So... I have two trucks.

1981, 4wd, 20R. This one's a keeper.
1991, 2wd, 22RE. This one's a beat-to-hell-and-back, I-can't-believe-it-still-runs, dear-god-what-is-that-thing beater I found abandoned a few years ago and got a title for. It's been the "village ride" for my friends and neighbors for 3 years now. I don't need or want it, and I doubt I'll get more than 1-1.5k for it.

I'm not very happy with the 20R. It starts reliably most of the time, stalls once in a while, misfires at idle, gets about 17mpg on 31's, pings when I get on it, and feels underpowered, rough, and janky. My plan is to eventually replace it with a 3L diesel, or perhaps a 2LT2 or 2LTE. This won't happen for at least a year or two, maybe longer.

I'm seriously impressed with the 91 and its 22RE. Despite 300k of hard miles and neglect, it has not once failed to start or broken down, and just plain... doesn't quit. The engine runs flawlessly and pulls hard all the way past 5k RPM. It has more than enough power, at least for the 2wd.

What would you do - sell the 91 2wd, and keep the 20R in the 81 until it gets its final engine? Or pull the 91's engine and throw it in the 81 as an interim measure for a couple of years? I suppose I could put the 20R back in the 91 too, but I'm not sure its value at that point would be worth the effort.

A tangential question: if the 91's trans is a W, will I be able to bolt it to my 81's transfer case without having to chase down a pile of parts?

 

I think with a good tune up and maybe a carb change you can make that 20r run as good as that beat up 300k mile 22re, depends if all the work swapping is worth it to you.

 

You won't be able to put a 2wd tranny to your transfercase. I agree with gillesdetrail, you could probably just tune it up or rebuild the carb and get that 20r running well. If it was me though I would put the 22re, but that's because that is the engine I would want in it. Would be silly to swap that all out and do it all again in a year. Why do you want a different engine if the 22re has "more than enough power?"

 

Sell/do whatever with the 91.
tune the 81 20R for now, get a good rebuilt 22R bottom end, get the 20R head rebuilt and do a 20/22R hybrid for the 81 and forget the diesel.
That's how I'd do it at least.

 

If the 22RE's compression numbers come out ok, is there any reason to be wary of its 300,000 miles?

 

I don't know about the 22RE as much, but my 81(early) 22R got to ~415k mi on the original engine before I pulled it. It didn't die, it was just really tired, so 300K on an RE doesn't mean it's dead, but it's probably due for a rebuild or will need one in the not to distant future.

 

If it runs fine and you have good oil pressure go and be blessed.

Swapping an RE into a carbed older truck is by no means rocket science but there will have to be a transference of electronics. The 20R and 22RE are realistically not far off in terms of power output. A toyhead/engnbldr/LCE cam and Weber would do wonders as would kicking your initial timing advance to 8-10 degrees btdc for that 20R. An adjustable cam gear and valve timing advance helps too. Any R engine without very serious mods can never be anything better than 'passable' in terms of power. Add a turbo or a blower and you can get decent power. By the time you start getting to the 140-150hp range a 3rz swap is best in terms of dollars.

I would second avoiding the diesel. I'd love one, but the L series is not renowned for being a good engine. It's tough to build a good light diesel. If you must go diesel a Cummins 4bt is the best option, but it will rattle that truck to death even with balance shafts. If you want to do a swap imo the best is a 2rz or 3rz. Look them up. Bigmike on Marlin has loads of info on it. A stock rz is going to output better power than a stock 22RET. Not to mention better mpg from a much smoother engine.

I like the R series a lot, but building one to as little as 180hp is very, very , super expensive.

 

I'm not after power, I'm after economy. Rarely do the expenses of an engine swap actually pay off in less than half a decade or so, but in this case, I already have a well-running 22RE truck that's all beat up and not worth much whole. I would not consider this swap at all if I had to buy an engine, let alone all the other bits. I'm not interested in buying any go-fast parts for either of the R engines; my budget will cover a rear main seal, timing chain guides, and not much else.

I've done considerable research on diesels, and concluded that a later L (well after they stopped selling them in the US) is the best for my needs. An 800-pound Cummins in a 3200 pound truck is out of the question.

Oil pressure? Good idea. I'll rig up a cheapie gauge and check.

 

Hey, it's your dollar. An RZ engine will further economy and be considerably less money to maintain than any L will. L engines weren't common to begin with and are becoming more and more expensive to maintain all the time. An RZ engine only requires moderately more work (electrical) to bolt into a first gen. You can get prefab mounts inexpensive and the RZ 5 speed bellhousing bolts right to the w56 just like the L will. Exhaust on the rz is even on the same side as the L.

Even if you have indeed spent considerable time looking into an L swap I would highly encourage you to look into an RZ. Just search bigmike on marlincrawler. With more availability, easier parts access, more future proof , more power and not substantially less economy it has a lot more to offer than the marginal at best L series.

If you aren't willing to even make some free mods to your 20R in the interim, the abysmal power output of the stock R engine is something your going to have to put up with until you do some kind of swap.

 

If you're after economy your best bet is to drive the 2wd until it croaks. The 2wd trucks average 8-10mpg more than the 4wd do. They weigh 8-900lbs less (my 76 scaled at 2400, my 82 4x4 scales at 3200 roughly) and sit much lower to the ground for better freeway mileage.

Also, a well-tuned and properly running 20R will have the same economy potential of a fuel injected 22RE. The only carb engines that do worse are either hopped-up a lot, broken or have a tuning issue. My 76 2wd, mildly cammed and Weber'd, averaged 28-29 mpg on three seperate trips from Seattle to Eugene, OR cruising at 65-75mph. Mixed with city driving my average was 24-27. The economy benefit, if there were one, from swapping in an RE would not be worth the effort realistically.

The only reason to put an RE in your 79 would be because you want to or had plans down the road that made fuel injection a logical choice. There is no practical benefit otherwise. Plus, being it has 300k on it, you could consider it's days numbered. If your 20R is lower mileage it would be most uneconomical to swap it for a 300k engine.

Just some other considerations since I have a keyboard in front of me now.

 

The reason I want a diesel is to be able to run biodiesel, and have no electronics but still reasonable efficiency. This decision is a bit arbitrary, more of a "peace of mind" thing that can't be dissuaded by mere numbers of fuel economy and parts costs. If I change my mind, though, an RZ is at the top of my list.

Anyway, my question is about a shorter-term (stopgap) solution. I can't keep the 2wd truck, I just thought I'd pull its engine to make a relatively small, incremental, and cheap improvement to the 4wd that I want to keep.

Free mods? I'm listening. A cam and Weber carb aren't free, though.

Again, it's not power I'm complaining about. The 20R's 90hp is adequate for my truck and driving style. I just want to get better than 15-20mpg.

 

You brought the power issue into play. It directly relates to economy, and all R engines (except maybe the Turbo) are underpowered for a 3200lb 4x4. There is a radical difference in weight that will make the 22RE seem disproportionately powerful vs the 20R. While RE's do produce a bit more HP, in most RPM's encountered in normal driving the difference is quite minimal.

15-20mpg is all you'll ever get from an R in 4wd form, regardless of fuel delivery system. Might be able to squeeze 22 if you are ridiculously light on the throttle. These trucks ride high with the aerodynamics of a refridgerator, there's not a lot that can be done besides.

Advancing your ignition timing to 8-10 degrees btdc, as I already suggested, won't hurt and will make it idle smoother and might pep it up in the bottom end. And it's free. Though with your pinging issue you'll want to be careful with advancing ignition timing. Probably bad or low grade fuel. Certainly a tuning issue. There are other things you can do as well. You can search the forum for all kinds of tuning tips on how to get you the sharpest edge possible on the balance between power and economy without gross expenditure. You might even find deals or free things from the generous and helpful yotatech body. I've given away jet kits, adaptors and various other bits myself to folks here and elsewhere.

If you were to make the effort of trying to retrofit an RE in place of the R you would find little hidden costs that would creep up here and there. That's just the nature of modifying vehicles.

Also, "This decision is a bit arbitrary, more of a "peace of mind" thing that can't be dissuaded by mere numbers of fuel economy and parts costs." You will find those mere numbers on real costs to be quite relevant. If not now, then later.

I just want to try to help you go into this with eyes wide open. I see folks with big ideas sell their vehicle half finished at a major loss quite often. I believe you can succeed at anything you wish to, just be aware and accept information for what it is.

 

Well, yes, I wouldn't say no to a bit more power as well. The main thing is that below 3k I can't use full power because it pings. Adjusting the ignition timing doesn't seem to make a bit of difference.

I drove a 98 Hiace AWD work van, loaded with easily 1000# of tools, powered by a ~100hp 2LTE up and down crazy Norwegian mountain roads. It was adequate; nothing more, nothing less. It was a lot more adequate in practice than the power/weight numbers would suggest in theory.

Hmpf. You're right about this; I've done major engine swaps in other vehicles and little things definitely creep up. And the more I look under the 2wd's hood the more little things I see that need to be addressed, and some of those can't be done free.

I didn't say they weren't relevant, just not decisive against the sum of the reasons I want a diesel. Few if any of us would be driving the vehicles we do if we made transportation decisions on strictly rational, numerical criteria. As a fellow vehicle enthusiast, I think you know what I mean.

I do appreciate the information and perspective, thanks.

 

Agreed.

I apologize if I come off strong and opinionated. I've been working on vehicles for 15 years and spent two of them at a Dodge dealer and Swift Transportation as a mechanic. I don't get the opprtunity to step outside my own little mechanical world much anymore and I really like to make sure, to a detail, that everyone understands what's going on. I love DIY folks, but it can be hard for people to separate desire from reality when they haven't seen or experienced the pitfalls of vehicle modification. I hate seeing people make unnecessarily expensive mistakes, and I don't mean to imply that's you or anyone else in particular.

Now, to try to solve that pinging issue. Have any ideas?

Lean condition, incorrect ignition timing, correct heat-range on the spark plugs, carbon buildup and low ocatane fuel can cause that.

Is it high-mileage or does it have any cooling system issues?

 

I would not bother swapping that 22re. Mine kicked a rod out at 338k miles so you may be approaching the fatigue limit of the rod bolts.

 

Hard-earned and useful words of caution, but as they say in another time and place, this ain't my first rodeo.

It's an 81 with a desmogged 20R in it. I was told it was rebuilt shortly before I bought it (three years ago) but other than no oil leaks and general cleanliness, I have no evidence for this whatsoever. I have no idea how many miles are on anything I haven't bought brand new. The block and carb could have 20k, could have 420k.

I run 87 octane "top tier" gas, and all ignition parts except the coil (Denso?) are 3 months old: Denso 3031 spark plugs, Denso 674003 plug wires, Beck/Arnley cap and rotor. When the old plugs came out, there was nothing noteworthy.

It runs about 2/3 up the normal range on my temp gauge, and will rise a tick (still comfortably below the red zone) on hot days in traffic. No other cooling system things worth mentioning.

Carbon buildup? Ok, how does an R motor like the Seafoam/smoke-out-your-zipcode treatment?

Lean condition? I suppose that means a carb rebuild? I bought a kit, just been dragging my feet on doing the job.

In addition to pinging it sputters at idle (misfiring slightly). There's no stumbling when I goose the throttle, and above 3k it's unrefined but sounds and feels ok.

Another nail in the coffin. Alright, I'll direct my efforts elsewhere and sell the 2wd whole and running.

 

Welp, if you pull your plugs, or a plug, you can check the heat range and condition. If the plug is sooty and black it's rich, white or very lightly tan it's probably lean. Tan or brown is about right. I googled your plug and the 3031 came back as a 5 heat range. I don't know the factory spec, but a colder plug like a 6 or 7 might be the ticket... I run 5's and have no problem on 87.

Seafoam is good stuff and I've used it often in crankcases and fuel tanks. It won't hurt.

The carb may just need adjustment. I don't like factory carbs and have no experience with 20/22R factory carbs specifically except to throw them out the door. The 22R carb is by far the better of the two, but that doesn't solve your problem. You can try searching the web/forum/youtube on 20r carb tuning and rule it out. Without any stumbling I question if it's lean...

Will it hesitate under load? An ignition system issue can cause sputtering at idle too. Does it idle real erratic and hunt a little? I ran across an interesting issue with my old dizzy; the springs on the mechanical advance loosened up and it would idle wierd. Worked fine when revved up but at low engine speed it was wonky and impossible to tune the jetting. A timing light would reflect this as the mark on the pulley would bounce around all over and the advace would be hard to accurately check. A manual check under the cap for cracked plastic around the reluctor/sensor (I'm assuming points were done on the 20R by this POINT, pun intended) and for slop in the advance mechanism, corrosion on the cap contacts and rotor contact and the spring tension on the center contact on the cap is easy and fast. You can check ohms on the wires as well. One could have a problem even if it is newer.

In the dark you could check around the ignition system for arcing and such, see if any insulation is bad or if any boots are arcing.

Did it run like this before the ignition parts were installed?

 

It's run like this since day one, perhaps a touch better since the tuneup. Those plugs and wires are OE spec. It does not hesitate. Idle is quite steady. I did put a timing light to it but don't remember what that showed.

 

Very strange to have detonation issues on a 20r, being that they are 8.4:1 comp ratio when new which is very low, I would put my money on timing and lean mixture I think. I also would not run any motor that has been abused and unmaintained, no matter how tough they supposedly are. (talking about the 22re).

And a good seafoam treatment through the carb done the proper way can't hurt just to see how it runs after.

 

That's all I can conclude as well. Unless you happen to have the worst luck in the world and have been getting the most awful fuel in the country on a consistent basis for three months. Please don't bring it here... lol.