| Author |
Message |
    
Glenn Simpson
New member
Username: trackhappy
Post Number: 1
Registered: 07-2009
| | Posted on Thursday, July 30, 2009 - 11:41 pm: | 
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Hi all.
We just bought a 38ft. cruiser with twin Perkins 4.236 diesels. The boat documentation all says 50HP, but web searches indicate 85HP... which is true??
Also stbd. runs at 120 F, port at 100 F. Seems way too low. Also takes ages to get there. She is fresh water cooled with raw water impeller pump and heat exchanger. I am guessing no thermostats, any comments? What temp should they run? What effect does cold running have? She seems to max out at 2200RPM under load, is this right?
Thanks.
Glenn. |
kit carsen
Member
Username: taswegian
Post Number: 12
Registered: 06-2009
| | Posted on Friday, July 31, 2009 - 07:04 am: |
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Hi Glenn.
The 4,236M engine specs are fairly flexible depends on who sold them generally accepted to be 82 hp@2600.I have seen them running thru to 2800rpm.check high idle speed if higher than 2200rpm you are probably over proped,running temp should be 182f.Running a cold engine will cause quick wear rates,possible smoke, louder injection noise,oil sludging and carbon fouling not forgetting colder hot water services if fitted.. Cheers, Tassie.. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 5
Registered: 07-2009
| | Posted on Thursday, September 17, 2009 - 01:17 am: |
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High idle is 2750 approx. I guess she is overpropped. I have been told they can alter my props to take some pitch off. Apparently 1 inch per 200 RPM, so ideally take off a little under 3 inches to get her up in RPM.
Does anybody know the part numbers for the thermostat and gasket for them? I am getting stony silence from local sources... |
Doug Tremble
Member
Username: shakey
Post Number: 35
Registered: 08-2009
| | Posted on Thursday, September 17, 2009 - 04:01 am: |
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G'day Glenn,
It would seem that your props are the rev problem.If you try Repco they will have them listed, as the same units are used in a lot of engines the joint is are easly made if you destroy the existing one; you need a 82c unit. Cheers, Shakey. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 6
Registered: 07-2009
| | Posted on Thursday, September 17, 2009 - 07:44 am: |
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Thanks Shakey.
I kept getting asked what diameter they were and what serial number the engines were but never got a call back when I supplied it. I'll pick up the standard ones from Repco and some gasket paper. Props will have to wait until she comes out for her next nappy change I guess. Apparently divers don't like the Brisbane River because of the current. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 8
Registered: 07-2009
| | Posted on Saturday, September 19, 2009 - 03:02 am: |
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OK. Bit the bullet and ordered standard 4236 ones..... WRONG!!!. Too small. Pulled her down today and I was only half right. She has thermostats, but they are 68 deg. C and testing one in a pot it seems to be right, starting to open at 55 degrees and fully open at 68-ish. A digital thermometer says they are running at more like 56 deg. on the engine whose thermostat I didn't test. That agrees with the engine gauge, which is good.
So I need 2.75" diameter thermostat but 82 is a long way higher than 68 or 55. Why would they fit a cold one like that??? |
Glenn Simpson
Member
Username: trackhappy
Post Number: 9
Registered: 07-2009
| | Posted on Saturday, September 19, 2009 - 06:12 pm: |
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Found a site that lists p/n 2485668 for the 4.236 at 72 deg. Maybe the 82 is for the later series 4236's??? Date code on the heat exchanger is hard to read,but I think it said something like (19)67. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 10
Registered: 07-2009
| | Posted on Monday, September 21, 2009 - 06:47 am: |
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Ordered 2485668 x 2. Will either make gaskets or use formagasket. Also getting replacement radiator caps as they are pretty old and one at least is faulty. The main hose from circ. pump to the header tank/heat exchanger is also old so will find a replacement pair for them.
I love fixing things, it will be great getting this right then onto those props...  |
Doug Tremble
Member
Username: shakey
Post Number: 36
Registered: 08-2009
| | Posted on Monday, September 21, 2009 - 08:14 am: |
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G'day Glenn,
Marine 4.236 Pollys are fitted with 82c thermos and 7.lb caps , they generally had bowman coolers fitted.Diecon engrs Brisbane make a lot of after parts. Shakey. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 11
Registered: 07-2009
| | Posted on Friday, September 25, 2009 - 06:50 am: |
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Thanks to everybody that responded with help and suggestions. For anybody interested, Agco part number 1446222M91, Thermostat BK08B is 78 degrees, 2.75" diameter to suit my 4.236 with Bowman heat exchanger. My local tractor dealer got a pair for me.
7 PSI caps are out of stock for some reason, so 16 it will be for now, although R*pco supplied really crappy ones rather than CPC like the originals, which seemed better quality. CPC have a type with a pressure relief lever (575-13L, 13PSI), which is a great safety feature on a boat particularly, however no 7PSI version. I will order a pair of those at 13 PSI just to have the safety factor. Also got a moulded radiator hose from which I can cut the two engine fresh water circ. pump to heat exchanger hoses. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 12
Registered: 07-2009
| | Posted on Sunday, September 27, 2009 - 06:06 am: |
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Got it all fitted today. Port now runs up to about 170 and sits there nicely. Starboard goes to 120 and sits there stubbornly and won't move. Unfortunately I left my laser thermometer at home (bought one just for this, J*YCAR $120) but I have to figure the sender or gauge is cactus. It does move from nothing to 120 when the key is turned on, so I am guessing sender.
Anyone happen to know what thread is on the 4.236 marine? It has two holes for senders, one above the other. Gauge is Teleflex.
Cheers.
Glenn. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 16
Registered: 07-2009
| | Posted on Saturday, October 17, 2009 - 05:50 pm: |
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Latest update... she is just running cold. Gauge reads exactly what she is running.Also a little down on loaded RPM compared to Port. Can injector pump timing make her run cool? They have an oil cooler on the heat exchanger, could there be too much oilflow through that maybe?? Gonna have to pull the heat exchanger again to be sure I did it right. Other than that, I am stumped. |
Doug Tremble
Member
Username: shakey
Post Number: 45
Registered: 08-2009
| | Posted on Saturday, October 17, 2009 - 09:16 pm: |
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G'day Gienn,
Yes, if timing is early this will give lower exhaust temps therefore the cooling system btu load will be reduced, the thermostat should react accordingly, oil flow will all so affect cooling, again thermostat should take care of that. Suggest checking thermostat fitting,temp rating, operation--valve movement correct, thermostat holder for corrosion,also change over thermo's see if problem follows.Just one of those head banging problems that come with boats!, even when you think you know what your doing. As they say if its got tits or pistons its trouble!
Good Luck,
Shakey. |
Glenn Simpson
Member
Username: trackhappy
Post Number: 17
Registered: 07-2009
| | Posted on Sunday, October 18, 2009 - 06:44 am: |
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Ahh Shakey you crack me up.... ;).
Pistons are just science and practice.... those other things you mention, well, I figured that out 25 years (Dec 22nd) ago. Feed them well, earn plenty to cover their needs, get a vasectomy, and nod a lot.
As for the engine, I suspect the injector pump needs some TLC (Like my Wife). Spend some money on it, and see what happens... ;). |
