless and top speed is 65mph barely. If there is a slight incline in the road I have to down shift to 3rd to be able to climb the hill. It literally runs out of power mid 4th gear.

@akwheeler If look closely at the picture whit the distributer, there is a sharpie mark on the distributer right where the purple wire is in the picture that is where the #1 cylinder is located. In this picture the timing mark on the fly wheel is where the #1 cylinder is at the top of the engine.
https://cimg8.ibsrv.net/gimg/www.yot...02f24c5ba6.jpg
I stuck a plastic whose in the in the spark plug whole and twisted the crank shaft till that cylinder was at the top. So I'm 100% sure that is TDC.
Turn the truck on, by the way it cranked on the 3rd starter revolution. Never ever started this fast. Ran the truck at idle speed for a while let it kind of warm up. Removed timing advanced vacuum, put the timing light to it and twisted the degree on the timing light to the max 60 degrees, so the mark on the crank matched the 85. Truck ran rough and kind of sluggish, low rpm. I do not have a tach and my cheap ass timing light does not have one either, now that I think about it I wish I would of bought a better timing light. Stopped the engine removed sparkplugs reset piston position to TDC, pulled the distributor out and twisted it counterclockwise one tooth and reinstalled everything. I wish I had some pictures of that to show the rotor position. Started the truck, it runs a little faster does not shake as much, idle is not so rough. The rmps are a little higher.
https://cimg8.ibsrv.net/gimg/www.yot...9d84631dff.jpg

At 30 degrees on the timing light setting the mark on the pully matches the 85 mark. (I don't know what that mark is called) No test drive yet. How am I doing so far?

terrible.
for one, the piston rises to TDC twice for each time the distributor rotates once. Only one of those times it will be at TDC on the COMPRESSION stroke.
But since it started and ran you got that part right.
Next, turn the knob on your timing light to zero and twist the distributor until your timing mark on the crank pulley lines up where the owner's manual or underhood sticker specifies, I don't know how many degrees it calls for. pretty sure 85 is actually 8.5 and in that case it is probably where your base timing should be set (vacuum advance disconnected and plugged, idle set at factory setting or close to it).

I believe that setting the idle to the right peed before setting the timing is important.
You can pick up a relatively inexpensive tach, or even a tach/dwell meter, at Harbor Freight, or just about any auto parts store. Set the idle speed, set the timing, recheck the idle speed. I think, very rarely, but once in a while I think, a tach would be a small, but well worth it, investment.
I bought my pickup in 88, and I had a tach/dwell meter from a few years before that, when I owned a 78 Chevy Luv 4WD pickup. I had purchased a timing light before that, even. I STILL have, and use, them both. Nearly a 40 year span. Not bad for a couple of auto parts store cheapies!

Good luck!
Pat☺

@akwheeler Timing set and truck is zippy again. First gear is short and they get longer as I they go up 3rd and 4th is really long and 5th even has some pull to it now. Got it on the freeway up to 78mph on a straight road, I'm passing Prius' again.
https://cimg4.ibsrv.net/gimg/www.yot...bdc4e5789f.jpg

@2ToyGuy You are right about a tack, but I don't want to spend any money yet. I need to buy all new dials in the truck the only ones that are working is the gas and temp gage. Looked on line and some auto parts store, and lost my mind :scared: at the prices of these. I want to take my time and make the right purchase, because that's what I will see every time I drive the truck. And if its not exactly what I want is going to drive me crazy. I did that with the dash board and ended doing the job twice. Can't afford to do that with dials

I'm having trouble passing smog, when I did the smog test the technician said my timing is 36 degrees advanced. So I tried resetting it again fallowed this by @13Swords Very clear instructions on how to do the job. Once I set the truck fired right up and runs, when checked with a timing light its 44 degrees advanced. Could the timing chain be so warped that its advancing the timing that much? What could cause the timing to be that advanced?