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30-07-2018, 16:47
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#91
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,396
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by O32
One thing with those zincs - they need to have good electrical contact back to the block. That Loctite might not be the best conductor! By the way, I 'think' my zincs have M8 thread.
The plugs front and back on my 2QM15 use a copper sealing washer. Should ensure good contact.
The cover plate at back of head has a gasket, but then maybe the bolts make sufficient contact. At the front, the copper washer contacts the cylinder that distributed cooling water. It screws directly into block. Maybe some metallic ant-seize on the block end of cylinder would maintain contact? Trouble is, that end always turns when you try and remove plug at front end.
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Yep, they are M8.
Loctite doesn't really affect performance of the zinc - maybe theoretically a tiny bit. I have measured the voltage drop across metal thread junctions with and without loctite and the increase in resistance was insignificant. I don't the numbers handy.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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30-07-2018, 16:55
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#92
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,396
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by charliehows
for some reason the lower anode in my eng. has a 3/8 thread where the others have 5/16 - so i bought a long zinc for something else, cut it into 3 and drilled/tapped the ends for 3/8, bought a long 3/8 bolt and cut it into 3 studs. now I have a zinc that fits (use loctite on the zinc end, lanolin on the eng. end). You could do something similiar if you can source some aluminium or magnesium bar in the right diameter - should be possible. You are probably getting quite a bit of protection just by winterizing your engine anyway.
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I've often wondered what is better, leaving an zinc protected cast iron block filled with water (fresh or salt) OR leaving it drained? Disregarding any freezing aspects of course.
Maybe a subject for a new thread?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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31-07-2018, 06:19
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#93
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by Wotname
I've often wondered what is better, leaving an zinc protected cast iron block filled with water (fresh or salt) OR leaving it drained? Disregarding any freezing aspects of course.
Maybe a subject for a new thread?
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Can't leave water in block here.
Most engines these days have closed system using glycol coolant. But those of us with old raw water cooled engines have to do something. I usually put intake water line into jugs of propylene glycol antifreeze and run exhaust into a bucket. On land. Run until A/F come out of exhaust. Then I drain engine and blow out block and exhaust manifold. A/F has corrosion inhibitors, so some say to not drain. It gets so cold here over winter, probably not much corrosion from air or A/F anyway.
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31-07-2018, 06:30
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#94
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
Back to head leak. In final stretch!
I have the head ready. Will pick up injectors and insulators today.
So now decision time - Do I spray copper on pre-coated gasket or not? Some of the car guys spray onto the head and block. Takes quite a bit of masking. Advantage might be that solvent in copper spray can't affect the pre-applied gasket sealants.
Hoye Tractor have a guide: https://www.hoyetractor.com/head-gasket.htm and say:
Quote:
Your new head gasket will install dry. Never use silicone or gasket adhesive. You can use a product called 'copper coat' if you want to. It is like a copper spray paint and goes on in a very fine layer and helps fill tiny imperfections.
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I realize, we are all DIYers here and I have read all the suggestions. Now time for me to decide! With skimmed head, one surface is almost perfect. Block is pretty good, but not perfect. Maybe Hoye's suggestion for light copper coat is way I will go. Although I like idea of spraying metal surfaces.
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31-07-2018, 06:57
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#95
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by Wotname
I've often wondered what is better, leaving an zinc protected cast iron block filled with water (fresh or salt) OR leaving it drained? Disregarding any freezing aspects of course.
Maybe a subject for a new thread?
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From a corrosion perspective it's not going to make much difference.
Oxygen is of course what causes corrosion, water is just a good carrier and interface. If you fill a 55 g drum with water and seal it, it will rust a little then the oxygen is consumed and rust stops. So an engine filled with water that doesn't have an interface with air will corrode the block a tiny bit, then corrosion stops
55 gl drums were used back in the 70's for thermal mass when we cared about making houses energy efficient
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31-07-2018, 07:08
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#96
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Registered User
Join Date: Jul 2016
Posts: 104
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Re: Yanmar 2QM1. Head gasket leaking
The indentations (beads) in the gasket do the sealing around the water/oil passages. Each of these beads also has a coating for the micro sealing of the surface roughness, so I don't see any need or advantage to mask and spray the block and head. Some copper spray on the beads may help, (not on the cylinder fire rings though) but it is important that the beads don't get too close to the passages, as seemed to be the case with your original gasket leak location.
Good luck. The end is in sight (I hope )
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31-07-2018, 07:20
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#97
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
Gasket has some small pieces of the black sealant missing at edge. I should touch it up, but maybe the copper spray will be sufficient. Don't know what that black sealant is. Could use some Permatex aircraft sealant. Only 1/8"x1/4" at most at one edge. Damaged despite in plastic still!
Different subject. Need to readjust valves once installed. Haven't seen this suggested, but it seems like an idea to not tighten the injectors down until valves are adjusted - because it allows engine to be cranked by hand to find TDC.
Anyone see anything wrong with that ?
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31-07-2018, 11:12
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#98
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Registered User
Join Date: Jul 2016
Posts: 104
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Re: Yanmar 2QM1. Head gasket leaking
I used to do calculations for these MLS gaskets, so some comments if I may which may help. The black coating is the gasket suppliers concoction of some sort of filled PTFE which rubs off the beads onto the head and block and seals the surface roughness at a "micro" level. The sheet steel should be spring steel with beads stamped around the water/oil passages. The beads are either double or single type contours which are V shaped or half-V shaped respectively. Being spring steel the beads remain elastic and give a more or less constant pressure sealing line of contact as the head deforms under hot/cold and cylinder pressure loading. So some half flexible extra sealant where the black stuff is missing wouldn't go amiss.
Good idea imo to wait with tightening the injectors till the valves are adjusted.
good luck
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31-07-2018, 15:59
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#99
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,396
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by O32
...........
Different subject. Need to readjust valves once installed. Haven't seen this suggested, but it seems like an idea to not tighten the injectors down until valves are adjusted - because it allows engine to be cranked by hand to find TDC.
Anyone see anything wrong with that ?
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No...
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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31-07-2018, 18:47
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#100
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,396
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by a64pilot
From a corrosion perspective it's not going to make much difference.
Oxygen is of course what causes corrosion, water is just a good carrier and interface. If you fill a 55 g drum with water and seal it, it will rust a little then the oxygen is consumed and rust stops. So an engine filled with water that doesn't have an interface with air will corrode the block a tiny bit, then corrosion stops
55 gl drums were used back in the 70's for thermal mass when we cared about making houses energy efficient
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Apologies to O32 for continuing off topic for a moment.
Oxygen is needed for corrosion to occur after all, it is oxidation! However some moisture is also required, think how well dry desert air is good for preventing corrosion.
However AFAIK, all cathodic protection requires a charge carrier (i.e. water etc) to work so if the block is drained, the zinc is no longer active; this suggests to me it would be better to leave sea water in the block rather than drain it. Again leaving aside freezing aspects.
But I ain't no expert in this field...
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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01-08-2018, 13:11
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#101
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
I installed head today.
Decided to copper spray just the block side seeing the head has been freshly machined. I used the Permatex copper Spray-a- gasket. I wish I hadn't! It is supposed to be fast drying. After 1/2 hr it had not even nearly dried. And some bits of fluff had attached themselves ( I did it on the dock).
I did some other work, then decided to carefully place gasket on the head holding it by edges because even after an hr it was still very tacky. I had test fitted gasket before the studs were all in place. I found that the new gasket now wouldn't go on over all 6 studs I guess they are not exactly parallel. I removed three of them which allowed the gasket to go on.
Re-installed and torqued studs. Then torqued head nuts in three stages to 112 ft.lbs. Max is 116 in manual - will re-torque in morning.
Maybe the Copper Coat product is better than the Permatex? I would think twice before using the Permatex again on a $60 gasket! I just hope I don't have to do this again!
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01-08-2018, 14:07
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#102
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Registered User
Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,309
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Re: Yanmar 2QM1. Head gasket leaking
fingers crossed - after all the effort you've put into this, i doubt you'll ever have to pull the head this century...
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01-08-2018, 14:20
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#103
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
Quote:
Originally Posted by charliehows
fingers crossed - after all the effort you've put into this, i doubt you'll ever have to pull the head this century...
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I hope you are right, but I was not too happy about the copper spray - I just was not prepared for it to take so long to dry . Resulting finish was not too smooth. Hopefully with it still tacky, the high pressure will have evened things out.
Time will tell!
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01-08-2018, 17:40
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#104
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Yanmar 2QM1. Head gasket leaking
I don’t think Copper Coat ever dries if I’m remembering correctly, but it is sticky as tree sap, I do remember that, and it’s like 5200, one drop can ruin your entire cars interior and get places you we’re sure you didn’t go.
Anyway, I don’t think it’s supposed to completely air dry like paint.
But I have never applied it to a head or block either, I hang the head gasket with a piece of wire and paint it. Then carefully only touching the edges put it on the block, and then the head of course.
The Teflon coated Head gaskets, used to be made by Fel-Pro, you don’t put anything on them, not sure if they even exist anymore, used to be blue.
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02-08-2018, 10:23
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#105
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Registered User
Join Date: Jun 2017
Location: Kingston
Boat: Ontario 32
Posts: 76
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Re: Yanmar 2QM1. Head gasket leaking
After re-installing rockers and adjusting valves, I realized that it will be difficult to re-torque the head bolts after running motor. There is no clearance for a socket on the head bolt nuts adjacent to the rockers.
Have to remove rockers first? Or maybe just the bolt that the two end rockers pivot on? Whatever, probably have to readjust valves again too.
Maybe this is not a problem for the 1-lungers? But it is on the 2QM15.
How did other 2QM owners handle this?
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