Nissan SD22 engine issues

[Cowtownflyer]

Hello, I recently purchased an older sailboat from 1974 which has a Nissan SD22 motor installed. The previous owner had dis-assembled some of the engine components. I am struggling with the cooling side of the equation.

Can anyone help me with photos of this engine in working order ? Or direct me to where I might locate a marine version manual for this engine. I did download a rebuild/service manual online. It is good, however, it does not address marine application engines. Cooling system assembly, heat exchanger and things of that nature.

Any help would be greatly appreciated ! Thank you, Jim

[GordMay]

Greetings and welcome aboard the CF, Jim.
The Nisson SD22 was also produced in a marine version, MN 22, by Chrysler Marine under license during the 1980s.

[Compass790]

Welcome to the learning curve. If you cannot locate any info specific to yr MN22 try looking up schematics for fresh water cooling system on a marine diesel on google or look at another marine engine manual as they have similar ways of working in general.If you have reasonable mechanical skills you may be able to nut it out from there
Google is your friend here if no-one on CF can supply you with a manual.
You are lucky you found CF, it's a mine of information, not infallible, you may have to sift thru for the nuggets sometimes but well worth it

[GILow]

Originally Posted by Cowtownflyer

Hello, I recently purchased an older sailboat from 1974 which has a Nissan SD22 motor installed. The previous owner had dis-assembled some of the engine components. I am struggling with the cooling side of the equation.

Can anyone help me with photos of this engine in working order ? Or direct me to where I might locate a marine version manual for this engine. I did download a rebuild/service manual online. It is good, however, it does not address marine application engines. Cooling system assembly, heat exchanger and things of that nature.

Any help would be greatly appreciated ! Thank you, Jim

Jim, I have the Nissan ED33, similar to the SD22, just a bit bigger and a hell of a lot noisier.

The original Diecon conversion of the ED33 engines (and if you are in Australia you probably have a Diecon conversion if it is a Nissan) just involved bolting on a very crude boxy water-cooled exhaust manifold that also doubled as the header tank. This was fed by coolant exiting the head through the thermostat housing, and sits in the cooling circuit in much the same place the radiator would have originally occupied. The output from the exhaust manifold tank went to a heat exchanger, usually mounted transversely above the bell housing, but I have seen an installation on a big motor boat where they'd moved the heat exchanger to a bulkhead beside the engine because they had the space. Water returns from the heat exchanger along the port side of the engine to the standard cooling water pump.

Now the SD22 seems to have the exhaust and intake manifolds on the same side, to I guess their exhaust cooling system must be a little different, but if you post pictures we can probably describe how it all should go back together.

Generally speaking though, most of the conversions of car/light truck engines I have seen simply take the output from the thermostat housing, use that water to cool the exhaust manifold, then pass the whole lot off to the heat exchanger before returning it to the engine. The thermodynamics of this make sense, since the exhaust manifold is the usually the hottest part so you don't want the water from that component anywhere near the engine until it has been cooled again and passing it hot water from the head is not such a problem because rate of heat transfer is proportional to the temperature difference.

[Compass790]

I suspect OP is USA based: "sailboat". If so he likely has the Chrysler variant

[Cowtownflyer]

Originally Posted by Compass790

I suspect OP is USA based: "sailboat". If so he likely has the Chrysler variant

You are correct, Sir !

[Cowtownflyer]

Originally Posted by GILow

Jim, I have the Nissan ED33, similar to the SD22, just a bit bigger and a hell of a lot noisier.

The original Diecon conversion of the ED33 engines (and if you are in Australia you probably have a Diecon conversion if it is a Nissan) just involved bolting on a very crude boxy water-cooled exhaust manifold that also doubled as the header tank. This was fed by coolant exiting the head through the thermostat housing, and sits in the cooling circuit in much the same place the radiator would have originally occupied. The output from the exhaust manifold tank went to a heat exchanger, usually mounted transversely above the bell housing, but I have seen an installation on a big motor boat where they'd moved the heat exchanger to a bulkhead beside the engine because they had the space. Water returns from the heat exchanger along the port side of the engine to the standard cooling water pump.

Now the SD22 seems to have the exhaust and intake manifolds on the same side, to I guess their exhaust cooling system must be a little different, but if you post pictures we can probably describe how it all should go back together.

Generally speaking though, most of the conversions of car/light truck engines I have seen simply take the output from the thermostat housing, use that water to cool the exhaust manifold, then pass the whole lot off to the heat exchanger before returning it to the engine. The thermodynamics of this make sense, since the exhaust manifold is the usually the hottest part so you don't want the water from that component anywhere near the engine until it has been cooled again and passing it hot water from the head is not such a problem because rate of heat transfer is proportional to the temperature difference.

Hey there, thank you for getting back with me. Yes, there is a heat exchanger mounted transversely at the back of the engine. There are water jackets within the marine exhaust manifold. There is also some type of exhaust riser that mounts to the rear of the exhaust manifold - the previous owner had removed this item and just recently returned it to me. I note that this "riser" blocks off the water jackets of the exhaust manifold when installed. I have not been there yet.
I will attempt to post a couple of photos. Sounds like you may be able to set me on the right track Mr. GILow

[GILow]

Originally Posted by Compass790

I suspect OP is USA based: "sailboat". If so he likely has the Chrysler variant

Very nice use of linguistic clues there! [emoji106]

[GILow]

Originally Posted by Cowtownflyer

Hey there, thank you for getting back with me. Yes, there is a heat exchanger mounted transversely at the back of the engine. There are water jackets within the marine exhaust manifold. There is also some type of exhaust riser that mounts to the rear of the exhaust manifold - the previous owner had removed this item and just recently returned it to me. I note that this "riser" blocks off the water jackets of the exhaust manifold when installed. I have not been there yet.

I will attempt to post a couple of photos. Sounds like you may be able to set me on the right track Mr. GILow

Interesting. The US “sailboat” variant seems similar in setup to the “outback Aussie” approach.

Yes, the exhaust riser on mine blocks off the end of my exhaust manifold jacket too. (This may be the norm for lots of marine engine conversions for all I know)

Now, looking at the photos I am a bit confused. Would you say the water leaving the thermostat housing goes to the exhaust manifold jacket or the heat exchanger on your setup?

[GILow]

OK, looking a little more at that second photo on something bigger than my phone, I think I can see how it is setup. Looks like the fresh water circuit is complete, hose from the top of the thermostat to the the heat exchanger. (The ribbed hose) And a return to the fresh water pump down the injector pump side of the engine.


Separate to this, there seems to be a second smaller hose running from the thermostat housing to a copper pipe (3/4 inch at a guess) this is either for heating water in an onboard hot water storage tank or, if it goes to the heat exchanger (hard to tell from the photos but this might be happening) then it is an anti airlock system to prevent a closed thermostat causing air bubbles and hotspots in the head.

What I cannot figure out, is how water gets to the exhaust manifold. This is important. Can you take more photos, this time from the front of the engine, showing more detail of the thermostat housing?

The two unused smaller hose fittings on the engine manifold side of the heat exchanger (assuming port side from the pics) are probably the raw water feed and exit. Hook those one of these up to the raw water pump. If it is a water cooled exhaust, the riser will have an injection fitting for raw water near to the top of the riser but on the downhill side, that is where the other raw water exit fitting on the heat exchanger usually goes.

When I say unused, I should probably say ONE appears unused, the other appears to be hoooked up to the hose running diagonally across the top of the engine. Where does that diagonal hose go" Raw water pump maybe?

Can't see a raw water pump in either of the photos. Should be visible from the front as it would be run from the V belt on a Nissan engine. Mine is on the Port side, but the ED33 has a cross flow head with the exhaust manifold on the starboard side and the intake on port, so the pump is easier to mount on the port side away from the exhaust manifold heat. On your engine, I'd expect the pump to be on the starboard side, all else being equal.

[GILow]

P.S. That's a much nicer exhaust manifold than my setup. Mine looks pretty darn crude in comparison.

[Cowtownflyer]

GILow, hello there.

I will take some additional pictures. Here's the deal with this boat. The previous owner did zero maintenance. And in fact, drained engine oil directly into the bilge from the motor which he did not clean up. The boat is taking on some water - I think, but cannot confirm that the water is coming in through the stuffing box. So I am currently dealing with this cleanup issue.
Prior to all this, apparently the boat had been left unattended for a lengthy period and took on so much water that the marina operators luckily noticed it was sinking and pumped it out. I am told by the previous owner that the motor had been completely submerged. It hasn't run since.

The engine turns over and I have tested the compression through the glow plug ports - it's the best I can do at this point. So I have a cold engine compression of about 300-320PSI on each cylinder. Should be minimum of 356psi on an intact and warm engine according to SD22 manual. So my objective is to disassemble the fuel side - rebuild the injector pump and injectors. Then address the cooling side. Because the cooling side was already disassembled, I don't have a clue how it goes back together - this is why I am seeking help. Note: the hot water tank is missing from the boat...

For your reference, this boat is a Challenger USA 35 built in Wilmington CA during the 70's. I purchased it just last week for basically nothing with the aim of breathing some life back into the thing. It is in the water at Lake Mead near Las Vegas. My goal is to refit so that I can transport to the ocean near San Diego CA.

[Compass790]

Incredible what people do! Draining used sump oil into the bilge is a new one on me.
Just want to relate a bit of experience here. I think it's a good plan to check for parts prices & availability of parts before you get in too deep. If you have time check what you need after stripping & make a parts list. You may find you can buy a good used engine for considerably less.
I went through a total rebuild on our Yanmar, New parts cost would have been over $2500. I rebuilt it for about $1100 using aftermarket parts, used parts & machining myself or getting mates to machine for mates ( buddys in American ) rates. But I could by a good reconditioned one for $ 1000 to $1500. Took a lotta hours chasing parts etc.
Parts prices for Yanmars are 1/2 the price in USA & used engines are more expensive on Ebay as compared to New Zealand so it might not be a fair comparison but it's the principle thats worth looking into.
The advantage of doing it yourself is you know the engine after that but it's a lotta time. Also you know it fits the engine bed, prop etc. You have to weigh up what's important to you I guess.
Hope this helps

[Cowtownflyer]

Originally Posted by Compass790

Incredible what people do! Draining used sump oil into the bilge is a new one on me.
Just want to relate a bit of experience here. I think it's a good plan to check for parts prices & availability of parts before you get in too deep. If you have time check what you need after stripping & make a parts list. You may find you can buy a good used engine for considerably less.
I went through a total rebuild on our Yanmar, New parts cost would have been over $2500. I rebuilt it for about $1100 using aftermarket parts, used parts & machining myself or getting mates to machine for mates ( buddys in American ) rates. But I could by a good reconditioned one for $ 1000 to $1500. Took a lotta hours chasing parts etc.
Parts prices for Yanmars are 1/2 the price in USA & used engines are more expensive on Ebay as compared to New Zealand so it might not be a fair comparison but it's the principle thats worth looking into.
The advantage of doing it yourself is you know the engine after that but it's a lotta time. Also you know it fits the engine bed, prop etc. You have to weigh up what's important to you I guess.
Hope this helps

Yes Sir. Draining engine oil into bilge is an incredibly stupid thing to do. The epitome of laziness I think. Toxic and dangerous. That said, I just today ordered this new product I found online to see if it won't help me. Oil Solutions powder from www.cleaningupoil.com. It better work as I am counting on it.


Cost of engine rebuilding - you don't have to tell me. I just finished up this BBC starting with a block only. By the time complete big $$$ for engine - not to mention everything else...another project I have - 70's jetboat.


Back to Nissan, I plan to spend as little as possible to see if I can get the motor to start and run. Hobbs states total of 645 hours on engine. That's pretty low hours for diesel motor so reckoning that it turns over, and I have compression, I would be nuts to do any more than just go through the systems and refurbish only as necessary. Can always address rebuild/replace issues at a later date if I can get the thing to start and run.

Cheers !

[Compass790]

Oh well if the hours are that low maybe the major problem may just be the P.O.'s ignorance.
Ok you have experience so you know what you are getting into. Good luck with it & let us know what you find & how you get on.
cheers