I've had my '79 2wd for about a year now and like having it around, but I'm trying to decide it if should deal with a low compression issue or send it down the road. Cylinder 1 is now at 70, down from 90 last year (other 3 cylinders are around 150). I highly suspect a valve problem (no appreciable change when wet testing) and am considering pulling the head and taking it to a machine shop. However, I have no idea what I should expect to pay for that sort of work. I tried calling around but the responses I got were just "bring it in so we can look." Well, easier said than done. I have about a grand in the truck and I'm not interested in pulling it all apart just to find out I have to dump another grand just to get it back together correctly.

Any insight on what to expect for price range?

Also, if I do pull the head, what other items do you recommend taking care of? Timing chain, water hoses, water pump, oil pump, fuel pump, pump pump?

 

sell it is about $500 truck

if you do the head you are on the right track- add water pump

 

Ive been in a similar situation before. I had a 93 Nissan D21 Hardbody with head gasket/head problems. I chose to sell it because it was one of three non-running trucks in my driveway. If I'd had more time and money to let it sit, I'd have kept it because I've never cracked into an engine before and at some point I'd like to build that skill set.
It's a hard question and it really depends on what you have time/money for right now. Once you add in how much money you've already got in the truck, then it becomes even harder. I've let a bunch of trucks go for various reasons and for the most part I have not regretted any of those decisions. But most of my trucks are junk to begin with. Right now I have trucks that I want and would hate to get rid of them. So maybe a good question is: is there another truck you'd rather have? If you sold this one would you be making room for something you want more?
Is it the truck in your profile pic? It looks clean.

 

Find a better running 20R from a Celica and swap it in. or just get another head and have the machine shop work that one, then do the swap.

 

It is the truck in my profile pic. There are many other trucks I would rather have, but at the price point I can afford I would just be buying another pile of problems. At least here I have sorted many of them out. As was pointed out, it's not worth much as is, so dealing with it might be worth the investment anyway. I like the idea of getting an old Celica, but around here they go for more than the price of these trucks so that's not an option. However, I may have a lead on something, hopefully more on that soon!

 

It's a nice looking truck. You just don't see them anymore on the east coast, and if you did it would have tremendous rust.
I found this link for a rebuilt head. Looks pretty reasonable @ $300 plus your core.
https://www.shop.headsonly.com/TOYOT...PICKUP-20R.htm

You really don't know unless you open it up but it's likely a burnt exhaust valve. perhaps you could fix it for the cost of the valve, gasket set and time to lap it in but
you are better off starting with a freshly rebuild head that's had all that work done. Then it should continue to run forever, unless it overheats. Put a fresh thermostat in if you do the work.
How many miles are on it?

 

How randomly nice is this: I searched "20r" in the local craigers and found this fully rebuild head, rocker arm assembly, valve cover and gasket for $140!

 

There’s your sign!

 

Man, hope you're right and that I didnt make a mistake, when I got home I saw this 4M stamped on the side. Any thoughts? It was listed as 20r head but the guy didnt know anything about it, was a family members project that was left in pieces for him to deal with.

 

Thats a 20r valve cover and it loks like a 20r head to me but i dont have any idea about what 4M means.

 

Ooo. Looks clean! Good luck with the rebuild. Keep us updated.

 

I really like that truck, I think you should definitely fix it! ........but I almost always say fix it rather than get rid of it, even if it does not make financial sense........

I hope that head works for you.

I have no idea what the 4-28, 4M, or the 28 means.

Does your truck have a mechanical fuel pump bolted to the head or an electric fuel pump in the tank? I know some 20R powered trucks had a mechanical pump and others had an electric pump, but I don't know which trucks had which.

I don't see the mechanical fuel pump hole or the fuel pump eccentric in the head you just got, so I was just wondering.

 

So, it's interesting (maybe just to me) that the head is very slightly different than mine, and I think its from a 1975-78 20r. I believe the design changed slightly in '79 with the addition of some bolt holes next to the distributor and a couple on the other side as well, maybe to accommodate smog equipment? The design then changed again with the addition of the fuel pump hole and eccentric.

What's it all mean for my truck? Well, the fuel pump is in the tank, so thankfully I'm good there. And the head gasket is the same design for all 20r's, so I'm hopeful the new one will mate properly.

I cleaned it up this evening, it's been sitting around for who knows how long so I had to evict the spiders and stink bugs that were living inside and get it prepped for installation. I already ordered a gasket set, water pump and a few block off plates from LCE. Tomorrow the old head is coming off, if I can find enough time. By then I should have an idea what's going on inside and whether or not the rebuilt head will work.

Here's the stamp on the side of my current head showing both the additional mounting holes and what looks like 5-28 and 4M. Successor to the 4-28? I'm not a cylinder head scientist but it does fit Toyota's pattern of counting up a digit. I'm sure someone around here knows.

 

Good golly miss molly, looks like I made the right call!

 

Yup, burnt exhaust valve!

 

Yep, that exhaust valve does not look too happy!

 

Finally finished, hard to find time with three kids, felt like I was working in 5 minute increments. Anyway, it runs and sounds considerably better (obviously). Hopefully, if I did everything correctly, it will last a few more years!

 

Lookin good there, Sizzle Chest...
Are you planning to get a new fan shroud?
They really do help with keeping the cooling system at max efficiency.

 

Haha, I knew someone would call me on that, I wanted a photo before it got dark out, in fact a few clamps were loose and the alternator wasn't tight yet either. I got the shroud back in and everything tightened up!

 

Great! so simple and super clean. The good ol' days.