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Old 11-09-2015, 07:33 AM   #61
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The Perkins service manual I have doesn't give specifications on blowby, compression or exhaust temperature. Nor do any of the suppliers I use have a compression test adapter to fit the Perkins engine.

You can get a reasonable idea of blowby by measuring crankcase pressure with a manometer or low pressure gauge on the dipstick tube. I don't have any guidelines from Perkins, but we generally use a rule of thumb that it should be less than one inch of water column assuming that your crankcase breathers are open.

We just finished the in-frame overhaul of a 6-354 in a piece of construction equipment, but that was due to having been started with ether and two pistons being destroyed. It's a PIA because of having to press in the sleeves, but other than that pretty much routine.

The one in "Rise 'n Shine" needs a rebuild on the sea water pump - I tried and failed to get the impeller out on Saturday because the cover screws are frozen - two of them refuse to turn with a screwdriver (Never-Sieze is called for...) and rather than wrestle with it in the boat, I'm going to yank the pump, bracket & all and give 'er a dose of love. New seal, coupling element, impeller, the works, mainly because I have no idea how long this impeller has been in there and from the looks of the pump it may have been a long time.

Also, I discovered the Vee-band clamp that holds the wet elbow to the exhaust manifold was loose. So, I'll pull it as well and give 'er a thorough inspection. My inclination is to order a new one just because of the age, but I'll have a look at the existing one first. This unit has at least one failed thermostat, so I'll replace them as well.

When all that is said & done, it should be in pretty good shape for next year.

Cheers!

J.S.
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Old 11-09-2015, 07:33 AM   #62
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Just to be clear...I did NOT modify MY Perkins, I only posted what someone else did.
However, if I still had the Perkins I would without a doubt convert the manifold to coolant cooled. I would use the same raw water pump, I would simply add a small generic heat exchanger to the circuit.
I would also coolant cool the intake air.
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Old 11-09-2015, 07:38 AM   #63
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The Perkins service manual I have doesn't give specifications on blowby, compression or exhaust temperature. Nor do any of the suppliers I use have a compression test adapter to fit the Perkins engine.
Well an adapter for compression testing DOES exist. A tech (from Noank Shipyard, they were a Perkins dealer at the time) did a compression test on mine in 1989 He actually took the readings with the engine running. I had never seen that done before.
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Old 11-09-2015, 01:27 PM   #64
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Well an adapter for compression testing DOES exist. A tech (from Noank Shipyard, they were a Perkins dealer at the time) did a compression test on mine in 1989 He actually took the readings with the engine running. I had never seen that done before.
Indeed they do exist. I had mine compression tested about 10 years ago and found a bad valve on one engine. The Perkins manual, that they sell to the public, doesn't reference the testing procedure. The attached video of compression testing a Perkins 4 cylinder engine is typical of the procedure and the adapter. Test results will probably be a little different for the 6.354, as the compression ratios are not the same, 22:1 verses 16.1 respectively.

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Old 11-09-2015, 05:22 PM   #65
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Originally Posted by jleonard View Post
Just to be clear...I did NOT modify MY Perkins, I only posted what someone else did.
However, if I still had the Perkins I would without a doubt convert the manifold to coolant cooled. I would use the same raw water pump, I would simply add a small generic heat exchanger to the circuit.
I would also coolant cool the intake air.
Thanks J, I should have noted that.

I agree about the exhaust manifold. And regards to the air charge cooler, the raw water is killing the cast iron housing. I've got it on my workbench and took at least a pound of scale out it, then wire wheeled and epoxied it. I'm also adding a zinc, although it might be useless. I think I'll eventually replace it, or fabricate a SS housing. The raw water goes through it first, on the suction side so I think any obstruction there is exacerbated. I've seen water under suction form vapor bubbles when going through occulusions.

But I'm skeptical of putting the hot freshwater through there, even it's just passed the main exchanger. I compared the air temp on both sides of the charge cooler and it went from 80 to 70 degrees, and that was before I cleaned it out.
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Old 11-09-2015, 05:34 PM   #66
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Originally Posted by Driftless View Post

You can get a reasonable idea of blowby by measuring crankcase pressure with a manometer or low pressure gauge on the dipstick tube. I don't have any guidelines from Perkins, but we generally use a rule of thumb that it should be less than one inch of water column assuming that your crankcase breathers are open. .

The one in "Rise 'n Shine" needs a rebuild on the sea water pump - I tried and failed to get the impeller out on Saturday because the cover screws are frozen - two of them refuse to turn with a screwdriver (Never-Sieze is called for...) and rather than wrestle with it in the boat, I'm going to yank the pump, bracket & all and give 'er a dose of love. New seal, coupling element, impeller, the works

J.S.
Great info. I did the same with my water pump and had to put nuts on the backside since the threads were shot. Are you replacing the water pump cam? Mine looked worn but didn't have a spare.

Regarding the blow-by, I took the breather hose and stuck it in a big garbage bag at 1000 RPMs in gear while tied up at the dock to simulate some load. The bag was taking forever to fill so I abandoned it and figure the blow-by is not bad. Can I just connect a clear loop of tubing to the dipstick with some water, and leave the breather hose open? Because that seems like there'd be no pressure at all. The breather runs to the suction side of the turbo. But It sounds a lot simpler than rigging up an oriface on the breather.
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Old 11-09-2015, 05:41 PM   #67
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I'm a bit anxious about the exhaust manifold, since it's slowly corroding away and once it leaks the engine it ruined. I pressure tested it, but that just means it's OK at the moment. Is there any way to gauge it's internal condition? I can't think of a worse situation, with extremely hot exhaust separated by a thin layer of iron to salt water in a place you can't inspect. If that manifold is anything like the Bowman cooler it's ready to leak. I have no info on the history either. I can say it looks good on the outside, but so did the Bowman.
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Old 11-09-2015, 05:58 PM   #68
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Originally Posted by Sweet marie View Post
My Perkins are plumbed to be flushed with fresh water after each use.
I was sceptical but after seeing the inside of the air charge cooler I'm leaning towards this more. My setup is complicated because the air charge cooler is on suction side, so I'd have to bypass the raw water pump somehow. And the reason I got this boat in the first place was because I was tired of flushing my other boat's raw cooled engine after every use. I wanted a boat I just shut down and walk away from. Maybe I could plumb something into my sweet water tank so I don't need to mess with a garden hose.
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Old 11-09-2015, 11:34 PM   #69
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I wanted a boat I just shut down and walk away from. Maybe I could plumb something into my sweet water tank so I don't need to mess with a garden hose.

That is a viable option, but you'd still need to keep the water tank topped off.
Ever considered keel cooling?
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Old 11-10-2015, 07:32 AM   #70
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But I'm skeptical of putting the hot freshwater through there, even it's just passed the main exchanger. I compared the air temp on both sides of the charge cooler and it went from 80 to 70 degrees, and that was before I cleaned it out.
Many engines have their after coolers cooled by antifreeze. Both Cummins and Cat have models that do. No it won't cool the air as much, but they are maintenance free (almost) and the air intake system won't be making water via condensation when you are running slow.

Quote:
Are you replacing the water pump cam? Mine looked worn but didn't have a spare.
A friend replaced the cam only on an original pump. That was the solution he was looking for to reduce his engine temp by 10 degrees. When compared to the old cam, the difference was obvious.
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Old 11-10-2015, 12:28 PM   #71
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I'm probably going to change the whole pump. There turns out to be two different pumps that were used on 6-354s. One is Jabsco 9700-1 (my engine) and the other is a Sherwood.

I can buy the pump for a lot less on line from various marine suppliers using the Jabsco number than from Perkins.

BTW: Dieselpartsdirect.com is a good source for Perkins parts, from a valve cover gasket to an entire in-frame overhaul kit. Just have your serial number before you email them.

Jleonard: Are you saying your friend wanted to drop the temperature of the engine and so he changed the cam in the sea water pump? Normally the temperature is regulated by the thermostats and the sea water pump is delivering much more water than is needed. If he's so short of sea water that the T-stats are wide open and it's still running hot, then I'd say the sea water pump must have been really totally shot.

Jabsco does offer "full cam" and "half cam" options on their pumps. The Perkins OEM pump was "full cam" according to the part number. Maybe he got a "half cam" one somewhere along the line?

Onward!

J.S.
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Old 11-10-2015, 01:54 PM   #72
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Jleonard: Are you saying your friend wanted to drop the temperature of the engine and so he changed the cam in the sea water pump? Normally the temperature is regulated by the thermostats and the sea water pump is delivering much more water than is needed. If he's so short of sea water that the T-stats are wide open and it's still running hot, then I'd say the sea water pump must have been really totally shot.
This friend was Mr PM. He changed impellers every season, etc. He noticed that over a few years the engine temp (on his gage) was creeping up. It got to be 10 deg more than he wanted to see after a few years.
So instead of simply replacing the impeller, he did a complete rebuild on the raw water pump. We compared the old cam to the new and the old was what I would call extremely worn (pump was about 8-10 years old).
That reduced his engine temp by 10 deg.
My point is that the cam is very important but normally overlooked.
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Old 11-12-2015, 05:34 PM   #73
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Generally $40 - $80. Anyone seen a spec for the Sherwood pump on the T6.354? The last time I had my pump out I didn't replace it due to time constraints but the tips looked blunted. I wonder if that's shortening the life of the impellor.
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Old 11-12-2015, 05:51 PM   #74
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Ever considered keel cooling?
On your tip I researched them. They look like the ideal solution but too much work for me to install and quite pricey.
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Old 11-13-2015, 06:54 AM   #75
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R.P.: The Sherwood pump is covered in an earlier post. Raw Water Pumps

I hope that link leads you to the correct post. (techno-klutz here, fingers crossed that it works.)

Someone mentioned keel cooling, which I've done before. The trouble is that unless you have an unusual trawler, it's challenging to convert to a dry exhaust. So, if you stay with a wet exhaust, you still need a sea water pump, etc. What is entirely feasible is to convert an engine to a conventional exhaust manifold and thermostat housing, such as would be used on a truck or generator, and mount an external heat exchanger somewhere in the engine bay and connect it to the engine with radiator hoses. I did this on a 120 HP Isuzu industrial engine and it works fine. We used a coolant expansion tank from a 3208 Caterpillar generator set, and wrapped the exhaust manifold and turbocharger with insulation, and the thing works very well.

The boat owner has an uber-dependable engine, the below deck exhaust temps are lower than with his old Lehman, and it doesn't leak a drop. Someday I'll get pictures and post them.

Onward!

JS
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Old 11-13-2015, 07:13 AM   #76
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Originally Posted by R_p_ryan View Post
Generally $40 - $80. Anyone seen a spec for the Sherwood pump on the T6.354? The last time I had my pump out I didn't replace it due to time constraints but the tips looked blunted. I wonder if that's shortening the life of the impellor.
No specs but I have a drawing of the RP-B-C pump. I'll attach it.


I also have operator's manual, workshop manual, parts manual for a 1978 Perkins T6.354 engine. If you want them e mail me
jleonard@globalsteering.com
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Old 11-13-2015, 10:56 AM   #77
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I'm a bit anxious about the exhaust manifold, since it's slowly corroding away and once it leaks the engine it ruined. I pressure tested it, but that just means it's OK at the moment. Is there any way to gauge it's internal condition? I can't think of a worse situation, with extremely hot exhaust separated by a thin layer of iron to salt water in a place you can't inspect. If that manifold is anything like the Bowman cooler it's ready to leak. I have no info on the history either. I can say it looks good on the outside, but so did the Bowman.
I agree, I converted my maniflod to FWC 11 years ago. I may have invented the procedure that everyone seems to use now . I did not replace the manifold but I did boil it out with lye. It is very easy to do with common items and a 3/4" pipe tap. I did mine not to save the manifold, but to save the turbo adapter which is no longer available, to get quicker warmups, and to prevent the distruction of the engine from a leaking manifold / turbo adapter. Perkins should have FWC'd this manifold in the first place. I attach 2 pics of the front hookup, I can't find a pic of the rear but can explain.
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Old 11-13-2015, 01:18 PM   #78
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I agree, I converted my maniflod to FWC ...
Excellent info. Did you notice a change in the temp at WOT?

I have a ton of questions, did you have to make any enhancements to the cooling system? I've heard about the coolant not flowing until the thermostat opens and overheating the manifold. Also there was a concern of introducing bubbles into the fresh water circuit as the coolant boils at some spots in the manifold. I've contemplated adding a second heat exchanger, and even a separate fresh water circuit for the manifold. Where the raw water currently goes through the manifold I would redirect it to the separate heat exchanger. All sorts of other design issues happen, like requiring a separate coolant reservoir and an electric hot water circulator pump, but they are cheap compared to a new manifold or a new engine. This titanium exchanger is only $400, I'd mount it on a bulkhead to keep it away from the engine vibrations http://goo.gl/5bSguu

It looks like you tap into the spot where the hoses run to my domestic hot water tank.

Thanks a ton for the info.

Robert
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Old 11-13-2015, 03:14 PM   #79
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If it were me, I would try it before adding a second heat xchanger.
If you boat in fairly cool waters, I believe you'll be ok.
Then plan B would be to add it. And I would tap into the current flow path leaving the run to the HW tank alone.
That's the way it was plumbed on the one that I saw several years ago IIRC.
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Old 11-13-2015, 03:44 PM   #80
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Excellent info. Did you notice a change in the temp at WOT?

I have a ton of questions, did you have to make any enhancements to the cooling system? I've heard about the coolant not flowing until the thermostat opens and overheating the manifold. Also there was a concern of introducing bubbles into the fresh water circuit as the coolant boils at some spots in the manifold. I've contemplated adding a second heat exchanger, and even a separate fresh water circuit for the manifold. Where the raw water currently goes through the manifold I would redirect it to the separate heat exchanger. All sorts of other design issues happen, like requiring a separate coolant reservoir and an electric hot water circulator pump, but they are cheap compared to a new manifold or a new engine. This titanium exchanger is only $400, I'd mount it on a bulkhead to keep it away from the engine vibrations CE Approved and 5 years guarantee Titanium Pool Heat Exchanger SP 210Kti S-in Heat Exchanger from Industry & Business on Aliexpress.com | Alibaba Group

It looks like you tap into the spot where the hoses run to my domestic hot water tank.

Thanks a ton for the info.

Robert
No enhancments to the cooling system. As you can see, my engine is horizontal but a vertical should be even easier. I have never had a problem of any kind altho I was told it would not work for several reasons that haven't been mentioned here. Just faster warm-ups, less smoke, and no smoke while trolling. No bubbles, no hot spots, no second heat exchanger, no pump, no tanks. The manifold is right where a huge heater would be if the engine were in a passanger bus so it's not rocket science, as with all things on a boat, simple is better.
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