Yep, all of that would do it. Still, if you have no idea on the age or miles on the timing chain, that could also be causing a timing problem. The timing mark jumping around like you described is a classic sign. If your timing isn't rock steady, you'll never get a consistent test result from smog. The timing chain drives the valve train from the crank & if it's not accurate, your valve timing will be off & could lead to higher emissions due to unburned fuel OR too lean of a condition (neither is good!). The new distributor may help a bit if your old one was also "sloppy" & causing some timing issues, but if that chain is stretched it's not going to solve the complete issue. The plastic backed timing chain guides on early 22R's are a very well known issue. They tend to break well before 50K miles & let the chain "slap around" & that throws off timing. If the chain is very loose it can even dig a channel into your riming cover, causing oil & coolant leaks. Are you hearing a fair amount of "valve noise" or clacking when it's running at idle? If so it could be a loose chain.

I don't personally like to deal with LCE (personal preference) & they have both timing sets, one with the plastic backed guides & 1 with the steel backed guides. Here's the later one:
https://www.lceperformance.com/20R-2...-p/1015000.htm

And here's the reason I don't buy from LCE; they are way overpriced. Have a look here:
https://www.rockauto.com/en/catalog/...iming+set,5756

The bottom three timing sets are all name brand & very good quality, all have the steel backed guides, and all are half price or less than LCE.

I know it's a LOT of work replacing a timing chain set but it's well worth it on these engines. The difference on my 20R once I got my new timing set in it was more than night & day.

Did you ever compression test this engine? Curious.

Also a thought about the "it's running wide open with no pressure on the throttle." I'd suspect a sticky throttle cable and/or a broken or missing return spring. As for the cable, if it's original it's 37 years old & has served well past it's prime; I'd replace it anyway. Here are some choices:
https://www.rockauto.com/en/catalog/...tor+cable,5892

It should be the 25.5" one but compare what you have with the pics. The Pioneer brand cables are good & much less at Rock Auto than you are going to find almost anywhere else.

 

Thanks for the links to rock auto. Those lower 3 are brands I have had good results from in the past. They don't show or mention gaskets. That's odd. But I can always purchase gaskets separate.
I'd did a compression test. 1 was 175, 2 at 180, 3 was 150 and 4 at 190. I think 3 was low due to the bad valve settings. I reset back to 8 and 12. Even with the cheap rebuilt distributer from Napa it was still not steady but it did improve. I think you and others have convinced me to change out the timing chain. I'll call rock and older the parts.

 

I did already order a new throttle cable too. Mine was binding a bit but it was the secondary linkage that I FUBARED up during the initial install. I get there yet.

 

You'll get there, keep at it. It takes time & effort to correct 37 years worth or wear & tear, but the results will be worth the effort. Keep us posted when you have anything new.

Thanks for the compression numbers. I agree, the one low reading was likely due to an incorrect valve setting. The improvement you mention with the NAPA distributor tracks; you eliminated any variance in the distributor due to wear. With the timing mark still not steady but "jumping around" while a timing light is on it is to me a sure sign of a slack timing chain. Besides, no telling how many miles are on the chain that's in there. A new timing set will make the engine timing rock steady.

About the gaskets, yes they usually are sold separately, more conveniently as "Timing Cover Gasket Sets". Here's the offerings on Rock Auto but they are generally available at local parts stores for about the same prices.
https://www.rockauto.com/en/catalog/...ket+/+set,5484

Also, I have no idea about the condition of your current one, but you might want to consider replacing your water pump while you're at it, since you have to take it off anyway to do the timing chain. There are usually about $30 at any parts store so it's cheap insurance for the future.

 

This truck has 270,000 miles on it. All original except the lost owner rebuilt the Asian carb or installed a rebuilt. I ordered the parts from Rock Auto. Timing chain kit is Seal Pro, timing chasing gasket set and seal, new water pump, new upper and lower hoses all for with shipping under LCE price. My front cover has 37 years of oil and dirt on it so before I put a wrench to it I'll decrease it on the truck. I'll take pictures as I work on it.
Thanks for all the great advice.
Mikr

 

Going good , removing all the cheap tied into the from cover. Those tricky Toyota engineers oh boy. That Smog pump mount is really bolted down. They even ran the mount under one Motor mount bolt. Sneaky suckers.
I'm very pleased with myself in ordering a New Water pump too. I noticed brass shavings setting in the thermostat goose neck and thought water pump. Grabbed the pump impeller and tried moving it. Now it was not leaking but good grief what a wobble. And I can see that the altenator can stay I just had to remove the top adjustment bracket.

 

So far I have the from cover prepped for removal. I used a breaker bar on the cam bolt and got it loose. Removed the distributer drive and fuel pump eccentric. Then breaker bar back on the crank to get it back to Zero. What is very odd is that I had pulled the # 1 plug but that quarter turn on the crank back to Zero pushed water out of the water pump cavity. Very odd. Makes me really wonder about the head gasket. But I'm almost positive that it's ok. Since I'm not removing the head I'll lower the front of the oil pan to allow getting the cover mounted and sealed. If I were pulling the head I would leave the pan alone. And I don't own a heavy duty impact. That's what the breaker bar is for. Put Bart back in and bump the starter it will loosen up. Then back to Zero setting.

 

Looks like you're doing pretty well with it. Make sure you locate the "hidden bolt" in the head that points downwards. It's usually invisible under a pool of oil in a little "well", located just in front of the cam gear & timing chain. The bolt attaches the front of the head to the top of the timing cover. Some people miss this & when they try to pry loose the timing cover they break the cover. Also be advised that part of the head gasket extends out to the rectangular space that the timing chain goes through. If you're careful taking the timing cover off it should stay intact. I just put some very thin RTV sealant on it (Permatex Ultra Black or Toyota FIPG Sealant or equivalent) when re-assembling to prevent oil leaks there in the future. 2 years later & still no leaks.

I figured the water pump might be due for a change; nice catch on the brass shavings. That & the pump shaft wobble are sure signs that pump didn't have too much longer to live. You should also be getting 4 new studs with your water pump for the fan flange connection. I installed mine with a drop each of Loctite Red just to make sure they never backed out of the water pump flange.

Also, in case you need them, here are the bolt tightening torque specs. The mm sizes listed are bolthead/nut sizes (wrench size).
Oilpan Bolts - 8-10 foot pounds
Valve Cover Nuts - 4-5 foot pounds
Nuts (4) for Water Pump Flange to Fan Flange - 14 foot pounds
Water Pump/Timing Cover Bolts - 10mm 14 foot pounds, 12mm 25 foot pounds
Crank Pulley Bolt - 116 foot pounds
Timing Chain Tensioner Bolt - 14 foot pounds
Bolts for Timing Chain Guides - 16 foot pounds
Cam Gear Bolt - 58 foot pounds

270,000 miles? That's still less than half the mileage my '78 has on it.

 

Removed the timing chain cover with no issues. I see that the oil pan gasket is Cork. Was that an original gasket material?
So far everything looks OK. I rented a Harmonic balance puller at Orielys this morning. It came right off.

 

So another question. From looking at my picture is that a good sign of a Timing chain that's very worn?

 

In cleaning up the engine block where the timing chain cover goes I found something odd. Either it has jumped time or the last installer paid no attention to the colored links. Crank and cam are setting right where they need to be. Or is this just the result of a Stretched timing chain?

 

I'll take these in order. Yes, the original oilpan gasket was cork & rubber composite, so that may be the original pan gasket. Whether you replace that or not at this point is up to you, but I'd do it. It would also give you the chance to clean out 37 years worth of crud, sludge & baked on crap on the inside of the pan & timing cover (your oil will stay much cleaner later!). It also gives you the chance to remove any loose pieces of plastic from worn/broken timing chain guides. New replacement pan gaskets are usually also usually cork & rubber composite but I have seen a few around that are Viton rubber. Either would work fine. Just remember not to over-tighten the pan bolts or you WILL get an oil leak at the pan flange. 8-10 foot pounds.

Yeah, I'd definitely say that chain is wayyyy stretched. It's that slack in the chain which causes the timing to jump around & not be consistent like it needs to be. In the pic the chain is so loose that you can push it over to touch the guide bolt. It's amazing that the guides aren't chewed up more than they are; you got lucky. At least the driver's side guide is intact so the chain had no chance to eat up your timing cover from the inside. I'm also looking at how much "baked-on" stuff is on the chain, which is a good indicator of how long it's been in use. Yep, it's due to be replaced IMO.

If the dots on the crank & cam gears are still lined up like they should be, it likely did not jump time. If the chain got loose enough to jump a tooth or two on the cam gear (most common way jumped timing happens due to loose chain), that gear would have stopped moving while the chain was not driving it, but the crank gear would have kept going. Then the marks on the gears would not be lined up. The "special color" link in the chain is only there as a visual installation aid. It's most likely that whoever did the chain last just didn't set that link on the dot on the cam gear. As long as the crank & cam are in the correct positions when the timing set is installed it will work fine. It really doesn't matter if the "special color" link is on the cam gear dot or not, just as long as the chain is engaged to drive the setup it will work as designed. For anyone wondering the answer is no, not having the "special color" link on the cam gear dot won't damage or hurt the chain or gears at all. Wear pattern & lifespan will still be the same too. This was just a slightly "sloppy" installation done by a previous mechanic.

By the way, I found something that might be of some help when putting this all back together. It's a pic & chart of all the timing cover/water pump bolt locations, the bolt sizes & lengths (super helpful) & the torque specs. I know it says '85 & up but the specs are still correct for '82 & even for 20R engines. Here it is.


Go by the specs shown on this chart, NOT the ones I posted before because some of those are not accurate, especially the Head to Timing Cover Bolt spec. I used this chart when I did my 20R timing set (but forgot about using it until now). 2 years later & it's all staying together OK.

 

Thanks for all the great help. And yes I'm pulling the oil pan.
I didn't think the colored links needed to be exactly lined up as that would not effect timing. Like you said probably old sloppy work.
That chart will really help. I used a piece of cardboard and punched the bolt through that and used a pen to say where they went. The head gasket is ok. It cleaned up just fine.
I watched a you tube vidio where the guy said to make sure to put a thread sealant on the bolt at the timing mark as it goes into the area where the tensioner is. So I'll do that to.

 

The "bright" or "colored" links are just an installation aid to make sure there is the correct amount of links between the cam and crank sprockets on the tensioned side (opposite side of the tensioner).

Due to the number of links on the tensioned (driver's) side and the number of links on the slack (tensioner) side, the " bright" links will no longer line up with the dots on the cam and crank sprockets once the engine is rotated most of the time.

Once you rotate the engine, the "bright" links no longer matter and just the cam and crank sprockets need to line up with each other.

 

Parts are arriving. Now tomorrow I'll drain the oil and pull the oil pan. I'll wipe the bottom end down and use a pin gauge to measure the bores. Then I can see real quick If it's stock or bored out. If the cylinders check out within factory tolerances and no horrible vertical scratches like the type caused by a broken ring then I may just pull the head. I'll check rod bearings for scuff marks too, hopefully rods and mains are OK. If it all looks OK then Hone and I'll install a set of gapless rings.
Now about the head. Who is the best with quality rebuilt heads at a reasonable cost?? I know sometimes quality does not go with a low price but I can hope.
Any help appreciated.

 

It's really satisfying to hear about someone doing a detailed & through job of things. Just glad to be of some small help in that. I also did the sheet of cardboard thing for the timing cover bolts when I did mine, even though I did have the chart as well. I was taking no chances on having to pull anything back apart & do it twice! The thread sealant on the bolt you mention is a very good idea. You'll also need some thread sealant on the very long bolt that goes near the top of the water pump, as it is actually tapped into a coollant chamber in the block.

When you pull the oilpan don't be alarmed if you happen to find some bits of plastic in there. Those would be bits of old timing chain guide & it's quite common to find them in there.

I don't have a lot of info on replacement cylinder heads but did find these 2:
https://www.oreillyauto.com/shop/b/e.../toyota/pickup

They are rebuilt units from a firm called ATK, which apparently has a long & fairly good reputation, according to Google search. You get everything except the rocker arm assembly for the price, even a new camshaft. There are 2 models of head, that differ in how many bolt holes there are on the intake manifold size; 15 hole & 20 hole. I believe the 20 hole is for EFI instead of carb'ed but I'm not certain. I'd just check the intake & start counting how many bolts you have on it.

 

Got the oil pan off. Thanks for my trusty air ratchet. Not all that much debris in it. Only one long sliver of what may have been attached to the timing chain giude. And lots of small pieces of a silicone sealant. I hate that stuff.
A sprayed staring fluid down the oil intake port until it ran clean out of the pickup screen and then sprayed the screen too. Clean now.

 

Head is off. All cylinders fail a leakdown test using gas. # 2 and 3 are in the worst condition with barnacles of Antifreeze on the valve heads. All the coolant hoses except radiator upper and lower are original as were most vacuum hoses. You can tell by looking at the coolant pipes that they did not use distilled water. I have them soaking with lime away.
Bores look good and can still see cross hatch. Bores measure OK too. So tomorrow I'll pull the piston. Order rings and a gasket set. I also found an Honest Machine Shop. He does desiel heads too. Or I can order one online.

 

I forgot, I have to order Rod bearings too. And a LCE header with a bolt up cat. And 2 new O2 sensors. I'm even considering a RV cam.

 

I'm looking at all the blocked coolant passages on the top of the block. EEEPPP!!!