I have an ol slant 6 that I got running yesterday. She's smoking like a chimney. Trying to figure out if I should swap the motor or nurse this one back to health. Lottsa blow buy coming out of the valve covers. Anything I should try before I ditch the motor for a v8? Diesel in the cylinders? Marvel oil? #6 is at 120 and the rest are between 130 and 140.
According to wiki it was a pretty rare base option between 69 and 73 though that truck in the front looks older than that.
If it's in an old truck, and you plan to drive it a lot of short trips, rebuild the six shooter. If you plan to drive it a lot of. Highway or plan to sell install an V8, no non HAMBer wants to buy a straigth six, because to "stupid and borring"-people, sixes are no good. But re-ring, re-gasket, small valve job and a carb/ignition upgrade. And you might be golden. But tell more about the vehicle, miles on odo-meter, how you use it, has it been standing for a long time, what oil, how old is the oil, does it have an oil filter and PCV? What year vehicle, what year engine, model and trans etc. Tell all, show all! And this time pics of, vehicle and engine left/right/center.
Nurse it back to health? Maybe an overhaul will fix it. LOL It could be stuck rings, or bad guides or both but the only way to know for sure is to open it up and while you got it open why not make it right.
I'd say it depends on what you want the vehicle to be, when you're done with it. Do you want to run a 198 six? or do you want a V8? or a diesel? If you don't want to have a six, then ditch it and get what you want. If you're ok with a six, and don't want to spend a lot of money, you could either do a ring job on the engine, or find another one that's in better condition. But see it run before you buy it!
If that is a D-series truck, it should be a 170 or 225. But trouble would be the same, but the question is would a 170 be worth the trouble. In terms of what you get for every dollar you put in. I have no experience with slant sixes, so I cant give you no advice on model, but more in the general stroke regarding excessive smoke, or about what I would do in your place.
Many posters of question like this assume that members of the HAMB are "Mind Readers"never full details of the problem..
You could try the diesel or mystery oil thing, but you might have to put a few miles on it before things clear up. I will tell you this, though. If it really is a 198, the rods have value all by themselves. One can build a "long rod" motor by using a 225 crank, 198 rods, and 2.2L, 4-banger pistons and matching rings. Just have to bore the cylinders to match the pistons. You end up with a bolt-together, 10.5 compression motor. (11:1 compression if you use normally aspirated, flat-top pistons.) If you do drop a V8 into it, go over to the slantsix.org board and offer the rods for sale. Roger
I had a 66 El Camino that had a 194 in it. Like a doofus, I rebuilt it. It wouldn't pull a sick woman off the pot. The most gutless car I ever owned. Couldn't pull a trailer, couldn't really put much of anything in the bed. SO, I would put a bigger engine in it if was going to keep it, no matter what. Those are neat trucks, good luck with it.
I don't know how you can have that good compression and bad rings. How many miles on it? How long has it been off the road? I have had a lot of slant sixes and they are a hard motor to wear out. If I had one that started and ran, and had that good compression I would give it a chance. If it has been off the road for years I would change the oil and filter, adjust the valves, tune it up and drive it. Maybe give it a shot of Bardahl or something to free sticky rings. Drive it 1000 miles and see if it comes around. On the other hand if it has more than 200,000 miles on it and has never had an oil change or tuneup there is a chance it is worn out.
What makes you think it's a 198? I thought they always used a 225 in trucks? Camera angles can be tricky but it looks like a short box fleetside Dodge truck 1971 or older. A slant six will haul one of those around nicely with any reasonable load and a few unreasonable ones. A little buzzy on the hiway and you won't want to go more than 60MPH. If you can live with such boring limits a slant six is an excellent choice. With a manual trans 20 MPG is a definite possibility and reliability and long life guaranteed. I drove similar trucks with slant six engines for years. On the other hand you could swap in a 318 or 360 and automatic over a weekend. Both will give better performance but kill mileage especially the 360. Both will work with the slant six rear axle and give more acceleration and top speed.
I keep coming back to the good compression and bad oil burning. This seems to point to stuck rings from sitting. In your case you could take the head off, drop the pan, and pull all the pistons without taking the engine out of the truck. The beam front axle makes this a cinch, since it does not get in the road of the pan the way an IFS does. If the engine is not badly worn and the cylinders are not tapered you could hone the cylinders put new rings on the old pistons and be ready to go for the cost of a gasket set and some rings. This would be a last resort if the rings don't free up with driving. In any case I would try it on the road before I made up my mind to do anything.
The Jalopy Journal
