1974 Chrysler Nissan CN4-33 exchange with 1982 SD-22

[plenzen]

Have not been here for a while and just read your post Tom.
IIRC in the CN-433 and CN-633 in some marine applications had double pulley alternators. I recall taking "matched sets" of belts on service calls. What I can’t recall is if they (engines) came equipped with the double pulleys or, if we had the crank pulleys made at a machine shop and the alternator ones came with the upgraded Motorola type “HO” alternators that were installed. I think the latter. The double pulley was to cure the very problem that you are talking about. As for the oil consumption that is not too bad. I can’t recall if you rebuilt the engine and put new liners/pistons/ and rings in or not. Even so, 1 qt a season is not outrageous. (In my opinion) Sounds like you are in a pretty mild environment for the most case and perhaps try a 15/40 Rotella or 15/40 Delo 400 and see what happens with that. If all else fails dump in a can or two of STP and “seal it up” with that.

Paul

[Tom Young]

I finally solved my belt eating problem. First, I fined tuned the alignment, that helped. I also installed a better seqmented Gates belt. Turns out, I was using too soft a belt. The other thing I did is install a simple switch that cuts my high output alternators output to 50%. That happens if batteries (3) are all discharged deeply. I have belt dusting problem down to very little and I went the last season with the same belt, no problems.

I rebuilt some galley cabinets and got this crazy idea. I used 1/4" Lexan on the back panel close to the engine. It's stronger than wood, has better temperature resistance, and it's a better sound deadening material.

The idea is now I can open the front door to check things like, belt problems, coolant leaks, even check various engine areas with a flashlight, for fluid leaks, all while the engine is running(sometimes 24 hour or more straight)!

See it running? Kids eyes pop out of their heads when I open the door.

[plenzen]

You are service mans dream.

Looks good too


After talking to another "old marine tech" from back in the day the Motorola's did come with the double pulleys

Just as an FYI

P

[Tom Young]

I just swapped my rebuilt and little used CN-33 injectors I saved into the SD-22. I shared the nozzle gasket info on that thread.

In re installing the injector return lines, I found a change. The CN-33 has individual injector return fittings that are plumbed via a metal return line header with short sections of hose.

The newer SD-22 has a one piece metal line connecting the fittings. A better set up(the rubber lines are prone to leaking)

Problem is, the SD-22 injectors have a channel in the top face the return line fittings sit on. There are two holes for the return fuel flow. They also have a copper washer between the injector and the fitting.

The CN-33 injectors have no channel just a flat face with one hole that feeds returned fuel through the fitting above.

I like the new SD-22 set up so I guess I'll give that a try on the CN-33 injectors. I can't use the copper washers though as it would be impossible to line up the tiny return flow holes. If that doesn't work(leaks), I'll have to go back to the CN-33 fittings and hose.

I don't know if you can dissemble the injectors(I doubt it) and switch the upper pieces without taking them back to the shop. It may be cheaper to just have the SD-22 injectors rebuilt.

Anyone have experience with this? Thanks.

[Tom Young]

I took some advice here and went with a multi grade oil the local boat yard uses. I think it was a Rotella in a 5-40 multi weight(I could be off on that).

I also found a leak! Because there are 2 oil senders on my SD22, one for the panel gauge and another for the alarm, I had the thread mix up going on(the 28 TPI vs 27 TPI). One sender was leaking a bit but I had missed it. Any oil leaking would go down the block and hit the rim that is the mating surface to the oil pan.

It would then travel along the rim and disappear behind the engine. Any occasional drips would go in the bilge. It wasn't until I removed the sender and it came off in my hand, that I realized where the leak was coming from. I now have that correctly threaded, sealed, and no leak at the sender.

I also had some leaking from the crankcase breather tube that was on the SD22. I noticed that was leaking at the weld between the tube and the breather that is bolted onto the block, not through the tube.

I went back to the original CN breather which has no tube, just a couple vents. Because those vents are turned upward, any oil that would presumably collect in the fine steel mesh inside, would drain back into the block after shut down.

Sure enough, that's what's been happening so far after about 30 hours running. No oil dripping yet. In heavier use(say 24 hour running), I wouldn't be surprised to see some oil run out.

Each of those three items didn't amount to much oil but at this point, I can just barely detect a change on the dip stick after 30 hours. I expect to burn a little, but overall I think my oil consumption(much of which was leakage) is comfortable now.

A big help has been buying one of those extending inspection mirrors. That helped spot leaks I can't seen because of the engines location in the boat.

One thing I haven't done is check the valves on this SD which I'll do soon. All in all, this is working out to be a great engine for the boat.

[Tom Young]

It is easy as I read on this forum. 7 were about perfect with a little drag of the feeler gauge. #5 had a large gap and needed an adjustment. I wonder why?

I also wonder, how close does the valve lash have to be before you get performance problems? Obviously, no gap is a compression problem, but a wider gap, up to a point, wouldn't effect too much? After a point, it would cause real problems.

I think #5 is the Exhaust for the 3rd cylinder. I surmise that means it opened a bit later than designed, and closed a bit sooner.

Now all 8 are doing what they were designed to do.

At any rate, it sounds great,...maybe even better now. At least that's what I'm telling myself.

[Nissan_Ranger]

Too much valve clearance = clatter with attendant rapid wear and loss of breathing in an engine that needs all the air it can get. I would make sure the rocker shaft and pushrod contact points aren't abnormally wearing as that would account for an abnormally large clearance.

N_R

[TOYoung]

Boat engines live a different life. Here in Maine, they're left all winter down inside deep, dark, damp bilges.

I change the oil and filter in the fall, and run it through the system before shutting it down for a 6 month sleep.

Come spring, there's a million things to do on a boat(I know, I do them all myself). Toward launch, I like to turn the engine over with the starter, several times, and let it sit to allow oil to move through the gallery.

With all there is to worry about on an old boat, there's few things as satisfying, as adjusting the throttle, pushing the glow plug switch for 20 seconds, and engaging the starter for just a second or two, and listen to an SD-22 diesel start, immediately, and go into a perfectly smooth idle.