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

[Tom Young]

[
Changing the IP as an assembly, complete with governor and timer assy, should be a snap. Make certain that your existing IP mounts to the timing cover with four studs & nuts. I would expect the swap to be merely nuts & bolts, with the important exception of removing the Timer assy. from the front of the IP. It must be removed to get the IP off, and there's a special tool to do the job. I've never used the tool, but I thought I'd warn you anyway.


I don't know if the governor at the rear of the IP can be interchanged, but I think there is a good possibility that it could be. Members Galen and zen have more experience at this detailed level than do I.

Thanks Al. So if I have no reason to remove the timing assembly (don't know why I would), it sounds straight forward. I may look into some help from a local diesel mechanic at the boatyard for this.

To this point alone, it's been a long journey. I'm pretty well set with writing the check for the used engine. He'll need a week or so to remove so I don't expect to get started for two weeks.

I still know the used engine carries a risk but I think this makes sense in my case. After looking into rebuilding, I was less confident the more I looked into it. And the price was getting high enough to make me look at a new engine. At that point, I'd be approaching what I have in the boat total.

I'll be just as happy with a good used one and look forward to learning more about the engine in the process. After all, my boats almost 50 years old, that's one of the reasons I like it. I'm also looking for a shop manual, thanks for pointing the reprint on ebay.

[Tom Young]

Setting up a cross beam and come along, I hung it in my garage where I could start to strip off parts.

On removing the IP; Thanks to those that answered PMs with suggestions. I tried to fabricate the puller suggested by Jescos mechanic but couldn't find the threaded pipe.

I ended up carefully using a simple two leg 4" puller. By filing the fingers a bit and using two nuts as spacers between the pullers center piece and the legs, I was able to grasp around the fragile outer rim and grab the thicker area of the gear. It didn't take all that much pressure and a few sharp raps on the pullers screw and each one popped off.

One difference in the two blocks (1974 CN4-33, 1982 SD-22), the mounting bolt holes for the motor mounts on the 720 PU application, don't exist on the CN) However, both mount options are on the SD-22.

[Tom Young]

has been the biggest task. The stuff to marinize the SD is getting cleaned, rust removed, primed and painted. A boat engine is usually very hard to get to, this has been a pleasure.

I reused the CN4-33 flywheel which has a simple drive plate bolted on for the marine gear. As well as torqueing and locktite, the CN4 has three small plates, each with two flywheel bolt holes. Once torqued, these plates get bend up and around the bolt heads to act as an additional lockwasher. I was able to re-use them. You can also see the CN housing I swapped which also has the rear mounting bolt holes cast in. The two plates simply hold the marine cooling system heat exchanger.



Other changes; Valve cover-the CN4-33 has a breather tap in the cover that pipes into the intake manifold. I followed the Jesco mechanics advice and left it. (There must have been a reason)

Water pumps, pulleys; This is where the SD saved me some space. The CN waterpump is the same body as the SD. The pressed on hub is different and requires the deeper pulley. All this is simply to get the WP pulley tight enough to the engine to allow two or more pulleys for marine/ industrial applications. This requires a closer pulley on the crankshaft as well. This stacking enables more pulleys to be applied.

I stuck with the SD configuration to take up less space. I don't need a third pulley (as my CN was equipped). Also, I eliminated the tach drive and cover from the CN. I plan to use and electronic with my alternator.

IP changes; The CN IP with manual governor is longer. You can't use the SD spin on oil filter housing. I had to reuse the CN assembly(with cartidge filters) but, I was able to re-use the cast oil plumbing set up which eliminates the CN hoses between the filter assembly and oil cooler .

The CN IP also wouldn't clear the SD oil dipstick tube. I was able to remove and bend the tube to fit.

The CN IP uses a different engine oil plumbing tap-both are available on the SD.

[Tom Young]

I tried cross referencing some of the gaskets from numbers I got here. In the end, it was easier to do a full order from Jesco.

I'm waiting on; manifold, IP, WP, thermostat housing to block, oil filter housing, O rings, marine manifold to riser.

The best step I've taken, is putting things together dry. This has revealed some of the changes I needed to make.

As you can see here, the marine manifold is a big heavy piece. It requires some fine tuning for the alternator bracket. I've improved the CN secondary fuel filter mounting.

The CN raw water pump you see left front, has a heavy bracket that goes behind the right front CN mount. It slides so was adjustable for the SD pulley location. Using the SD WP pulley, timing gear cover, alternator bracket (different than the CN), secondary filter location, and stock pulley on the main shaft, has shrunk the size a few inches. This will be a plus in the boat.

I've kept the SD pan. The CN, due to the angle of installation (prop shaft about 7 degrees?), leaves an undrainable sump. The SD rear sump will get the CN oil plug which is drilled and tapped and plumbs to a drain line for pumping. The SD foward sump can be reached to drain the last cup or so.

Hopefully, I'll be putting it back in a week or so. I'm happy with how it's gone, so far.

[asavage]

. . . the CN4 has three small plates, each with two flywheel bolt holes. Once torqued, these plates get bend up and around the bolt heads to act as an additional lockwasher. I was able to re-use them.

A typical SD22 uses the same bolt lockplates:
(click on any image for larger)


Great pics, Tom; I appreciate your logging the details here.

[Tom Young]

And I used locktite as well.

Now that I have recieved gaskets, I can put it back together. I'd appreciate any feedback on the following;

The manifold gasket Jesco sent is a layed (2 I think) steel compression like gasket. I'm looking for installation info on them. Does anyone have any advice? It's an expensive item at 18.00 or so. It's likely used in the industrial applications and for my marine manifold. They had the special gasket from this manifold to the exhaust riser connection.

They sent me the wrong IP gasket (I should have been more specific here), the 3 hole instead of 4. The mechanic thought I would be ok using the existing (it's in great shape although compressed I suspect) using a little sealant. I know this isn't an area of much oil pressure, and this would likely work. But I was concerned I may have to adjust the timing afterward. He said if I was careful lining up the reference marks on the IP and timing gear case, it's not likely I would need to adjust the timing. That would be fine, but if I did, the silicone might make that difficult.

It's a pretty simple gasket, I could also look for material to make one. I'm trying very hard to eliminate any oil leaks but I don't want to wait for another California to Maine order. (It's only a 2 dollar light paper gasket)

In general, for water pump, thermostat housing, do folks reccommend using a sealant (I would suspect yes)? Also, never seize on the bolts and nuts?

I'm wondering too on the O rings for the oil filter housing to cooler, should those be oiled before assembly? BTW, Jesco charges 4 dollars and change for each of the 4.

[asavage]

They sent me the wrong IP gasket (I should have been more specific here), the 3 hole instead of 4. The mechanic thought I would be ok using the existing (it's in great shape although compressed I suspect) using a little sealant. I know this isn't an area of much oil pressure, and this would likely work. But I was concerned I may have to adjust the timing afterward. He said if I was careful lining up the reference marks on the IP and timing gear case, it's not likely I would need to adjust the timing. That would be fine, but if I did, the silicone might make that difficult.

My first SD leaked at that gasket; I never had the IP off or even loosened. The leak was minor but annoying. Even more annoying in a boat.

Because using any kind of sealant will make adjustment impossible, I don't think you can get away with sealant on both sides of that gasket.

The gasket could be fabricated easily (ie it would take me about 30-45 minutes). Thicker stock could be used, it won't materially affect anything. I would probably pay the USPS Priority (under $5) and have one sent, but if you're chomping to assemble, go ahead and cut one, it's only time, no real downside.

In general, for water pump, thermostat housing, do folks recommend using a sealant (I would suspect yes)?

I pretty much always use RTV in those areas. A thin coating -- it's very easy to use too much. For something easier to use and much more fuel-resistant, I use Gasgacinch (AKA "gorilla snot"), from my motorcycle shop days. I don't use it as much these days, but it's a very good product. The cans have always had a purple datecode stamped/inked on the bottom of each can, so you can tell how old it is before you buy it. Around here, it's gotten a bit harder to find lately, but I use so little of it that that hasn't been a hassle. The downside of Gasgacinch is that you have to be very careful upon disassembly if you want to save the gasket (it has better adhesion qualities than RTV).

Also, never seize on the bolts and nuts?

Anti-seize on any fastener that will come in contact with water or coolant; that will see high heat (over 350°F); where a fastener threads into aluminum: those places are all good candidates for anti-seize. I do not have a preference for the lead-based or copper-based or nickel-based anti-seize compounds.

I'm wondering too on the O rings for the oil filter housing to cooler, should those be oiled before assembly? BTW, Jesco charges 4 dollars and change for each of the 4.

I don't feel they need lubricating but it won't hurt. Depending upon your assembly technique, you might want to use a grease daub to help retain them whilst offering up the assembly to the block.

If you haven't already, read the SD Oil Cooler thread for dimensions and part Nos. for alternate source for those o-rings. I'll give you your next set

[Tom Young]

I lowered the engine back down into my truck. With the hoist on the travelift at the boat, we were able to get it back down onto the mounts.



Then with the transmission installed (not enough room to install it outside), I realigned the transmission coupling to the drive shaft and reconnected hoses, wires, exhaust, etc. etc.


Many improvements were made in the "new" engine. An especially nice improvement was finding a generic air filter at an auto parts store. Simply a bolt on for a 5 1/4" carb., I had to build a disk out of 16 gauge metal 5 1/2" diameter with a 2" hole in the center. I "knocked" an edge around the outer diameter using a hammer and a round pulley for an anvil. This edge simply centers the disk on the 5 1/4" face of the air cleaner. The 2" hole goes over the 2" hole in the manifold and the 2 pieces plus filter are through bolted back on. It's a light duty element which should be plenty for the dust free marine environment and certainly better than the cage and foam filters CN4-33s came with.



Yesterday, after launching the boat, the moment of truth arrived. I took it easy for sometime making a few minors adjustments and checking for leaks, noises, etc.

I'm happy to say, the results are beyond my expectations. Of course the new smoothness felt at idle is foreign. That jumping timing gear (see above) was causing alot of noise an uneveness. Beyond the small faint gray of a running diesel, there's no smoking.

Heading out to sea, I took the engine slowly up through the rpms. I very quickly reached hull speed motoring into a 10 knot wind and small sea. I realize now, the old engine may have needed some aligning on the beds as there was an almost total lack of vibration we used to feel.

I ran the engine to operating temperature which is now a bit lower with the cooling system cleaned and operating correctly. One of the more important things this process has taught me is how important things like flushing the cooling system periodically are. Tearing the old engine down showed alot of build up inside the cooling passages.

A few side notes; I carefully aligned the timing marks on the CN4-33 IP with the housing on reinstallation. It's running perfectly so I won't time it beyond that for now.

The cooling system is now operating correctly. Previous problems with losing coolant were due to corrosion in the seating area of the radiator cap on the manifold. This is covered in User Rigs- CN4-33 Radiator cap.

I've chased a few leaks. One oil that was simply tightening the drain plug on the filter housing. Using the SD22 cast oil channels from the oil cooler to the CN4-33 cannister oil filter housing is a great improvement. I've had leaks with the hoses on the CN4-33 .

If you make this upgrade to a CN4-33, put it all together loosely on the block before tightening. I had to do this twice to get the bolts to line up on the block. Despite still having to use the cannister and elements (the SD-22 spin off housing will NOT fit with the longer CN4-33 IP), I like this set-up that eliminates the hoses.

[kvw613]

When I saw those pics of the blue M4-33, I jumped. I'll bet someone can tell me the fuel and oil filter part numbers (WIX?) for that engine. I tried a lookup based upon Nissan 720 PU, but that gave me the wrong parts.

Also, the coolant hose that exits the block and goes back in behind the injector pump. I ended up cutting a Chrysler bypass hose, but if anyone has the exact part number, that would be greatly appreciated.

[Tom Young]

number and get the oil and fuel filters from Jesco out of California. You probably have those but if not, I can get them for you.

The SD 22 in the 720 PUs has a cartridge oil filter that won't fit the CN-33 which has a canister that takes a different element.

It would be great to know if you could cross those filters with another more available part.

Tell me about your boat and engine. Thanks.

[Tom Young]

And it's working very well. I've since changed the air filter set up. One problem unrelated to the engine has been my alternator. Being a high output Balmar atlernator, it can put quite a load on the belt when batteries are deeply discharged. That load has created some belt slipping which in turn creates rubber dust. That dust is right next to the air filter. I've gone to a larger filter which has improved things. Still the belt situation needs to be resolved. My next step is to try a larger belt. I'm now running a Gates 3/8" but I think a 1/2" may improve things. The Balmar pulley is set for either, the SD-22 pulleys look like they might work as well.

The SD 22 starts quickly, without fail, and runs smoothly. It uses about a gallon of diesel in an hour and half running time.

The only small problem I see is some oil consumption. It doesn't appear to be compression related as it's not visible in the smoke. It's not a large amount either. I add about a quart a season which last season was about 150 hours.

One thing I wonder is, the CN-33 has an oil breather hose that runs from a tap in the valve cover to the intake manifold. The mechanic at Jesco reccomended I swap the SD-22 valve cover (which does not have this tap and breather set up) for the CN-33 cover. The mechanic figured Nissan wanted that breather set up for some reason on it's industrial application and mechanical IP governor as I have, so I agreed.

Perhaps some oil splash is pulled through this breather set up. And then again on a boat, the engine is often running for hours at an angle of 30 or so degrees which could increase oil use?

Also, the CN-33 has a small housing crankcase breather similar to the SD-22 on the side of the block. On the SD-22 I've heard here it may drip some oil. on the CN, any oil is contained in the breather presumably to evaporate? At any rate, it doesn't drip.

Being in a boat, the engine is kept clean and painted. I see the smallest drip from anywhere so I know there is no leaking.

Any thoughts on this amount of oil consumption?

Not a big problem, a quart a season, and could easily be passed off on the age of this engine. It had few real miles use but is an 80's block.

Thanks again for keeping this site up and running Al. I stop in regularly.

Another note: I've changed my email to tomyoungdesign@gmail.com

[Nissan_Ranger]

Let's look at it in terms of driving a car... 30 miles per hour for 150 hours is 4500 miles. That's not too bad a rate of oil consumption for an older design mechanical diesel... I based that on the fuel consumption rate. I had at one time tried 15W40 diesel oil in my SD22 and had a ferocious consumption rate which was quartered when I went to a good diesel graded 10W30 synthetic oil. It may just be that your SD22 doesn't like the oil you are feeding it...

HTH,

N_R

[Nissan_Ranger]

You might try fitting a larger diameter pulley on the alternator which would give your belt a little bit more to bite on and increase mechanical advantage of the drive pulley. Both reasons will help the belt wear situation. The trade off is slightly reduced output at idle which is fine in this case as these older diesels don't take kindly to extended periods of idling.

[Tom Young]

Let's look at it in terms of driving a car... 30 miles per hour for 150 hours is 4500 miles. That's not too bad a rate of oil consumption for an older design mechanical diesel... I based that on the fuel consumption rate. I had at one time tried 15W40 diesel oil in my SD22 and had a ferocious consumption rate which was quartered when I went to a good diesel graded 10W30 synthetic oil. It may just be that your SD22 doesn't like the oil you are feeding it...

HTH,

N_R

Thanks, that's kind of what I wanted to hear. I thought I'd read something about oil usage differences in an older design of diesel like this. I hadn't thought about the type of oil though. I've been using a good quality CD oil from the boatyard but not paying attention to weights or type. I think I've used a single grade 30 or 40 weight oil. Use is usually in warm temps and I always try to run it long enough to get everything well heated.

As I change the oil about every 100 hours, would synthetic be worth the cost?

And on the pulley, that's something I may try after going up a size in belt. Thanks for the help.

[Nissan_Ranger]

As I change the oil about every 100 hours, would synthetic be worth the cost?

And on the pulley, that's something I may try after going up a size in belt. Thanks for the help.

For me, synthetic oil is the best oil I can think of putting into my engine. After I changed up, the first thing I noticed was that the oil pressure built up faster on a cold night start-up. The engine rolled over much easier when cold and started significantly quicker than with the dino oil.
There was a very modest increase in fuel mileage. The additive package held up better than the dino according to oil analysis with the soot contamination being the 'worst' figure at just under 50 percent allowable being reached. I change the oil and filter every 5000km. I use the Quaker state product as a fair compromise between quality and cost. I've always held the belief that oil is cheaper than an engine rebuild. I'm coming up to the 200000 km point on my engine and it runs as well as the day I put it into service. Minimal blow-by and less than 2 liters consumption between oil changes.

I base the pulley suggestion on my observation of engines and electrical equipment used in both stationary and farm tractor apps. The original equipment pulleys on those are in almost all cases significantly larger than those found in automotive service where there is a much larger demand on the alternator especially during the winter with attendant cold weather and long periods of darkness.

HTH, YMMV

N_R